Effect of dorsal periaqueductal grey lesion on baroreflex and cardiovascular response to air-jet stress

Abstract

Certain areas within the periaqueductal grey (PAG) have been implicated in cardiovascular regulation. The influence of excitotoxic lesions of the caudal dorsal periaqueductal grey on the baroreceptor-heart rate reflex and the cardiovascular response to air-jet stress was examined in awake Wistar-Kyoto rats. Pressor (11 ± 2 mmHg) and tachycardic (25 ± 4 beats/min) responses to air-jet were not influenced by the lesion. Similarly, the resting MAP and HR were unchanged. However, the gain of the baroreflex was reduced from -3.9 ± 0.1 to -2.8 ± 0.3 beats/min per mmHg and the upper threshold was increased from 120 ± 5 to 135 ± 7 mmHg in the lesioned group. These observations suggest that although ..