| Objective:To establish the model of conflictive psychological stress in rats and investigate the mechanism of5-HT in conflictive psychological stress on rats’sleep phrase and sleep rhythm.Methods:1. Established the model of conflictive psychological stress in rats.The improved Vogel drinking conflictive model was used to establish the model of conflictive psychological stress in rats. The changes of weight, concentration of corticosterone (CORT) in serum and ethological parameters of rats were monitored. Then, the successfully copied standard of the model was established.2. The effect of conflictive psychological stress on sleep phase and sleep rhythm of rats.The cortical electroencephalography was used to monitor EEG and EMG of rats after suffering one week conflictive psychological stress to investigate the effect on sleep phase and sleep rhythm of rats.3. The mechanism of5-HT in conflictive psychological stress on rats’ sleep phrase and sleep rhythm.3.1The effect of conflictive psychological stress on neurotransmitters in CNS.The Elisa method was used to evaluate the concentration of5-HT, TPH and5-HIAA in hypothalamus, amygdale and raphe nuclei. Then,5-HIAA/5-HT was worked out.3.2The effect of5-HTP on sleep phase and sleep rhythm of rats suffering to conflictive psychological stress.EEG and EMG of rats were monitorered after the precursor of5-HT,5-HTP, was injected to investigate the effect of5-HTP on sleep phase and rhythm of conflictive psychological stress rats.3.3The effect of conflictive psychological stress on concentration of tryptophane(trp) in peripheral blood.The HPLC was used to evaluate the concentration of trp in peripheral blood3.4The effect of Sertraline on sleep phase and sleep rhythm of rats suffering to conflictive psychological stress.Sertraline was injected to evaluate the effect of inhibitor of5-HT resorption in presynaptic membrane on sleep phase and sleep rhythm.3.5The effect of conflictive psychological stress on the expression of Slc6a4and Htrla in amygdale.PCR was used to evaluate the expression of Slc6a4and Htrla in amygdala after suffering to conflictive psychological stressResults:1. Established the model of conflictive psychological stress in rats.Compared with vehicle, rats in the model group showed increased concentration of CORT(P<0.05) and decreased body weight(P<0.05). In the open-field maze, however, the rats in model group showed more number of times of defecation(P<0.05), they passed less grids(P<0.05), showed less erect standing with hindlimb(P<0.05) and grooming(P<0.05).2. The effect of conflictive psychological stress on sleep phase and sleep rhythm of rats.Compared with vehicle, rats in model group showed less LS, SWS, REM, and TS(P<0.05). The ratio of every sleep phase in TS changed significantly (P<0.05) except for REM. The duration of sleep phase in model group reduced and the number of awakening increased; sleep tended to be fragmentation.3. The mechanism of5-HT in conflictive psychological stress on rats’ sleep phrase and sleep rhythm. 3.1The effect of conflictive psychological stress on neurotransmitters in CNS.Rats in model group showed lower concentration of5-HT in hypothalamus, amygdale and raphe nuclei(P<0.05). The concentration of TPH decreased significantly in amygdale and raphe nuclei (P<0.05). Though the concentration of TPH showed the trend to decrease in hypothalamus, no significance in statistics was performed (P>0.05). The concentration of5-HIAA decreased significantly in amygdale and hypothalamus (P<0.05). Though the concentration of5-HIAA showed the trend to decrease in raphe nuclei, no significance in statistics was performed (P>0.05). The specific value of5-HIAA/5-HT decreased significantly in raphe nuclei (P<0.05) Though the specific value of5-HIAA/5-HT showed the trend to decrease in amygdale and hypothalamus, no significance in statistics was performed (P>0.05)3.2The effect of5-HTP on sleep phase and sleep rhythm of rats suffering to conflictive psychological stress.Compared with model group, rats in5-HTP group showed more LS, SWS, REM, and TS (P<0.05). The ratio of LS in TS decreased significantly (P<0.05), while the SWS increased significantly (P<0.05). But the ratio of REM in TS did not change (P>0.05). The duration of sleep phase in5-HTP group increased and the number of awakening reduced. Sleep of rats in5-HTP group tended to be continuous and concentrated.3.3The effect of conflictive psychological stress on concentration of tryptophane (trp) in peripheral blood.Compared with vehicle, the concentration of trp in peripheral blood of rats in model group decreased significantly (P<0.05)3.4The effect of Sertraline on sleep phase and sleep rhythm of rats suffering to conflictive psychological stress. Compared with model group, rats in sertraline group showed more LS, SWS, REM, and TS (P<0.05). The ratio of LS in TS decreased significantly (P<0.05), while the SWS increased significantly (P<0.05). But the ratio of REM in TS did not change (P>0.05). The duration of sleep phase in sertraline group increased and the number of awakening reduced. Sleep of rats in sertraline group tended to be continuous and concentrated.3.5The effect of conflictive psychological stress on the expression of Slc6a4and Htrla in amygdale.Compared with vehicle, the expression of Slc6a4in amygdale increased significantly of rats in model group while the expression of Htrla showed the trend to decrease.Conclusion:Conflictive psychological stress can affect sleep phase and sleep rhythm of rats. The mechanism involved that it can reduce the concentration of5-HT and the excitability of5-HT energetic nervous system in the brain, reduce the synthesis of5-HT in CNS, promote synaptic cleft of5-HT resorption and reduced5-HT1A receptor in postsynaptic membrane. |
PDF Full Text Request