title: Development of tolerance to the excitatory effect of morphine and cross-tolerance to the inhibitory action of beta-endorphin in the isolated rat vas deferens.
mesh_terms: D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004361:Drug Tolerance; D004558:Electric Stimulation; D004723:Endorphins / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects* / Q000502:physiology
chemical_list: D004723:Endorphins; D009270:Naloxone; D009020:Morphine