title: Cross tolerance between morphine and methionine-enkephalin.
mesh_terms: D000818:Animals; D004361:Drug Tolerance; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008024:Ligands / Q000494:pharmacology*; D008297:Male; D008715:Methionine; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology*; D011955:Receptors, Drug; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D008024:Ligands; D009419:Nerve Tissue Proteins; D009842:Oligopeptides; D011955:Receptors, Drug; D009020:Morphine; D008715:Methionine