Spinal nociceptin inhibits septide but not N-methyl-D-aspartate-induced nociceptive behavior in rats.
Nociceptin can induce spinal analgesia in rats. Here, we tested the ability of nociceptin to inhibit the nociceptive behavior (biting, scratching, licking) induced by intrathecal administration of N-methyl-D-aspartate (4 microg) or the tachykinin NK(1) receptor agonist, septide (0.5 microg), in rats. Intrathecal nociceptin (3-30 nmol) did not modify the NMDA-induced behavior. However, coadministration of nociceptin (1-10 nmol) inhibited the septide-induced excitatory response. This inhibition was unaffected by systemic (10 mg/kg) or intrathecal (30 nmol) administration of naloxone, but intrathecal coadministration of the ORL1 (opioid receptor-like type 1) receptor antagonist [Nphe(1)]nociceptin-(1-13)-NH(2) (30-90 nmol) prevented it, suggesting the involvement of ORL1 receptors.
Villanueva
Noemí
N
Departamento de Medicina, Facultad de Medicina, Laboratorio de Farmacología, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, C/ Julián Clavería 6, 33006 Oviedo, Asturias, Spain.
Lastra
Ana
A
Hidalgo
Agustín
A
Baamonde
Ana
A
Menéndez
Luis
L
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D007278:Injections, Spinal; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists; D018847:Opioid Peptides / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000502:physiology; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000094942:Nociceptin Receptor; D000097629:Nociceptin
D016202:N-Methylaspartate; D009270:Naloxone; D009292:Narcotic Antagonists; D018847:Opioid Peptides; D010446:Peptide Fragments; D011761:Pyrrolidonecarboxylic Acid; D011957:Receptors, Opioid; D013373:Substance P; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C054725:septide; C000722285:Oprl1 protein, rat