title: [Direct evidences of calcium traffic through pacemaker channel].
abstract: Recently, it was shown that pacemaker f/HCN channel might be permeable not only for Na+ and K+, but also for calcium ions. Pacemaker channel HCN2 was expressed in ovarian cell culture of Chinese hamster. In the patch clamp experiments the calcium current with low amplitude 0.06±-0.87 nA and open probability 0.48% (±3.02 at -110 mV, n = 6, Ca2+ 2 mmol) was measured. HCN2-Ca2+ current significantly activated with cyclic adenosinemonophosphate by increasing of open probability and inhibited by specific If-blocker ivabradine. The calcium ion current was also shown in f-channels of neonatal rats ventriculocytes. Thus, the calcium ions conduction through HCN2 and native f-channel at physiological concentrations of extracellular fluid and physiological membrane potentials of cardiomyocytes was demonstrated.
authors.forename: N Sh
authors.initials: NSh
authors.lastname: Zagidullin
authors.forename: V N
authors.initials: VN
authors.lastname: Tsygan
authors.forename: I Sh
authors.initials: ISh
authors.lastname: Sagitov
authors.forename: Sh Z
authors.initials: ShZ
authors.lastname: Zagidullin
mesh_terms: D000200:Action Potentials; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000494:pharmacology; D006352:Heart Ventricles / Q000166:cytology; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017136:Ion Transport; D000077550:Ivabradine; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D051381:Rats
chemical_list: D001552:Benzazepines; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D000077550:Ivabradine; D000242:Cyclic AMP; D002118:Calcium