Patterns of adrenergic receptors and adrenergic agonists underlying cardiovascular responses to a psychological challenge.

Numerous physiological and biochemical factors contribute to the dynamic regulation of the cardiovascular system. This study used a cluster analytic statistical technique to discern patterns of adrenergic receptors and adrenergic agonists underlying cardiovascular responses to a laboratory challenge. Fifty hypertensive and normotensive black and white individuals had their beta- and alpha-adrenergic receptor sensitivity determined through agonist infusions. Norepinephrine, epinephrine, blood pressure, and heart rate responses to a standardized mental arithmetic task were also obtained. The cluster analysis identified four subgroups of individuals having distinct patterns of receptor and neurohormonal regulation of end-organ responses. In general, the data indicated that end-organ cardiovascular responses are, in part determined by the sensitivity of adrenergic receptors and the accompanying catecholamine responses. The findings also suggest that for some individuals nonadrenergic factors play a more dominant role than adrenergic mechanisms in determining cardiovascular pressor responses.