Sympathetic nerve activity to the spleen, kidney, and heart in response to baroceptor input.

NINOMIYA, ISHIO, NAOKO NISIMARU, AND HIROSHI IRISAWA. Sympathetic nerve activity to the spleen, kidney, and heart in response to baroceptor input. Am. J. Physiol. 221(5): 1346-1351. 1971.-The effects of the baroceptor reflex on sympathetic nerve activity (SNA) to spleen, kidney, and heart were analyzed in anesthetized cats. The baroceptor reflex times of SNA to the spleen, kidney, and heart were 292, 199, and 164 msec, respectively. SNA to these organs changed almost inversely to changes in the absolute mean aortic pressure between 100 and 150 mm Hg. Within this pressure range the gain of baroceptor-sympathetic systems to the spleen, heart, and kidney were 5.2, 3.2, and 2.7, respectively. SNA was reduced to the noise level at the mean aortic pressure of 148, 167 and 173 mm Hg in splenic, cardiac and renal nerves, respectively. Changes of SNA were not identical among the three nerves studied in response to occlusion of the common carotid arteries, to electrical stimulation of the aortic nerve, to change in the isolated carotid sinus pressure, or to hemorrhage. The effects of baroceptor reflex on SNA to both kidneys were almost the same, but there was some difference in the reflex time. It is concluded that the effects of baroceptor reflex on SNA to functionally different organs are quantitatively nonuniform.