IMBECU   20882
INSTITUTO DE MEDICINA Y BIOLOGIA EXPERIMENTAL DE CUYO
Unidad Ejecutora - UE
artículos
Título:
A novel electrophysiologic effect of melatonin on ischemia/reperfusion-induced arrhythmias in isolated rat hearts
Autor/es:
EMILIANO DIEZ; LAURA PRADOS; ADRIANA CARRIÓN; AMIRA PONCE ZUMINO; ROBERTO MIATELLO
Revista:
JOURNAL OF PINEAL RESEARCH
Editorial:
Wiley-Blackwell
Referencias:
Lugar: Singapore; Año: 2008 vol. 46 p. 155 - 160
ISSN:
0742-3098
Resumen:
Abstract: 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 lm 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 lm melatonin-treated
hearts. By contrast, it returned to preischemic levels in hearts given 20 and
50 lm melatonin. Melatonin reduced the incidence of reperfusion
arrhythmias from 100% in control to 50% in 5 and 10 lm, to 40%in 20 lmlm 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 lm melatonin-treated
hearts. By contrast, it returned to preischemic levels in hearts given 20 and
50 lm melatonin. Melatonin reduced the incidence of reperfusion
arrhythmias from 100% in control to 50% in 5 and 10 lm, to 40%in 20 lmlm melatonin-treated
hearts. By contrast, it returned to preischemic levels in hearts given 20 and
50 lm melatonin. Melatonin reduced the incidence of reperfusion
arrhythmias from 100% in control to 50% in 5 and 10 lm, to 40%in 20 lmlm melatonin. Melatonin reduced the incidence of reperfusion
arrhythmias from 100% in control to 50% in 5 and 10 lm, to 40%in 20 lmlm, to 40%in 20 lm
and 30% in 50 lm 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 lm lengthened APD and promoted an improved protection. This
latter effect should be considered when in vivo applications of melatonin are
considered.lm 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 lm lengthened APD and promoted an improved protection. This
latter effect should be considered when in vivo applications of melatonin are
considered.lm lengthened APD and promoted an improved protection. This
latter effect should be considered when in vivo applications of melatonin are
considered.