title: Effects of naltrexone, and d-amphetamine, and their interaction on the stimulus control of choice behavior of rats.
abstract: The hypothesis that endogenous opioid peptides modulate attentional processes was tested. The effects of the opioid antagonist naltrexone (NALT), d-amphetamine (AMP), and their interaction were investigated in rats trained in a two-choice task in which the position of a short-duration light served as a cue for food-reinforced responses. NALT (0.25, 1.0, 5.0, and 10.0 mg/kg) produced no significant changes in performance (accuracy, choice latency, and food retrieval time). As predicted, AMP induced dose-dependent biphasic effects. Low doses of AMP (0.25 and 0.5 mg/kg) significantly enhanced accuracy, decreased choice latency, and lengthened food retrieval time; 1.25 mg/kg AMP disrupted accuracy, increased choice latency, and further lengthened food retrieval time. The combination of NALT (0.25, 1.0, and 10.0 mg/kg) and subthreshold doses of AMP (0.07 and 0.1 mg/kg) had no effect on performance except for an increase in food retrieval time with 10.0 mg/kg NALT, whereas the combination of NALT and moderate doses of AMP (0.5 and 1.0 mg/kg) disrupted accuracy, increased choice latencies, and lengthened food retrieval time. These results do not support the hypothesis that endogenous opioid peptides play a vital role in attentional processes or that opioid antagonists may be useful in the treatment of attentional deficit disorders.
authors.affiliation: Cleveland State University, Psychology Department, OH 44115.
authors.forename: D M
authors.initials: DM
authors.lastname: Grilly
authors.forename: G C
authors.initials: GC
authors.lastname: Gowans
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004192:Discrimination, Psychological / Q000187:drug effects; D004347:Drug Interactions; D008297:Male; D009271:Naltrexone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D009271:Naltrexone; D003913:Dextroamphetamine