Related Experiment Video
Updated: Aug 19, 2026

Tissue Preparation and Immunostaining of Mouse Sensory Nerve Fibers Innervating Skin and Limb Bones
Published on: January 26, 2012
Endogenous nociceptin signaling and stress-induced analgesia
1Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17, 41100 Ferrara, Italy.
Abstract:
Nociceptin/orphanin FQ (NC) and its receptor (OP4) have been implicated in pain transmission. The aim of the present study was to investigate the role of the NC/OP4 system in stress-induced analgesia (SIA). The tail-withdrawal assay was performed in mice stressed by forced swimming in water at 15 degrees C (high severity swims) or 32 degrees C (low severity swims). High severity swims produced a naloxone-insensitive antinociceptive effect which was blocked by supraspinal NC (1 nmol). The selective OP4 receptor antagonist, [Nphe1]NC(-13)NH2 (30 nmol), was inactive by itself, but prevented the effect of NC. Low severity swims produced a milder analgesic effect that was partially antagonized by naloxone, completely blocked by NC and potentiated by [Nphe1]NC(-13)NH2. These findings confirm the anti-analgesic role of supraspinal NC and suggest that endogenous NC signaling counteracts the opioid component of SIA.
Related Concept Videos
Nociception
NF-κB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
Analgesia and Pain Management
Pain

