INHIBITORY EFFECT OF NOCICEPTIN ON EXCITATORY BUT NOT INHIBITORY TRANSMISSION IN RAT SPINAL DORSAL HORN NEURONES

Nociceptin, or orphanin FQ, is a 17 amino-acid peptide which is a newly discovered endogenous ligand for the opioid-like G-protein coupled receptor, ORLI, and suggested to participate in modulating nociceptive transmission. We examined the actions of nociceptin on excitatory and inhibitory transmission in substantia gelatinosa (SG) neurons in the dorsal horn of adult rat spinal cord slices by use of the blind whole-cell patch-clamp technique. Nociceptin induced an outward current at-70 mV in a dose-dependent manner (EC_(50)=0.23μM);