
==== Front
PLoS One
PLoS One
plos
PLOS ONE
1932-6203
Public Library of Science San Francisco, CA USA

10.1371/journal.pone.0308632
PONE-D-23-30357
Research Article
Biology and Life Sciences
Psychology
Developmental Psychology
Pervasive Developmental Disorders
Autism Spectrum Disorder
Social Sciences
Psychology
Developmental Psychology
Pervasive Developmental Disorders
Autism Spectrum Disorder
Biology and Life Sciences
Psychology
Developmental Psychology
Pervasive Developmental Disorders
Autism Spectrum Disorder
Autism
Social Sciences
Psychology
Developmental Psychology
Pervasive Developmental Disorders
Autism Spectrum Disorder
Autism
Medicine and Health Sciences
Medical Conditions
Neurodevelopmental Disorders
Autism
Biology and Life Sciences
Neuroscience
Developmental Neuroscience
Neurodevelopmental Disorders
Autism
Medicine and Health Sciences
Neurology
Neurodevelopmental Disorders
Autism
Biology and Life Sciences
Neuroscience
Cognitive Science
Cognition
Memory
Short Term Memory
Biology and Life Sciences
Neuroscience
Learning and Memory
Memory
Short Term Memory
Biology and Life Sciences
Organisms
Eukaryota
Animals
Vertebrates
Amniotes
Mammals
Rodents
Mice
Biology and Life Sciences
Zoology
Animals
Vertebrates
Amniotes
Mammals
Rodents
Mice
Biology and Life Sciences
Psychology
Behavior
Animal Behavior
Social Sciences
Psychology
Behavior
Animal Behavior
Biology and Life Sciences
Zoology
Animal Behavior
Biology and Life Sciences
Cell Biology
Cellular Types
Animal Cells
Neurons
Biology and Life Sciences
Neuroscience
Cellular Neuroscience
Neurons
Research and Analysis Methods
Animal Studies
Experimental Organism Systems
Model Organisms
Mouse Models
Research and Analysis Methods
Model Organisms
Mouse Models
Research and Analysis Methods
Animal Studies
Experimental Organism Systems
Animal Models
Mouse Models
Biology and Life Sciences
Biochemistry
Neurochemistry
Neurotransmitters
Biogenic Amines
Histamine
Biology and Life Sciences
Neuroscience
Neurochemistry
Neurotransmitters
Biogenic Amines
Histamine
Physical Sciences
Chemistry
Chemical Compounds
Organic Compounds
Histamine
Physical Sciences
Chemistry
Organic Chemistry
Organic Compounds
Histamine
Pharmacological intervention of behavioural traits and brain histopathology of prenatal valproic acid-induced mouse model of autism
Pharmacological intervention of behavioural traits in autistic mice
https://orcid.org/0000-0001-6770-4457
Neelotpol Sharmind Conceptualization Data curation Formal analysis Investigation Methodology Supervision Validation Writing – original draft Writing – review & editing 1 *
Rezwan Rifat Conceptualization Data curation Investigation Methodology Project administration Resources Writing – original draft Writing – review & editing 1
Singh Timothy Conceptualization Data curation Investigation Methodology Project administration Resources Writing – original draft Writing – review & editing 1
Mayesha Iffat Islam Data curation Formal analysis Investigation Writing – original draft Writing – review & editing 1
https://orcid.org/0009-0008-1441-1915
Saba Sayedatus Data curation Formal analysis Investigation Writing – review & editing 2
https://orcid.org/0000-0003-0495-4808
Jamiruddin Mohd Raeed Data curation Formal analysis Methodology Validation Writing – original draft Writing – review & editing 1
1 School of Pharmacy, Brac University, Dhaka, Bangladesh
2 Department of Clinical Pathology, Dhaka Medical College Hospital, Dhaka, Bangladesh
Wang Xiaona Editor
Children’s Hospital Affiliated of Zhengzhou University: Zhengzhou Children’s Hospital, CHINA
Competing Interests: The authors have declared that no competing interests exist.

* E-mail: sharmind@bracu.ac.bd
24 9 2024
2024
19 9 e030863218 9 2023
27 7 2024
© 2024 Neelotpol et al
2024
Neelotpol et al
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Autism spectrum disorder (ASD) is one of the leading causes of distorted social communication, impaired speech, hyperactivity, anxiety, and stereotyped repetitive behaviour. The aetiology of ASD is complex; therefore, multiple drugs have been suggested to manage the symptoms. Studies with histamine H3 receptor (H3R) blockers and acetylcholinesterase (AchE) blockers are considered potential therapeutic agents for the management of various cognitive impairments. Therefore, the aim of this study was to evaluate the neuro-behavioural effects of Betahistine, an H3R antagonist, and Donepezil, an acetylcholinesterase inhibitor on Swiss albino mouse model of autism. The mice were intraperitoneally injected with valproic acid (VPA) on the embryonic 12.5th day to induce autism-like symptoms in their offspring. This induced autism-like symptoms persists throughout the life. After administration of different experimental doses, various locomotor tests: Open Field, Hole-Board, Hole Cross and behavioural tests by Y-Maze Spontaneous Alternation and histopathology of brain were performed and compared with the control and negative control (NC1) groups of mice. The behavioural Y-Maze test exhibits significant improvement (p <0.01) on the short term memory of the test subjects upon administration of lower dose of Betahistine along with MAO-B inhibitor Rasagiline once compared with the NC1 group (VPA-exposed mice). Furthermore, the tests showed significant reduction in locomotion in line crossing (p <0.05), rearing (p <0.001) of the Open Field Test, and the Hole Cross Test (p <0.01) with administration of higher dose of Betahistine. Both of these effects were observed upon administration of acetylcholinesterase inhibitor, Donepezil. Brain-histopathology showed lower neuronal loss and degeneration in the treated groups of mice in comparison with the NC1 VPA-exposed mice. Administration of Betahistine and Rasagiline ameliorates symptoms like memory deficit and hyperactivity, proving their therapeutic effects. The effects found are dose dependent. The findings suggest that H3R might be a viable target for the treatment of ASD.

The author(s) received no specific funding for this work. Data AvailabilityAll relevant data are within the manuscript and its Supporting Information files.
Data Availability

All relevant data are within the manuscript and its Supporting Information files.
==== Body
pmcIntroduction

Autism Spectrum Disorder (ASD) is an umbrella term that accounts for a number of neurodevelopmental conditions with a wide range of symptoms with varying severity. Adoption of repetitive behaviours, impairment of social interactions and relations are common traits of ASD [1]. ASDs begins in childhood and persist throughout life [2,3]. However, it cannot be detected prior to 2-3 years of maturity in a child as the symptoms are not identifiable in infants. The frequent episodes that are observed in individuals with ASD are epilepsy, depression, anxiety, and attention deficit hyperactivity disorder (ADHD) [4].

Recent studies showed that the median global autism prevalence rate is 100/10,000 (range: 1.09/10,000 to 436.0/10,000), where the median male-female ratio is 4:2. A median of 33.0% of autism cases with co-occurring intellectual disability was recorded [1]. Presently, the prevalence rate of autism is higher which maybe due to improved awareness, expansion of diagnostic criteria, better diagnostic tools and improved reporting.

Irrespective of an increase in the prevalence of ASD, the pathophysiological framework of ASD has not yet been fully established. A combination of heterogeneous factors such as genetic predisposition, and environmental exposure mainly during pregnancy are the known causative factors of autism [2]. Currently, there are no objective diagnostic test and a cure is yet to be found. Risperidone and aripiprazole has been approved by FDA for the control of ASD symptom [5]. However, no particular treatment holds promising therapeutic effects for all autistic individuals. Therefore, a successful pharmacological intervention strategy is required to improve symptomatic behaviours.

Recent studies showed that the brain histaminergic system is one of the attractive pharmacological targets for therapeutic purposes. The histaminergic system is involved in modulating cognition and behaviour and can play a role in microglial activation and neuroinflammation [6]. Henceforth, researchers focused on different histamine receptor (H1R, H2R, H3R, and H4R) antagonists to treat VPA-exposed mice [7–12]. Niaprazine, famotidine, scopolamine, which are H1R, H2R and, H3R antagonists, respectively, showed behavioural improvement in ASD [9], schizophrenia (SCH) [10], Alzheimer’s disease (AD), and narcolepsy [13]. Studies showed that multitargeting histamine and dopamine receptors also yielded significant results in ameliorating neuronal oxidative stress and repetitive behaviours [14].

Histamine or its analogues through receptor binding mediates multiple brain functions in addition to homeostasis and immunity such as circadian-feeding cycle, sleep-wake regulation and learning [15]. Studies showed that antagonism of H3 hetero-receptors accelerates the corticolimbic liberation of acetylcholine, norepinephrine, glutamate, dopamine, serotonin, and gamma-aminobutyric acid (GABA) [7–12]. Such antagonism regulates higher brain function and maintains homeostasis of the nervous system [15]. Interestingly, Rasagiline (N-Propargyl-1-[R]-aminoindan), a selective, reversible MAO-B inhibitor, has been shown to increase levels of striatal extracellular dopamine at a lower dose (over 2 weeks) [16,17]. Similarly, a combination of H3 receptor blocker and MAO-B inhibitor shows a synergistic effect in the increase of dopamine in the brain [18].

