Objective： To investigate the activation （phosphorylation） and subcellular localization of extracellular signal-regulated kinase （ERK1/2）, as well as the possible mechanism, following cerebral ischemia and ischem...Objective： To investigate the activation （phosphorylation） and subcellular localization of extracellular signal-regulated kinase （ERK1/2）, as well as the possible mechanism, following cerebral ischemia and ischemia/reperfusion in rat hippocampus. Methods： Transient brain ischemia was induced by the four-vessel occlusion method in Sprague-Dawley rats. Western blot analysis. Results： During cerebral ischemia without reperfusion ERK1/2 activation immediately increased with a peak at 5 min and then decreased in the cytosol fraction, which was paralleled by the increase of ERK1/2 activation in the nucleus fraction. During reperfusion, ERK1/2 was activated with peaks occurring at 10 min in the cytosol and at 30 min in the nucleus, respectively. Under those conditions, the protein expressions had no significant change. In order to clarify the possible mechanism of ERK1/2 activation, the rats were intraperitoneally administrated with N-methyl-D-aspartate （NMDA） receptor antagonist dextromethorphan （DM）, L-type voltage-gated Ca^2＋ channel （L-VGCC） antagonist nifedipine （ND） 20 rain before ischemia, finding that DM and ND markedly prevented ERK1/2 activation of nucleus fraction induced by reperfusion, not by ischemia. Conclusion： These results suggested that the nuclear translocation mainly occurred during ischemia, while ischemia-reperfusion induced ERK1/2 activation both in the cytosol and the nucleus. Two type calcium channels contributed, at least partially, to the activation of ERK1/2.展开更多
基金Supported by grants from the Education Departmental Natural Science Research Funds of Hebei and Jiangsu Provinces of China (200510604KJD310207)the Key Project of the National Natural Science Foundation of China (No. 30330190).
文摘Objective： To investigate the activation （phosphorylation） and subcellular localization of extracellular signal-regulated kinase （ERK1/2）, as well as the possible mechanism, following cerebral ischemia and ischemia/reperfusion in rat hippocampus. Methods： Transient brain ischemia was induced by the four-vessel occlusion method in Sprague-Dawley rats. Western blot analysis. Results： During cerebral ischemia without reperfusion ERK1/2 activation immediately increased with a peak at 5 min and then decreased in the cytosol fraction, which was paralleled by the increase of ERK1/2 activation in the nucleus fraction. During reperfusion, ERK1/2 was activated with peaks occurring at 10 min in the cytosol and at 30 min in the nucleus, respectively. Under those conditions, the protein expressions had no significant change. In order to clarify the possible mechanism of ERK1/2 activation, the rats were intraperitoneally administrated with N-methyl-D-aspartate （NMDA） receptor antagonist dextromethorphan （DM）, L-type voltage-gated Ca^2＋ channel （L-VGCC） antagonist nifedipine （ND） 20 rain before ischemia, finding that DM and ND markedly prevented ERK1/2 activation of nucleus fraction induced by reperfusion, not by ischemia. Conclusion： These results suggested that the nuclear translocation mainly occurred during ischemia, while ischemia-reperfusion induced ERK1/2 activation both in the cytosol and the nucleus. Two type calcium channels contributed, at least partially, to the activation of ERK1/2.
