Effect Orphanin FQ On The Membrane Of Rat DRG Neurons And Its Ionic Basis

orphanin OF (OFQ) is a newly discovered endogenous opioid peptide,widely distributes in central and peripheral tissue and participates in various physiological function. Dorsal root ganglion (DRG)is primary sensory neuron central place and somatic sensations transmit to center part. DRG neurons are pseudounipolar neurons and have integral effect on different sensory input information. At present, effects on central nervous system of OFQ have been reported, but no report involved in effect on primary sensory of OFQ. This experiment establish on DRG preparation of Wistar rat in vitro, and used intracellular microelectrode recording technology to study effect of orphanin FQ on the membrane of rat DRG neurons and its inoic basis.MethodsUnder etherization condition,we make laminectomy, dissociate L4-L5 DRG, fix DRG and BSS solution perfuse DRG. The effect of OFQ on DRG neurones were studied by intracellular microelectrode recording in neonatal Wistar rats(two or three weeks). We proved that DRG neurons exist OFQ receptor and have effects of orphanin FQ on the membrane. We also apply ionic substitution and channel blockers to study OFQ mechanism of action.ResultsIn the 271 neurons examined, the resting membrane potential of cells were - 45±7.63 mV (n=271). During the application of OFQ (10^-10～3×10^-7mol/L), three types of the membrane potential changes were observed: (1)hyperpolarization response, (2)depolarization...