Platelet activity and salt sensitivity in the pathogenesis of systemic (essential) hypertension in black Africans.
Black essential hypertensive patients with a mean arterial pressure of 125 +/- 3 mm Hg (mean +/- SEM), and age and sex matched normotensive subjects with a mean arterial pressure of 89 +/- 2 mm Hg were studied under baseline conditions, after five days of salt restriction and after five days of salt loading. Salt sensitivity was defined as an increase of mean blood pressure exceeding 5% when progressing from low to high sodium intake. In vitro platelet responsiveness was assessed by aggregometry, and in vitro platelet activity by estimation of beta-thromboglobulin (BTG) in plasma and thromboxane B2 (TXB2) excretion rate. Salt sensitivity was present in 66% of hypertensive and 55% of the normotensive subjects. An increased platelet aggregability to ADP (25%), to epinephrine (34%) and to collagen (12%) was found in parallel with an increased in vivo platelet activity (BTG increased by 55% and TXB2 by 18%) in the hypertensives. All changes were significantly exaggerated in the salt sensitive as compared to salt resistant hypertensive patients.
Somova
L
L
Department of Physiology, University of Zimbabwe, Mount Pleasant, Harare.
Mufunda
J
J
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D044383:Black People; D001794:Blood Pressure / Q000187:drug effects; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D015539:Platelet Activation; D010974:Platelet Aggregation / Q000187:drug effects; D017673:Sodium Chloride, Dietary / Q000009:adverse effects*; D013929:Thromboxane B2 / Q000652:urine; D015030:Zimbabwe; D001620:beta-Thromboglobulin / Q000378:metabolism
D017673:Sodium Chloride, Dietary; D001620:beta-Thromboglobulin; D013929:Thromboxane B2; D000244:Adenosine Diphosphate