KATP Channel Mediate the Protective Effect of Hypercarbonic Preconditioning on Myocardial Cells / 天津医药

ABSTRACT

Objective: To investigate the function of the ATP-sensitive K+(KATP) channel activation on the protective effect of hypercarbonic acidosis preconditioning on rabbit myocardial cells. Methods: Thirty-two rabbits were randomly divided into 4 groups (n = 8 for each group) pseudo-operation group (group P), ischemia and reperfusion group(group IR), hypercarbonic acidosis group(group H) and hypercarbonic acidosis+ glybenzcyclamide group (group H+G). Animals were ventilated normally in group IR and group P, tidal volume 15 mL/kg, breathing rate 35 bpm .The PETCO_2 was maintained at the level of 40-50 mm Hg for 30 minutes. Animals received low-frequency, low volume ventilation in group H group H+G, tidal volume 10 ml/kg, breathing rate 25 bpm to achieve hypercarbonic acidosis. The target value of PETCO_2 was 75-85 mm Hg. This value was maintained for 5 minutes. The animals then were ventilated normally to make the PETCO_2 return to 40-50 mm Hg. Animals were injected with 0.3 mg/kg glybenzcyclamide 10min before achieving hypercarbonic acidosis with hypoventilation in group H+G. Animals received ligation of left anterior branch artery for 30 minutes and reperfusion for 180 minutes in each group except P group. The myocardial ischemia area, the myocardial infarction area and their ratios were calculated by the ismaeil methods. Results: The ratio of the myocardial infarction area to the myocardial ischemia was significantly less in group H than those of group IR and group H+G (P 0.05). Conclusion: Hypercarbonic acidosis preconditioning can protect the cardiomyocytes by activating the KATP channel.