Am J Physiol Cell Physiol Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 267: C731-C737, 1994;
0363-6143/94 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ramkumar, V.
Right arrow Articles by Rybak, L. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ramkumar, V.
Right arrow Articles by Rybak, L. P.

AJP - Cell Physiology, Vol 267, Issue 3 C731-C737, Copyright © 1994 by American Physiological Society

ARTICLES

Identification of A1 adenosine receptors in rat cochlea coupled to inhibition of adenylyl cyclase

V. Ramkumar, R. Ravi, M. C. Wilson, T. W. Gettys, C. Whitworth and L. P. Rybak
Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-9230.

A1 adenosine receptors (A1ARs) are found in a number of tissues in the body where their physiological roles have been identified. In the cochlea, neither the existence of these receptors nor a physiological role of adenosine has been described previously. Membranes prepared from rat cochlea demonstrated high affinity and saturable binding to N6-2-(4-amino-3-[125I]iodophenyl)ethyladenosine ([125I]APNEA), an A1AR agonist, with maximum binding capacity and dissociation constant values being 40.5 +/- 0.5 fmol/mg protein and 1.28 +/- 0.03 nM, respectively. Adenosine analogues competed for [125I]APNEA binding sites with a rank order of potency characteristic of these sites being the A1AR. The [125I]APNEA binding was significantly reduced by pertussis toxin, indicating coupling of these receptors with the Gi and/or Go proteins in cochlear membranes. Photoaffinity labeling of the receptor protein with the A1AR agonist N6-2-(4-azido-3[125I]iodophenyl)ethyladenosine showed specific labeling of a 36-kDa receptor protein. Activation of the A1AR with R-phenylisopropyladenosine (R-PIA) led to inhibition of forskolin-stimulated adenylyl cyclase activity. Amplification of reverse-transcribed RNA derived from cochlear tissue by polymerase chain reaction (using primers for the bovine A1AR) yielded a 770-bp product that hybridized to an A1AR cDNA probe on Southern blots. These data indicate the presence of an inhibitory receptor in the peripheral auditory system, which may play an important role in modulating auditory functions.


This article has been cited by other articles:


Home page
 Pharmacol. Rev.Home page
V. Ralevic and G. Burnstock
Receptors for Purines and Pyrimidines
Pharmacol. Rev., September 1, 1998; 50(3): 413 - 492.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online