The grant has been ongoing since September 1983. The original study had as its purpose to ascertain similarities and differences in the etiology of hypertension for Blacks and whites and to identify those biobehavioral factors contributing to the excess risk for hypertension among Blacks. Myocardial, blood pressure, and renal responses (sodium and potassium handling) to laboratory and naturalistic stressors were evaluated in young adult normotensive or marginally hypertensive Black and white men. Behavioral stressors included competitive, reaction time tasks (active coping) as well as more passive coping conditions. Data were collected on family history of hypertension, family social class background, Type A behavior, propensity for anger and hostility, and coping style. The role of the sympathetic nervous system in mediating these effects was assessed by the use of beta-adrenergic antagonists.