Influence of renal sympathetic nerve stimulation on renal function in the primate

In anesthetized Macaca fascicularis monkeys renal sympathetic nerves were stimulated electrically while changes in renal function were measured. The range of stimulation frequencies was 0.25-4.0 Hz. In the primate the stimulation threshold for changes in renal vascular resistance at a renal perfusion pressure of 100 mmHg was between 1 and 2 Hz. Vascular resistance increased progressively at higher stimulation frequencies. The threshold for changes in sodium reabsorption was somewhat lower (between 0.5 and 1 Hz). At higher stimulation frequencies sodium excretion was dramatically reduced. Renin secretion was not significantly affected at 0.25 and 0.5 Hz stimulation and rose significantly only at stimulation frequencies of 1.0 Hz or above. Thus renal sympathetic nerves in the primate appear to influence renal vascular resistance and electrolyte excretion in a manner that is quantitatively similar to that seen in other species. However, in the primate it was not possible to stimulate renin secretion in the absence of changes in renal blood flow and sodium reabsorption.