Resistance to myocardial infarction induced by heat stress and the effect of ATP-sensitive potassium channel blockade in the rat isolated heart.
1. Heat stress (HS) is known to protect against myocardial ischaemia-reperfusion injury by improving mechanical dysfunction and decreasing necrosis. However, the mechanisms responsible for this form of cardioprotection remain to be elucidated. ATP-sensitive potassium (K(ATP)) channels have been shown to be involved in the delayed phase of protection following ischaemic preconditioning, a phenomenon closely resembling the HS-induced cardioprotection. The aim of this study was thus to investigate the role of K(ATP) channels in HS-induced protection of the isolated rat heart. 2. Twenty four hours after whole body heat stress (at 42 degrees C for 15 min) or sham anaesthesia, isolated perfused hearts were subjected to a 15 min stabilization period followed by a 15 min infusion of either 10 microM glibenclamide (Glib), 100 microM sodium 5-hydroxydecanoate (5HD) or vehicle (0.04% DMSO). Regional ischaemia (35 min) and reperfusion (120 min) were then performed. 3. Prior heat stress significantly reduced infarct-to-risk ratio (from 42.4+/-2.4% to 19.4+/-2.9, P<0.001). This resistance to myocardial infarction was abolished in both Glib-treated (40.1+/-1.8% vs 42.3+/-1.8%) and 5HD-treated (41.2+/-1.8% vs 41.8+/-1.2%) groups. 4. The results of this study suggest that K(ATP) channel activation contributes to the cytoprotective response induced by heat stress.
Joyeux
M
M
Laboratoire de Pharmacologie Cardiovasculaire Expérimentale-Biomolécules, Université Joseph Fourier, La Tronche, France.
Godin-Ribuot
D
D
Ribuot
C
C
D000818:Animals; D006321:Heart / Q000187:drug effects*; D018882:Heat Stress Disorders / Q000503:physiopathology*; D006439:Hemodynamics; D066298:In Vitro Techniques; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D051381:Rats
C510692:Kcnj1 protein, rat; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying