Effect of dorsal periaqueductal grey lesion on baroreflex and cardiovascular response to air-jet stress.
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 the caudal dorsal PAG does not appear to exert a tonic influence on vasomotor tone or mediate the air-jet response, it may provide a facilitatory input to the baroreceptor-heart rate reflex.
Lam
W
W
University of Melbourne, Department of Medicine, Austin Hospital, Heidelberg, Victoria, Australia.
Louis
W J
WJ
Verberne
A J
AJ
D000818:Animals; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D008297:Male; D016202:N-Methylaspartate / Q000633:toxicity; D010487:Periaqueductal Gray / Q000033:anatomy & histology / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D011921:Rats, Inbred WKY; D013238:Stereotaxic Techniques; D013312:Stress, Physiological / Q000503:physiopathology*
D016202:N-Methylaspartate