Various doses of bupropion HCl (Wellbatrin) (5, 10, and 20 mg/kg), a new phenylaminoketone antidepressant, were employed as cues in a two-lever operant discrimination from saline control injections in rats on an FR10 schedule of food reinforcement. Subjects reached and maintained a high level of discrimination in the O vs 20 mg/kg bupropion stimulus condition but not at the lower doses. In generalization testing, the following compounds produced dose-related responding on the bupropion lever: viloxazine, nomifensine, caffeine, d-amphetamine, cocaine, methylphenidate, and benzylpiperazine. Drugs that failed to show dose-related generalization included phenethylamine, thyrotropin-releasing hormone, imipramine, nortriptyline, amitriptyline, desipramine, mianserin, chlordiazepoxide, diazepam, scopolamine, phenobarbital, and morphine. With the important exception of viloxazine, the generalization profile of bupropion seems to reflect its previously reported locomotor stimulant effects in the rat rather than its antidepressant activity and suggests that species differences exist between man and rat with regard to the pharmacologic activity of this new antidepressant.
Adult male hooded rats responding on three contact sensors for food reinforcement were trained to acquire a different three-response sequence each day. Twelve threeresponse sequences were used: with minor exceptions, the series of 12 was run four times in two rats and twice in one rat. Elapsed time and error rate for a given sequence declined over sessions and within sessions. Some sequences generated higher error rates than others. Results were generally consistent with previous results from pigeons emitting four-response sequences. Application to the testing of drugs for therapeutic effects on cognitive deficits associated with aging is discussed.Key words: repeated acquisition, chained schedule, contact sensor, rat Repeated acquisition is an operant procedure in which the subject earns reinforcement by acquiring a different response sequence in successive sessions. Boren designed the original paradigm using the monkey [Boren and Devine, 19681. Most of the published data on repeated acquisition were generated in the pigeon. The standard chain procedure developed by D.M. Thompson required the bird to make four responses on three keys in a specified sequence to obtain food, with the sequence being changed from session to session [Thompson, 19701. Error rate was reduced to a steady state within sessions and from day to day after about 30 sessions, with the exception that "easy" sequences, including leftmiddle-right (LMR) or right-middle-left (RML), produced lower error rates than other sequences [Thompson, 197 11. With sequences selected to be equivalent in several waysexcluding those involving LMR, RML, RR, MM, LL, or repetition of the same sequence within two or three sessions-overall accuracy was either impaired or not changed by the following psychoactive drugs:
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.