CONICET | Buscador de Institutos y Recursos Humanos

The aim of this study was to analyze the effects of brief vagal stimulation (VS) applied before ischemia on acute myocardial infarction and its long-term benefits on an experimental ischemia/reperfusion and non-reperfusion model.Material and methods: Male FVB mice were randomly assigned to different groups. A regional myocardial ischemia during 45 min, followed by either 2 hours or 28 days of reperfusion, with or without 10 min of pre-ischemic vagal stimulation (VS) was performed. In order to evaluate the participation of muscarinic receptors, atropine was administrated during VS. Left ventricular function (LVF) was assessed by echocardiography and catheterization of the left ventricle. Morphometric parameters were also analyzed by a comparison of both ventricles weight (VW) and lungs weight (LW) with the length of the tale (TL) and the tibia (TiL). Finally, infarct size (IS) on the 2h reperfused hearts was measured with TTC. Results: VS+IR-2h presented smaller IS compared to IR-2h and administration of atropine reverted the protection. On the other hand, while the IR-28d group showed a significantly higher LVEDP with a lower EF and SF compared to the Sham-28d group, and VS reverted these findings, the administration of atropine did not reduced echocardiographic parameters. A reduction in EF and SF was observed in the group without reperfusion. EV improves ventricular function and this was not reversed with atropine. Finally, both in the group with ischemia and reperfusion and in the group without reperfusion there was an increase in ventricular weight that was not reduced with the EV.In conclusion, brief VS applied before ischemia confers cardioprotection, reducing the acute infarct size and improving long-term LVF independently of the action of muscarinic receptor and infarct size.