Central amygdaloid lesions attenuate cardiovascular responses to acute stress in rats with borderline hypertension.

The present study tested the hypothesis that lesions of the central nucleus of the amygdala (CeA) would reduce the cardiovascular responses to acute stress in a rodent model that is genetically predisposed toward hypertension. Male borderline hypertensive rats (BHR) were given bilateral electrolytic lesions directed to destroy the CeA or were subjected to a sham procedure. Direct measurements of blood pressure and heart rate were recorded during rest, during 10 min of acute stress, and for 10 min following stress. Analysis of the data revealed that BHR with CeA lesions had a significant attenuation of the stress-induced pressor response compared to sham-operated subjects. Behavioral measures taken in an open field chamber before and after lesions revealed no differences in numbers of squares crossed or rearings. These results suggest that the CeA is an important neural structure in mediating cardiovascular responses to acute stress in a model susceptible to environmentally induced hypertension.