Phenytoin reversal and prevention of morphine-induced catalepsy in the rat.
The interaction of morphine sulphate and phenytoin was studied with respect to morphine-induced catalepsy in the rat using a previously described method for measuring degree of immobility. As expected, catalepsy developed several minutes after intravenous morphine and lasted for more than ninety minutes. Intravenous phenytoin, 35 mg/kg, given fifteen min prior to or following the administration of morphine, 1 mg/kg, significantly prevented, or reversed, morphine-induced catalepsy. Control experiments revealed that the antagonistic effect was due solely to the morphine-phenytoin interaction. A similar effect was found with naloxone, 0.2 mg/kg. The data are discussed in terms of possible sites of interaction, including synaptosomal calcium metabolism.
D000818:Animals; D001921:Brain / Q000187:drug effects; D002375:Catalepsy / Q000139:chemically induced / Q000517:prevention & control*; D006801:Humans; D009020:Morphine / Q000037:antagonists & inhibitors*; D009270:Naloxone / Q000494:pharmacology; D014677:Pharmaceutical Vehicles; D010672:Phenytoin / Q000494:pharmacology*; D051381:Rats
D014677:Pharmaceutical Vehicles; D009270:Naloxone; D010672:Phenytoin; D009020:Morphine