Uretero-Renal Reflex Facilitating Renal Vasoconstrictor Responses to Emotional Stress

Abstract

In trained and conscious dogs, with ureters exteriorized in flank skin-flaps to facilitate the simultaneous determination of unilateral renal function, it was determined that unilateral irritation of the ureter reflexly produced a decrease in renal plasma flow and glomerular filtration rate in the ipsilateral kidney. Three unilateral renal response patterns were observed on catheterizing the ureter. This uretero-renal reflex was always unilateral and ipsilateral with respect to the stimulated ureter, and could be blocked by anesthetizing the ureter, denervating and/or transplanting the kidney. It was determined that sensory fibers from the ureter communicate reflexly with renal efferent vasoconstrictor fibers. These ureteral afferent fibers pass up the entire length of the ureter where they probably enter the splanchnic nerves. Afferent discharges from the stimulated ureter, whether acute or subliminal, selectively promoting the recruitment of preganglionic neurons, effectively facilitate renal nerve pathways to the kidney under conditions of sympathetic activation (stress). It was concluded that the mechanism of action of this uretero-renal (viscero-visceral) reflex, and its functional significance to renal vasomotor regulation, is that of a facilitating phenomenon. By this facilitating action it channelizes sympathetic activity into efferent renal nerve pathways, exposing the kidney to an exaggerated impact from general and nonspecific environmental stress factors.