快速眼球运动睡眠剥夺及γ-氨基丁酸能药物干预对大鼠认知功能的影响

目的 建立快速眼球运动(REM)睡眠剥夺和下丘脑穹隆周围核微量渗析大鼠模型,研究不同程度REM睡眠剥夺和恢复对SD大鼠认知功能、下丘脑泌素(Hcrt)能系统和γ-氨基丁酸(GABA)能系统的影响及其可能机制.方法 将雄性SD大鼠随机分为对照组和REM睡眠剥夺组,REM睡眠剥夺组又分非手术对照组(nonOP)、假手术对照组(Sham)、GABAA受体拈抗剂SR-95531组(SR)和GABA再摄取抑制剂NO-711组(NO).采用改良多平台水环境法(MMPM)建立REM睡眠剥夺SD大鼠模型,利用Morris水迷宫测定大鼠在不同程度REM睡眠剥夺对认知功能的影响变化,采用免疫荧光技术检测下丘脑Hcrt神经元数量形态和原癌基因(Fos)表达、下丘脑GABA的A型受体α1(GABAA Rα1)亚单位表达累积吸光度值;采用高效液相色谱仪(HPLC)测定下丘脑GABA和谷氨酸(Glu)含量.建立穹隆周围核微量渗析SD大鼠模型,观察GABAA受体拈抗剂SR-95531和GABA再摄取抑制剂NO-711对上述指标的影响.结果 REM睡眠剥夺导致nonOP组和Sham组SD大鼠认知功能下降、下丘脑外侧区Fos阳性细胞总数和Fos-Hcrt双阳性细胞(F+&H+)数量增加、下丘脑GABA含量和GABAA Rα1表达增加,且变化程度均与REM睡眠剥夺时间长短呈正相关.但上述指标的变化都能够在不同程度睡眠恢复后得以修正.NO组与对照组比较,睡眠剥夺期间认知功能下降、下丘脑外侧区Fos阳性细胞总数和F+&H+数量增加(F=9.56、12.14、10.12,P＜0.05),且增加程度均与REM睡眠剥夺时间长短呈正相关;但睡眠恢复后差异无统计学意义.SR组与对照组比较,睡眠剥夺期间差异无统计学意义,但睡眠恢复期间认知功能下降、下丘脑外侧区Fos阳性细胞总数和F+&H+数量增加(F=12.03、11.38、8.36,均P＜0.05).SR组GABA含量和GABAA Rα1表达在全部5个时间点均明显增加(F=11.36、14.67,均P＜0.05),而NO组仅在SD 5d的GABAA Rα1表达明显增加(F=12.06,P＜0.05).结论 在REM睡眠剥夺和恢复过程中,GABA能系统存在自身调节机制,但无论是其再摄取抑制剂NO-711还是受体竞争剂SR-95531,均对认知功能下降产生不利影响,因此GABA能系统并不是治疗失眠的最理想靶点.Hcrt能神经元系统和GABA能系统之间存在相互抑制的作用,可以通过降低Hcrt神经元激活来改善睡眠的效果.并据此推断,Hcrt能系统可能是诱导睡眠和治疗失眠的潜在理想靶点.

Effects of rapid eye movement sleep deprivation and GABAergic drug intervention on cognition in rats

Objective To establish an animal model of rapid eye movement (REM) sleep deprivation (SD) and an animal model for perifornical nucleus microdialysis and investigate the change of cognition, hypocretinergic system and GABAergic system in rats' hypothalamus after various degrees of REM sleep deprivation and sleep revival and two GABAergic drugs intervention. Methods The modified multiple platform method (MMPM)was used to establish sleep deprivation model and the cognitive function was assessed by Morris' water maze. Immunofluorescence technique was used to analyze the number of Hypocretin (Hcrt) immunoreactive neurons, total Fos immunoreactive neurons, Hcrt and Fos colabeled neurons, and the integrated optical density ( IA ) of GABAA Rαl immunoreactive area in rats' hypothalamus.High performance liquid chromatograph (HPLC) was used to quantitatively analyze the level of GABA and Gluin in the rats' hypothalamus. Two GABAergic drugs, a selective GABAA R antagonist, SR-95531, and a selective blocker of type 1 GABA transporter (uptake blocker), NO-711, were used for perifornical nucleus microdialysis. Results There was no statistically significant difference in tests between CC and TC ( Define CC and TC). There was a significant decrease (P ＜ 0. 05 ) of cognitive function measured by Morris maze test in SD 3 d, SD 5 d and RS 6 h of SD groups compared with CC and TC groups. Number of Fos immunoreactive, F+ &H+ immunoreactive neuronsand IA of GABAA Rαl immunoreactive area were all significantly increased ( P ＜ 0. 05 ). Content of GABA measured by HPLC was also increased ( P ＜ 0. 05 ). However, all these changes were partly reversed by sleep revival SR-95531 and NO-711 had different effect on these changes. Conclusions Sleep deprivation, no matter mild or severe, has adverse effects on cognitive function. Activities of both GABAergic and Hcrtergic system are increased during REMSD. These two neurons system could be regulated by each other and the relationship between them is positive correlation. GABAergic system also had self-regulation during REMSD, but microdialysision of either SR-95531 or NO-711 acquired adverse effects on cognitive function of rats. So GABAergic system is not an optimal therapeutic target. Because GABAergic and Hcrtergic system has inhibitory effect on each other,suppressing activity of Hcrtergic system might be a promising therapeutic target.