Contrasting interactions of pipradrol, d-amphetamine, cocaine, cocaine analogues, apomorphine and other drugs with conditioned reinforcement

The effects of various psychomotor stimulant drugs and drugs outside this class were examined on the efficacy of stimuli previously paired with reinforcement or reward (conditioned reinforcers, CR) in controlling responding. Pipradrol (5-45 mumol/kg), d-amphetamine (1.25-15.0 mumol/kg), and the cocaine analogues WIN 35,428 (0.1-30.0 mumol/kg) and in one of two determinations WIN 35,065-2 (0.1-29.0 mumol/kg) all generally increased responding on a lever providing CR, but did not change or decreased responding on a lever providing no CR (NCR). Cocaine (5-125 mumol/kg) and chlordiazepoxide (3.75-60.0 mumol/kg) had no significant effects. Morphine (3.2-32.0 mumol/kg) and alpha-flupenthixol (0.02-2.0 mumol/kg) generally reduced responding on both levers. Apomorphine (0.1-1.0 mumol/kg) generally increased responding on both levers. Neurochemical data showed that d-amphetamine was generally more potent than pipradrol in its effects on in vitro monoamine uptake and release.