Effects Of Ketamine On Learning And Memory Function And Expression Of Immediate Early Genes In Hippocampus Of Minor Rats

Objective: To study the effects of ketamine on learning and memory function and Egr-1expression in hippocampus of minor rats.Methods: Twenty male Sprague-Dawley rats of21days old were randomly divided intotwo groups, each group of10, namely of ketamine group (Ket group) and normal salinecontrol group (Ns group). These minor rats could feed and water freely except for theexperimental time. Rats in Ket Group were intraperitoneally injected with50mg/kgketamine, and those in Ns group were administrated with same amount of normal salinefor6days. Rats were observed and monitored to maintain the vital signs during the druginjection. Morris water maze place navigation test was adopted to explore the learningand memory function at24h after the final injection. In an hour of the final MWMspatial probe test rats were anesthesia with10%chloral hydrate（400mg/kg）intraperitoneal injection. The sections of hippocampus were quickly obtained on ice,and levels of Egr-1were analyzed by quantitative real time PCR and western blot.Results:(1) In Morris water maze test the latency in place navigation of Ket group wassignificantly longer than that of Ns group (P <0.05), the times of crossing the platformand total swimming distance were significantly decreased (P <0.05).(2) A certainamount of Egr-1mRNA were expressed in hippocampus of the two experiment groups. But compared with Ns group, Ket group Egr-1mRNA expression was lower, and hadthe obvious statistical difference (P <0.05).(3) It was revealed that the expression ofhippocampal immediate early gene Egr-1protein in Ket group was significantly lowerthan that in Ns group (P <0.05).Conclusion: Repeated administration of sub-anesthesia doses drugs ketamine in minorrats may result in learning and memory impairment and the decrease of Egr-1expression. Inhibition of Egr-1expression post ketamine administration might play animportant role in the behavior change of minor rats.