Localization of the vasopressin V1a and V2 receptors within the renal cortical and medullary circulation
Park, F.; Mattson, D.L.; Skelton, M.M.; Cowley, A.W.
American Journal of Physiology 273(1 Pt 2): R243-R251
1997
ISSN/ISBN: 0002-9513 PMID: 9249556 Document Number: 474233
Arginine vasopressin (AVP) is a potent vasoconstrictor that preferentially reduces renal medullary blood flow through the stimulation of the vasopressin V-1a receptor (V-1aR). Studies have also shown that the vasopressin V-2 receptor (V-2R) may modulate AVP-mediated vasoconstriction. At present, the distribution of the V-1aR and V-2R within the renal cortical and medullary microcirculation has not been determined. This study was designed to localize the transcriptional and translational sites of the V-1aR and V-2R in microdissected intrarenal vascular segments from both the cortex and medulla, specifically the interlobar, arcuate, and interlobular arteries; afferent and efferent arterioles; glomeruli; and single outer medullary vasa recta capillaries using reverse transcription-polymerase chain reaction and Western blot analyses. The results indicated that V-1aR mRNA and proteins were present in the isolated cortical or medullary vasculature, but the V-2R mRNA and proteins were not found. This study suggests that the vasoconstrictor action of AVP within the renal medulla is mediated through the V-1aR and that the modulatory V-2R-mediated vasodilation is probably through the release of paracrine hormones found within the renal interstitial or tubular cells.