ischaemic preconditioning in isolated rat heart
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چکیده
Objective: To assess whether the protective effect of ischaemic preconditioning (IPC) on endothelial function in coronary arteries of the rat involves prostaglandins. Methods: Isolated rat hearts perfused under constant flow conditions were exposed to 30 min of partial ischaemia (flow-rate 1 ml /min) followed by 20 min of reperfusion, after which coronaries were precontracted with U-46619 0.1 mM, and the coronary response to the endothelium-dependent vasodilator, serotonin (5-HT, 10 mM), was compared to that of the endotheliumindependent vasodilator, sodium nitroprusside (SNP, 3 mM). Prostaglandin production was blocked with a perfusion of indomethacin 10 mM started 15 min before IPC or a corresponding sham period and stopped just before the 20-min reperfusion period. Results: In untreated hearts, ischaemia diminished selectively 5-HT-induced vasodilatation, compared to sham hearts. The vasodilatation by SNP was unaffected after ischaemia and reperfusion. IPC (5 min of zero-flow ischaemia followed by 10 min reperfusion before the 30-min partial ischaemia) preserved the vasodilatation produced by 5-HT. Enzymeimmunoassays showed an increased production of PGE in the IPC 2 group. Treatment of hearts with indomethacin blocked the protective effect of IPC on the vasodilatation produced by 5-HT and decreased the production of PGE . A 5-min perfusion with 3 nM PGE started 15 min before the partial ischaemia, protected the endothelium. This 2 2 was blocked by 1 mM chelerythrine, but not by 0.3 mM glibenclamide. Conclusions: These results suggest that IPC affords protection to endothelial function in coronary arteries of the rat partially via the release of PGE . Under our experimental conditions, the protective 2 effect of PGE is mediated by PKC. 2000 Elsevier Science B.V. All rights reserved. 2
منابع مشابه
Effects of Postconditioning, Preconditioning and Perfusion of L-carnitine During Whole Period of Ischemia/ Reperfusion on Cardiac Hemodynamic Functions and Myocardial Infarction Size in Isolated Rat Heart
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