Response of venous membrane potentials to calcium blockade in spontaneous hypertension.

Abstract

SUMMARY In situ measurements of transmembrane potential (Em) were made in vascular smooth muscle cells (VSM) of small (250-500 /xm) veins in an externalized mesenteric loop in 13-to 15-weekold anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto normotensive controls (WKY). Following local chemical sympathetic denervation with 6-hydroxydopamine, VSM in SHR hyperpolarized from a control value of -37 ± 0.6 to -51 ± 0.4 mV while E ra in WKY remained at -5 0 ± 0.