Changes in the sensitivity of aortic baroreceptors under the influence of the sympathetic nervous system

: A dependence of the activity of the aortic baroceptors on the aortic pressure in stimulation of a branch of the stellate ganglion innervating the aortic baroceptor zone was studied in experiments on cats. The sympathetic stimulation failed to change the threshold of baroceptors (80 mm Hg) and their activity within the pressure range of 80-140 mm Hg. With higher aortic pressure the sympathetic stimulation decreased the baroceptor activity. As a result, an increase of the baroceptor activity with pressure was less and maximal activity was attained at higher aortic pressure (greater by an average of 32 mm Hg). The action mechanism of the influence of the sympathetic innervation on the baroceptor sensitivity, and physiological significance of this phenomenon are discussed.