title: Elevated levels of enkephalin in morphine-dependent rats.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D004361:Drug Tolerance; D006801:Humans; D008024:Ligands; D009020:Morphine / Q000378:metabolism; D009270:Naloxone / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism*; D051381:Rats; D011955:Receptors, Drug; D019966:Substance-Related Disorders / Q000378:metabolism*
chemical_list: D008024:Ligands; D009419:Nerve Tissue Proteins; D009842:Oligopeptides; D011955:Receptors, Drug; D009270:Naloxone; D009020:Morphine