Bradykinin is a mediator, but unlikely a trigger, of antiarrhythmic effects of ischemic preconditioning.
J Cardiovasc Electrophysiol
; 18(1): 93-9, 2007 Jan.
Article
em En
| MEDLINE
| ID: mdl-17229306
ABSTRACT
OBJECTIVE:
Brief reversible ischemic episodes (ischemic preconditioning, IPC) protect the heart against arrhythmias during a subsequent prolonged low-flow ischemia. We have recently shown that this protection involves release of bradykinin, activation of bradykinin B2 receptors followed by opening of sarcolemmal, but not mitochondrial ATP-sensitive K+ channels. The goal of this study was to clarify a trigger and/or mediator role of bradykinin in the antiarrhythmic effects of IPC during low-flow ischemia.METHODS:
Isolated perfused rat hearts underwent 60 minutes of low-flow ischemia induced by reducing perfusion pressure followed by 60 minutes of reperfusion. Preconditioning was induced by 2 x 5 minutes episodes of zero-flow ischemia. In yet other groups, preconditioned or non-preconditioned hearts were treated either with bradykinin (10 nmol/L) or with HOE 140 (bradykinin B2 receptor antagonist, 100 nmol/L).RESULTS:
IPC reduced the number of ventricular premature beats, as well as the incidence of ventricular tachycardia and of ventricular fibrillation during low-flow ischemia. In addition, this protection was abolished by HOE 140 given during low-flow ischemia. Pharmacological preconditioning using short bradykinin perfusion instead of IPC did not show antiarrhythmic effects. However, bradykinin administered during low-flow ischemia and reperfusion reduced the number of ventricular premature beats and the incidence of ventricular tachycardia and of ventricular fibrillation during low-flow ischemia.CONCLUSION:
Bradykinin is a mediator, but unlikely a trigger, of antiarrhythmic effects of IPC during low-flow ischemia.
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Base de dados:
MEDLINE
Assunto principal:
Fibrilação Ventricular
/
Bradicinina
/
Taquicardia Ventricular
/
Precondicionamento Isquêmico Miocárdico
/
Ventrículos do Coração
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article