Nociceptin inhibits non‐adrenergic non‐cholinergic contraction in guinea‐pig airway

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Abstract
Electrical field stimulation (EFS) of guinea‐pig isolated main bronchi induced a non‐adrenergic non‐cholinergic (NANC) contractile response. Nociceptin (0.01–1 μM) significantly inhibited the contractile response to EFS (PP>0.05). The μ‐, δ‐ and κ‐opioid receptor antagonists, naloxone (0.3 μM), naltrindole (3 μM) and nor‐binaltorphimine (1 μM), respectively, did not significantly affect the inhibitory effect of nociceptin (0.03 μM; P>0.05). The novel nociceptin antagonist, [Phe1ψ(CH2‐NH)Gly2]nociceptin(1–13)NH2 (0.03–1 μM); the σ ligands, carbetapentane (30 μM), 3‐phenylpiperidine (30–100 μM) and (+)‐cyclazocine (10–100 μM) significantly reversed the inhibitory effect of nociceptin (0.03 μM, PP>0.05). EFS of guinea‐pig bronchial preparations significantly increased SP‐LI release above basal SP‐LI (PPn=5) inhibition of EFS‐induced release of SP‐LI. Nociceptin reduces the release of sensory neuropeptides induced by EFS, but not capsaicin, from guinea‐pig airways. These experiments provide further evidence for a role for nociceptin in regulating the release of sensory neuropeptides in response to EFS. British Journal of Pharmacology (1998) 125, 510–516; doi:10.1038/sj.bjp.0702068