OBJECTIVETo study the effects of calcium and calmodulin dependent kinase against hypoxic neuronal injury and its possible mechanisms.

METHODSEmbryonic cortical neurons of 17-day pregnant embryo Sprague-Dawley rats were cultured in vitro and the cultured neurons were randomly allocated into different groups that exposed to hypoxia or hypoxia +calcium channel antagonist. Nimodipine and MK-801 were used to block the L-voltage sensitive calcium channel and NMDA receptor respectively before hypoxia. The methyl thiazolyl tetrazolium (MTT) method was used to determine the cell viability. Fluo-4AM, an intracellular calcium indictor, was used to detect the changes of intracellular calcium after hypoxia. The expressions of CaMKII and CaMKIV were detected by Western blot.

RESULTSThe cell viability of the nimodipine or MK-801-treated groups was significantly higher than that of the untreated hypoxia group. The intracellular calcium level of the nimodipine-treated group decreased rapidly after hypoxia. Compared to nimodipine treatment, MK-801 treatment could inhibit hypoxia-induced calcium influx for a longer time. Nimodipine treatment decreased the CaMKII expression while MK-801 treatment decreased the CaMKIV expression.

CONCLUSIONSNimodipine and MK-801 protect neurons from hypoxic injury possibly by the inhibition of CaMKII and CaMKIV expressions respectively.