[Study of NO action on calcium-activated potassium channel of the rat artery smooth muscle cells].
Nitric oxide (NO) released from the endothelium or from NO-donors is a powerful vasodilator. Its effect is mediated partly by vascular smooth muscle high conductance calcium-activated potassium (Kca) channels. Contradictory data exist as to whether NO activated the KCa channel directly or indirectly via protein kinase G (PKG). Thus the hypothesis that NO-donors can activate the KCa directly was investigated using the patch-clamp technique and freshly isolated smooth muscle cells from the rat tail artery. In inside-out experiments, the activity of KCa-channels was increased 1.61 +/- 0.20-fold (n = 10) by 10 microM SNP and 1.45 +/- 0.17-fold (n = 8) by 10 microM SNAP. However, the activity of KCa channels was also increased 1.46 +/- 0.20-fold (n = 8) by addition of the experimental bath solution. Thus these results suggest that NO released from NO-donors cannot activate KCa channel of the rat tail artery smooth muscle cells directly.
Gribkova
I V
IV
Institute of Experimental o Cardiology, 15a Cherepkovskaya St., 121552, Moscow, Russia.
Schubert
R
R
Serebriakov
V N
VN
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism / Q000502:physiology*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011921:Rats, Inbred WKY; D013623:Tail / Q000098:blood supply; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D020030:Nitric Oxide Donors; D024681:Potassium Channels, Calcium-Activated; D009569:Nitric Oxide