PMID- 10400919
OWN - NLM
STAT- MEDLINE
DCOM- 19991026
LR  - 20190706
IS  - 1524-4571 (Electronic)
IS  - 0009-7330 (Linking)
VI  - 85
IP  - 1
DP  - 1999 Jul 9
TI  - Distribution and prevalence of hyperpolarization-activated cation channel (HCN)
      mRNA expression in cardiac tissues.
PG  - e1-6
AB  - HCN cation channel mRNA expression was determined in the rabbit heart and
      neonatal and adult rat ventricle using RNase protection assays. In the rabbit SA 
      node, the dominant HCN transcript is HCN4, representing >81% of the total HCN
      message. HCN1 is also expressed, representing >18% of the total HCN mRNA. Rabbit 
      Purkinje fibers contained almost equal amounts of HCN1 and HCN4 transcripts with 
      low levels of HCN2, whereas rabbit ventricle contained predominantly HCN2. The SA
      node contained 25 times the total HCN message of Purkinje fibers and 140 times
      the total HCN message of ventricle. No reports of hyperpolarization-activated
      current (If) exist in rabbit Purkinje fibers, and we could not record If in
      rabbit ventricular myocytes. To investigate the possible role of isoform
      switching in determining the voltage dependence of If, we determined the
      prevalence of HCN isoforms in neonatal and adult rat ventricle. We had previously
      determined the threshold for activation of If to be approximately -70 mV in
      neonatal rat ventricle and -113 mV in adult rat ventricle. In both neonatal and
      adult rat ventricle, only HCN2 and HCN4 transcripts are present. The ratio of
      HCN2 to HCN4 is approximately 5:1 in the neonate and 13:1 in the adult. Taken
      together, these results suggest that different cardiac regions express different 
      isoforms of the HCN family. The HCN1 and HCN4 isoforms are most closely
      associated with a depolarized threshold for If activation, whereas the HCN2
      isoform is associated with a more negative activation curve.
FAU - Shi, W
AU  - Shi W
AD  - Institute of Molecular Cardiology, State University of New York at Stony Brook,
      NY 11794-8661, USA.
FAU - Wymore, R
AU  - Wymore R
FAU - Yu, H
AU  - Yu H
FAU - Wu, J
AU  - Wu J
FAU - Wymore, R T
AU  - Wymore RT
FAU - Pan, Z
AU  - Pan Z
FAU - Robinson, R B
AU  - Robinson RB
FAU - Dixon, J E
AU  - Dixon JE
FAU - McKinnon, D
AU  - McKinnon D
FAU - Cohen, I S
AU  - Cohen IS
LA  - eng
GR  - HL20558/HL/NHLBI NIH HHS/United States
GR  - HL28958/HL/NHLBI NIH HHS/United States
GR  - NS29755/NS/NINDS NIH HHS/United States
GR  - etc.
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Circ Res
JT  - Circulation research
JID - 0047103
RN  - 0 (Ion Channels)
RN  - 0 (Protein Isoforms)
RN  - 0 (RNA, Messenger)
SB  - IM
MH  - Animals
MH  - Animals, Newborn
MH  - Electrophysiology
MH  - Heart Ventricles/*metabolism
MH  - Ion Channels/genetics/*metabolism
MH  - Protein Isoforms/genetics/metabolism
MH  - RNA, Messenger/genetics
MH  - Rabbits
MH  - Rats
MH  - Sinoatrial Node/*metabolism/physiology
MH  - Ventricular Function
EDAT- 1999/07/13 00:00
MHDA- 1999/07/13 00:01
CRDT- 1999/07/13 00:00
PHST- 1999/07/13 00:00 [pubmed]
PHST- 1999/07/13 00:01 [medline]
PHST- 1999/07/13 00:00 [entrez]
AID - 10.1161/01.res.85.1.e1 [doi]
PST - ppublish
SO  - Circ Res. 1999 Jul 9;85(1):e1-6. doi: 10.1161/01.res.85.1.e1.