The cholinergic system is responsible for various key functions such as memory formation, cognitive flexibility, and brain plasticity [19,20], besides it being a key mediator of early stage neural and synaptic development [21]. Decreased acetylcholine levels were observed in the temporal lobe and grey matter of ASD phenotypes which serves as an indicator that cholinergic imbalance might have a link with the pathophysiology of ASD. Furthermore, VPA-exposed mice have been previously reported to have a decreased choline peak level due to increased acetylcholinesterase up-regulation in the synaptic cleft [19]. Delayed and malformed cortical neuronal development in cholinergic neurons disrupted early postnatal brain development in rats along with hypertrophy and hyperplasia [21].

Research on the histaminergic pathway as well as the cholinergic system could shed some light on the ASD pathophysiology and might bring viable treatment options in future as both of the pathways have been previously reported to be involved in development of ASD phenotypic outcomes [14,22]. Therefore, the aim of this study was to perform observational tests of varying doses of acetylcholinesterase inhibitor Donepezil, and histamine H3 inhibitor, Betahistine, both alone and in combination with MAO-B inhibitor Rasagiline, and its ameliorating effects on autism-like behaviour and brain neuronal degradation.

Materials and methods

Materials

Chemicals

Valproic acid sodium salt (P4543-10G) and sodium chloride were provided by Sanofi Aventis Bangladesh (Sigma-Aldrich Co., USA). Betahistine dihydrochloride (H3R antagonist), Rasagiline mesylate (MAO-B inhibitor), and Donepezil hydrochloride monohydrate (acetylcholinesterase inhibitor) were provided by Square Pharmaceuticals Limited, Bangladesh (Hetero Drugs Ltd., India).

Animals

Healthy male and female Swiss albino mice, 8 weeks of age, weighing 30–35 g were obtained from the Pharmacology Laboratory, Jahangirnagar University. Animals were housed in polypropylene cages with proper bedding, water and food. The environment was regulated at 25°C±1°C temperature and 45–55% relative humidity, with a 12:12 h light/dark cycle.

Methods

Preparing animals for the experiment

Male and female mice were allowed to mate overnight. Pregnancy confirmation was carried out by the observation of vaginal plug or spermatozoa and was designated as embryonic day 0.5 (E0.5). The pregnant mice were caged separately and distributed randomly into two groups: VPA group (n=10), and saline group (n=5). Sodium valproate was dissolved in isotonic 0.9% sodium chloride solution and was given intraperitoneally on the embryonic day 12.5 (E12.5) [23,24] at a dose of 600 mg/kg [25,26]. On the other hand, another group of mice received the same volume of normal saline without sodium valproate at the same time (Control group). The day of birth of the offspring was considered as the postnatal day zero (P0). The mice pups were randomly caged and allowed to be weaned till postnatal day 21 (P21). After P21, the offspring of the same sex were housed separately (4-5 per cage).

Preparation of drug doses

Betahistine dihydrochloride, Rasagiline mesylate, and Donepezil hydrochloride monohydrate were administered upon mixing with water. An oral dose of Betahistine dihydrochloride of 3mg/kg was administered in combination with 0.8mg/kg of Rasagiline (T1) [21–23] and a larger dose of 30mg/kg was administered alone (T2) [21,23]. Three Donepezil oral doses of 0.3mg/kg (T3), 0.6mg/kg (T4) and 1mg/kg (T5) were administered [24]. All the reagents used in the study were of analytical grade. The doses were dissolved in water and given in 0.5ml solution.

Study design

All the animals were treated humanely throughout the experimental period and maximum care was taken in case of handling following the internationally accepted guide for the care and use of laboratory animals, published by the US National Institutes of Health (NIH Publication No. 85-23, Revised in 1985). The offspring were divided into 8 groups where each group consists of 6 mice. Thirty-six autistic offspring were taken from a VPA induced mother: five treated groups (T1, T2, T3, T4 and T5) and a negative control group 1 (NC1) (0.5 ml of water) were created from them. Healthy offspring from the healthy mothers were divided into two groups – a control group (0.5 ml of water) and a negative control group 2 (0.8mg/kg Rasagiline). All the experimental mice were housed with ad libitum access to food and water and were caged in a (60 ×38 ×20 cm3) cage under a controlled temperature of 21±5°C with a 12-h light/dark cycle. All the doses were administered once per day by oral gavage for 21 days from postnatal day 44 (P44) until postnatal day 64 (P64). Starting from postnatal day 51 (P51), the behavioural tests and locomotor tests were carried on. All the doses and saline were administered 30-40 minutes before each behavioural test. All the tests were conducted within 30 to 45 minutes after administration of the doses and between 9:00 am and 3:00 pm (Fig 1). After the completion of the neurobehavioural tests, each mouse was sacrificed following the study protocol and prepared for histopathological test.

10.1371/journal.pone.0308632.g001 Fig 1 Schematic diagram of doses, and time schedule for the behavioural and locomotor tests in healthy and VPA-induced mice.

Pregnant mice were given VPA (600 mg/kg, i.p.) on embryonic day 12.5 (E12.5). Drugs were given by oral gavage from postnatal day 44 (P44) until postnatal day 64 (P64) for a total of 21 days. Behavioural tests were conducted starting from P51. OFT: Open Field Test; HBT: Hole Board Test; HCT: Hole Cross Test.

Behavioural tests

Y-maze test. The Y-maze consisted of 3 limbs marked A, B and C. All the limbs of the maze were 120° apart from one another. The dimensions of each arm were (21 x 7 x 15.5 cm). The mouse was placed in the distal part of the arm of the instrument, facing the centre. Then it was allowed to roam inside the maze freely for 8 minutes. All of the arms were opened during this test. The session was recorded. After testing all the mice, the records were observed and their alternations of the arm entries were enumerated along with their total arm entry. Percentage (%) Alternation was calculated using the following formula.

%Alternation=NumberofAlternations[(Totalnumberofarmentries−2)×100]

The maze was cleaned with a 70% ethanol solution after testing each subject [25,26].

Locomotor tests

Open-field Test (OFT). In this test, a square shaped box with dimensions of (50 × 50 × 35 cm) was used. The mice were placed in the centre of the open field box and were allowed to explore freely inside the box for 5 minutes. The experiment was conducted in a moderately lighted condition. The activities and movements of the mice were recorded [27].

The following parameters were monitored: 1) Line crossing: Frequency of mouse crossing grid lines with all four paws 2) Rearing: the mouse reared on its hind paws while in the peripheral 3) Central area frequency: the frequency of mouse entry with all four paws in the arena centre 4) Defecation and urination [28]. Furthermore, the box was cleaned with a 70% ethanol solution after testing each subject.

Hole-Board Test (HBT). In this test, a wooden hole-board apparatus was used, with dimensions of (68 × 68 × 40 cm). The hole-board was made of wooden apparatus with 16 evenly spaced holes (3 cm in diameter) and 25 cm in height. A mouse was placed at the centre of the device and allowed to explore the apparatus for 5 minutes. The following behavioural patterns were observed and recorded: 1) new area entry/Line crossing: entry inside a new area with all of its four paws. 2) head-dip: the subject dips its head to a minimum depth of ear level so that the ear is levelled with the floor. The test was conducted in dimmed lighting conditions for 5 minutes [29]. After each trial the apparatus and objects were cleaned with 70% ethanol solution.

Hole-Cross Test (HCT). A wooden hole-cross apparatus was used for this test. The apparatus had a dimension of 30 × 20 × 14 cm. A fixed partition with a 3 cm hole carved inside was placed in the middle. Each test mouse was allowed to roam in the apparatus without any disturbance for 5 minutes and the number of passages were recorded. The apparatus was cleaned with a 70% ethanol solution after testing each subject [30,31].

Histopathology

At the end of the 64th day of the experiment, the animals were euthanized as per the study protocol, using an overdose of ketamine (500 mg/kg, i.p.) and the anaesthetic effect was confirmed by “toe pinch”. The whole brains of the mice were excised, weighed and preserved in 10% neutral buffered formalin. After few days, the brains of each mouse were routinely processed for histological studies using the Haematoxylin and Eosin (H&E) staining method. Finally, those tissues were examined under a light microscope (Olympus, CX43, Japan) for visualization. Photomicrographs of the brain sections were taken with the help of Olympus, D22 camera.

Statistical analysis

Statistical analyses were carried out by using IBM SPSS Statistics version 26 for Windows (SPSS, Chicago, IL). The data were checked for skewness and the test for normality was performed using Q-Q plot. One-way analysis of variance (ANOVA) was performed in multiple pairwise comparisons followed by Fisher’s least significant difference (LSD). p-values less than 0.05 were considered as statistically significant.

Ethical approval

Ethical approval has been granted by the Biosafety, Biosecurity & Ethical Committee, Faculty of Biological Sciences, Jahangirnagar University, Savar, Dhaka, Bangladesh (Ref No: BBEC, JU/M 2020 (9)2). Throughout the experimental period animals were treated and handled as per the internationally accepted guideline for the care and use of laboratory animals, published by the US National Institutes of Health (NIH Publication No. 85-23, Revised in 1985).

