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 Na+ and K+ gradients. 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. In addition, in essential hypertensive patients, total plasma cholesterol was inversely related to both platelet 5-HT content (n = 15, r = -0.594, P less than 0.02) and maximal velocity of 5-HT uptake (n = 15, r = -0.717, P less than 0.003). In normotensive control subjects, no variation of platelet 5-HT content with cholesterol was observed. This suggests that the platelet membranes of essential hypertensive patients are more sensitive to increases in plasma cholesterol than those of normotensive subjects.
Guicheney
P
P
Département de Pharmacologie, INSERM U6, Hôpital Necker, Paris, France.
Devynck
M A
MA
Cloix
J F
JF
Pernollet
M G
MG
Grichois
M L
ML
Meyer
P
P
D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D002298:Cardenolides; D002784:Cholesterol / Q000097:blood*; D004077:Digoxin; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010042:Ouabain / Q000378:metabolism; D012503:Saponins; D012701:Serotonin / Q000097:blood*; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood
D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D012701:Serotonin; D010042:Ouabain; D004077:Digoxin; D002784:Cholesterol; D000254:Sodium-Potassium-Exchanging ATPase