Increases in vascular alpha 1-adrenoceptor affinity and PI turnover in DOCA-salt hypertensive rats.

The pD2 value for norepinephrine and the pA2 value for prazosin in mesenteric larger resistance vessels from deoxycorticosterone acetate (DOCA)-salt hypertensive rats were significantly higher than the values of normotensive rats, suggesting that alpha 1-adrenoceptors have a higher affinity in hypertensive rats. The accumulation of [3H]inositol monophosphate induced by norepinephrine was significantly greater in the mesenteric artery from hypertensive rats than in the mesenteric artery from normotensive rats. These results suggest that the enhanced phosphatidylinositol turnover seen in DOCA-salt hypertensive rats may contribute, at least partly, to the higher affinity of alpha 1-adrenoceptors.