A novel electrophysiologic effect of melatonin on ischemia/reperfusion- induced arrhythmias in isolated rat hearts

Authors
Diez, Emiliano Raúl; Prados, Laura Vanina; Carrión, Adriana; Ponce Zumino, Amira Zulma; Miatello, Roberto Miguel
Publication Year
2009
Language
English
Format
article
Status
Published version
Description
Reperfusion after a short period of cardiac ischemia triggers ventricular arrhythmias attributable to ionic imbalance and oxidative stress. Melatonin offers some degree of protection, but its effects on the cardiac action potentials are unknown. We evaluated the effects of 5, 10, 20 and 50 μm melatonin in isolated perfused rat hearts subjected to 10 min of regional ischemia. ECG and membrane potentials were synchronously displayed. After 15 min of reperfusion, total antioxidant capacity (TAC) was determined. Melatonin did not change the ischemic depolarization nor the action potential amplitude depression, but at the end of ischemia the action potential duration (APD) decreased in control and 5 μm melatonin-treated hearts. By contrast, it returned to preischemic levels in hearts given 20 and 50 μm melatonin. Melatonin reduced the incidence of reperfusion arrhythmias from 100% in control to 50% in 5 and 10 μm, to 40% in 20 μm and 30% in 50 μm hearts. TAC values were higher at all melatonin concentrations. We conclude that melatonin reduced the incidence of reperfusion arrhythmias because of its antioxidant effects. In addition, at 20 and 50 μm lengthened APD and promoted an improved protection. This latter effect should be considered when in vivo applications of melatonin are considered.
Fil: Diez, Emiliano Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina
Fil: Prados, Laura Vanina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina
Fil: Carrión, Adriana. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina
Fil: Ponce Zumino, Amira Zulma. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Miatello, Roberto Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina
Subject
ANTIOXIDANT
ARRHYTHMIAS
ELECTROPHYSIOLOGY
ISCHEMIA-REPERFUSION INJURY
MELATONIN
RAT
TRANSMEMBRANE ACTION POTENTIAL
Medicina Critica y de Emergencia
Medicina Clínica
CIENCIAS MÉDICAS Y DE LA SALUD
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/79665