title: Some thoughts on the significance of enkephalin, the endogenous ligand.
mesh_terms: D000818:Animals; D004361:Drug Tolerance; D006168:Guinea Pigs; D000882:Haplorhini; D006801:Humans; D007082:Ileum / Q000187:drug effects; D008024:Ligands; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D008954:Models, Biological; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists; D009294:Narcotics / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D011955:Receptors, Drug; D012995:Solubility; D019966:Substance-Related Disorders; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D008024:Ligands; D009292:Narcotic Antagonists; D009294:Narcotics; D010455:Peptides; D011955:Receptors, Drug; D009270:Naloxone; D009020:Morphine