EFFECTS OF CAPTOPRIL AND PROPRANOLOL ON COGNITIVE FUNCTION AND CEREBRAL BLOOD-FLOW IN AGED HYPERTENSIVE RATS

Chronic hypertension has been reported to produce adverse cognitive ef fects in elderly individuals, perhaps by altering central nervous syst em hemodynamics. The beneficial or adverse effects of antihypertensive drugs on these processes are not well understood. We examined the eff ects of catopril (90 mg/kg/day) and propranolol (80 mg/kg/day) on cogn itive function and brain blood flow in hypertensive and normotensive r ats. Cognitive function was assessed by the Morris water maze, and reg ional brain blood flow was measured by the [C-14]iodoantipyrine method . Nineteen-month-old propranolol treated hypertensive mts exhibited po orer performance (p < .05) than control rats and had lower brain blood flows, particularly in white matter regions (p < .01). Captopril-trea ted hypertensive rats did not differ significantly from control rats w ith regard to either cognitive performance or brain bloodflow. In the normotensive rats, there were no effects of either drug on cognitive p erformance or brain blood flow. Thus, blood pressure reduction by prop ranolol but not captopril has an adverse effect on cognitive function and brain blood flow in hypertensive rats.