Effects of propranolol on cardiovascular and neuroendocrine responses to mental arithmetic in type A men.

ABSTRACT

beta-Adrenergic hyperreactivity has been proposed as a pathogenic mechanism of increased coronary risk in Type A individuals. This study compared the effects of propranolol, diazepam, and placebo on cardiovascular and neuroendocrine responses to a stressful cognitive task in six young Type A males. Although diazepam did not differ from placebo, propranolol attenuated heart rate and norepinephrine responses and enhanced cortisol responses to the task. Findings suggest that propranolol has reciprocal effects on the norepinephrine and cortisol components of the "fight-flight" response. Possible central nervous system mechanisms are described.