| Objective:We designed this experiment to observe the effects of leptin on the anxiety behavior in REM sleep deprived rats,and to explore the potential role of leptin and neuropeptide Y(NPY) on the anxiety behavior in sleep deprived rats and hence the molecular mechanism of effect of sleep deprivation on anxiety behavior.Methods:A total of 90 male Wistar rats,with body weight ranging from 200 to 240 g,were randomizedly divided into 9 groups on average.The 9 groups were as follows:living together in home cage(controls) for 24 hours,72 hours and 120 hours with NS,REM sleep deprived for 24 hours,72 hours and 120 hours with leptin,and REM sleep deprived for 24 hours,72 hours and 120 hours with NS.The agentia were administrated by intraperitoneal injection.We deployed the single platform(SP) method to build the REM sleep deprivation model,observe the effect of leptin and NS on the anxiety behavior in REM sleep deprived rats(24 hours,72 hours and 120 hours) respectively,by useing the elevated plus-maze(EPM) to test the anxiety behavior of rats. The level of NPY mRNA was measured through the RT-PCR.Results:1.Chronic REM sleep deprivation decreased the body weight in rats.The REM sleep deprived for 72 hours with leptin groups and REM sleep deprived for 72 hours with NS groups have a significant difference with the cage controls groups(F=20.40,P=0.00),but no significant difference was found between leptin and NS sleep deprivation groups.2.Anxiety behavior results in rats:The total number of open arm entries and close arm entries were increased in acute REM sleep deprived for 24 hours(F=5.32,P=0.01) with leptin groups and NS groups,increased in REM sleep deprived with NS for 120 hours groups but decreased in REM sleep deprived with leptin for 120 hours groups(F=15.06,P=0.00) compared with the cage controls groups,but no significant difference was found among groups of REM sleep deprived with leptin,REM sleep deprived with NS and the cage controls for 72 hours.The open arm entries(χ~2=21.55,P=0.00) and open arm time(χ~2=22.53,P=0.00) were increased in chronic REM sleep deprived for 120 hours with NS groups,but it were decreased in REM sleep deprived for 120 hours with leptin groups,no significant difference was found among groups of the REM sleep deprived for 24 hours and 72 hours with leptin or NS and the cage controls.3.RT-PCR results shows that when compared with the controls groups(NPY/GAPDH,0.752852 v.s0.817095v.s.0.750960),chronic REM sleep deprivation led to the increases of neuropeptide Y mRNA level in hypothalamus,and this level to increased gradually with increasing time of REM of sleep deprived(NPY/GAPDH,1.020000 v.s.1.011080 v.s.1.064368).Leptin inhibited the expression of neuropeptide Y mRNA in hypothalamus,and the level of neuropeptide Y decreased gradually with increasing time of REM sleep deprived(NPY/GAPDH,0.913255 v.s.0.837611 v.s.0.612655).Conclusion:1.Chronic REM sleep deprivation decreases the body weight in rats.2.Chronic REM sleep deprivation can change the locomotor activity in rats.The increased locomotor activity was found in acute and chronic REM sleep deprivation groups.The locomotor activity was decreased in chronic REM sleep deprivation with leptin.3.The changes between REM sleep deprivation and anxiety behavior in rats are correlated with time increasing.Acute REM sleep deprivation could not influence the anxiety behavior in rats. Chronic REM sleep deprivation could decrease the anxiety behavior in rats,but leptin could eliminate this effect,which means leptin may participate in the anxiolytic-like effect of chronic sleep deprivation.4.Chronic REM sleep deprivation leads increase neuropeptide Y mRNA level in hypothalamus. Leptin can inhibit the express of neuropeptide Y mRNA in hypothalamus.Meanwhile,these changes were correlated with anxiety behavior,which indicate that the decreased leptin level leads to the increase of neuropeptide Y level might be the mechanism of the anxiolytic-like effect on REM sleep deprivation.
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