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Titolo:
Role of endothelial cells in modulation of contractility induced by hexarelin in rat ventricle
Autore:
Bedendi, I; Gallo, MP; Malan, D; Levi, RC; Alloatti, G;
Indirizzi:
Dipartimento Biol Anim & Uomo, I-10123 Turin, Italy Dipartimento Biol Anim& Uomo Turin Italy I-10123 , I-10123 Turin, Italy Univ Turin, Ist Nazl Fis Mat, Unita TO Uni, I-10123 Turin, Italy Univ Turin Turin Italy I-10123 s Mat, Unita TO Uni, I-10123 Turin, Italy
Titolo Testata:
LIFE SCIENCES
fascicolo: 18, volume: 69, anno: 2001,
pagine: 2189 - 2201
SICI:
0024-3205(20010921)69:18<2189:ROECIM>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
HORMONE-RELEASING PEPTIDE; GROWTH-HORMONE; NITRIC-OXIDE; HEART; MUSCLE; HYPOPITUITARISM; PROSTACYCLIN; PERFORMANCE; DYSFUNCTION; MYOCARDIUM;
Keywords:
hexarelin; cardiac muscle; endothelial cell; prostaglandins; nitric oxide; contractility;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Alloatti, G Dipartimento Biol Anim & Uomo, Via Acad Albertina 13, I-10123 Turin, Italy Dipartimento Biol Anim & Uomo Via Acad Albertina 13 Turin Italy I-10123
Citazione:
I. Bedendi et al., "Role of endothelial cells in modulation of contractility induced by hexarelin in rat ventricle", LIFE SCI, 69(18), 2001, pp. 2189-2201

Abstract

The synthetic growth hormone (GH) secretagogue hexarelin has important cardiac effects, that include a reduction of dysfunction in ischemic-reperfused hearts from GH-deficient rats after a chronic treatment and an increase of ejection fraction in acutely treated men. To investigate the mechanisms of its cardiac activity, we studied the effects of hexarelin (1-10 muM) on contractility of rat papillary muscles. We observed, in hexarelin treated papillary muscles, an improved recovery of contractility after anoxia. Hexarelin induced time- and frequency-dependent inotropic effects on papillary muscle. These effects were a transient increase in contractile force, abolished by propranolol (0.2 muM), followed by a reduction at low (60-240/min), but not at high (400-600/min) beating frequencies. The typical negative force-frequency relationship present in rat papillary muscles was therefore modified, and a minor increase in diastolic tension occurred after a sudden increase in stimulus frequency. Blockade of NO synthesis with 1 mM L-NAME, partially altered the response to hexarelin. MK-677 (1 muM), a non peptidyl GH secretagogue, reduced contractility, but did not alter the force-frequency relationship. The remaining effects of hexarelin were absent in papillarymuscles pre-treated with indomethacin (1 muM), or after removal of endocardial endothelium with 0.5% triton X-100. The release of the prostacyclin metabolite 6-keto-PGF(1a) was increased during reoxygenation after a period of anoxia in hexarelin treated papillary muscles. Hexarelin had no significant effect on calcium transients and on I-Ca measured in isolated ventricular cells. These findings suggest that the effects of hexarelin are mainly due to endothelium-released PGI(2). (C) 2001 Elsevier Science Inc. All rightsreserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/07/20 alle ore 16:46:14