ANGIOTENSIN-II EXCITES VASOMOTOR NEURONS BUT NOT RESPIRATORY NEURONS IN THE ROSTRAL AND CAUDAL VENTROLATERAL MEDULLA

We examined the vasomotor and respiratory effects of angiotensin II microinjection into the rabbit ventrolateral medulla (VLM). Angiotensin II in the rostral and caudal VLM increased and decreased arterial pressure, respectively, but had no effect on phrenic nerve activity. In contrast, L-glutamate injections into the same areas altered both arterial pressure and phrenic nerve activity. The results suggest that angiotensin II may activate specifically vasomotor neurons but not respiratory neurons in the VLM.