Catecholamines and cardiovascular function in aging.

When perspectives from studies that range from measurements of the stress response in intact humans to measurements of subcellular biochemistry in animal models are integrated, a diminished responsiveness to beta-adrenergic modulation is among the most notable changes that occur in the cardiovascular system with advancing age. In contrast, alpha-adrenergic responsiveness, of the vasculature at least, appears to remain intact. It is noteworthy that a diminished effectiveness of some aspects of autonomic modulation has been demonstrated in many other body organs as well. The precise molecular mechanisms for the age effects remain to be explained (as do the precise mechanisms of catecholamine modulation of cell function per se), and these mechanisms need not be the same from one tissue to the next, or from one age period to another within the same tissue. An elucidation of these mechanisms that result in a diminution in the effectiveness of beta-adrenergic modulation of cardiovascular function with aging and a determination of whether this can in part be reversed or prevented by changes in life-style (for example, physical activity or modification of nutrition) require additional investigation.