|
|
||||||||
1 Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506; and 2 Department of Pharmacology, Creighton School of Medicine, Omaha, Nebraska 68178
It was previously shown that K+ secretion by vestibular dark cell epithelium is under control of G protein-coupled receptors of the P2Y family in the apical membrane that are activated by both purine and uridine nucleotides (P2Y2, P2Y4, or P2Y6). The present study was conducted to determine the subtype of purinergic receptor and to test whether these receptors undergo desensitization. The transepithelial short-circuit current represents electrogenic K+ secretion and was found to be reduced by UTP, ATP, and diadenosine tetraphosphate, but not UDP. Neither pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS, 30 µM) nor suramin (100 µM) inhibited the effect of UTP. The potencies of the agonists were consistent with rodent P2Y4 and P2Y2, but not P2Y6, receptors. The ineffectiveness of suramin was consistent with P2Y4, but not P2Y2. Transcripts for both P2Y2 and P2Y4 were found in vestibular labyrinth. Sustained exposure to ATP or UTP for 15 min caused a constant depression of short-circuit current with no apparent desensitization. The results support the conclusion that regulation of K+ secretion across vestibular dark cell epithelium occurs by P2Y4 receptors without desensitization of the response.
desensitization; inner ear; vestibular labyrinth; gerbil
This article has been cited by other articles:
![]() |
J. E Matos, B Robaye, J. M Boeynaems, R Beauwens, and J Leipziger K+ secretion activated by luminal P2Y2 and P2Y4 receptors in mouse colon J. Physiol., April 1, 2005; 564(1): 269 - 279. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. C. Wolff, A.-D. Qi, T. K. Harden, and R. A. Nicholas Polarized expression of human P2Y receptors in epithelial cells from kidney, lung, and colon Am J Physiol Cell Physiol, March 1, 2005; 288(3): C624 - C632. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. R. Dubyak Knock-Out Mice Reveal Tissue-Specific Roles of P2Y Receptor Subtypes in Different Epithelia Mol. Pharmacol., April 1, 2003; 63(4): 773 - 776. [Full Text] [PDF] |
||||
![]() |
B. Robaye, E. Ghanem, F. Wilkin, D. Fokan, W. Van Driessche, S. Schurmans, J.-M. Boeynaems, and R. Beauwens Loss of Nucleotide Regulation of Epithelial Chloride Transport in the Jejunum of P2Y4-Null Mice Mol. Pharmacol., April 1, 2003; 63(4): 777 - 783. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Leipziger Control of epithelial transport via luminal P2 receptors Am J Physiol Renal Physiol, March 1, 2003; 284(3): F419 - F432. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. H. Lee, T. Chiba, and D. C. Marcus P2X2 Receptor Mediates Stimulation of Parasensory Cation Absorption by Cochlear Outer Sulcus Cells and Vestibular Transitional Cells J. Neurosci., December 1, 2001; 21(23): 9168 - 9174. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |