Expression of inositol 1,4,5-triphosphate receptor type I in the myocardial tissue of rats with endotoxic shock

Objective To investigate the changes of inositol 1,4,5-triphosphate receptor type I （ IP3 R I ） expression in the myocardial tissue of rats with endotoxic shock and probe the possible mechanisms of myocardial depression. Methods Thirty-three male Wistar rats were divided into four groups：control group （n = 6 ） were injected normal saline（ 4 ml/kg ）, and the other 3 groups （n = 9 ） were injected endotoxin via femoral vein with a different dose of 10 mg/kg, 5 mg/kg, and the artificial sacrificed group （ 10 mg/kg, the rats were sacrificed when the mean arterial pressure was first rapidly decreased, then gradually increased to the normal level）. IP3R I expression in the myocardial tissue of rats was detected by immunohistochemistry, Western blot and colloidal gold immunoelectron microscopy technique. Results IP3RIexpressions were increased significantly in each group of rats with endotoxic shock than in the control group （ P 〈 0. 01 ）, and most obviously enhanced in the the artificial sacrificed group. The expression of IP3RIwas related to the level of mean arterial pressure. Ectopic expression of IP3RIwas observed around the cell membrane of the cardiac myocytes. Conclusion （ 1 ） The expression of IP3 Rlenhances in the myocardial tissue of rats with endotoxic shock, and exists ectopic expression. （2） The expression of IP3 RIwas related to the level of mean arterial pressure. （3） IP3RI may be related to the cardiac contractility and involved in the regulation of mean arterial pressure. Key words: Endotoxic shock ;  Myocardium ;  Inositol 1,4,5-triphosphate receptor type I ;  Rat