Progressive ratio and fixed ratio schedules of cocaine-maintained responding in baboons
| Autor: | L D Bradford, Roland R. Griffiths, Joseph V. Brady |
|---|---|
| Rok vydání: | 1979 |
| Předmět: |
Pharmacology
Male Schedule Reinforcement Schedule Time Factors Dose-Response Relationship Drug business.industry medicine.medical_treatment Breaking point Haplorhini Dose–response relationship Animal science Cocaine Conditioning Medicine Animals Conditioning Operant Progressive ratio Point function business Fixed ratio Saline Papio |
| Zdroj: | Psychopharmacology. 65(2) |
| ISSN: | 0033-3158 |
| Popis: | Responding maintained under progressive ratio (PR) and fixed ratio (FR 160) schedules of IV saline or cocaine (0.01-4.0 mg/kg) injections was studied in baboons. Each injection was followed by a time-out period which was 3-h with the PR schedule and was either 3 or 12 with the FR schedule. On the PR schedule the ratio requirement was systematically increased each day until reaching the 'breaking point' at which self-injection performance fell below a criterion level (one or zero injections per day). Overall response rates on the PR schedule increased with progressive increases in the ratio until a maximum at which an abrupt reduction in responding occurred. With the 3-h time-out the dose-breaking point function on the PR schedule was similar to the dose-response rate function on the FR schedule. These dose-effect functions were inverted U-shaped curves characterized by a graded ascending limb (0.01-0.32 mg/kg) and a downturn at the highest doses (3.0-4.0 mg/kg). On the FR schedule the downturn in the dose-response rate function was attributable to a cumulative drug effect as revealed by manipulation of time-out duration and analysis of sequential interresponse time distributions and cumulative response records. PR and FR schedules provide similar information about the relative reinforcing efficacy of different cocaine doses. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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