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Titolo:
Functional desensitization to isoproterenol without reducing cAMP production in canine failing cardiocytes
Autore:
Laurent, CE; Cardinal, R; Rousseau, G; Vermeulen, M; Bouchard, C; Wilkinson, M; Armour, JA; Bouvier, M;
Indirizzi:
Hop Sacre Coeur, Ctr Rech, Montreal, PQ H4J 1C5, Canada Hop Sacre Coeur Montreal PQ Canada H4J 1C5 , Montreal, PQ H4J 1C5, Canada Univ Montreal, Fac Med, Dept Pharmacol, Montreal, PQ H3C 3J7, Canada Univ Montreal Montreal PQ Canada H3C 3J7 ol, Montreal, PQ H3C 3J7, Canada Univ Montreal, Fac Med, Dept Biochim, Montreal, PQ H3C 3J7, Canada Univ Montreal Montreal PQ Canada H3C 3J7 im, Montreal, PQ H3C 3J7, Canada Dalhousie Univ, Fac Med, Dept Physiol & Biophys, Halifax, NS B3H 4B7, Canada Dalhousie Univ Halifax NS Canada B3H 4B7 hys, Halifax, NS B3H 4B7, Canada Dalhousie Univ, Fac Med, Dept Obstet & Gynaecol, Halifax, NS B3H 4B7, Canada Dalhousie Univ Halifax NS Canada B3H 4B7 col, Halifax, NS B3H 4B7, Canada
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
fascicolo: 2, volume: 280, anno: 2001,
pagine: R355 - R364
SICI:
0363-6119(200102)280:2<R355:FDTIWR>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONGESTIVE-HEART-FAILURE; BETA-ADRENERGIC RECEPTORS; EFFERENT SYMPATHETIC NEURONS; VENTRICULAR MYOCYTES; DOWN-REGULATION; QUANTITATIVE-ANALYSIS; TACHYCARDIA; DOGS; BINDING; CONTRACTION;
Keywords:
alpha-adrenergic receptor; heart failure; cardiomyocytes; adenylyl cyclase; contraction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Cardinal, R Hop Sacre Coeur, Ctr Rech, 5400 Blvd Gouin Ouest, Montreal, PQH4J 1C5, Canada Hop Sacre Coeur 5400 Blvd Gouin Ouest Montreal PQ Canada H4J 1C5
Citazione:
C.E. Laurent et al., "Functional desensitization to isoproterenol without reducing cAMP production in canine failing cardiocytes", AM J P-REG, 280(2), 2001, pp. R355-R364

Abstract

To corroborate alterations in the functional responses to beta -adrenergicreceptor (beta -AR) stimulation with changes in beta -AR signaling in failing cardiomyocytes, contractile and L-type Ca2+ current responses to isoproterenol along with stimulated cAMP generation were compared among cardiomyocytes isolated from canines with tachycardia-induced heart failure or healthy hearts. The magnitude of shortening of failing cardiomyocytes was significantly depressed (by 22 +/- 4.4%) under basal conditions, and the maximal response to isoproterenol was significantly reduced (by 45 +/- 18%). Similar results were obtained when the responses in the rate of contraction and rate of relaxation to isoproterenol were considered. The L-type Ca2+ currentamplitude measured in failing cardiomyocytes under basal conditions was unchanged, but the responses to isoproterenol were significantly reduced compared with healthy cells. Isoproterenol-stimulated cAMP generation was similar in sarcolemmal membranes derived from the homogenates of failing (45 +/-6.8) and healthy cardiomyocytes (52 +/- 8.5 pmol cAMP. mg protein(-1) . min(-1)). However, stimulated cAMP generation was found to be significantly reduced when the membranes were derived from the homogenates of whole tissue(failing: 67 +/- 8.1 vs. healthy: 140 +/- 27.8 pmol cAMP.mg protein(-1).min(-1)). Total beta -AR density was not reduced in membranes derived from either whole tissue or isolated cardiomyocyte homogenates, but the beta (1)/beta (2) ratio was significantly reduced in the former (faitachycardia-induced heart failure, reduction in the functional responses of isolated cardiomyocytes to beta -AR stimulation may be attributed to alterations in the excitation-contraction machinery rather than to limitation of cAMP generation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 11:59:26