title: Determinants of platelet intracellular free calcium in essential hypertension and effect of stimulation by arginine vasopressin.
abstract: The aim of this study was to determine platelet intracellular free calcium with respect to age, sex, race, and agonist stimulation in patients with essential hypertension compared with normotensive subjects. Intracellular free calcium was measured, using Fura-2-AM, in 42 normotensive and 52 patients with untreated essential hypertension. Of these, 22 pairs were age, sex, and race matched. The intracellular free calcium response to agonist stimulation was measured in the presence of 1 mumol/L arginine vasopressin (AVP). Intracellular calcium was significantly raised in patients with hypertension in both the matched and unmatched groups with values (means +/- SEM) in the matched group of 68.4 +/- 2.6 nmol/L for the hypertensives and 60.2 +/- 2.1 nmol/L for the normotensives (n = 22; P < or = .02) and in the unmatched group of 63.3 +/- 1.8 nmol/L (n = 52) and 57.6 +/- 1.4 nmol/L (n = 42, P < or = .02), respectively. There was no sex difference but intracellular calcium was significantly lower in black hypertensives compared with white hypertensives (P < .005). A significant correlation with blood pressure was only observed in the combined normotensive and hypertensive group (r = 0.23; P = .030). There was no significant correlation with age in any group (even when excluding the black individuals), but in the hypertensive group there was a significant correlation with serum cholesterol (r = 0.34, P = .02; n = 46).(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Department of Physiological Medicine, St. George's Hospital Medical School, London, England.
authors: M A
authors: MA
authors: Miller
authors: G A
authors: GA
authors: Sagnella
authors: N D
authors: ND
authors: Markandu
authors: G A
authors: GA
authors: MacGregor
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism; D001127:Arginine Vasopressin / Q000494:pharmacology*; D044466:Asian People; D044383:Black People; D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000097:blood*; D005260:Female; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000208:ethnology; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D044465:White People
chemical_list: D005456:Fluorescent Dyes; C049925:fura-2-am; D001127:Arginine Vasopressin; D002118:Calcium; D016257:Fura-2