Endothelin receptor mrna expression in the renal medulla identified
by in situ rt-pcr.
Chow, Li Hui, Shiela Subramanian, Gerard J Nuovo, Frederick Miller,
and Edward P Nord.
Division of Nephrology, Department of Medicine, and *Department of
Pathology, School of Medicine, State University of New York at Stony
Brook, Stony Brook, NY 11794
APStracts 2:0075F, 1995.
Three subtypes of endothelin receptors (ET-Rs) have been identified by
cDNA cloning, namely ET-RA, ET-RB and ET-RC. In the current study the
precise cellular distribution of the ET receptor subtypes in the
renal medulla was explored by detecting the corresponding PCR
-amplified cDNAs by in situ reverse transcription and the polymerase
chain reaction (in situ RT-PCR). The PCR amplified cDNAs were
detected either by direct incorporation using digoxigenin-dUTP (dig
-dUTP) as a nucleotide substrate in the PCR reaction, or by in situ
hybridization (ISH) with the dig-dUTP-labeled probe. ET-RB mRNA was
detected exclusively in the epithelial cells of the inner and outer
medullary collecting duct. In contrast, ET-RA message was observed
primarily in interstitial cells and pericytes of the vasae rectae in
the outer and inner medulla. Southern blot analysis of PCR amplified
cDNAs reverse transcribed from extracted RNA of rat renal medulla
confirmed the specificity of the RT-PCR products. ET-RC mRNA was not
detected. We conclude that ET-RB is the major ET receptor found in
rat renal medulla and is expressed exclusively on inner medullary
collecting duct cells (IMCD). The pattern of ET-R mRNA expression
described, suggests different physiologic actions for ET on the
diverse cellular structures of the renal medulla.
Received 1 July 1994; accepted in final form 2 May 1995.
APS Manuscript Number F218-4.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 9 May 1995.