Dynamic changes of nuclear translocation of extracellular signal-regulated kinase 1/2 after culture of hippocampal neurons in magnesium-free medium

Abstract

Objective To observe the phosphorylation of extraceUular signal-regulated kinase (p-ERK1/2) and its nuclear translocation at different time points after the hippocampal neurons were cul-tured in the magnesium-free medium, and discuss the changes of ERK1/2 signal pathway after epileptic injury of hippocampal neurons. Methods Hippocampal neurons from newly-born Wistar rats were cul-tured with NB medium and B-27 for 9 days, and then were transferred to the magnesium-free medium to induce epileptic injury to the hippocampal neurons. The distribution of p-ERK1/2 in the hippocampal neurons before and after the epileptic injury was observed under laser scanning confocal microscope, and the expression of p-ERK1/2 at different time points after culturing the hippocampal neurons in the magne-sium-free medium was detected by Western blot. Results Before the epileptic injury of hippocampal neurons, p-ERK1/2 mainly expressed in the cytoplasm and axoplasm of the neurons. While after the epi-leptic injury, the expression of p-ERK1/2 was detected in the cytoplasm, axoplasm and nucleus of the neurons. The expression of p-ERK1/2 was increased one hour after the epileptic injury, and peaked at hour 3 (p-ERK1:2.2838±0.1 186; p-ERK2:4.1 273±0.0 927). There was significant difference in the expression of p-ERK1/2 between the hippocampal neurons cultured with or without magnesium-free medium (P < 0.05). Conclusion Epileptic injury may induce increased expression of p-ERK1/2 in hippocampal neurons, and the activated ERK1/2 signal pathway may be associated with the epileptic dis-charge in neurons. Key words: Neurons; Extracelluar-signal-regulated MAP kinases; Epileptic injury