Cerebral regional cortical blood flow response during joint stimulation in cats

Noxious stimulation of an elbow joint in the anesthetized cat increases cerebral blood flow over broad, bilateral areas of the cerebral cortex and increases systemic blood pressure. In order to eliminate the confounding effects of elevated blood pressure on cerebral blood flow, we re-examined this phenomenon in cats with a transected spinal cord at the T1 level. Noxious stimulation of an elbow joint resulted in a significant increase in blood flow in the forelimb area of the contralateral primary somatosensory cortex; the blood pressure remained unchanged. These data in cats suggest that the previously described bilateral increase in cerebral blood flow following noxious joint stimulation was due, in part, to the increased blood pressure.