Protective effect of M3 receptor on H2O2 -induced apoptosis of rat myocardial cells in vitro.
OBJECTIVE
To observe the effect of activation of M3 receptor on H2O2 induced apoptosis in cultured rat myocytes and to investigate its possible mechanisms.


METHODS
Isolated neonatal cardiomyocytes were cultured. Morphologic changes were observed by microscopy. The apoptosis in cardiomyocyte was detected by terminal deoxynucleotide transferase directed d-UTP nick and end labeling (TUNEL) assay. The expression of apoptosis-related protein in Bcl-2 and Fas was measured by immunohistochemistry assay. [Ca2+]i in single cardiomyocyte loaded with Fluo 3-AM was measured by confocal microscope.


RESULTS
H2O2-mediated myocyte apoptosis was attenuated by M3 receptor agonist choline (10 mmol x L(-1)). Pretreatment of cardiac myocytes with choline also increased Bcl-2, decreased Fas expression, and inhibited the increase in FI value of [Ca2+]i in H2O2-stimulated cardiac myocytes. However, blockade of M3 receptor by 4DAMP (10 nmol x L(-1)) completely inhibited the effects of choline on H2O2-stimulated cardiac myocytes.


CONCLUSIONS
Activation of M3 receptor showed protective effect on H2O2-induced apoptosis in cultured rat myocytes and this effect might be related to modulating the expression of some genes including Bcl-2 and Fas as well as the downregulation of [Ca2+]i.
Liu
Yan
Y
Department of Pharmacology, Bio-pharmaceutical Key Laboratory of Heilongjiang Province-Incubator of State Key Laboratory, Harbin Medical University, Harbin 150086, China.
Sun
Hong-Li
HL
Wu
Hong
H
Gao
Yan-Hui
YH
Li
Hu-Lun
HL
Yang
Bao-Feng
BF
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002794:Choline / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043587:Receptor, Muscarinic M3 / Q000819:agonists*; D019014:fas Receptor / Q000378:metabolism
D019253:Proto-Oncogene Proteins c-bcl-2; D043587:Receptor, Muscarinic M3; D019014:fas Receptor; D006861:Hydrogen Peroxide; D002794:Choline; D002118:Calcium