Result

Y-maze test

In the Y-maze test, there was a significant difference of spontaneous alternation % between the control group (C) and the negative control 1 group (NC1) of mice (p <0.001). In addition, the treated group 1 (T1: 3 mg/kg Betahistine + 0.8 mg/kg Rasagiline) (p <0.01), treated group 2 (T2: 30 mg/kg of Betahistine) (p <0.05) (Fig 2A), treated group 3 (T3: 0.3mg/kg of Donepezil) (p <0.001), treated group 4 (T4: 0.6 mg/kg of Donepezil) (p <0.001), and treated group 5 (T5:1 mg/kg of Donepezil) (p <0.001) (Fig 2B) demonstrated a significantly increased level of alternation compared to the negative control 1 group. Moreover, the changes found between the control group (healthy mice) and the treated groups were insignificant (Fig 2).

10.1371/journal.pone.0308632.g002 Fig 2 Graphical representation of spontaneous alternation percentage in Y-maze test (Mean±SE).

(A) Spontaneous alternation percentage in Y-maze test of Betahistine, compared to negative control group 1. (B) Spontaneous alternation percentage in Y-maze test of Donepezil, compared to negative control group 1. (*p < 0.05, **p < 0.01 and ***p < 0.001). When compared with the control group, the treated groups did not show any significant difference (indicates as n.s i.e. non-significant).

Open-field test

In the open field test certain parameters were observed, such as: line crossing, rearing, central area frequency, urination and defecation (Fig 3).

10.1371/journal.pone.0308632.g003 Fig 3 Graphical representation of Open-field test (Mean±SE).

(A&B) Line crossing test of Betahistine and Donepezil, respectively. (C&D) Rearing test of Betahistine and Donepezil, respectively. (E&F) Central area frequency test of Betahistine and Donepezil, respectively. The following symbols: *, **, *** and Δ, ΔΔ, ΔΔΔ represents level of significance (p-values) at 5%, 1% and 0.1% level, when compared the treated groups with negative control 1 group and control group, respectively. n.s indicates non-significant.

Line Crossing: In the open-field line crossing test, there was a significant difference between control group (C) and negative control 1 group (NC1) (p <0.001). In the Betahistine doses, the T1 group did not show any significant difference over the negative control 1 group, while the T2 group demonstrated a significantly decreased line crossing (p <0.01). However, no significant difference was observed between the control group and the negative control 2 group (0.8 mg/kg Rasagiline on healthy mice). In the case of Donepezil, the T3, T4, and T5 group all exhibited a significantly lower line crossing in comparison with the negative control 1 group (p <0.001). Moreover, the T4 group and T5 group demonstrated a significant decrease in line crossing (p <0.001) with the control group (Fig 3A and 3B).

In the case of the open-field rearing test, a significantly lower movement was observed between the Control group and the NC1 group (p <0.001). The T1 group showed a significant decrease (p <0.05), while the T2, T3, T4, and T5 group exhibited a highly significant decrease (p <0.001) in rearing, compared to the negative control 1 group. Although, both the T1 and T5 groups showed a significant difference (p <0.05) when compared to the control group, no significant difference was observed between the control group and the negative control 2 group in this regard (Fig 3C and 3D).

The negative control 1 group did not show any significant difference from the control group in the case of open-field central area frequency. While the T1 group did not show any significant difference, the T2 (p <0.05), T3 (p <0.01) and T4 & T5 group (p <0.001) showed significantly decreased effect when compared with the negative control 1 group. Moreover, the T4 (p <0.05) and the T5 group (p <0.01) showed a significant reduction compared to the control group. In addition, the control group and negative control 2 group did not have any significant difference (Fig 3E and 3F).

While in urination the overall tests did not show any significant difference across the groups, there were significant differences in the frequency of defecation between the control and the negative control 1 group. The T3 group had significantly decreased (p <0.05) defecation frequency in comparison with the NC1 group. On the contrary, the T1, T2, T4 and T5 group did not show any significant difference with the NC1 group. However, a significantly decreased effect was observed between the T3 group (p <0.01), T4 group (p <0.05) and the T5 group (p <0.01) when compared with the control group. Defecation frequency was not significant between the negative control 2 group and the control group (not shown here).

Hole-board test

In the hole-board test two parameters were observed, such as: line crossing, and head dipping.

Line crossing: In case of hole-board line crossing test, no difference was observed between the negative control 1 and the control group. When compared with the negative control 1 group, the T2, T3 group (p <0.01), and the T4, T5 group (p <0.001) showed highly significant differences i.e. lower line crossing. However, a significant difference was also observed in the T4 group with the control group (p <0.01). In contrast, The T1 group did not show any significant difference over the negative control 1 group. Moreover, no significant differences were observed between the control group and the negative control 2 group (Fig 4A and 4B).

10.1371/journal.pone.0308632.g004 Fig 4 Graphical representation of Hole-board test (Mean±SE).

(A&B) Line cross test of Betahistine and Donepezil, respecgively. (C&D) Head Dipping test of Betahistine and Donepezil, respectively. The following symbols: *, **, *** and Δ, ΔΔ, ΔΔΔ represents level of significance (p-values) at 5%, 1% and 0.1% level, when compared the treated groups with negative control 1 group and control group, respectively; n.s indicates non-significant.

Head dipping: No significant difference was observed between the control and the negative control 1 group in the hole-board head dipping test. Significant differences were observed in the T3 (p <0.01), T4 and T5 groups (p <0.001) when compared with the negative control 1 group. However, the T3 (p <0.01), T4, and the T5 groups also showed significantly lower number of head dipping in comparison with the control group (p <0.001) (Fig 4C and 4D). No significant differences were observed between the control group and the negative control 2 group (not shown in the figure).

Hole-cross test

In the hole-cross test, a significant increase was observed in the negative control 1 group when compared with the control group (p <0.001). The T2 group showed significant decline over the negative control 1 group (p <0.01). Moreover, the T3, T4 and the T5 group showed significant decline (p <0.001) in hole crossing when compared with the negative control 1 group. However, the T1 group did not show any significant difference over the negative control 1 group. Furthermore, the T1 group had a significant difference with the control group (p <0.001) (Fig 5A and 5B). No significant differences were observed between the control group and the negative control 2 group (not shown in the figure).

10.1371/journal.pone.0308632.g005 Fig 5 Graphical representation of Hole-cross test (Mean±SE).

(A&B) Hole-cross test of Betahistine and Donepezil, respectively. The following symbols: *, **, *** and Δ, ΔΔ, ΔΔΔ represents level of significance (p-values) at 5%, 1% and 0.1% level, when compared the treated groups with negative control 1 group and control group, respectively. n.s indicates non-significant.

Histopathology

Microscopic observation (qualitative) of the control group and the negative control 2 group were unremarkable. In negative control 1 group, neuronal loss in cornue ammonis and subculum area and a few degenerated neurons (both dark and eosinophilic) were observed. Treated group 1 showed mild gliosis, neuronal loss in cornue ammonis, and dilated ventricles. In treated group 2, neuronal degeneration, a few apoptotic cells, neuropil vacuation and marked neuronal loss in cerebral cortex and hippocampus were observed. Treated group 3 showed thinning of hippocampus, degenerated neuron and moderate gliosis in cerebral cortex. In treated group 4, degenerated neurons in cerebral cortex and hippocampus, thinning of hippocampus, moderate gliosis in the cerebral cortex were observed. In the treated group 5, degenerated neurons in amygdala and neuronal loss in cortex were observed. Negative control 1 group showed more neuronal losses in cerebral cortex and hippocampus than the treated groups of mice. Moreover, reactive gliosis were more in the treated groups (Fig 6A–6H).

10.1371/journal.pone.0308632.g006 Fig 6 Histopathology of the mouse brain.

(A) Unremarkable microscopic observation in the control group (100X). (B) Neuron degeneration was observed in the negative control 1 group (40X). (C) Mild gliosis, neuronal loss in cornue ammonis, and dilated ventricles were observed in treated group 1 (40X). (D) Neuronal degeneration, a few apoptotic cells, and neuronal loss were observed in Treated group 2 (100X). (E) Thinning of hippocampus, degenerated neuron and moderate gliosis were observed in treated group 3 (100X). (F) Thinning of hippocampus, degenerated neuron and moderate gliosis were observed in treated group 4 (400X). (G) Degenerated neurons in amygdala and neuronal loss in the cortex were observed in treated group 5 (400X). (H) Unremarkable microscopic observation in negative control 2 (40X).

Discussion

This study examined the behavioural and brain-histopathological effect of Betahistine and Donepezil on VPA-exposed mice. Betahistine is an H3R antagonist and Donepezil is an acetylcholinesterase inhibitor. These two drugs with different doses evaluated short-term memory function, locomotor activities, and fear, anxiety-related behaviour of autistic Swiss albino mice. The Y-maze test in our experiment showed that these two drugs may play an important role in the retention of short-term memory function. Significantly increased locomotor activities in the negative control 1 group compared to the control group proves the hyperactivity of the VPA-exposed. By performing different behavioural tests, Betahistine and Donepezil showed reduced hyperactivity at different doses. Moreover, negative control 1 group showed more neuronal losses in cerebral cortex and hippocampus than the treated groups of mice.

The T3 group shows similar behavioural outcomes as the control group in amelioration of hyperactivity, and anxiety, and preserving short-term memory in our tests and in other studies as well [32]. It is noteworthy that, in fear-induced response tests for novel stimuli hole board head dipping, Fig 5B there was no significant difference between the healthy (control) and the ASD-inflicted mice (negative control group 1). Alternatively, the T1 and the T2 groups showed promising results in ameliorating anxiety-induced hyperactivity and short-term memory preservation, respectively. The effects of the T1 and the T2 dose are mutually exclusive, whereby one does not influence the effect of the other.

