A G Protein-coupled Receptor Heterodimer Between Mu-opioid Receptor And Oxytocin Receptor

Morphine can take lots of pharmacological roles including analgesis,modification of immunal function and neuroendocrine.The signal pathway mediated by mu-opioid receptor (MOR)is the main machenism of morphine effects.However,some effects of morphine such as inhibition of oxytcoin synthesis and releases induced by chronic morphine treatment have been explicated by the mechanism.Both mu-opioid receptor and oxytocin receptor(OTR)belong to G protein coupled receptors(GPCRs)family A and can form homodimers/oligomers and heterodimers.To explore the molecular machenism of morphine inhibitting effect on oxytocin synthesis and secretion,the methods of biochemistry and biophysics were used to examine whether there was direct interaction between mu-opioid receptor and oxytocin receptor,which could provide a new pathway of morphine and the molecular experimental data to apply opioid medicines powerfully.Firstly cloning rat mu-opioid receptor and oxytoxin receptor in the PIRES vector.After plasmid PIRES MOR-OTR was transfected into COS7/CHO cell,the expression of protein MOR and OTR was confirmed with fluerescent-immunocytochemistry.Immunoprecipitation was used to investigate the heterodimerization of mu-opioid receptor and oxytocin receptor in the cultrued cell and rat brain lysis. Secondly createing mu-opioid receptor and oxytocin receptor fusion proteins with CFP and YFP,which are cloned in the pECFPN1 and pEYFPN1 vectors,respectively.And then a biophysics methor-FRET was used to detect the heterodimer between mu-opioid receptor and oxytocin receptor in living cells.This reseach further identify the MOR-OTR dimer.The results showed that MOR and OTR formed heterodimer in the transfected COS7/CHO cells and rat brain.