select ad.sno,ad.journal,ad.title,ad.author_names,ad.abstract,ad.abstractlink,j.j_name,vi.* from articles_data ad left join journals j on j.journal=ad.journal left join vol_issues vi on vi.issue_id_en=ad.issue_id where ad.sno_en='49114' and ad.lang_id='6' and j.lang_id='6' and vi.lang_id='6'
ISSN: 2155-6148
Takayuki Miura, Uno Imaizumi, Munetaka Furuya, Jun Shirahama, Hirofumi Arisaka and Kazu-ichi Yoshida
Objectives: The present study aimed to investigate whether ischemic or sevoflurane-induced preconditioning exerts infarct size limiting effects and depresses ischemia-reperfusion arrhythmias through opening of mitochondrial KATP channels in rabbits in vivo.
Methods: Rabbits anesthetized with ketamine and xylazine given intramuscularly underwent 30 min of left anterior descending coronary artery (LAD) occlusion followed by 3 hrs of reperfusion. Before this, rabbits were randomized into one of five groups. Control rabbits received no intervention before 30 min LAD occlusion and 3 h reperfusion (Group-C). The ischemia-preconditioned (IP) rabbits underwent 5 min LAD occlusion followed by 10 min of reperfusion before prolonged ischemia-reperfusion (Group-IP). In the sevoflurane (S)–preconditioned group, 30 min of sevoflurane exposure at a 1.5% end-tidal concentration was followed by 15 min of washout before prolonged ischemia-reperfusion (Group-S). The selective mitochondrial KATP channel blocker, 5-hydroxy-decanoate (5-HD, 5 mg/kg) was given intravenously 10 min before ischemic preconditioning and sevoflurane exposure, respectively (Group-5-HD-IP, Group-5-HD-S). An electrocardiogram was recorded throughout the experiment via lead 2 of the standard electrocardiogram. At the end of the 3 hrs reperfusion period, area at risk (R) and infarct size (I) were measured.
Results: RPP decreased in Group-5-HD-IP and Group-5-HD-S compared with Group-S at 30 min after ischemia. The ratio of R to left ventricular mass showed no significant difference among all groups. I/R values of each group were 51.6 ± 3.0% in Group-C, 33.3 ± 4.7% in Group-IP, 36.6 ± 4.8% in Group-S, 48.9 ± 5.2% in Group-5-HD-IP, 54.8 ± 4.2% in Group-Group-5-HD-S. There was no significant difference in duration of arrhythmias during myocardial ischemia and reperfusion among 5 groups.
Conclusion: Ischemic preconditioning and sevoflurane-induced preconditioning exert infarct size limiting effects through opening of mitochondrial KATP channels. However, ischemic preconditioning and sevoflurane-induced preconditioning do not have antiarrhythmic effects. This suggests that the opening of mitochondrial KATP channels does not cause antiarrhythmic effects.