Oxygen-derived free radicals contribute to baroreceptor dysfunction in atherosclerotic rabbits

Abstract

The goal of the present study was to determine whether oxygen-derived free radicals contribute to baroreceptor dysfunction in atherosclerosis. Baroreceptor activity was measured from the carotid sinus nerve during pressure ramps in isolated carotid sinuses of anesthetized rabbits. Rabbits fed a 0.5% to 1.0% cholesterol diet for 7.9±0.4 months (mean±SE; range, 5.5 to 10) developed atherosclerotic lesions in the carotid sinuses. Maximum baroreceptor activity measured at 140 mm Hg and the slope of the pressure- activity curve were reduced in atherosclerotic (n=15) compared with normal (n=13) rabbits (425±34 versus 721±30 spikes per second and 6.2±0.6 versus 10.8±0.8 spikes per second per mm Hg, respectively, P