[Effect of SNP on KCa of resistance vascular smooth muscle cell membrane in SHRsp].
OBJECTIVE
To investigate the effect of sodium nitroprusside (SNP) on calcium activated potassium channels (KCa) of mesenteric arterial A4-A5 branches resistence vascular smooth muscle cell membrane in Stroke-prone Spontaneously Hypertensive Rats (SHRsp) and its normotensive control WKY rats.


METHODS
Cell-attached patch clamp technique was used.


RESULTS
It was found that SNP could activate the KCa of the resistance vascular smooth muscle in both SHRsp and WKY. Under the same dose of SNP (1 nmol/L), the conductance and channel current amplitude etc. of the activated KCa in SHRsp were smaller than that in WKY rats. Given the same dose of 8-Br-cGMP (10 mumol/L), the cGMP activation of SHRsp KCa was less potentiated than that of WKY, appeared very similar to SNP/NO activation.


CONCLUSIONS
The results suggested the KCa of hypertensive resistance vascular smooth muscle membrane appearing weaker response to relaxing factor EDRF/NO.
Zheng
Y
Y
Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005.
Wang
G
G
Bao
G
G
Qu
J
J
Wang
X
X
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002469:Cell Separation; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000473:pathology; D009131:Muscle, Smooth, Vascular / Q000473:pathology*; D009599:Nitroprusside / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014665:Vasodilator Agents / Q000494:pharmacology*
D015221:Potassium Channels; D014665:Vasodilator Agents; D009599:Nitroprusside; D002118:Calcium