Platelet 5-HT content and uptake in essential hypertension role of endogenous digitalis-like factors and plasma cholesterol

A decrease in platelet 5-HT content linked to partial inhibition of 5-HT uptake has been described in essential hypertension. Transport of 5-HT through platelet membrane is dependent upon transmembranal Naand Kgradients. It is inhibited by Na,K-ATPase inhibitors such as ouabain and endogenous digitalis-like compounds isolated from hemodiafiltrate. The activity of such compounds in plasma extracts, measured by inhibition of Na,K-ATPase or ouabain binding to human erythrocytes, and platelet 5-HT content were determined in parallel in essential hypertensive patients. Significant negative correlations were observed between these parameters in men, suggesting that high levels of digitalis-like compounds can affect platelet 5-HT content.