Induction of VPA during the neural tube closure period showed higher occurrence of development of autism [19,24]. Since nervous system formation occurs during the embryonic days 11-17, a high dose of valproic acid (600 mg/kg) was injected intraperitoneally into pregnant mother mice on the embryonic 12.5th day ⁠to ensure the development of autism in offspring [23,25,26,33,34]. VPA is reported to change the physiology of the progenitor cells in the developing foetus in such a way that they tend to up-regulate acetylcholinesterase during the foetal development period while persisting even after birth, possibly throughout life [19,24]. Interestingly, alterations in the excitatory and inhibitory balance lie behind various traits of ASD. Elevation of E/I ratio (Alterations in the balance between neuronal excitation and inhibition) in the medial prefrontal cortex or mice introduced ASD-like symptoms in them which serve as an indicator of increased excitatory signals to be a key mediator behind their impaired behavioural effects [5].

In this study Betahistine, an H3R antagonist was studied to observe for behavioural improvement in ASD. Previously different doses of Betahistine for mice, for example 0.3 mg/kg, 3 mg/kg, 30 mg/kg and 2 mg/kg of body weight were used [35]. Betahistine dose of 0.3 mg/kg is recognized as suboptimal for H3R inhibition. In addition, 2 mg/kg oral dose of Betahistine for 8 days creates drug tolerance and undergoes first-pass metabolism [36]. Henceforth, these doses were abandoned for this study, while 30 mg/kg of Betahistine and 3 mg/kg of Betahistine along with 0.8 mg/kg of Rasagiline were included [35,37,38].

The oral dose of 0.3 mg/kg, 0.6mg/kg and 1 mg/kg of Donepezil was selected for this experiment based on previous reporting [32]. Acetylcholine gives its effects upon binding with acetylcholine receptors namely nicotinic and muscarinic receptors. However, for Donepezil, it is extremely hard to pinpoint which receptors give the desired effect [39]. Moreover, whether agonists or antagonists should be used also remains an issue. For this particular reason acetylcholinesterase inhibitors were used to inhibit the breakdown of already existing choline analogues.

The Y-maze spontaneous alternation test as a viable indicator to evaluate short-term memory of the test subjects presented significant decline (p <0.001) of spontaneous alternation % in the negative control 1 group in comparison with the control group. This suggests impaired short-term memory which is a trait of ASD phenotypes [40]. In contrast, a significant development in preserving short-term memory was observed in the T1, T3, T4, and T5 groups.

The increased spontaneous percent alternation in the T1 group suggests amelioration of short-term memory deficits though the mechanism is not clear. The H3R is a G-protein coupled receptor which functions as an autoreceptor, controlling the release of histamine as well as a heteroreceptor, modulating release of neurotransmitters [41]. The development in T1 group might be due to changes caused by H3R heteroreceptor antagonism. It has been noted that Betahistine along with Rasagiline, brings forth a change in the pattern of release of neurotransmitters such as dopamine, serotonin, acetylcholine and GABA, by histaminergic neurons in the tuberomammillary nucleus in the posterior hypothalamus region of the brain [2,15,42]. It is noteworthy that H1R loss of function can bring memory enhancing effects [15]. Betahistine, being a partial agonist of H1R [14], improved the memory deficit conditions in the T1 group which may be likely due to competitive binding with full agonists. Interestingly, the T2 group presented less significant development. Although the Betahistine dose was higher, MAO-B inhibitors were not used in this case. Previously, Betahistine has been regarded as a modulating neurotransmitter for histaminergic system due to its affinity for H1 and H3 receptors which is comparable to histamine while presenting no affinity towards H2 receptors [43]. Saturation of the H3 or H1 receptors might be responsible in this regard since the MAO-B was not available here to reduce the oxidation of the neurotransmitters.

Histamine level in the brain is low but its turnover is high [15]. Hence the less availability of histamine might be responsible for the change through partial H1R agonism due to the competitive binding with full agonists. Moreover, H3 antagonists can decrease neurodegeneration by increasing phosphorylation of intracellular proteins which are important to carry out the neurodegeneration process [42]. Studies have reported that 0.8mg/kg of Rasagiline alone does not have significant neuroprotective effects in transgenic mice models of neurodegeneration [37]. This finding strongly implies that the enhanced effect found in this result is due to the synergistic effects of Betahistine and Rasagiline used in combination and not due to neuroprotective abilities of MAO-B inhibitor Rasagiline only. H3R antagonists can be potential therapeutic agents for treating memory impairments and hyperactivity as H3R were previously targeted for Alzheimer’s disease and attention deficit hyperactivity disorder (ADHD) treatment [22,41,44,45]. In the study, evidence in support of the claim was observed in the Negative Control 2 group (NC2) with no significant change in short-term memory retention when compared with the Control group (C).

Inhibition of breakdown of acetylcholine analogues might be a key factor in T3, T4 and T5 groups’ development in preserving short term memory. However, the increment of dose does not show a linear relationship with the behavioural outcomes. The reason for this phenomenon is unclear. The cholinergic system has been reported to regulate memory, attention and cognitive flexibility, it is possible that the shortage of adequate acetylcholine due to the rightward shift in the upregulation of acetylcholinesterase or choline deficiency has been corrected or ameliorated to some extent by the use of Donepezil. A trend of downregulation of M1 muscarinic receptors and several nicotinic receptors have been reported in ASD phenotypes with an increase in 7 subunit nicotinic receptors [22,39,41,46]. Without establishing their function in the nervous system, it is very hard to theorize their part in the pathophysiology of ASD although their role in ASD is almost certain [46].

The significantly increased line crossing and rearing in the negative control group 1 in comparison with the control group suggests the development of hyperactivity which can also be observed in ASD phenotypes. A significant decrease of line crossing can be observed in the T2, T3, T4 and T5 group which is suggestive of mitigation of hyperactivity. However, the T5 group has decreased horizontal movement severely beyond desired level as the effect is significantly lower than the control group.

Nevertheless, the mice in Donepezil groups (T3, T4, T5) were significantly less active in the Y-maze test although the alternations were accurate. This behaviour of significantly reduced thigmotaxis is also reflected in the Open Field, Hole Board and Hole Cross tests.

The vertical and horizontal movement in the apparatus is significantly reduced which is an indicator of anxiogenic effects. In the open field line crossing, rearing and central area crossing test, the significant decline in all the treated groups reflects the anxiogenic effect when compared with the untreated VPA-exposed mice (NC1). In other word, it can also be said that Betahistine and Donepezil may have the ability to reduce hyperactivity. Interestingly, the two doses of Betahistine (T1 & T2) showed increased activities and Donepezil doses (T3, T4, & T5) showed significantly decreased activities when compared with the healthy mice (C). However, to conclude about the anxiolytic and anxiogenic effect of both the drugs, more studies needs to be conducted.

The open field defecation test is suggestive of development of anxiety-like traits in the negative control 1 group. Although the T3 group ameliorated the symptom, the frequency of defecation decreased below desired level.

The hole-board line crossing tests’ inability to show significant difference between the control group and the negative control 1 group is suggestive of normal anxiogenic response under fear-based conditions in valproic acid-induced mice. That said, the T4 group and the T5 group have significantly decreased the line crossing.

Similarly, the absence of significant difference in head dipping frequency suggests that the neophilic-neophobic response was normal as well. The significant changes observed in the T3, T4 and T5 group is suggestive of anxiogenic activity, although further investigations are required to support these data.

A decline was observed in hole crossing frequency in the T2 group. Betahistine does not show sedative properties [47]. Nonetheless, H1R loss of function can lead to anxiolytic effects [14]. It is possible that the change was brought about by partial H1R agonism due to competitive binding with full agonists. Another probable reason could be histamine H1R tolerance since Betahistine can increase histamine synthesis by blocking H3R autoreceptors [33,48]. However, in another experiment conducted on similar specimen [36], 30 mg/kg of oral dose of Betahistine for 8 days shows significant increase in t-MeHA, (tele-methylhistamine) which is an index for measuring histaminergic neuronal activity. This data strongly suggests that inverse agonism in H3R autoreceptors result in the amplification of activities in the histaminergic neurons [36,41]. Therefore, the behavioural activities of T1 and T2 groups of mice found in our study could also result from the amplification of histaminergic neuronal activities due to H3R inverse agonism.

The decline in hole crossing frequency observed in the Donepezil treated groups (T3, T4, and the T5 group) for these tests were unlikely brought about by sedation since Donepezil has not yet been reported to cause sedative effects. However, in different studies it has been shown that, choline concentrations are negatively associated with anxiety symptoms [41,49,50]. It is possible that the increase in acetylcholine might be the reason behind the significantly decreased hole crossing in the Donepezil treated groups.

The mice in the NC1 group and the treated groups showed neuronal loss and degeneration, gliosis, and thinning of hippocampus. The hippocampus of the brain is responsible for the formation of new memory and the processing of short-term memory into long term memory [51]. Changes in brain-histomorphology were prominent in the NC1 group compared to treated groups of mice. However, no measurement has been conducted to quantify the difference. Due to the lack of neuronal regeneration in the brain, the treated groups of mice presented neuronal degeneration. In addition to it, reactive gliosis, where more glial cells supporting the nerve cells are created, was observed more in the treated groups. However, the precise origin and subsequent fate of the glial cells reacting to injury are unknown [52].

