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Titolo:
CORONARY FLOW STIMULATES AURICULAR-VENTRICULAR TRANSMISSION IN THE ISOLATED-PERFUSED GUINEA-PIG HEART
Autore:
RUBIO R; CEBALLOS G; SUAREZ J;
Indirizzi:
UNIV VIRGINIA,DEPT PHYSIOL,JORDAN HALL CHARLOTTESVILLE VA 22908
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 4, volume: 38, anno: 1995,
pagine: 1177 - 1185
SICI:
0363-6135(1995)38:4<1177:CFSATI>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
CYCLIC-AMP; ADENOSINE; RELEASE; PROSTACYCLIN; ENDOTHELIUM; MODULATION; RECEPTORS; PRESSURE; HYPOXIA; RABBIT;
Keywords:
SHEARING FORCES; ENDOTHELIAL GLYCOCALYX; ENDOTHELIAL FACTORS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
R. Rubio et al., "CORONARY FLOW STIMULATES AURICULAR-VENTRICULAR TRANSMISSION IN THE ISOLATED-PERFUSED GUINEA-PIG HEART", American journal of physiology. Heart and circulatory physiology, 38(4), 1995, pp. 1177-1185

Abstract

In the heart in situ coronary flow stimulates oxygen consumption, glycolytic flux, myocardial contractility, and the release of bioactive substances. Studies have indicated that the coronary flow-enhanced contraction is similar to a hormonelike effect because the enhanced contraction results from an elevation in intracellular free calcium. In fact, if extracellular calcium is raised sufficiently, the contraction amplitude rises and remains constant and independent of coronary flow. Wehypothesized that coronary flow could also stimulate other calcium-dependent cardiac functions such as auricular-ventricular (A-V) transmission. This hypothesis was tested in isolated guinea pig hearts perfused at constant flow. Our results show that increases in coronary flow (6-25 ml/min range) decrease the A-V delay solely as a result of reduced propagation time in the A-V node and not in atrial or ventricular propagation. When coronary vascular resistance was altered by dilation (nitroglycerin, bradykinin, nitroprusside, and adenosine) or by constriction (angiotensin II), this dromotropic effect of flow remained the same despite wide changes in perfusing pressure. Also, this dromotropiceffect of flow was not altered by energy-altering substrates in the perfusate or by perfusion of adenosine receptor blockers. Furthermore, the effectiveness of flow as a dromotropic stimulus varied inversely with changes in calcium entry caused either by elevation or reduction of extracellular calcium. In addition, enhanced viscosity of the perfusing medium amplifies the positive dromotropic effect of flow.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/10/20 alle ore 05:55:04