ArticlesIncreasing the Selectivity of Drug Discrimination Procedures
Section snippets
Subjects
Experimentally naive male, Sprague–Dawley rats (n = 22), 60 days old at the beginning of experimentation, were purchased from Charles River Breeding Laboratories, Wilmington, MA. They were housed individually in a colony maintained on a 12 L:12D schedule, with lights on from 0700–1900 h. Temperature and relative humidity were held constant at 20–22°C and 40–50%, respectively. Initially, animals had free access to both food and water. Five days before training, access to water was restricted for
Results
The acquisition of the LSD-saline and LSD-other discriminations are shown in Fig. 1. Criterion was attained rapidly in both groups of animals, 24 sessions in the LSD-saline group (top), and 31 sessions in the LSD-other group (bottom), and did not differ significantly as a function of training condition, t(20) = 1.22, p = 0.2. In addition, rates of responding were relatively high, at least when compared with those reported previously in this laboratory (7). The average rate for each animal in
Discussion
The results of this experiment indicate that rats can be trained to discriminate LSD from a group of “other” drugs consisting of a CNS depressant, pentobarbital, a CNS stimulant, cocaine, and saline. Thus, they confirm and extend the work of Overton (15) to a different class of compounds (hallucinogens rather than depressants). Thus far, however, the limits of the LSD discrimination have not been explored by varying either drugs or doses in the “other” group. This task should be undertaken
Acknowledgements
This work was supported by USPHS Research Grant DA02543 from the National Institute on Drug Abuse.
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Present address: Department of Public Health, University of South Carolina, Columbia, SC 29208.