title: Competitive antagonism of morphine action in vitro by calcium.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009020:Morphine / Q000037:antagonists & inhibitors*; D009469:Neuromuscular Junction / Q000187:drug effects
chemical_list: D009020:Morphine; D002118:Calcium