The Characteristics And Regulations Of Calcium-Activated Potassium Channel In Resistance Vascular Smooth Muscle Cells During Hypertension

The peripheral resistance of circulation is increased during hypertension, that is induced by resistance vessel smooth muscle inordinate contraction. Intracellular Ca²⁺ is important to initiate vessel smooth muscle contraction, but the calcium-activated potassium channel, as the direct and potent negative feedback mechanism to control the intracellular Ca²⁺ concentration, plays a more important role in regulation of membrane potential and vascular smooth muscle tone. Untill now there is no any evidence indicated whether this negative feedback might be varied in resistance vascular smooth muscle cells during hypertension, The puroose of the present study was by using patch clamp technique to systematically investigate the mechanism by which calcium-activated potassium channel in resistance vascular smooth muscle cells involved in hypertention.Male adult Stroke-prone spontaneously hypertensive rats (SHRsp) and normotensive wistar-kyoto rats (WKY) were selected as experimental animals, blood pressure being 170+16.3mmHg and 100+10.5mmHg respectively. Single smooth muscle cells of mesenteric A₄ , A₅ branches resistance vessel from SHRsp and WKY rats weredispersed enzymatically . Channel activity was studied by using the patch clamp techniques in whole-cell, cell-attached, and inside-out configurations.The results followed:1. The changes of resting membrane potential and potassium current...