The involvement of the anterior cingulate cortex in blood pressure control.

The visceromotor nature of the rat anterior cingulate cortex was investigated by electrically stimulating this area in both anesthetized and awake animals. Initial studies demonstrated that electrical stimulation of any division of the anterior cingulate cortex elicits a significant fall in blood pressure in the sodium pentobarbital-anesthetized rat. Depressor responses were greatest (up to 50% decreases) following stimulation of the ventral third of the anterior cingulate cortex. Heart rate was not altered by cingulate cortex stimulation. In the awake animal, stimulation of previously identified depressor sites in the rostral third of the pregenual cingulate cortex elicited pressor responses. In contrast, stimulation of the caudal third of this cortex elicited depressor responses, and stimulation of the middle third elicited biphasic (pressor followed by depressor) responses. These results indicate that the anterior cingulate cortex is a visceromotor region which may provide a cortical output for the regulation of blood pressure responses associated with learning and or stress.