Anti-nociceptive activity of narcotic agonists and partial agonists in mice given biogenic amines by intracerebroventricular injection.
Using a tail immersion technique in mice, the anti-nociceptive activity of some narcotic agonists (diamorphine, etorphine, morphine and pethidine), partial agonists (cyclazocine, nalorphine and pentazocine) and naloxone have been determined alone, and after the intracerbroventricular (ICV) injection of 5-hydroxytryptamine (5-HT) or noradrenaline (NA). In common with morphine, the anti-nociceptive effects of each agonist and partial agonist studied were significantly increased by ICV 5-HT, and significantly attenuated by ICV NA. The marginal anti-nociceptive activity of naloxone was not significantly affected by the ICV injection of either amine. It is concluded that the anti-nociceptive effects of all narcotic agonist and partial agonist agents are determined by the balance within the brain of the activities of the two amines, 5-HT and NA.
D000698:Analgesia; D000818:Animals; D001923:Brain Chemistry; D002552:Cerebral Ventricles; D004347:Drug Interactions; D007267:Injections; D008297:Male; D008614:Meperidine / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D009020:Morphine / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D010423:Pentazocine / Q000494:pharmacology; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*
D009292:Narcotic Antagonists; D009294:Narcotics; D012701:Serotonin; D009020:Morphine; D008614:Meperidine; D010423:Pentazocine; D009638:Norepinephrine