Rats were trained to respond on a variable interval 60 sec (VI-60) schedule of water reinforcement. Phencyclidine (PCD) in doses of 0.25, 0.5, and 1.0 mg/kg i.p. increased response rates, respectively, to 118%, 140%, and 143% of the control rates. In contrast, doses of 2.0 and 4.0 mg/kg decreased response rates to 73% and 6% of the control rates. In the tolerance study, one group of rats received daily treatments of 4.0 mg/kg PCD immediately prior to the operant session, while a second group received the same daily dose of PCD after the operant session. When both groups of animals were treated prior to the operant session on a test day, they both displayed complete tolerance to the rate depressant effect of PCD. These results indicate that the observed tolerance to PCD was not dependent on behavioral compensatory mechanisms.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)