Lesions of the caudal periaqueductal gray prevent compensation of arterial pressure during hemorrhage.
Arterial pressure normally changes very little during small hemorrhage. In cats with bilateral lesions of the region of the caudal periaqueductal gray arterial pressure and renal vascular resistance decreased rapidly and precipitously during a 10 ml/kg X 3 min-1 hemorrhage. This lack of compensation was pronounced in response to a hemorrhage one week after lesioning but was not seen 1 h after lesioning in separate experiments. The critical region appears anterior and dorsal to the locus coeruleus and medial to the parabrachial nuclei.
D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume; D001835:Body Weight; D001931:Brain Mapping; D002415:Cats; D006339:Heart Rate; D006470:Hemorrhage / Q000503:physiopathology*; D008125:Locus Coeruleus / Q000502:physiology; D010487:Periaqueductal Gray / Q000503:physiopathology*; D012018:Reflex / Q000502:physiology; D014655:Vascular Resistance; D014661:Vasoconstriction