Effects Of REM Sleep Deprivation On Brain Monoamines And Adenosine In Depression-model Rats Treated With Chronic Stresses

Backgrounds and Objective: Adenosine as a neuromodulator can modulate some neurotransmitters by integrating with adenosine receptors. On the other hand, adenosine is also thought to be a sleep factor.At present, a few studies indicate that adenosine and its receptors have some relations with the process of depression and antidepressant. It is known that sleep deprivation has an antidepressant-like effect. But up to now, the mechanisms of the acute antidepressant effect of sleep deprivation have not been clarified.Most of previous studies focused mainly on monoamine neurotransmitter systems. Some interactional factors may take part in this progress,we think. Is adenosine involved in sleep deprivation? Whether the concentration of adenosine in different encephalic regions change or not during the process? What are the relations between the adenosine and the monoamine neurotransmitters? There are questions remained at present.The current study is designed to investigate the effects of 72-hour REM (rapid eye movement) sleep deprivation on monoamines and adenosine in rats treated with chronic mild unpredicted stresses.Materials and Methods: Sprague-Dawley rats were divided into four groups randomly: 1) normal control group, 2)the depression-model group,3)depression-model +sleep deprivation group,4)depression-model +72 hours tank control group. Two classical models were adopted to build depression-model,one is chronic mild unpredicted stresses,and the other is sub-raising. The REMSD group used a small platform water environment, in order to remove the influence of water environment, a big platform was used as a control condition. Using the forced swimming test observe the change of the duration of immobility of rats which was immersed in the water of 25℃temperature for 5 min; using the high-performance liquid chromatography with Photodiode Array Detector detect the concentration of adenosine and inosine in hippocampus, hypothalamus and striatum; using the high-performance liquid chromatography with fluorescence detection detect concentration of monoamines. Excel 2003 and SPSS 13.0 statistical software were used for the analysis.Results:1)After chronic mild unpredicted stresses, the duration of immobility of rats increased in the groups which were adopted the treatment,corresponding,it decreased in the REMSD group after 72h rapid eye movement sleep deprivation.2)5-HT and NE levels were found to have significant differences in the hippocampus or hypothalamus among the different groups .The concentration of dopamine in hippocampus and hypothalamus couldn't be detected by HPLC-FLD. The concentration of dopamine in striatum of REMSD group is higher than that of depression-model group.3)Adenosine and inosine levels were found to have significant differences in hippocampus or hypothalamus among the different groups.Conclusions:1.72 hours of REMSD could significantly improve the depressive behavior induced by chronic mild unpredicted stresses;2.REMSD increases 5-HT and NE concentrations in Hippocampus, which play an important role in rapid antidepressant;3.5-HT in hypothalamus seems to be related to the process of REMSD antidepressant, but not norepinephrine;4.The change of adenosine in Hippocampus and Hypothalamus may take part in the REMSD antidepressant process,These results suggest that the REMSD reverses chronic mild unpredictable stresses-induced depressive behavior in rats. The enhanced 5-HT transportation by REMSD is one of the reasons in rapid antidepressant effect,and adenosine may take parts in this process.