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

Abstract

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. Key words: Sleep deprivation; Cognition; Gamma-aminobutyric acid; Neuropeptides; Intracellular signaling peptides and proteins; Rats