Sinoaortic denervation in the nonhuman primate.

There is considerable controversy as to whether removal of baroreceptor input by sinoaortic deafferentation leads to a sustained hypertension in quadripeds. Because of the importance of the baroreflex during postural changes, the effects of baroreceptor denervation may be even more profound in the primate. In this study, six adult male baboons (Papio anubis) were maintained on a tether system to examine the acute and sustained effects of aortic and combined carotid sinus and aortic baroreceptor deafferentation. Mean arterial pressure (MAP) averaged over 24 h increased from 86 +/- 4.0 to 105 +/- 5.5 mmHg after aortic denervation. One week after sinoaortic deafferentation, arterial pressure rose to 129 +/- 12.9 mmHg and then receded to 97 +/- 4.4 mmHg at 4 wk postdenervation. The lability of arterial pressure (measured as the mean of the standard deviations over 24 h) did not change with aortic denervation but increased at 1 and 4 wk after complete baroreceptor denervation. These studies indicate that baroreceptor deafferentation in the primate results in an acute increase in arterial pressure, the lability of arterial pressure, and heart rate. However, by 4 wk postdenervation, the level and lability of arterial pressure are decreased but remain significantly elevated.