Yohimbine-induced stimulus control in the rat.
Rats were first trained in a 2-lever operant test chamber using a fixed ratio 10 schedule of water reinforcement. Discrimination training was then begun. In sessions following the injection (i.p.) of yohimbine . HC1 (3 mg/kg), responses on 1 of the 2 levers were reinforced. In sessions following the injection of saline, responses on the remaining lever were reinforced. The distribution of responses between the 2 levers prior to reinforcement provided an index of discrimination. The criterion for stimulus control was set at 80% correct responses in each of five consecutive sessions. In a group of six rats, criterion performance was begun after a mean of 33 sessions. Cross tests were conducted in yohimbine-trained subjects with d-amphetamine, harmaline, and LSD. Each test drug yielded intermediate results, i.e., response distribution was significantly different from both the yohimbine and the saline training conditions. No significant antagonism of yohimbine-induced stimulus control was achieved with BC-105, phentolamine, or butaclamol, purported antagonists at serotonergic, alpha-adrenergic, and dopaminergic receptor sites, respectively.
D000818:Animals; D002069:Butaclamol / Q000494:pharmacology; D003913:Dextroamphetamine / Q000494:pharmacology; D004192:Discrimination, Psychological / Q000187:drug effects*; D005260:Female; D006246:Harmaline / Q000494:pharmacology; D008238:Lysergic Acid Diethylamide / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D010918:Pizotyline / Q000494:pharmacology; D051381:Rats; D012702:Serotonin Antagonists / Q000494:pharmacology; D013997:Time Factors; D015016:Yohimbine / Q000494:pharmacology*
D012702:Serotonin Antagonists; D010918:Pizotyline; D015016:Yohimbine; D008238:Lysergic Acid Diethylamide; D002069:Butaclamol; D006246:Harmaline; D003913:Dextroamphetamine; D010646:Phentolamine