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Titolo:
IDENTIFICATION OF A(1) ADENOSINE RECEPTORS IN RAT COCHLEA COUPLED TO INHIBITION OF ADENYLYL-CYCLASE
Autore:
RAMKUMAR V; RAVI R; WILSON MC; GETTYS TW; WHITWORTH C; RYBAK LP;
Indirizzi:
SO ILLINOIS UNIV,SCH MED,DEPT PHARMACOL,POB 19230 SPRINGFIELD IL 62794 MED UNIV S CAROLINA,DEPT MED CHARLESTON SC 29425
Titolo Testata:
The American journal of physiology
fascicolo: 3, volume: 267, anno: 1994,
parte:, 1
pagine: 30000731 - 30000737
SICI:
0002-9513(1994)267:3<30000731:IOAARI>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
PROTEIN ALPHA-SUBUNITS; GUINEA-PIG COCHLEA; OUTER HAIR-CELLS; INNER-EAR; LIGAND-BINDING; NEUROTRANSMISSION; ACTIVATION; SUBTYPES; RELEASE; SYSTEM;
Keywords:
PURINERGIC RECEPTOR; G PROTEINS; ADENOSINE 3',5'-CYCLIC MONOPHOSPHATE; PERIPHERAL AUDITORY SYSTEM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
42
Recensione:
Indirizzi per estratti:
Citazione:
V. Ramkumar et al., "IDENTIFICATION OF A(1) ADENOSINE RECEPTORS IN RAT COCHLEA COUPLED TO INHIBITION OF ADENYLYL-CYCLASE", The American journal of physiology, 267(3), 1994, pp. 30000731-30000737

Abstract

A(1) adenosine receptors (A(1)ARs) 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 N-6-2-(4-amino-3-[I-125]iodophenyl)ethyladenosine ([I-125]APNEA), an A(1)AR 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 [I-125]APNEA binding sites with a rank order of potency characteristic of these sites being the A(1)AR. The [I-125]APNEA binding was significantly reduced by pertussis toxin, indicating coupling of these receptors with the G(i) and/or G(o)proteins in cochlear membranes. Photoaffinity labeling of the receptor protein with the A(1)AR agonist N-6-2-(4-azido-3-[I-125] iodophenyl)ethyladenosine showed specific labeling of a 36-kDa receptor protein. Activation of the A(1)AR 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 A(1)AR) yielded a770-bp product that hybridized to an A(1)AR cDNA probe on Southern blots. These data indicate the presence of an inhibitory receptor in theperipheral auditory system, which may play an important role in modulating auditory functions.

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Documento generato il 03/07/20 alle ore 00:54:29