Tolerance to morphine-induced increases in [14C]catecholamine synthesis in mouse brain.
Morphine sulfate increased the incorporation of carbon-14-labeled tyrosine into labeled catecholamines in the mouse brain. Tolerance was manifested by a shift to the right in the dose-response curve for morphine after mice were treated repeatedly with morphine. Naloxone, a specific morphine antagonist, also shifted the dose-response curve for morphine to the right.
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D002247:Carbon Isotopes; D002395:Catecholamines / Q000096:biosynthesis*; D004361:Drug Tolerance; D007274:Injections, Intraperitoneal; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism
D002247:Carbon Isotopes; D002395:Catecholamines; D009292:Narcotic Antagonists; D014443:Tyrosine; D009020:Morphine