Effects of SCH-23390 and raclopride on cocaine discrimination in male and female Wistar rats.
Male and female rats were trained to discriminate 10.0 mg/kg cocaine from saline in a two-lever discrimination task. Injection-appropriate responding was reinforced by food pellet presentation on a tandem random-interval 30-s fixed-ratio 10 schedule. Generalization testing was conducted in extinction 10 min following an injection of saline, 1.0, 3.0, 5.6, or 10.0 mg/kg cocaine. No differences in the generalization gradients and ED(50)s were observed between male and female rats. Following the determination of the cocaine generalization gradient, the dopamine D(1) antagonist SCH-23390 (0.01-0.10 mg/kg) and the dopamine D(2) antagonist raclopride (0.1-1.6 mg/kg) were administered (independently) prior to the injection of the training dose of cocaine (10.0 mg/kg). Cocaine-antagonism tests were conducted in extinction. It was found, for each dopamine antagonist, that as the dose increased, the percentage of cocaine-appropriate responding decreased. No sex differences were observed between these generalization gradients.
Anderson
K G
KG
Department of Psychology, University of Florida, Gainesville, FL 32611-2250, USA.
van Haaren
F
F
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D003042:Cocaine / Q000494:pharmacology*; D003463:Cues; D004193:Discrimination Learning / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004971:Estrus / Q000502:physiology; D005260:Female; D005795:Generalization, Stimulus / Q000187:drug effects; D008297:Male; D020891:Raclopride / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors; D012727:Sex Characteristics
D001552:Benzazepines; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D018765:Dopamine Uptake Inhibitors; D017447:Receptors, Dopamine D1; D020891:Raclopride; D003042:Cocaine