A three-choice haloperidol-saline-cocaine drug discrimination task in rats.
This study was conducted to test whether rats could be trained and successfully maintain a three-choice drug discrimination task using 0.1 mg/kg haloperidol (SC, 2-h pretreatment), saline (IP or SC, 2 h and 15 min pretreatment), and 10 mg/kg cocaine (IP, 15-min pretreatment) as training stimuli. Six male Sprague-Dawley rats achieved criterion performance for stimulus control by these training stimuli under a fixed-ratio-5 schedule of food reinforced lever-press responding in an average of 164 training sessions. Dose-response functions for cocaine and haloperidol demonstrated both quantitative and qualitative specificity of the training stimuli. The data also are presented along a single pharmacological continuum (agonist-antagonist) that we hypothesize to represent a parallel subjective or interoceptive stimulus continuum associated with the drug injections. Based on the previous multidimensional model of drug stimuli dimensionality (3), this specific stimulus dimension is characterized as an unidimensional bipolar continuum represented by the hypothetical states of hedonia or euphoria on one end (cocaine) and anhedonia or depression on the opponent end (haloperidol), with a neutral (saline) centroid region. We propose that this specific three-choice drug discrimination task in rats may function as an animal analog of the subjective states associated with cocaine abuse and the subsequent withdrawal or, crash, in humans (7,8,21).
Gauvin
D V
DV
Department of Psychiatry and Behavioral Sciences, University of Oklahoma Health Sciences Center, Oklahoma City 73190-3000.
Goulden
K L
KL
Holloway
F A
FA
D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005795:Generalization, Stimulus / Q000187:drug effects; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule
D003042:Cocaine; D006220:Haloperidol