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Titolo:
BETA-ADRENOCEPTORS IN THE TROUT (ONCORHYNCHUS-MYKISS) HEART - CHARACTERIZATION, QUANTIFICATION, AND EFFECTS OF REPEATED CATECHOLAMINE EXPOSURE
Autore:
GAMPERL AK; WILKINSON M; BOUTILIER RG;
Indirizzi:
SIMON FRASER UNIV,DEPT BIOL SCI BURNABY V5A 1S6 BC CANADA DALHOUSIE UNIV,DEPT BIOL HALIFAX B3H 4J1 NS CANADA DALHOUSIE UNIV,DEPT PHYSIOL & BIOPHYS HALIFAX B3H 4H7 NS CANADA UNIV CAMBRIDGE,DEPT ZOOL CAMBRIDGE CB2 3EJ ENGLAND
Titolo Testata:
General and comparative endocrinology
fascicolo: 2, volume: 95, anno: 1994,
pagine: 259 - 272
SICI:
0016-6480(1994)95:2<259:BITT(H>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
BROKEN-CELL PREPARATIONS; GUINEA-PIG HEART; RAINBOW-TROUT; ADRENERGIC-RECEPTORS; VENTRICULAR MYOCYTES; ANGUILLA-ROSTRATA; SALMO-GAIRDNERI; CARDIAC TISSUE; BINDING; INTACT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
51
Recensione:
Indirizzi per estratti:
Citazione:
A.K. Gamperl et al., "BETA-ADRENOCEPTORS IN THE TROUT (ONCORHYNCHUS-MYKISS) HEART - CHARACTERIZATION, QUANTIFICATION, AND EFFECTS OF REPEATED CATECHOLAMINE EXPOSURE", General and comparative endocrinology, 95(2), 1994, pp. 259-272

Abstract

Specific binding of the hydrophilic radioligand [H-3]CGP-12177 to cell surface (functional) beta-adrenoreceptors was quantified in ventricular micropunches (2 mm diameter, 350 mu m thickness) from seawater-acclimated rainbow trout held at 7-9 degrees. Binding was stereospecific,saturable, of high affinity, and displaceable by appropriate agonistsand antagonists. Phentolamine failed to displace [H-3]CGP at concentrations up to 10(-4) M, indicating an absence of [H-3]CGP binding to alpha-adrenergic receptors. Trout ventricular beta-adrenoreceptors are exclusively of the beta(2) type. This conclusion is based on (1) the IC50 value for the beta(2)-antagonist ICI 118551 (2.9 x 10(-6) M); (2) the inability of the beta(1)-antagonist atenolol to displace [3H]CGP from beta-adrenoreceptors; and (3) the order of agonist-binding affinity(isoproterenol > epinephrine much greater than norepinephrine). The B-max and K-d values for [H-3]CGP binding to myocardial tissue were approximately 0.04 fmol mu g protein(-1) and 0.25 nM, respectively. The B-max value indicates that the density of cell surface (functional) beta-adrenoreceptors in the ventricle was 12,000 sites per cell or 3.38 sites per mu m(2) of sarcolemma. The K-d and B-max values for [H-3]CGP binding to ventricular beta-adrenoreceptors were unaffected by the in vivo administration of five bolus catecholamine injections (4.0 mu g kg(-1) epinephrine, 2.0 mu g kg(-1) norepinephrine). This suggests thatstress-induced increases in plasma catecholamines are unlikely to cause the down-regulation of heart beta-adrenoreceptors in fish. The method described here represents a simple but powerful technique for the quantification and characterization of adrenergic receptors in the fishheart. (C) 1994 Academic Press, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 20:53:57