Intrarenal blood flow in carotid sinus nerve stimulation and hemorrhage in dogs.

The present study was undertaken to compare the role of the sympathetic nervous system, in hemorrhage, with that of hypotension in producing renal blood flow (RBF) redistribution. Ten mongrel dogs were prepared for the determination of RBF distrubition by injecting 85Kr dissolved in saline into the renal artery to obtain renal radioactivity curves. RBF distribution was determined a) at control, b) during a 15-min period of hypotension produced by electrical stimulation (10 v-60Hz) of the left carotid sinus nerve (nerve of Hering), c) 15 min after hemorrhage to a blood pressure equivalent to that of stimulation and d) during hemorrhage plus a 15-min period of stimulation. Hypotension caused by stimulation left component I blood flow unchanged (at approximately 492 ml/min/100 g) but resulted in an increase in component II flow from 93 +/- 8 to 155 +/- 20 ml/min/100 g. Hemorrhage caused a 60% reduction in component I blood flow rate, leaving component II unchanged. Partial reversal of hemorrhage effects on distrubiton of RBF was obtained by restimulation of the nerve of Hering. It appears that RBF distribution, as controlled by the carotid sinus, may involve primarily component I flow, with the redistribution between components I and II during hemorrhage possibly involving other mechanisms.