Time-dependent generalization of morphine stimulus properties to meperidine: antagonism by naloxone.
The time course of the stimulus generalization to morphine by meperidine (20 mg/kg) was determined in rats trained to discriminate morphine (10 mg/kg) from saline in a standard two-lever procedure with food reinforcement. It was found that morphine lever selection following meperidine was a strictly time-dependent phenomenon. Naloxone (0.3 mg/kg) antagonized the stimulus properties of both morphine and meperidine; however, the antagonism was significantly more pronounced against morphine. The results suggest that there may be certain differences in the neuropharmacology of the stimulus properties of morphine and meperidine.
Bartoletti
M
M
Institute of Pharmacology, University of Bologna, Italy.
Gaiardi
M
M
Gubellini
C
C
Bacchi
A
A
Babbini
M
M
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004192:Discrimination, Psychological / Q000187:drug effects; D008297:Male; D008614:Meperidine / Q000494:pharmacology*; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D012965:Sodium Chloride / Q000494:pharmacology; D013268:Stimulation, Chemical; D013997:Time Factors
D009270:Naloxone; D012965:Sodium Chloride; D009020:Morphine; D008614:Meperidine