DIFFERENTIAL CONTROL OF GLOMERULAR CAPILLARY PRESSURE BY TWO POPULATIONS OF RENAL NERVES

摘要

The renal nerves constrict the renal vasculature causing decreases in renal blood flow (RBF) and glomerular filtration rate (GFR). Whether renal haemodynamics are influenced by changes in renal nerve activity within the physiological range is a matter of debate. We have identified two morphologically distinct populations of nerves within the kidney, which are differentially distributed to the renal afferent and efferent arterioles. TYPE I nerves almost exclusively innervate the afferent arteriole whereas TYPE II nerves are distributed equally on the afferent and efferent arterioles. We have also demonstrated that TYPE II nerves are immuno-reactive for neuropeptide Y while TYPE I nerves are not.This lead us to hypothesise that in the kidney, distinct populations of nerves innervate specific effector tissues and that these nerves may be selectively activated, setting the basis for the differential neural control of GFR. In physiological studies, we demonstrated that differential changes in glomerular capillary pressure occurred in response to graded reflex activation of the renal nerves, compatible with our hypothesis. These responses were independent of activation of the renin-angiotensin system.