title: The effect of morphine and some other narcotic analgesics on brain tryptophan concentrations.
abstract: An acute dose of morphine increased brain tryptophan in mice. This effect was not prevented by naloxone nor was it produced by other narcotic analgesics. Dextrorphan, but not levorphanol, had a similar effect to morphine. A large dose of tryptophan had no effect on the antinociceptive action of morphine in mice. Morphine increased brain tryptophan in rats. This effect was prevented by naloxone. A large dose of tryptophan antagonised the antinociceptive action of morphine in the rat.
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003917:Dextrorphan / Q000494:pharmacology; D005260:Female; D007981:Levorphanol / Q000494:pharmacology; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000188:drug therapy; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D000701:Analgesics, Opioid; D003917:Dextrorphan; D007981:Levorphanol; D009270:Naloxone; D009020:Morphine; D014364:Tryptophan