PMID- 10199853
OWN - NLM
STAT- MEDLINE
DCOM- 19990513
LR  - 20191103
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 276
IP  - 4 Pt 2
DP  - 1999 Apr
TI  - Estradiol modulates vascular response to melatonin in rat caudal artery.
PG  - H1281-8
AB  - The purpose of this study was to determine whether estrogen modulates the
      function of vascular melatonin receptors. We used the rat caudal artery and found
      that the contractile effects of melatonin were influenced by the estrous cycle,
      ovariectomy, and estrogen replacement. In arterial ring segments isolated from
      female rats, melatonin potentiated, in a concentration-dependent manner,
      contractions produced either by adrenergic nerve stimulation or by phenylephrine.
      Constrictor responses to melatonin were smaller in arteries from female rats in
      proestrus compared with other stages of the estrous cycle and after ovariectomy. 
      Administration of 17beta-estradiol to ovariectomized female rats also resulted in
      decreased constriction of isolated arteries to melatonin; however, in vitro
      addition of 17beta-estradiol (10(-7) M) had no effect. In the caudal artery,
      melatonin appears to act on two receptor subtypes that mediate contraction and
      relaxation, respectively. The selective melatonin MT2-receptor antagonist
      4-phenyl-2-propionamidotetraline (4P-PDOT) enhanced constrictor responses to
      melatonin in arterial segments from intact female rats, consistent with the
      inhibition of MT2 receptor-mediated relaxation. In contrast, 4P-PDOT had no
      significant effect in arteries from ovariectomized female rats. However, when
      estradiol was replaced in vivo, the effect of 4P-PDOT on melatonin responses was 
      restored. Thus circulating estradiol appears to enhance MT2 melatonin-receptor
      function in the thermoregulatory caudal artery of the female rat resulting in
      increased vasodilatation in response to melatonin.
FAU - Doolen, S
AU  - Doolen S
AD  - Department of Pharmacology, College of Medicine, University of California,
      Irvine, California 92697-4625, USA.
FAU - Krause, D N
AU  - Krause DN
FAU - Duckles, S P
AU  - Duckles SP
LA  - eng
GR  - HL-50775/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 0 (4-phenyl-2-propionamidotetraline)
RN  - 0 (Receptors, Cell Surface)
RN  - 0 (Receptors, Cytoplasmic and Nuclear)
RN  - 0 (Receptors, Melatonin)
RN  - 0 (Tetrahydronaphthalenes)
RN  - 4TI98Z838E (Estradiol)
RN  - JL5DK93RCL (Melatonin)
SB  - IM
MH  - Adrenergic Fibers/physiology
MH  - Animals
MH  - Arteries/drug effects/innervation
MH  - Electric Stimulation
MH  - Estradiol/*pharmacology
MH  - Estrus/physiology
MH  - Female
MH  - In Vitro Techniques
MH  - Melatonin/*pharmacology
MH  - Ovariectomy
MH  - Rats
MH  - Rats, Inbred F344
MH  - Receptors, Cell Surface/antagonists & inhibitors
MH  - Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
MH  - Receptors, Melatonin
MH  - Tail/*blood supply
MH  - Tetrahydronaphthalenes/pharmacology
MH  - Time Factors
EDAT- 1999/04/13 00:00
MHDA- 1999/04/13 00:01
CRDT- 1999/04/13 00:00
PHST- 1999/04/13 00:00 [pubmed]
PHST- 1999/04/13 00:01 [medline]
PHST- 1999/04/13 00:00 [entrez]
AID - 10.1152/ajpheart.1999.276.4.h1281 [doi]
PST - ppublish
SO  - Am J Physiol. 1999 Apr;276(4 Pt 2):H1281-8. doi:
      10.1152/ajpheart.1999.276.4.h1281.