The role of cytoplasmic calcium in the regulation of the resting potential in the pulmonary veins myocardium in rats and mice.
We have demonstrated the phenomenon of Са(2+)-induced hyperpolarization in the myocardium of pulmonary veins (PVs) in rats. An increase in cytoplasmic calcium [Са(2+)] i was shown to shift the resting potential (RP) in the PVs towards more negative values. The compounds inducing an increase in [Са(2+)] i , such as isoproterenol (10 μM), caffeine (5 mM), and ryanodine (0.01 μM), caused hyperpolarization of 10 ± 2, 9 ± 1.3, and 4.1 ± 2 mV, respectively. The inhibition of calcium-dependent potassium currents (IKCa) did not change RP of PVs under the control conditions and did not affect the Са(2+)-induced hyperpolarization.
Russian Cardiologic Research and Manufacturing Complex, Ministry of Health of the Russian Federation, Moscow, Russia. vm-karimova@mail.ru.
V M
VM
Karimova
Russian Cardiologic Research and Manufacturing Complex, Ministry of Health of the Russian Federation, Moscow, Russia.
V S
VS
Kuzmin
Russian Cardiologic Research and Manufacturing Complex, Ministry of Health of the Russian Federation, Moscow, Russia.
N A
NA
Undrovinas
Russian Cardiologic Research and Manufacturing Complex, Ministry of Health of the Russian Federation, Moscow, Russia.
L V
LV
Rozenshtraukh
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009206:Myocardium / Q000378:metabolism*; D011667:Pulmonary Veins / Q000378:metabolism*; D051381:Rats; D012433:Ryanodine / Q000494:pharmacology
D012433:Ryanodine; D002110:Caffeine; D007545:Isoproterenol; D002118:Calcium