[The role of voltage gated K(+) channels in the modulation of resting membrane potential of myocytes isolated from rat resistance arteries].
K+ current which take part in the controlling of membrane potential in myocytes isolated from rat resistance mesenteric arteries have been investigated using conventional patch clamp method. The mean resting potential of myocytes was--37 mV. Charybdotoxin (200 nM)--selective blocker of large conductance Ca(2+)-activated K+ (KCa) channels--inhibited transmembrane outward K+ current by 60%. 1 mM of tetraethylammonium inhibited outward K+ current same as 200 nM of charybdotoxin, also it inhibited spontaneous spike-like hyperpolarizations and did not affect the membrane potential. Transmembrane current had a 4 aminopyridine (4-AP) sensitive component of delayed rectifier current (KV). Addition of 5 mM of 4-AP evoked membrane depolarization with mean significance of 12.0 +/- 1.5 mV in 5 from 7 single myocytes which had resting potential in the range of -50 ... -35 mV. The obtained results suggest that large conductance KCa channels do not determine the resting potential, but may serve as a negative feedback mechanism at the considerable membrane depolarization. In contrast, 4-AP sensitive KV current take part in the controlling of the resting membrane potential of single myocytes from rat resistance mesenteric arteries.
Harhun
M I
MI
A. A. Bogomolet Institute of Physiology, National Academy of Sciences of Ukraine, Kiev.
Belevich
A E
AE
Povstyan
O V
OV
Shuba
M F
MF
D000818:Animals; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008638:Mesenteric Arteries / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000295:instrumentation; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*
D015221:Potassium Channels
Rol' potentsialkerovannykh kaliievykh kanaliv u formuvanni membrannoho potentsialu spokoiu miotsytiv rezystyvnykh arteriï shchura.