title: Role of mitochondrial permeability transition pore and mitochondrial ATP-sensitive potassium channels in the protective effects of ischemic preconditioning in isolated hearts from fed and fasted rats.
abstract: The aim of the present study was to assess whether the protective effects of ischemic preconditioning (PC) are associated with activation of the mitochondrial ATP-sensitive potassium channels (mitoKATP) and if there is any relationship between the activity of these channels and the mitochondrial permeability transition pore (MPTP) opening in ischemic-reperfused rat hearts under different nutritional conditions. Langendorff-perfused hearts of fed and 24-h fasted rats were exposed to 25 min of no-flow global ischemia plus 30 min of reperfusion. Fasting accelerated functional recovery and attenuated MPTP opening. The mitoKATP blocker, 5-hydroxydecanoic (HD), did not influence functional recovery and MPTP opening induced by ischemia-reperfusion in the fed hearts but partially reversed the beneficial effects of fasting. PC and the mitoKATP opener, diazoxide (DZ), improved functional recovery, preserved cell viability, and inhibited MPTP opening in both fed and fasted hearts. The protection elicited by PC and DZ on contractile recovery and MPTP opening was reversed by HD, which did not affect cell viability. Altogether, these results argue for a role of mitoKATP and its impact on preservation mitochondrial inner membrane permeability as a relevant factor in the improvement of contractile function in the ischemic-reperfused rat heart. They also suggest that the functional protection elicited by PC may be related to this mechanism.
authors.affiliation: Physiology Unit, Department of Biological Sciences, Faculty of Pharmacy and Biochemistry, University of Buenos Aires and IQUIMEFA-CONICET, 1113, Buenos Aires, Argentina, gmarina@ffyb.uba.ar.
authors.forename: M G Marina
authors.initials: MG
authors.lastname: Prendes
authors.forename: R
authors.initials: R
authors.lastname: Hermann
authors.forename: M E
authors.initials: ME
authors.lastname: Torresin
authors.forename: D
authors.initials: D
authors.lastname: Vélez
authors.forename: E A
authors.initials: EA
authors.lastname: Savino
authors.forename: A
authors.initials: A
authors.lastname: Varela
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D003652:Decanoic Acids / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D003981:Diazoxide / Q000494:pharmacology; D005215:Fasting / Q000378:metabolism; D005260:Female; D006880:Hydroxy Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism*; D000083162:Mitochondrial Permeability Transition Pore; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000503:physiopathology / Q000517:prevention & control*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000819:agonists / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002316:Cardiotonic Agents; D003652:Decanoic Acids; D006880:Hydroxy Acids; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D026902:Potassium Channel Blockers; D015221:Potassium Channels; C117780:mitochondrial K(ATP) channel; C052853:5-hydroxydecanoic acid; D003847:Deoxyglucose; D003981:Diazoxide