Effect of ketamine on ERK expression in hippocampal neural cells and the ability of learning behavior in minor rats

Objective To study the effects of ketamine on ERK expression in hippocampal neural cells and the ability of learning behavior in minor rats.Methods Forty-eight Sprague-Dawley rats of 21 days old were randomly divided into 6 groups:empty control group(C),training group(T) and ketamine group.The ketamine group was subdivided into groups of 6 h(K6),12 h(K12),24 h(K24) and 72 h(K72) after injection.The rats in ketamine groups were intraperitoneally anesthetized with 50 mg/kg ketamine.The Y-maze was used to test the ability of learning and spatial localization on rats at 6,12,24,and 72 h.Group T only received light-electricity integrated training.At the end of training,all rats were killed and the ERK1,ERK2 and p-ERK1/2 were tested using immunhistochemistry.ResultsThe learning times and total reaction time(TRT) of K6,K12,K24 groups were significantly different from those of group T(P0.05).The expression of p-ERK1/2 was little to be detected in the hippocampus of group C,while that of ERK1 and ERK2 was more.Immunohistochemical staining showed that the level of ERK1,ERK2 and p-ERK1/2 in all rats which received light-electricity integrated training increased remarkably compared with that in group C(P0.01).The expression of ERK1,ERK2 and p-ERK1/2 in hippocampal neural cells of K6,K12 groups significantly decreased compared with that of group T(P0.05).Conclusion Administration of ketamine 50 mg/kg may impair the learning ability of 21 days old rats in short term,and ERK signal transduction pathway may be involved in the impairment of ketamine.