Behavioral effects of morphine, levorphanol, dextrorphan and naloxone in the frog Rana pipiens.
Systemic morphine induces explosive motor behavior and generalized muscular rigidity in frogs. Naloxone does not reverse either of these effects of morphine but at high doses causes muscular flaccidity and unresponsiveness to stimulation. Intraspinal morphine induces rigidity, but not explosive motor behavior, and this action is blocked by naloxone. Behavioral effects are seen rarely after intraspinal levorphanol (rigidity) and never after intraspinal dextrorphan or naloxone. In contrast to systemic morphine and naloxone, systemic levorphanol and dextrorphan are lethal to frogs at high doses.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003917:Dextrorphan / Q000494:pharmacology; D007279:Injections, Subcutaneous; D007981:Levorphanol / Q000494:pharmacology; D009020:Morphine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D009127:Muscle Rigidity / Q000139:chemically induced; D009270:Naloxone / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D011894:Rana pipiens; D013997:Time Factors
D009294:Narcotics; D003917:Dextrorphan; D007981:Levorphanol; D009270:Naloxone; D009020:Morphine