| Objective: Serotonin 1A receptor(5-HT1AR)and orexin type 1receptor(OX1R)are closely related to the occurrence of depression,and both of them are G protein coupled receptors.The above two receptors can be dimerized to form a dimer.the formation of this dimer not only opens up a new way to understand the mechanism of neurotransmission,but also opens a new angle for understanding the pathogenesis of depressive disorder and new drug development.In this experiment,double immunofluorescence experiment was used to verify the co-localization of 5-HT1 AR and OX1 R on the cell membrane of prefrontal cortex,which is the premise of dimerization of the two receptors.Then the interferon peptide which can prevent the formation of this dimer was injected into the lateral ventricle of the rats.The behavioral indexes of depression,the expression of neurotrophic factors(BDNF),p-CREB and postsynaptic density protein(PSD-95)in the hippocampus in the prefrontal cortex between the interfering peptide group and the model group were compared to further reveal the mechanism of 5-HT1AR-OX1 R heterodimer and interfering peptide in depressive disorder.Its unique pharmacological and functional properties may become a new breakthrough in the treatment of depressive disorders.Methods: The rat model of depression was established by using the method of orphaned plus chronic unpredictable mild stimulation(CUMS)for 28 days.The success of the model was determined by comparing the body weight,sugar preference rate and forced swimming resting time of rats in each group.After successful modeling,the rats were divided into normal control group,depression model group,5-HT1AR-TM4 group,5-HT1AR-TM5 group and OX1R-TM5 group.The synthesis of5-HT1AR/ OX1 R dimer was inhibited by intracerebroventricular injection of interfering peptides 5-HT1AR-TM4,5-HT1AR-TM5 and OX1R-TM5,respectively.The behavior of the rats was detected 6 days after injection.Double immunofluorescence technique was used to verify the co-localization of 5-HT1 AR and OX1 R on the cell membrane of the prefrontal lobe.Using Western blot technique to detect BDNF and p-CREB,an important index of depressive disorder in prefrontal cortex of rats.Detection of synaptic-related PSD-95 protein expression in rat hippocampus by western blot technique.Results: The main results were as follows:(1)the depression model of SD rats was established by CUMS method.The behavioral results showed that compared with the normal control group,the body weight and sugar preference rate of rats in the model group and interference peptide group decreased significantly,and the resting time of forced swimming increased significantly.It shows that the modeling is successful and follow-up experiments can be carried out.(2)six days after injection of interfering peptide,the behavior of rats in each group was statistically analyzed,and the results showed that compared with the control group,the depressive behavior of the model group was not improved.Compared with the model group,the depressive behavior of the interference peptide group was significantly relieved.(3)the co-expression of 5-HT1 AR and OX1 R was detected in the same cell membrane in the prefrontal cortex of rats by immunofluorescence method.(4)the protein expressions of BDNF,p-CREB and PSD-95 in the brain of rats in each group were detected by Western blot method.The results showed that compared with the control group,the protein expressions of BDNF,p-CREB in the prefrontal cortex and PSD-95 in the hippocampus of the model group were significantly lower than those of the control group.Compared with the model group,the protein expressions of BDNF,p-CREB and hippocampal PSD-95 in the prefrontal cortex of rats in the interference peptide group were significantly higher than those in the model group.Conclusion: The results of this study show that 5-HT1 AR and OX1 R can be co-located on the cell membrane of rat prefrontal cortex.The analysis and comparison of the behavior and the protein expression of BDNF,p-CREB and PSD-95 in brain tissue of depressive rats after injection of interfering peptide showed that 5-HT1AR-TM4,5-HT1AR-TM5 and OX1R-TM5 interfered with the formation of5-HT1AR/OX1 R heterodimer could alleviate the state of depression and provide a new idea for the treatment of depressive disorder. |
