Biochemical abnormalities of venous plasma membrane fraction isolated from spontaneously hypertensive rats.

Alkaline phosphatase activity and Ca2+ accumulation were examined in the isolated plasma membrane fractions from small arteries and veins of spontaneously hypertensive (SHR) and normotensive (WKY). Increased Ca2+ binding by plasma membrane fractions from veins, decreased ATP-dependent Ca2+ accumulation by those from arteries and increased alkaline phosphatase activity in both fractions from SHR were observed. We conclude that biochemical abnormalities in vascular smooth muscle cell membrane cannot be explained solely as adaptive changes induced by elevated blood pressure.