The purpose of the study is to explore the hypothesis that subsets of black patients with high blood pressure have one or more functional polymorphism of the 3 alpha adrenergic receptor (A2AR) genes and that combination of these mutations increase the overall prevalence of thrombotic stroke, hyperinsulinemia, hypertriglyceridemia, or salt sensitivity. The investigators plan to identify discrete subsets of black patients with essential hypertension compare them to well defined normotensives and determine if polymorphisms of the C10 and C2 A2AR genes are associated with a particular phenotypic expression in American blacks with and without hypertension. They have identified a polymorphism of the C10 A2AR gene which is associated with hypertension and a polymorphism in the C2AR gene associated with hyperinsulinemia. There are four specific aims. First to identify a discrete subset of black men and women with and without hypertension with polymorphisms of the A2AR genes encoded by chromosome 10 and 2. Second, to determine if specific polymorphisms of C10A2AR are associated with differences in the expression of platelet A2AR number, binding or aggregation; or decrease baroreceptor activity. Third to determine if polymorphisms of the chromosome 2 A2AR mediate hyperinsulinemia and adipocyte lipolysis in blacks. Finally to identify the A2AR encoding tissue-specific expression of the A2AR in the kidney and determine if genetic polymorphism of the receptor are associated with decreased natriuresis in black patients.
