Effects of ketamine on learning and memory function and expression of Egr-1 in hippocampus of minor rats

Objective: To investigate the effects of ketamine on learning and memory function and expression of early growth responsive gene-1 (Egr-1) in hippocampus of minor rats. Methods: Twenty minor SD rats were randomly divided into normal saline control group (Ns group) and ketamine group (Ket group). Rats in Ket group were intraperitoneally injected with 50 mg/kg ketamine, and those in Ns group were administrated with same amount of normal saline for 6 d. Morris water maze test was adopted to explore the learning and memory function at 24 h after the final injection. The sections of hippocampus were obtained at 1 h of the final Morris water maze test, and the expression of Egr-1 mRNA and protein was determined by Real-Time PCR and Western blotting respectively. Results: In Morris water maze test, the latency in place navigation in Ket group was significantly longer than that in Ns group (P<0.05), and the times of crossing the platform and total swimming distance in Ket group were significantly decreased compared with Ns group (P<0.05). It was revealed that the expression of Egr-1 mRNA and protein in Ket group was significantly lower than that in Ns group (P<0.05). Conclusion: Application of ketamine in minor rats may result in learning and memory impairment, and the mechanism may be associated with the down-regulation of expression of Egr-1 in hippocampus.