Abstract
In erythrocyte membrane of SHRSP, Ca influx and release rates were accelerated from hypertension developing stage before Ca-ATPase activities were lowered. These changes were preceded by the onset of hypertension. In cytoplasmic membrane the stractural changes would play more important role than regulation mechanism of Ca influx and Ca release through Ca-ATPase. This present results do not conflict with the Ca effect on tonus of isolated rat aortic strips
