[Spontaneous transient outward currents in smooth muscle cells of the rat tail artery].
Spontaneous transient outward currents (STOCs) were studied in the rat tail artery smooth muscle cells using standard patch-clamp recording techniques in the whole-cell configuration. STOCs evoked by membrane depolarization from -30 to 20 mV varied in size from 50 to 1000 pA, their amplitude increased with membrane depolarization. These currents were inhibited by 1 mM TEA+. Both the frequency and the transferred charge (Q) were decreased in the absence of the extracellular Ca2+ or in the presence of the selective blocker of voltage-gated L-type Ca2+ channels nifedipine. Application of caffeine at 1 mM increased both Q and the frequency of STOCs generation. These results indicate that STOCs are carried by large conductance Ca(2+)-dependent K+ channels and Ca2+ influx plays an important role in their activation.
Reznikov
V L
VL
A. A. Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kiev.
Shuba
M F
MF
D000818:Animals; D001158:Arteries / Q000166:cytology; D002110:Caffeine / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000502:physiology*; D004553:Electric Conductivity; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009543:Nifedipine / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D013623:Tail / Q000098:blood supply*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D013757:Tetraethylammonium Compounds; D002110:Caffeine; D009543:Nifedipine