THE INCREASE OF FEMORAL ARTERIAL FLOW BY STIMULATING THE DORSAL AND VENTRAL MEDULLA IN CATS

1. In chloralose-urethane anaesthetized cats, the dorsal cardiovascula r reactive area (DCRA) in the parvocellular reticular nucleus dorsomed ial to the facial nucleus, and the ventral cardiovascular reactive are a (VCRA) ventromedial to the facial nucleus, were stimulated by microi njections of sodium glutamate (100-200 nmol) or electric current. 2. S timulation of DCRA, with a long latency of 15-20 s, elicited a marked increase of blood flow in the contralateral femoral artery with little change to moderate increase in systemic arterial blood pressure (ABP) . In the relatively dorsal portion of DCRA, however, a smaller increas e of blood flow in the ipsilateral femoral artery was elicited. 3. On the other hand, stimulation of VCRA with a short latency (3-5 s) evoke d an increase of blood flow in both femoral arteries which was more pr ominent on the contralateral side. The responses were accompanied with decreases in the blood flow of other vascular beds with only a slight increase or minimal change in ABP. 4. The data suggest that DCRA and VCRA are both viscerotopically organized to alter the resistance of in dividual vascular beds for redistribution of blood flow.