title: Further evidence for a motility substitution test as a tool to detect the narcotic character of new drugs in rats.
abstract: Time effects of three doses of codeine, d-propoxyphene, meperidine and dextromethorphan upon locomotor activity have been investigated in naive rats as well as in animals treated chronically with 20 mg/kg of morphine daily. The first three drugs exhibited a motility pattern qualitatively similar to that of morphine; in chronically-treated rats cross-tolerance occurred to acute depressant effects and cross-sensitization to acute excitatory effects. In the case of meperidine however cross-sensitization appeared to be small. Dextromethorphan presented effects similar to morphine only in a very large dose. The present data, together with those of previous work, demonstrate that a locomotor activity substitution test may predict the morphine-like addictive properties of a drug.
mesh_terms: D000818:Animals; D003915:Dextromethorphan / Q000494:pharmacology; D011431:Dextropropoxyphene / Q000494:pharmacology; D008297:Male; D008614:Meperidine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D009294:Narcotics; D003915:Dextromethorphan; D008614:Meperidine; D011431:Dextropropoxyphene