Evidence that [Phe¹ψ(CH₂‐NH)Gly²]nociceptin‐(1‐13)‐NH₂, a peripheral ORL‐1 receptor antagonist, acts as an agonist in the rat spinal cord

Abstract

[Phe 1 ψ(CH 2 ‐NH)Gly 2 ]nociceptin‐(1‐13)‐NH 2 , a pseudopeptide analogue of nociceptin is an antagonist in peripheral assays. Here, using in vivo electrophysiological recordings of dorsal horn neurones, [Phe 1 ψ(CH 2 ‐NH)Gly 2 ]nociceptin‐(1‐13)‐NH 2 appears to have agonist activity after spinal administration. The noxious evoked activity of the neurones was inhibited by [Phe 1 ψ(CH 2 ‐NH)Gly 2 ]nociceptin‐(1‐13)‐NH 2 , which was as potent as nociceptin itself. British Journal of Pharmacology (1998) 125 , 949–952; doi: 10.1038/sj.bjp.0702188