EFFECTS OF PROPRANOLOL ON PRESSOR RESPONSE TO NOXIOUS STIMULI IN HYPERTENSIVE PATIENTS

Propranolol was administered orally in doses up to 150 mg. daily to 11 hospitalized patients with hypertension of mild to moderate severity. Although the compound significantly lowered the basal pulse rate and the chronotropic response to pressor stimuli, it failed to affect either the basal blood pressure or the pressor response to cold and ischemic pain. Urinary catecholamine excretion in response to the stimuli similarly was unaffected although plasma free fatty acid mobilization tended to be dampened. When contolled for responses to hospitalization and placebo, the effect of propranolol on ambulatory blood pressures was negligible. The failure to influence reactivity of the blood pressure to noxious stimuli, despite blockage of beta adrenergic receptors by propranolol, is interpreted as indicating persistence and probable potentiation of alpha adrenergic receptors and peripheral vasoconstrictive mechanisms. © 1968.