Pre-trial cocaine and performance in rat

Comparison of stimulants and hallucinogens on shuttle avoidance in rats

Rats were trained to a high level of performance of a conditioned avoidance response in a shuttlebox to test effects of several classical stimulants in comparison to a variety of hallucinogens. A previously-reported biphasic pattern of effects of mescaline on shuttle avoidance was replicated and extended to 12 other hallucinogens of both phenylethylamine and indolealkylamine classes. Response patterns of hallucinogens could be differentiated from 3 stimulants and from a methoxyamphetamine compound that lacks hallucinogenic activity.

Cocaine as a discriminative cue in rats: interactions with neuroleptics and other drugs

Rats were trained to discriminate between the effects of 4 mg/kg of cocaine HCl and saline (1 ml/kg) in a T-shaped maze. When the animals reliably differentiated the imposed training conditions (cocaine vs. no drug), test sessions were interspersed in between the regular training sessions. Test trials resulted in a median effective dose (ED50) of 1.6 mg/kg of cocaine, and the duration of the discriminable effects of cocaine in producing 50% cocaine-appropriate responding was 57.9 min postinjection. Pretreatment with neuroleptics (pimozide, haloperidol, and chlorpromazine), but not with propranolol, phenoxybenzamine, alpha-methyl-para-tyrosine, or physostigmine, attenuated the cocaine discrimination. Data are discussed with reference to previous results from amphetamine discriminations.