Effects of ketamine on nNOS activity and CAPON expression in prefrontal lobe of mentally depressed rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of ketamine on neuronal nitric oxide synthase (nNOS) activity and carboxy-terminal PDZ ligand of nNOS (CAPON) expression in the prefrontal lobe of mentally depressed rats.Methods Adult male Sprague-Dawley rats,aged 2.5-3.0 months,weighing 210-260 g,were used in the study.Menial depression was induced by exposing the rats to chronic unpredictable mild stress.Twenty-four animals in which mental depression was successfully induced were randomly divided into 2 groups (n =12 each)mental depression group (group D) and ketamine group (group K).Another 12 rats were chosen and served as control group (group C).Group K received intraperitoneal ketamine 10 mg/kg once a day for 7 consecutive days,while groups C and D received intraperitoneal normal saline 10 ml/kg instead of ketamine.Sucrose preference test and open field test were performed before administration and at 1 day after the end of administration.The total distance,number of rearing and sucrose preference percentage (SPP) were recorded.The rats were sacrificed 1 day after the last test for determination of the expression of nNOS and CAPON protein (using immuno-histochemistry)and mRNA (by RT-PCR) in the prefrontal lobe.Results Compared with group C,the total distance was shortened,the number of rearing and SPP were significantly decreased,the expression of nNOS protein and mRNA was up-regulated and the expression of CAPON protein and mRNA was down-regulated in groups D and K (P ＜ 0.05).Compared with group D,the total distance was prolonged,the number of rearing and SPP were significantly increased,the expression of nNOS and mRNA was down-regulated and the expression of CAPON protein and mRNA was up-regulated in group K (P ＜ 0.05).Conclusion Ketamine can improve the depressive state through promoting the expression of CAPON and inhibiting nNOS activity in the prefrontal lobe of mentally depressed rats.