Conclusion

This study was conducted to evaluate if Betahistine or Donepezil can ameliorate the symptoms of autism. The results suggest both the drugs have potential to ameliorate short-term memory deficits. Furthermore, all the doses of the two drugs have the potential to reduce hyperactivity. Further research should be continued for the proper justification of the effects of the drugs. Therefore, both Betahistine (alone and in combination with Rasagiline) and Donepezil (low dose 0.3mg/kg) have potential as a therapeutic agent to ameliorate some of the symptoms found in ASD affected individuals. It can play a role in managing hyperactivity in individuals with ADHD, however, more study will be required to understand its mechanism of action as well as studies into its toxicity effects.

Supporting information

S1 Dataset Dataset of behavioural traits of valproic acid-induced mouse model.

(PDF)

We are thankful to Sanofi Aventis Bangladesh, Square Pharmaceuticals Limited, Bangladesh, for providing the chemicals used in this study. We also acknowledge our gratitude to the Pharmacology Laboratory at Jahangirnagar University, for providing us laboratory support. Lastly, but not the least, we also acknowledge the contribution of Fariha Tarannum in referencing.

Abbreviations

ASD Autism Spectrum Disorder

H3R Histamine 3 Receptor

VPA Valproic Acid

OFT Open Field Test

HBT Hole Board Test

HCT Hole Cross Test

10.1371/journal.pone.0308632.r001
Decision Letter 0
Martino Tommaso Academic Editor
© 2024 Tommaso Martino
2024
Tommaso Martino
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submission Version0
10 Nov 2023

PONE-D-23-30357Pharmacological intervention of behavioural traits of autism spectrum disorder in a prenatal valproic acid-induced mouse model of autismPLOS ONE

Dear Dr. Neelotpol,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Dec 25 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Tommaso Martino, M.D.

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Journal requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. We note that Figure 2 in your submission contain copyrighted images. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

1. You may seek permission from the original copyright holder of Figure 2 to publish the content specifically under the CC BY 4.0 license.

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an "Other" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

2. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: I Don't Know

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: - A Figure is needed to show the affinities and selectivity of test compound betahistine.

- When discussing the involvement of histaminergic and/or cholinergic neurotransmission in the observed effects for betahistine, cite the following siginificant studies in your discussion;

1) Eissa N, Al Awad M, Venkatachalam K, Jayaprakash P, Thomas SD, Zhong S, Stark H, Sadek B. Simultaneous antagonism at H3R/D2R/D3R reduces autism-like self-grooming and aggressive behaviors by mitigating MAPK activation in mice. Int. J. Mol. Sci. 2023; 24:526.

2) Saad AK, Akour A, Mahboob A, AbuRuz S, Sadek B. Role of brain modulators in neurodevelopment: focus on autism spectrum disorder and associated comorbidities. Pharmaceuticals 2022, 15:612.

3) Eissa N, Venkatachalam K, Jayaprakash P, Falkenstein M, Frank A, Reiner-Link D, Stark H, Sadek B. The multi-targeting ligand ST-2223 with histamine H3 receptor and dopamine D2/D3 receptor antagonist properties mitigates autism-like repetitive behaviors and brain oxidative stress in mice. Int. J. Mol. Sci. 2021; 22(4), 1947.

4) Eissa N, Azimullah S, Jayaprakash P, Jayaraj RL, Reiner D, Ojha SK, Beiram R, Stark H, Łażewska D, Kieć-Kononowicz K, Sadek B. The dual-active histamine H3 receptor antagonist and acetylcholine esterase inhibitor E100 alleviates autistic-like behaviors and oxidative stress in valproic acid induced autism in mice. Int. J. Mol. Sci. 2020; 21(11), 3996.

- References to justify the selected and used doses of all test compounds are missing.

-Quality of all Figures should be improved, were difficult to read.

Reviewer #2: 1. The authors chose to treat the rats from PND44 to 64. Why this particular time window, frequency and duration of treatment? What is the authors' hypothesis when treating after weaning, when the neurodevelopmental period is mostly completed? Of note, relieving effects of treatment observed in nearly young adults are encouraging.

2. The term ‘Alteration’ and ‘alternation’ is written interchangeably in Y maze in methods and results section. It should be spontaneous alternation and not alteration. Correct it.

3. Data representation: histograms with scatter plots are highly recommended to allow the reader to assess the animal numbers per group and the dispersion of individual data at a glance.

4. Autistic mice: avoid using such wording; use the terms "VPA-exposed mice" instead.

5. In abstract it is mentioned that “After administration of the experimental doses, various locomotor tests: Open Field, Hole-Board, Hole Cross tests and behavioural tests: Y-Maze Spontaneous Alternation Test were performed and compared with positive and negative control groups”. What is the positive control group that is mentioned in this statement, which is nowhere mentioned in the rest of manuscript?

6. What is the significance of combining betahistine and rasagiline, why were both the drugs given in combination in T1 group? Kindly add the significance in the manuscript.

7. Authors have concluded that drugs have potential to ameliorate short-term memory deficits, it is recommended to perform other behavioral parameters for memory assessment like, Morris water maze, Radial Arm maze and Novel object recognition, to have better glance into the cognitive outcomes.

8. Furthermore it is recommended to report the histopathological changes in the appropriate regions of the brain of VPA exposed mice, using hematoxylin and eosin stain and Nissl stain, and also estimation of levels of acetyl choline and histamine in the VPA exposed mice and treated mice is highly recommended. These basic investigations will make the preliminary findings from this study more reliable and convincing for further research into these molecules and their mechanisms in ASD.

Reviewer #3: 1. In Lines 23 and 26 leave space after ‘p’ to be consistent. Apply this to the results section too.

2. Sometimes the authors mentioned autism and other times ASD. Please be consistent.

3. Why were the 2 mice genders used? Will this not have any impact on the behavior results?

4. I suggest that the second group of healthy offspring from the healthy mothers (NC2) to be Betahistine dihydrochloride of 3mg/kg in combination with 0.8mg/kg of Rasagiline to ensure that there are no off-target effects due to the combination of the drugs. This is important as especially there is no absence of in vitro profile of the combination of these drugs. Why the current NC2 is used?

5. Is there any results for the effects of Rasagiline only in VPA-induced mouse of ASD on all behavioral tests studied?

6. Line 343 mentions ‘In the study evidence in support of the claim was observed in the Negative control 2 group (NC2) whereby no significant change in short-term memory retention when compared with the Control group (C). To test for the neuroprotective effect of rasagiline, the effect of rasagiline only should be tested on an ASD mouse model of ASD. This group is missed.

7. The quality of all the figures is poor. Figures with high resolution need to be added.

8. In Figure 1, add the full name of the behavioral tests or mention them in the figure caption.

9. In Line 223, 224, and 343 the control and negative control 1 should all be in small letters as it is throughout the paper.

10. Elaboration is required on how betahistine showed anxiolytic and donepezil showed anxiogenic properties at different doses.

11. In Line 286 remove the bracket.

12. In Lines 292 and 292 ‘embryonic’ should be in small letters.

13. In 294 remove the extra space.

14. The authors should mention VPA-induced mice, not valproic acid-induced mice throughout the paper. The abbreviations should be described the first time in the text only.

15. In line 404, rephrase the sentence. There are no types of ASD patients.

16. Please check the manuscript for the English language.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Bassem Sadek

Reviewer #2: No

Reviewer #3: Yes: Nermin Eissa

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Attachment Submitted filename: Comments PONE-D-23-30357.docx

10.1371/journal.pone.0308632.r002
Author response to Decision Letter 0
Submission Version1
20 Apr 2024

Journal requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

Response: We have made sure all the PLOS ONE’S style requirements for fie naming have been followed throughout the manuscript.

2. We note that Figure 2 in your submission contains copyrighted images. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

1. You may seek permission from the original copyright holder of Figure 2 to publish the content specifically under the CC BY 4.0 license.

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an "Other" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

2. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

Response: Since we did not incorporate figures for any test, therefore, we have removed Figure 2 to avoid copyrighting issues.

Response to the reviewers' comments:

Reviewer #1:

● A Figure is needed to show the affinities and selectivity of test compound betahistine.

Response: Thank you for your suggestion. This study does not focus on the molecular mechanism of betahistine. Our aim was to study the behavioural mechanism of betahistine on VPA-induced mice. The affinity and selectivity of betahistine has already been established and information regarding its binding affinity and selectivity has been referred to in the revised manuscript in line 397-399 and line 401-403 with reference 43. On our next project we are considering studying the molecular mechanism of betahistine over its behavioural pattern.

● When discussing the involvement of histaminergic and/or cholinergic neurotransmission in the observed effects for betahistine, cite the following significant studies in your discussion;

1) Eissa N, Al Awad M, Venkatachalam K, Jayaprakash P, Thomas SD, Zhong S, Stark H, Sadek B. Simultaneous antagonism at H3R/D2R/D3R reduces autism-like self-grooming and aggressive behaviours by mitigating MAPK activation in mice. Int. J. Mol. Sci. 2023; 24:526.

2) Saad AK, Akour A, Mahboob A, AbuRuz S, Sadek B. Role of brain modulators in neurodevelopment: focus on autism spectrum disorder and associated comorbidities. Pharmaceuticals 2022, 15:612.

