Role of vagal and sinoaortic baroreflexes in circulatory adjustments to passive head up tilt.

ABSTRACT

To evaluate the contribution of vagal and sinoaortic baroreflexes in circulatory adjustments anaesthetized rabbits were subjected to 70 degree head up tilt with (i) both reflexes intact; (ii) after elimination of sinoaortic reflexes; (iii) after elimination of vagal reflexes; and (iv) after elimination of both categories of reflexes. The results suggest that vagal mediated baroreflexes from cardiopulmonary baroreceptors contribute significantly in circulatory adjustments to passive head up tilt while sinoaortic baroreflexes play the major role.