ABSTRACT
AIM: To investigate whether glycine receptor is involved in the protection of glycine against(anoxia/reoxygenation) injury in cardiomyocytes by detecting oxygen free radical metabolism,apoptosis and intracellular calcium overload.METHODS: The neonatal rat cardiomyocytes were cultured and exposed to anoxia and reoxygenation((A/R)) in the presence of glycine receptor antagonist,glycine or in free chloride buffer.The superoxide dismutase(SOD) activity,the contents of malondialdehyde(MDA) and nitric oxide(NO),the intracellular free calcium concentration and the apoptotic rate in the cardiomyocytes were determined.RESULTS: SOD activity and NO content in cardiomyocytes were lower,but MDA content,intracellular free calcium concentration and apoptotic rate in cardiomyocytes were higher in A/R group than those in control.Pretreatment with glycine inhibited the above changes caused by A/R,which was reversed by strychnine treatment and in the free chloride medium.CONCLUSIONS: Glycine inhibits free radical production,attenuates calcium overload,decreases apoptotic rate and increases SOD activity and NO release in cardiomyocytes exposed to(A/R).These findings suggest that glycine exerts a protective effect against A/R injury via glycine receptor and glycine protects the neonatal rat cardiomycytes from A/R-induced injury in a chloride-dependent manner.