Prostanoid signalling, localization and expression of ip receptors
in rat thick ascending limb cells.
H[acute]ebert, Richard L., Tim O_connor, Chris Neville, Kevin D.
Burns, Odette Laneuville and Linda N. Peterson,.
Departments of Cellular and Molecular Medicine1 of Medicine2 of
Biochemistry, Microbiology and Immunology3 and of Paediatrics4,
Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada, K1H
8M5.
APStracts 5:0161F, 1998.
It is widely held that only one prostacyclin (IP) receptor exists
which can couple to guanine sti-mulatory nucleotide binding proteins
(Gs) leading to activation of adenyl cyclase. Although IP receptor
mRNA is expressed in vascular arterial smooth muscle cells,
platelets, and with lower level expression in mature thymocytes,
splenic lymphocytes and megakaryocytes, there is no molecular
evidence for IP receptor expression in renal epithelial cells. The
purpose of the present study was to obtain molecular evidence for the
expression and localization of the IP receptor and to study the
signalling pathways of IP receptor in rat medullary thick ascending
limb (mTAL). Biochemical studies showed that IP prostanoids do not
increase cyclicAMP in rat mTAL. Howe-ver, in the presence of
vasopressin, inhibition of cAMP formation by PGI2 analogues is
pertussis toxin sensitive and does not activate protein kinase C. In
situ hybridization studies localized IP receptor mRNA expression to
mTAL in the rat kidney outer medulla. The results of RT-PCR of
freshly isolated RNA from mTAL, using primers specific for the mouse
IP receptor cDNA pro-duced an amplification product of the correct
predicted size and containing an expected NcoI endonuclease
restriction site. We conclude that rat renal epithelial cells express
the IP receptor, coupled to inhibition of cAMP production.
Received 2 June 1998; accepted in final form 3 September 1998.
APS Manuscript Number F139-6.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 21 September 1998