Endorphin release: cross tolerance to morphine.
D000818:Animals; D004361:Drug Tolerance; D004558:Electric Stimulation; D004723:Endorphins / Q000378:metabolism*; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence / Q000378:metabolism / Q000503:physiopathology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D009197:Myenteric Plexus / Q000187:drug effects / Q000378:metabolism; D009270:Naloxone / Q000494:pharmacology
D004723:Endorphins; D009270:Naloxone; D009020:Morphine