硝普钠对SHRsp阻力血管平滑肌钙激活钾通道的影响

目的 观察硝基类扩血管药硝普钠（ｓｏｄｉｎｍ ｎｉｔｒｏｐｒｕｓｓｉｄｅｍ,ＳＮＰ）对卒中易感型自发高血压大鼠（ＳＨＲｓｐ）及其正常血压对照ＷＫＹ大鼠肠系膜动脉Ａ４－Ａ５分支阻力血管平滑肌钙激活钾通道（ＫＣａ）的作用。方法 用细胞贴附式膜片箝（ｏａｔｃｈ ｃｌａｍｐ）技术。结果 发现ＳＮＰ可激活ＳＨＲｓｐ与ＷＫＹ阻力血管平滑肌ＫＣａ。在同等剂量（１ ｎｍｏｌ／Ｌ）ＳＮＰ作用下,被激活的ＳＨＲｓｐ

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.