title: Characteristic of antinociceptive effect of a tetrapeptide, Asn-Ala-Gly-Ala (NAGA).
abstract: The characteristic of the antinociceptive effect of a tetrapeptide, Asn-Ala-Gly-Ala (NAGA), was examined. Intracisternal (i.cist.) administration of NAGA to mice produced dose-dependent and long-lasting antinociceptive effect as evaluated by the hot plate and tail flick methods. NAGA-induced antinociception was reversed by naloxone (2 mg/kg), reserpine (2 mg/kg X 2 d) and alpha-methyl-p-tyrosine (100 mg/kg). NAGA (10 microM) did not significantly affect the actions of opioid peptides on the electrically evoked twitches of the myenteric plexus-longitudinal muscle strips from the guinea-pig esophagus and strips of the mouse vas deferens. NAGA-induced antinociception was scarcely affected by p-chlorophenylalanine (PCPA, 300 mg/kg X 2 d) and methysergide (2 mg/kg). From the above results, it was suggested that the antinociceptive effect of NAGA may involve the participation of endogenous opioid peptides and endogenous catecholamines.
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D008784:Methysergide / Q000494:pharmacology; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D012110:Reserpine / Q000494:pharmacology; D012684:Sensory Thresholds / Q000187:drug effects; D013997:Time Factors; D019805:alpha-Methyltyrosine
chemical_list: D000700:Analgesics; D008781:Methyltyrosines; D009842:Oligopeptides; D009270:Naloxone; D019805:alpha-Methyltyrosine; C038175:asparaginyl-alanyl-glycyl-alanine; D012110:Reserpine; D008784:Methysergide