3) Eissa N, Venkatachalam K, Jayaprakash P, Falkenstein M, Frank A, Reiner-Link D, Stark H, Sadek B. The multi-targeting ligand ST-2223 with histamine H3 receptor and dopamine D2/D3 receptor antagonist properties mitigates autism-like repetitive behaviours and brain oxidative stress in mice. Int. J. Mol. Sci. 2021; 22(4), 1947.

4) Eissa N, Azimullah S, Jayaprakash P, Jayaraj RL, Reiner D, Ojha SK, Beiram R, Stark H, Łażewska D, Kieć-Kononowicz K, Sadek B. The dual-active histamine H3 receptor antagonist and acetylcholine esterase inhibitor E100 alleviates autistic-like behaviours and oxidative stress in valproic acid induced autism in mice. Int. J. Mol. Sci. 2020; 21(11), 3996.

Response: Thank you for your suggestion. We have cited the aforementioned studies in our discussion.

Reference 01 can be found as reference 41 in line number: 389,413, 423, 460, and 465.

Reference 02 can be found as reference 46 in line number: 423 and 425.

Reference 03 can be found as reference 14 in line number: 68, 88, 395, and 453.

Reference 04 can be found as reference 24 in line number: 113, 124, and 358.

● References to justify the selected and used doses of all test compounds are missing.

Response: Thank you for your comment. The doses were reviewed from the referenced articles. Some doses were modified, which are justified in the discussion section. Betahistine and Rasagiline doses were justified in line 457-460 using reference no 33,36, 41 & 48 in the manuscript. Donepezil doses were justified in line 462-466 using reference no 41,49 & 50 in the manuscript.

● Quality of all Figures should be improved, as they are difficult to read.

Response: Thank you for your suggestion. The quality of all the figures have now been improved.

Reviewer #2:

1. The authors chose to treat the rats from PND44 to 64. Why this particular time window, frequency and duration of treatment? What is the authors' hypothesis when treating after weaning, when the neurodevelopmental period is mostly completed? Of note, relieving effects of treatment observed in nearly young adults are encouraging.

Response: Your query is appreciated. The time window selected for dosage and performing of behavioural studies were done according to the referenced article number 23 of our manuscript.

The dosages are administered after weaning and not at a young age.

2. The term ‘Alteration’ and ‘alternation’ is written interchangeably in Y maze in the methods and results section. It should be spontaneous alternation and not alteration. Correct it.

Response: Thank you for your notification. Recommended changes have been made accordingly in the line numbers 216 & 432.

3. Data representation: histograms with scatter plots are highly recommended to allow the reader to assess the animal numbers per group and the dispersion of individual data at a glance.

Response: We appreciate this valuable suggestion. In this manuscript, the quality of the existing figures have been improved according to the other two reviewer’s suggestion. In addition, as per your suggestion, the number of animals per group have been mentioned in the method section.

4. Autistic mice: avoid using such wording; use the terms "VPA-exposed mice" instead.

Response: Thank you for your notification. Changes have been made accordingly. (Line-26,33, 64.82,342,347,437)

5. In abstract it is mentioned that “After administration of the experimental doses, various locomotor tests: Open Field, Hole-Board, Hole Cross tests and behavioural tests: Y-Maze Spontaneous Alternation Test were performed and compared with positive and negative control groups”. What is the positive control group that is mentioned in this statement, which is nowhere mentioned in the rest of the manuscript?

Response: Thank you for your reply. In Line 23 the control group is mentioned as 'positive control'. The word has been changed to control instead of positive control.

6. What is the significance of combining betahistine and rasagiline, why were both the drugs given in combination in the T1 group? Kindly add the significance in the manuscript.

Response: Thank you for your query. The significance of combining betahistine and rasagiline has been mentioned in line 406-411.

7. Authors have concluded that drugs have potential to ameliorate short-term memory deficits, it is recommended to perform other behavioural parameters for memory assessment like, Morris water maze, Radial Arm maze and Novel object recognition, to have a better glance into the cognitive outcomes.

Response: We are grateful for the suggestion you have provided. We did not mention about these tests in the ethical permission, hence it is not possible for us to conduct these experiments. Moreover, we have already sacrificed the mice for histopathological data. We will consider your valuable suggestions for future studies.

8. Furthermore it is recommended to report the histopathological changes in the appropriate regions of the brain of VPA-exposed mice, using hematoxylin and eosin stain and Nissl stain, and also estimation of levels of acetylcholine and histamine in the VPA-exposed mice and treated mice is highly recommended. These basic investigations will make the preliminary findings from this study more reliable and convincing for further research into these molecules and their mechanisms in ASD.

Response: Thank you for this important suggestion. Now we have incorporated the findings of histopathology which, we believe, have improved the quality of the study.

Reviewer #3:

1. In Lines 23 and 26 leave space after ‘p’ to be consistent. Apply this to the results section too.

Response: Thank you for your notification. Recommended changes have been made accordingly in line 24 and 27. For consistency, we have checked the whole manuscript carefully.

2. Sometimes the authors mentioned autism and other times ASD. Please be consistent.

Response: Thank you for your notification. Recommended changes have been made throughout the manuscript, accordingly.

3. Why were the 2 mice genders used? Will this not have any impact on the behavior results?

Response: Thank you for your valuable comment. There was a shortage of VPA-induced mice pups to conduct the whole experiment with only one specific gender since some of the VPA- induced mother mice died before giving birth. Hence, we have compared the male treated groups with male control groups. Similarly, the female treated groups were compared with female control groups. We did not draw a contrast between the male or female groups.

4. I suggest that the second group of healthy offspring from the healthy mothers (NC2) to be Betahistine dihydrochloride of 3mg/kg in combination with 0.8mg/kg of Rasagiline to ensure that there are no off-target effects due to the combination of the drugs. This is important as especially there is no absence of in vitro profile of the combination of these drugs. Why is the current NC2 used?

Response: We extend our gratitude for your input. Both Rasagiline and Betahistine have passed clinical trials and their safety is not in question. Moreover, due to the shortage of mice pups this group was avoided.

To negate the effects of rasagiline on VPA-induced mice we have used 0.8mg/kg of rasagiline on healthy mice as the negative control 2 group (NC2). The NC2 group helps us to understand if any derogatory effects arose from the administration of Rasagiline.

5. Is there any results for the effects of Rasagiline only in VPA-induced mouse of ASD on all behavioral tests studied?

Response: We thank you for your query. We did not test the effects of 0.8mg/kg of Rasagiline only in VPA-induced mice. Sufficient VPA-injected mother mice did not survive to give birth to the required number of mice pups to make this VPA-induced group. An explanation of which has now been added in the methodology section. Moreover, the project did not aim to evaluate MAO-B Rasagiline’s effect separately on VPA induced mice. Furthermore, we have referenced a study that reported 0.8mg/kg of rasagiline alone could not significantly give any neuroprotective effects in transgenic mice models of neurodegeneration in line 409, reference 37.

6. Line 343 mentions ‘In the study evidence in support of the claim was observed in the Negative control 2 group (NC2) whereby no significant change in short-term memory retention when compared with the Control group (C). To test for the neuroprotective effect of rasagiline, the effect of rasagiline only should be tested on an ASD mouse model of ASD. This group is missed.

Response: Thank you for your suggestion. Rasagiline of 0.8mg/kg was added to T1 group to counteract the tolerance initiated by 3mg/kg of Betahistine in subjects after 8 days of administration, which has been discussed in the manuscript line 389-393 (Reference 2, 15, 42). The experiment did not aim to evaluate MAO-B inhibitor rasagiline’s effect on VPA induced mice. Hence this group was avoided. We will consider it for future studies.

7. The quality of all the figures is poor. Figures with high resolution need to be added.

Response: Thank you for your suggestion. The quality of the figures have been improved now as per the suggestion.

8. In Figure 1, add the full name of the behavioral tests or mention them in the figure caption.

Response: Thank you for your notification. We have added them accordingly.

9. In Line 223, 224, and 343 the control and negative control 1 should all be in small letters as it is throughout the paper.

Response: Thank you for your notification. We have changed it throughout the manuscript.

10. Elaboration is required on how betahistine showed anxiolytic and donepezil showed anxiogenic properties at different doses.

Response: Thank you for your query. Since the focus of the study was to evaluate the behavioural trait of two drugs on VPA-induced mouse model, it is hard to make any comment about the anxiolytic and anxiogenic effect of the drugs by conducting only few neuro-behavioural tests. That is why, we have rephrased the sentence to better reflect our thought with regards to the experiments that we have carried out.

11. In Line 286 remove the bracket.

Response: Thank you for your comment. Bracket has been removed as per the advice.

12. In Lines 292 and 292 ‘embryonic’ should be in small letters.

Response: Thank you for your comment. Recommended changes have been made accordingly.

13. In 294 remove the extra space.

Response: Thank you for your notification. Extra space has been removed.

14. The authors should mention VPA-induced mice, not valproic acid-induced mice throughout the paper. The abbreviations should be described the first time in the text only.

Response: Thank you for your suggestion. We have changed it throughout the manuscript.

15. In line 404, rephrase the sentence. There are no types of ASD patients.

Response: Thank you for your insight. We have changed accordingly.

16. Please check the manuscript for the English language.

Response: We have checked the manuscript for the English language.

