Increased platelet cytosolic free calcium concentration in essential hypertension.
Cytosolic free calcium concentration [Ca2+] was studied in platelets of hypertensive patients with the use of the fluorescent indicator Quin 2/AM. Cytosolic free Ca2+ was significantly higher in platelets of hypertensive patients than in those of normotensive subjects (241 +/- 9 versus 192 +/- 7 nmol/l, n = 58 and 57, respectively P less than 0.001). When all 115 subjects were included, there was a significant correlation between cytosolic free Ca2+ and systolic or diastolic blood pressure (r = 0.262, P less than 0.0025 and r = 0.251, P less than 0.0025, respectively). Intracellular Quin 2 concentration was measured to evaluate the formaldehyde production (a product of Quin 2/AM hydrolysis which has been described as reducing the adenosine triphosphate (ATP) production). The Quin 2 concentrations in platelets of the two groups of subjects were observed to be similar (0.41 +/- 0.03 versus 0.38 +/- 0.03 mmol/l, n = 8 and 7 for hypertensives and normotensives, respectively). The effects of prostaglandin E1 (PGE1), an adenylate cyclase stimulator, on cytosolic free Ca2+ were studied. The presence of 10(-7) mol/l PGE1 lowered the Ca2+ in platelets of hypertensive patients only, suppressing the difference between the two groups.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000527:Alprostadil / Q000494:pharmacology; D001792:Blood Platelets / Q000648:ultrastructure*; D001794:Blood Pressure; D002118:Calcium / Q000032:analysis*; D003600:Cytosol / Q000032:analysis*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D013050:Spectrometry, Fluorescence
D000527:Alprostadil; D002118:Calcium