title: Effect of an Ilex paraguariensis (yerba mate) extract on infarct size in isolated rat hearts: the mechanisms involved.
abstract: Tea made from Ilex paraguariensis (IP) dried and minced leaves is a beverage widely consumed by large populations in South America as a source of caffeine (stimulant action) and for its medicinal properties. However, there is little information about the action of IP on the myocardium in the ischemia-reperfusion condition. Therefore, the objective of this study was to examine the effects of an aqueous extract of IP on infarct size in a model of regional ischemia. Isolated rat hearts were perfused by the Langendorff technique and subjected to 40 min of coronary artery occlusion followed by 60 min of reperfusion (ischemic control hearts). Other hearts received IP 30 μg mL(-1) during the first 10 min of reperfusion in the absence or presence of l(G)-nitro-l-arginine methyl ester [l-NAME, a nitric oxide synthase (NOS) inhibitor]. The infarct size was determined by triphenyltetrazolium chloride (TTC) staining. Post-ischemic myocardial function and coronary perfusion were also assessed. Cardiac oxidative damage was evaluated by using the thiobarbituric acid reactive substance (TBARS) concentration and the reduced glutathione (GSH) content. To analyze the mechanisms involved, the expressions of phosphorylated forms of eNOS and Akt were measured. In isolated mitochondria the Ca(2+)-induced mitochondrial permeability transition pore (mPTP) opening was determined. IP significantly decreased the infarct size and improved post-ischemic myocardial function and coronary perfusion. TBARS decreased, GSH was partially preserved, the levels of P-eNOS and P-Akt increased and mPTP opening diminished after IP addition. These changes were abolished by l-NAME. Therefore, our data demonstrate that acute treatment with IP only during reperfusion was effective in reducing myocardial post-ischemic alterations. These actions would be mediated by a decrease of mitochondrial permeability through IP-activated Akt/eNOS-dependent pathways.
authors.affiliation: Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata-CONICET, La Plata, Argentina. smosca@med.unlp.edu.ar.
authors.forename: Luisa F
authors.initials: LF
authors.lastname: González Arbeláez
authors.affiliation: Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata-CONICET, La Plata, Argentina. smosca@med.unlp.edu.ar.
authors.forename: Juliana C
authors.initials: JC
authors.lastname: Fantinelli
authors.affiliation: Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata-CONICET, La Plata, Argentina. smosca@med.unlp.edu.ar.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ciocci Pardo
authors.affiliation: Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata-CONICET, La Plata, Argentina. smosca@med.unlp.edu.ar.
authors.forename: Claudia I
authors.initials: CI
authors.lastname: Caldiz
authors.affiliation: Departament de Farmacologia, Facultat de Farmàcia, Universitat de València, Spain.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Ríos
authors.affiliation: Cátedra de Farmacología Básica, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, CIC, Provincia de Buenos Aires, La Plata, Argentina.
authors.forename: Guillermo R
authors.initials: GR
authors.lastname: Schinella
authors.affiliation: Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata-CONICET, La Plata, Argentina. smosca@med.unlp.edu.ar.
authors.forename: Susana M
authors.initials: SM
authors.lastname: Mosca
mesh_terms: D000818:Animals; D005978:Glutathione / Q000378:metabolism; D006321:Heart / Q000187:drug effects*; D006801:Humans; D030019:Ilex paraguariensis / Q000737:chemistry*; D066298:In Vitro Techniques; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D010936:Plant Extracts; D019001:Nitric Oxide Synthase; D005978:Glutathione