Title: Role of inducible nitric oxide synthase in delayed cardioprotection induced by remifentanil preconditioning in rats
Abstract: Objective To evaluate the role of inducible nitric oxide synthase (iNOS) in the delayed cardioprotection induced by remifentanil preconditioning in rots. Methods Thirty-six adult male Wistar rats,weighing 250-300 g, were randomly divided into 6 groups (n = 6 each). Myocardial ischemia was induced by 5 min, repeating 3 times at 5 min intervals. In greup Ⅱ rots were treated with iv SMT (a selective iNOS inhibitor)10 mg/kg at 10 min before myocardial ischemia. In group Ⅲ iv SMT 10 mg/kg was injected following the infusion with iv SMT 10 mg/kg at 10 min before myocardial isehemia. In group Ⅵ iv SMT 10 mg/kg was injected following the infusion of remifentanil. HR and MAP were recorded before ischemia and every 15 min during ischemia period and every 30 min during reperfasion period. The rote-pressure product (RPP) was calculated. The blood samples from right internal carotid artery were obtained for determination of plasma activity of CK-MB immediately before ischemia, at 30 min of ischemia and at 120 min of reperfusion. The animals were then killed and heart,s removed to measure the left ventricle area (LVA), the myocardial infarct area (IA) and the area at risk (AAR), and AAR/LVA, IA/LVA and IA/AAR were calculated. Results There were no significant differences in HR, MAP,RPP and AAR/LVA at every measurement point during the experiment among all groups. As compared to group Ⅰ ,Ⅱ and Ⅲ, plasma activity of CK-MB, IA/LVA and IA/KAR were significantly decreased at 30 min of ischemia and 120 min of reperfusion in group Ⅳ and Ⅵ . There were no significant differences in plasma activity of CK-MB,IAJLVA and IA/AAR between group Ⅰ,Ⅱ and Ⅲ . Plasma activity of CK-MB, IA/LVA and IA/AAR were significantly higher at 30 min of ischemia and 120 min of reperfusion in group Ⅴ than in group Ⅳ . Plasma activity of CK-MB, IA/LVA and IA/AAR were significantly lower at 30 min of ischemia and 120 min of reperfusion in group Ⅵ than in group Ⅴ . Conclusion iNOS is involved in the delayed cardioproteetion induced by remifentanil preconditioning in rats, and it is a mediator but not a trigger.
Key words:
Nitric-oxide synthase; Piperidines ; lschemic preconditioning; Myocardial reperfusion injury
Publication Year: 2009
Publication Date: 2009-08-20
Language: en
Type: article
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