Attachment Submitted filename: Response to Reviewers.docx

10.1371/journal.pone.0308632.r003
Decision Letter 1
Wang Xiaona Academic Editor
© 2024 Xiaona Wang
2024
Xiaona Wang
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submission Version1
29 Jul 2024

Pharmacological intervention of behavioural traits and brain histopathology of prenatal valproic acid-induced mouse model of autism

PONE-D-23-30357R1

Dear Dr. Neelotpol,  

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Xiaona Wang, Ph.D

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: Authors have addressed all the queries and with the histopathological data, the data is more convincing. However, authors could have provided the histopathological data for each interventional group.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: Yes: Kajal Rawat

**********

10.1371/journal.pone.0308632.r004
Acceptance letter
Wang Xiaona Academic Editor
© 2024 Xiaona Wang
2024
Xiaona Wang
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
13 Sep 2024

PONE-D-23-30357R1

PLOS ONE

Dear Dr. Neelotpol,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team.

At this stage, our production department will prepare your paper for publication. This includes ensuring the following:

* All references, tables, and figures are properly cited

* All relevant supporting information is included in the manuscript submission,

* There are no issues that prevent the paper from being properly typeset

If revisions are needed, the production department will contact you directly to resolve them. If no revisions are needed, you will receive an email when the publication date has been set. At this time, we do not offer pre-publication proofs to authors during production of the accepted work. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few weeks to review your paper and let you know the next and final steps.

Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

If we can help with anything else, please email us at customercare@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Associate Professor Xiaona Wang

