Increase in renin release after sionaortic denervation and cervical vagotomy

Abstract

The role of the vagi in the control of renin secretion was investigated in dogs maintained on a high-salt diet. Renal perfusion pressure was maintained relatively constant by the manipulation of a suprarenal aortic snare. Mean arterial blood pressure (MAP), plasma renin activity (PRA), and packed cell volume (PCV) increased after sinoaortic denervation and cervical vagotomy. Cooling of cervical vagi to 3-5 degrees C had the same effect as vagotomy. There was no change in MAP, PRA, and PCV in sham-operated animals. Propranolol prevented the increase in PRA following sinoaortic denervation and vagotomy, but not that in MAP or PCV. In splenectomized dogs, PCV still showed increases after sinoaortic denervation and vagotomy. It is suggested that the removal of sinoaortic and/or vagal inhibitory effects on the vasomotor center causes increases in sympathetic discharge to the adrenal medulla and the peripheral vessels, and that this in turn leads to the increase in MAP. The increase in sympathetic discharge to the adrenal medulla and the kidney causes the increases in PRA.

Increase in Renin Release after Sinoaortic Denervation and Cervical Vagotomy in Anesthetized Dogs (II)

“…In dogs maintained on a high-salt diet sinoaortic denervation caused increases in mean arterial pressure (MAP), PRA, and PCV, and cervical vagotomy caused further increases in these variables. This confirms an earlier report (2). Figure In the animals whose kidneys had been denervated 7-1 0 days previously, sinoaortic denervation caused increases in mean MAP from 133.1 +_ 5.4 mm Hg during control periods to 181.9 2 8.0 mm Hg ( P < 0.005) 60 min after sinoaortic denervation; it increased further to reach 21 1.…”

“…Mancia et al (5) have shown in the dog and Clement et al (8) in the rabbit that cervical vagotomy causes an increase in sympathetic discharge to the renal nerves. We also showed in our earlier report that infusion of propranolol abolishes the increase in PRA that follows cervical vagotomy (2). In the present series of experiments, we show as well that in dogs whose kidneys have been denervated for 7 to 10 days, cervical vagotomy causes only a slight, but not statistically significant, increase in PRA (Fig.…”

“…The general surgical procedure was essentially the same as that previously described (2). The animals were anesthetized with 30 mg/kg of sodium pentobarbital and ventilated with a Harvard respirator.…”

“…Plasma renin activity (PRA) was determined by a radioimmunoassay method modified from that of Katz and Smith (4) and described in detail in an earlier paper (2). Packed cell volume (PCV) was determined by the microcapillary method.…”

“…Previously we demonstrated that cervical vagotomy, both in intact dogs and in dogs previously subjected to sinoaortic denervation, increases plasma renin activity (PRA) despite high-sodium diets (1,2). We reported also that this increase in PRA resulting from cervical vagotomy could be blocked by infusion of propranolol or by renal denervation, results that suggest that this increase in PRA is mediated by increased sympathetic discharge to the kidney (1,2). In the earlier experiments the kidneys were denervated immediately before the measurement of PRA, and PRA usually rose as arterial blood pressure decreased.…”