The Expressions Of PBR In The Brainstem Of PCPA-induced Insomnia Rats

ObjectivesTo make p-chlorophenylalanine(PCPA) induced experimental insomnia model, and design normal saline control group and diazepam interference group at the same time.Test the expression of mRNA and protein of the PBR in brain stem of them in order to investigate the relationship between PBR and insomnia. Methods1. Grouping and building model: thirty-six adult male Sprague Dawley(SD) rats whose weight are 180-220g were randomly divided into three groups.①Model group: PCPA was injected intraperitoneally by 300mg/kg every day at 8:30-9:00 AM for 2 days to establish model of insomnia. PCPA dissolved into a suspension fluid with a slightly alkaline saline (pH:7-8) and prepared by 1ml/100g; then distilled water administered intragastrically with 1ml/100g/d begin at the 3rd day for 5 days;②Control group: All steps were the same with group one, but PCPA was insteaded by saline.③Interference group: Distilled water was replaced by diazepam in model group,0.92mg/kg/d for 5 days. Diazepam tablets dissolved in distilled water, according to 1ml/100g preparation of aqueous solution.2. Experimental observation of animal behavior and body weight measurement: Regularly observe the behavior of rats everyday, video recorde the activity of rats half-hour per 3 hours, compare the changes among three groups at vertical and horizontal two-way. Weigh and record all rats' weight when they into group, before intraperitoneal injection, before administered and before decapitation at 8:00～8:20.3. Animals in each group were decapitated rapidly at the 6th day after intragastricly begin. Took the brain stem from rat and stored them in negative 80 degrees refrigerator.4. The expressions of PBR in the brainstem were detected by RT-PCR and WB. Results1. Behavioral performance: No significant change in control group; the sleep-wake rhythm disappeared in model and intervention group at 28h after the first intraperitoneal injection of PCPA suspension,94.4% were induced into insomnia; in intervention group rats, insomnia symptoms were gradually restored after the administration of diazepam compared to model group.2. Weight change: When into group and before the first intraperitoneal injection, three group rats weigh fairly; before administered, the weight of model group are equivalent to intervention group' s, but both lower than the control group' s(q=5.403, p<0.01; q=5.508, p<0.01); before decapitation, model and intervention group' s reduced to control group(q=12.214, p<0.01; q=8.045, p<0.01), at the same time, intervention group's than in model group's increased (q=4.166, p<0.05).3. Comparing with interference group and control group, the expression of mRNA of PBR in model group was up-regulated (p<0.05). However, intervention and control groups showed no difference (p>0.05).4. Comparing with interference group and control group, the expression of protein of PBR in model group was up-regulated (p<0.05). However, intervention and control groups showed no difference (p>0.05). Conclusions1. The up-regulation of the expression of PBR may involved in the mechanisms of hyperexcitability that lead to acute insomnia.2. According to the obtained results, rats exhibited behavioral, weight alterations after PCPA-induced acute insomnia.