Academic Editor

PLOS ONE
==== Refs
References

1 Zeidan J , Fombonne E , Scorah J , Ibrahim A , Durkin MS , Saxena S , et al . Global prevalence of autism: A systematic review update. Autism Research [Internet]. 2022;15 (5 ):778–90. Available from: https://onlinelibrary.wiley.com/doi/abs/ doi: 10.1002/aur.2696 35238171
2 Baronio D , Castro K , Gonchoroski T , Melo GM de , Nunes GDF , Bambini-Junior V , et al . Effects of an H3R Antagonist on the Animal Model of Autism Induced by Prenatal Exposure to Valproic Acid. PLoS One [Internet]. 2015 Jan;10 (1 ):e0116363. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0116363. doi: 10.1371/journal.pone.0116363 25560049
3 Andres C. Molecular genetics and animal models in autistic disorder. Brain Res Bull [Internet]. 2002 Jan;57 (1 ):109–19. Available from: https://www.sciencedirect.com/science/article/pii/S0361923001006426. doi: 10.1016/s0361-9230(01)00642-6 11827743
4 WHO. Autism spectrum disorders & other developmental disorders from raising awareness to building capacity. World Health Organization, Geneva, Switzerland. 2013;1 (September):1–36.
5 Torre-Ubieta L de la , Won H , Stein JL , Geschwind DH . Advancing the understanding of autism disease mechanisms through genetics. Nat Med [Internet]. 2016 Apr;22 (4 ):345. Available from: /pmc/articles/PMC5072455/. doi: 10.1038/nm.4071 27050589
6 Wright C , Shin JH , Rajpurohit A , Deep-Soboslay A , Collado-Torres L , Brandon NJ , et al . Altered expression of histamine signaling genes in autism spectrum disorder. Transl Psychiatry [Internet]. 2017;7 (5 ):e1126. Available from: http://www.ncbi.nlm.nih.gov/pubmed/28485729. doi: 10.1038/tp.2017.87 28485729
7 Sadek B , Saad A , Sadeq A , Jalal F , Stark H . Histamine H3 receptor as a potential target for cognitive symptoms in neuropsychiatric diseases. Behavioural Brain Research [Internet]. 2016 Oct;312 :415–30. Available from: https://www.sciencedirect.com/science/article/pii/S0166432816304168. doi: 10.1016/j.bbr.2016.06.051 27363923
8 Panula P , Chazot PL , Cowart M , Gutzmer R , Leurs R , Liu WLS , et al . International Union of Basic and Clinical Pharmacology. XCVIII. Histamine Receptors. Ohlstein EH, editor. Pharmacol Rev [Internet]. 2015 Jul;67 (3 ):601–55. Available from: https://pharmrev.aspetjournals.org/content/67/3/601.26084539
9 Wong HHL , Smith RG . Patterns of Complementary and Alternative Medical Therapy Use in Children Diagnosed with Autism Spectrum Disorders. J Autism Dev Disord [Internet]. 2006 Oct;36 (7 ):901–9. Available from: doi: 10.1007/s10803-006-0131-0 16897395
10 Witkin JM , Nelson DL . Selective histamine H3 receptor antagonists for treatment of cognitive deficiencies and other disorders of the central nervous system. Pharmacol Ther [Internet]. 2004 Jul;103 (1 ):1–20. Available from: https://www.sciencedirect.com/science/article/pii/S0163725804000683. doi: 10.1016/j.pharmthera.2004.05.001 15251226
11 Findling RL . Pharmacologic treatment of behavioral symptoms in autism and pervasive developmental disorders. J Clin Psychiatry. 2005;66 Suppl 10 :26–31. 16401147
12 Matson JL , Sipes M , Fodstad JC , Fitzgerald ME . Issues in the Management of Challenging Behaviours of Adults with Autism Spectrum Disorder. CNS Drugs [Internet]. 2011 Jul;25 (7 ):597–606. Available from: doi: 10.2165/11591700-000000000-00000 21699271
13 Dong H , Zhang W , Zeng X , Hu G , Zhang H , He S , et al . Histamine induces upregulated expression of histamine receptors and increases release of inflammatory mediators from microglia. Mol Neurobiol. 2014 Jun;49 (3 ):1487–500. doi: 10.1007/s12035-014-8697-6 24752587
14 Eissa N , Venkatachalam K , Jayaprakash P , Falkenstein M , Dubiel M , Frank A , et al . The Multi-Targeting Ligand ST-2223 with Histamine H3 Receptor and Dopamine D2/D3 Receptor Antagonist Properties Mitigates Autism-Like Repetitive Behaviors and Brain Oxidative Stress in Mice. Int J Mol Sci [Internet]. 2021 Feb 2 [cited 2024 Feb 10];22 (4 ):1–21. Available from: https://pubmed.ncbi.nlm.nih.gov/33669336/.
15 Haas HL , Sergeeva OA , Selbach O . Histamine in the nervous system. Physiol Rev [Internet]. 2008 Jul;88 (3 ):1183–241. Available from: http://www.ncbi.nlm.nih.gov/pubmed/18626069. doi: 10.1152/physrev.00043.2007 18626069
16 Jost WH . A critical appraisal of MAO-B inhibitors in the treatment of Parkinson’s disease. J Neural Transm [Internet]. 2022;129 (5–6 ):723–36. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9188534/. doi: 10.1007/s00702-022-02465-w 35107654
17 Finberg JPM . Pharmacology of Rasagiline, a New MAO-B Inhibitor Drug for the Treatment of Parkinson’s Disease with Neuroprotective Potential. Rambam Maimonides Med J [Internet]. 2010 Jul;1 (1 ):e0003. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3721659/. doi: 10.5041/RMMJ.10003 23908775
18 Łażewska D , Siwek A , Olejarz-Maciej A , Doroz-Płonka A , Wiktorowska-Owczarek A , Jóźwiak-Bębenista M , et al . Dual Targeting Ligands—Histamine H3 Receptor Ligands with Monoamine Oxidase B Inhibitory Activity—In Vitro and In Vivo Evaluation. Pharmaceutics [Internet]. 2022 Oct;14 (10 ):2187. Available from: https://www.mdpi.com/1999-4923/14/10/2187. doi: 10.3390/pharmaceutics14102187 36297622
19 Kim JW , Seung H , Kim KC , Gonzales ELT , Oh HA , Yang SM , et al . Agmatine rescues autistic behaviors in the valproic acid-induced animal model of autism. Neuropharmacology. 2017;113. doi: 10.1016/j.neuropharm.2016.09.014 27638451
20 Ragozzino ME , Pal SN , Unick K , Stefani MR , Gold PE . Modulation of Hippocampal Acetylcholine Release and Spontaneous Alternation Scores by Intrahippocampal Glucose Injections. Journal of Neuroscience [Internet]. 1998 Feb;18 (4 ):1595–601. Available from: https://www.jneurosci.org/content/18/4/1595. doi: 10.1523/JNEUROSCI.18-04-01595.1998 9454864
21 Handen BL , Johnson CR , McAuliffe-Bellin S , Murray PJ , Hardan AY . Safety and Efficacy of Donepezil in Children and Adolescents with Autism: Neuropsychological Measures. J Child Adolesc Psychopharmacol [Internet]. 2011 Feb;21 (1 ):43. Available from: /pmc/articles/PMC3037196/. doi: 10.1089/cap.2010.0024 21309696
22 Eissa N , Jayaprakash P , Stark H , Łażewska D , Kieć-Kononowicz K , Sadek B . Simultaneous Blockade of Histamine H3 Receptors and Inhibition of Acetylcholine Esterase Alleviate Autistic-Like Behaviors in BTBR T+ tf/J Mouse Model of Autism. Biomolecules. 2020 Aug;10 (9 ):1251. doi: 10.3390/biom10091251 32872194
23 Eissa N , Jayaprakash P , Azimullah S , Ojha SK , Al-Houqani M , Jalal FY , et al . The histamine H3R antagonist DL77 attenuates autistic behaviors in a prenatal valproic acid-induced mouse model of autism. Sci Rep. 2018 Dec;8 (1 ).
24 Eissa N , Azimullah S , Jayaprakash P , Jayaraj RL , Reiner D , Ojha SK , et al . The dual-active histamine H3 receptor antagonist and acetylcholine esterase inhibitor E100 ameliorates stereotyped repetitive behavior and neuroinflammmation in sodium valproate induced autism in mice. Chem Biol Interact [Internet]. 2019 Oct 1 [cited 2024 Feb 10];312. Available from: https://pubmed.ncbi.nlm.nih.gov/31369746/.31153983
25 Ornoy A , Weinstein-Fudim L , Ergaz Z . Molecular Sciences Prevention or Amelioration of Autism-Like Symptoms in Animal Models: Will it Bring Us Closer to Treating Human ASD? 2019; Available from: www.mdpi.com/journal/ijms.
26 Al-Amin MM , Rahman MM , Khan FR , Zaman F , Reza HM . Astaxanthin improves behavioral disorder and oxidative stress in prenatal valproic acid-induced mice model of autism. Behavioural Brain Research [Internet]. 2015 Jun;286 :112–21. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25732953. doi: 10.1016/j.bbr.2015.02.041 25732953
27 Ibi D , Fujiki Y , Koide N , Nakasai G , Takaba R , Hiramatsu M . Paternal valproic acid exposure in mice triggers behavioral alterations in offspring. Neurotoxicol Teratol. 2019 Nov;76 . doi: 10.1016/j.ntt.2019.106837 31654689
28 Carola V , D’Olimpio F , Brunamonti E , Mangia F , Renzi P . Evaluation of the elevated plus-maze and open-field tests for the assessment of anxiety-related behaviour in inbred mice. Behavioural Brain Research. 2002 Aug;134 (1–2 ):49–57. doi: 10.1016/s0166-4328(01)00452-1 12191791
29 Brown GR , Nemes C . The exploratory behaviour of rats in the hole-board apparatus: Is head-dipping a valid measure of neophilia? Behavioural Processes. 2008 Jul;78 (3 ):442–8. doi: 10.1016/j.beproc.2008.02.019 18406075
30 Takagi K , Watanabe M , Saito H . Studies of the spontaneous movement of animals by the hole cross test; effect of 2-dimethyl-aminoethanol and its acyl esters on the central nervous system. Jpn J Pharmacol. 1971 Dec;21 (6 ):797–810. doi: 10.1254/jjp.21.797 5316865
31 Moniruzzaman M , Bhattacharjee PS , Pretty MR , Hossain MS . Sedative and Anxiolytic-Like Actions of Ethanol Extract of Leaves of Glinus oppositifolius (Linn.) Aug. DC. Evidence-based Complementary and Alternative Medicine. 2016;2016 . doi: 10.1155/2016/8541017 27413390
32 Kawashiri T , Shimizu S , Shigematsu N , Kobayashi D , Shimazoe T . Donepezil ameliorates oxaliplatin-induced peripheral neuropathy via a neuroprotective effect. J Pharmacol Sci. 2019 Jul;140 (3 ):291–4. doi: 10.1016/j.jphs.2019.05.009 31377017
33 Baronio D , Castro K , Gonchoroski T , Melo GM De , Nunes GDF , Bambini-Junior V , et al . Effects of an H3R antagonist on the animal model of autism induced by prenatal exposure to valproic acid. PLoS One. 2015 Jan;10 (1 ). doi: 10.1371/journal.pone.0116363 25560049
34 Sakade Y , Yamanaka K , Soumiya H , Furukawa S , Fukumitsu H . Exposure to valproic acid during middle to late-stage corticogenesis induces learning and social behavioral abnormalities with attention deficit/hyperactivity in adult mice. Biomed Res [Internet]. 2019;40 (5 ):179–88. Available from: http://www.ncbi.nlm.nih.gov/pubmed/31597903. doi: 10.2220/biomedres.40.179 31597903
35 Lacour M , Sterkers O . Histamine and Betahistine in the Treatment of Vertigo. CNS Drugs [Internet]. 2001 Nov;15 (11 ):853–70. Available from: https://link.springer.com/article/10.2165/00023210-200115110-00004.11700150
36 Gbahou F , Davenas E , Morisset S , Arrang JMJM . Effects of Betahistine at Histamine H3 receptors: Mixed inverse agonism/agonism in vitro and partial inverse agonism in vivo. Journal of Pharmacology and Experimental Therapeutics [Internet]. 2010 Sep;334 (3 ):945–54. Available from: doi: 10.1124/jpet.110.168633 20530654
37 Stefanova N , Poewe W , Wenning GK . Rasagiline is neuroprotective in a transgenic model of multiple system atrophy. Exp Neurol. 2008 Apr;210 (2 ):421–7. doi: 10.1016/j.expneurol.2007.11.022 18222424
38 Hösli L , Haas HL . Effects of histamine, histidine and imidazole acetic acid on neurones of the medulla oblongata of the cat. Experientia [Internet]. 1971 Nov;27 (11 ):1311–2. Available from: https://pubmed.ncbi.nlm.nih.gov/5134291/. doi: 10.1007/BF02136707 5134291
39 Karvat G , Kimchi T . Acetylcholine elevation relieves cognitive rigidity and social deficiency in a mouse model of autism. Neuropsychopharmacology. 2014 Mar;39 (4 ):831–40. doi: 10.1038/npp.2013.274 24096295
40 Kraeuter AK , Guest PC , Sarnyai ZN . The Y-Maze for Assessment of Spatial Working and Reference Memory in Mic e. 2019;1916 :105–11. Available from: 10.1007/978-1-4939-8994-2_10.
41 Eissa N , Awad M Al , Thomas SD , Venkatachalam K , Jayaprakash P , Zhong S , et al . Simultaneous Antagonism at H3R/D2R/D3R Reduces Autism-like Self-Grooming and Aggressive Behaviors by Mitigating MAPK Activation in Mice. International Journal of Molecular Sciences 2023, Vol 24 , Page 526 [Internet]. 2022 Dec 28 [cited 2024 Feb 10];24(1 ):526. Available from: https://www.mdpi.com/1422-0067/24/1/526/htm.
42 Chandrasekhar K. H3 antagonists and postoperative cognitive dysfunction. J Anaesthesiol Clin Pharmacol [Internet]. 2019 Jun;35 (2 ). Available from: https://pubmed.ncbi.nlm.nih.gov/31303701/.
43 Fossati A , Barone D , Benvenuti C . Binding affinity profile of betahistine and its metabolites for central histamine receptors of rodents. Pharmacol Res. 2001 Apr 1;43 (4 ):389–92. doi: 10.1006/phrs.2000.0795 11352543
44 Leurs R , Bakker RA , Timmerman H , Esch IJP de . The histamine H3 receptor: from gene cloning to H3 receptor drugs. Nat Rev Drug Discov [Internet]. 2005 Feb;4 (2 ):107–20. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15665857. doi: 10.1038/nrd1631 15665857
45 Liu Y , Zeng H , Pediani JD , Ward RJ , Chen LYY , Wu N , et al . No Title. 2018 Jun;285 (12 ):2319–36. Available from: http://www.ncbi.nlm.nih.gov/pubmed/29701013.
46 Saad AK , Akour A , Mahboob A , Aburuz S , Sadek B . Role of Brain Modulators in Neurodevelopment: Focus on Autism Spectrum Disorder and Associated Comorbidities. Pharmaceuticals (Basel) [Internet]. 2022 May 1 [cited 2024 Feb 10];15 (5 ). Available from: https://pubmed.ncbi.nlm.nih.gov/35631438/. doi: 10.3390/ph15050612 35631438
47 Motamed H , Moezzi M , Rooyfard AD , Angali KA , Izadi Z . A Comparison of the Effects and Side Effects of Oral Betahistine with Injectable Promethazine in the Treatment of Acute Peripheral Vertigo in Emergency. J Clin Med Res. 2017;9 (12 ):994–7. doi: 10.14740/jocmr3093w 29163732
48 Tighilet B , Léonard J , Watabe I , Bernard-Demanze L , Lacour M . Betahistine treatment in a cat model of vestibular pathology: Pharmacokinetic and pharmacodynamic approaches. Front Neurol. 2018 Jun;9 (JUN).
49 Bjelland I , Tell GS , Vollset SE , Konstantinova S , Ueland PM . Choline in anxiety and depression: the Hordaland Health Study. Am J Clin Nutr. 2009 Oct;90 (4 ):1056–60. doi: 10.3945/ajcn.2009.27493 19656836
50 Watson CJ , Lydic R , Baghdoyan HA . Sleep duration varies as a function of glutamate and GABA in rat pontine reticular formation. J Neurochem. 2011 Aug;118 (4 ):571–80. doi: 10.1111/j.1471-4159.2011.07350.x 21679185
51 Voss JL , Bridge DJ , Cohen NJ , Walker JA . A Closer Look at the Hippocampus and Memory. Vol. 21 , Trends in Cognitive Sciences. 2017.
52 Roumier A , Pascual O , Béchade C , Wakselman S , Poncer JC , Réal E , et al . Prenatal activation of microglia induces delayed impairment of glutamatergic synaptic function. PLoS One. 2008;3 (7 ). doi: 10.1371/journal.pone.0002595 18612411
