Possible noradrenergic involvement in naloxone potentiation of apomorphine-induced stereotypic climbing in mice.
Apomorphine-induced stereotypic climbing behavior in mice was significantly potentiated by pretreatment with the opiate receptor blocker naloxone. In animals additionally pretreated with alpha-methyl-p-tyrosine, brain levels of norepinephrine (NE) and dopamine (DA) were markedly reduced and naloxone potentiation of apomorphine-induced stereotypic climbing was blocked. In mice pretreated with diethyldithiocarbamic acid, brain NE was slightly reduced, brain DA was slightly elevated but naloxone potentiation of apomorphine-induced stereotypic climbing was unaltered. In animals pretreated with reserpine, both brain NE and DA were significantly reduced by naloxone potentiation of apomorphine-induced stereotypic climbing was not affected. In other experiments, pretreatment with low doses of the alpha-adrenergic receptor blocker BE-2254 failed to suppress climbing activity induced by apomorphine alone but did successfully prevent naloxone potentiation of apomorphine-induced stereotypic climbing. These findings suggest the possibility that NE and alpha-adrenergic receptors might play a role in the potentiating influence of naloxone upon apomorphine-induced stereotypic climbing activity in mice.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001921:Brain / Q000378:metabolism; D004050:Ditiocarb / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism; D004357:Drug Synergism; D006801:Humans; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D009270:Naloxone / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology*; D012110:Reserpine / Q000494:pharmacology; D013239:Stereotyped Behavior / Q000187:drug effects*; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D009270:Naloxone; D019805:alpha-Methyltyrosine; D012110:Reserpine; D004050:Ditiocarb; D001058:Apomorphine; D004298:Dopamine; D009638:Norepinephrine