title: The regulation of L-type Ca2+ currents in rat cardiac myocytes.
abstract: The regulation of L-type Ca2+ current in isolated rat cardiac cells was studied using the perforated patch-clamp technique. A dual effect of the cAMP-dependent phosphorylation activator, isoproterenol, at different holding potentials (V(h)) was shown. The currents increased at V(h) = -50 mV and decreased at V(h) = -30 mV. A dihydropyridine agonist, BAY K 8644, and isoproterenol had an additive effect on the activation of Ca2+ channels at holding potentials close to the resting potential. The additivity was disturbed at more positive V(h). The activating effect of BAY K 8644 did not virtually change in the presence of a protein kinase blocker, H8, and a phosphatase activator, acetylcholine. The results were interpreted within the framework of a two-site phosphorylation model with two independent pathways of Ca2+ current regulation.
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region.
authors.forename: N I
authors.initials: NI
authors.lastname: Markevich
authors.forename: A F
authors.initials: AF
authors.lastname: Korystova
authors.forename: A S
authors.initials: AS
authors.lastname: Grichenko
authors.forename: D A
authors.initials: DA
authors.lastname: Lankina
authors.forename: Y M
authors.initials: YM
authors.lastname: Kokoz
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002120:Calcium Channel Agonists / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000502:physiology*; D002478:Cells, Cultured; D004553:Electric Conductivity; D004594:Electrophysiology; D007545:Isoproterenol / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D007700:Kinetics; D009206:Myocardium / Q000166:cytology; D010766:Phosphorylation; D051381:Rats
chemical_list: D000318:Adrenergic beta-Agonists; D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D007546:Isoquinolines; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; C053177:N-(2-(methylamino)ethyl)-5-isoquinolinesulfonamide; D007545:Isoproterenol; D000109:Acetylcholine