EFFECTS OF COCAINE ON PERFORMANCE UNDER FIXED-INTERVAL SCHEDULES WITH A SMALL TANDEM RATIO REQUIREMENT

• Published in: Journal of the experimental analysis of behavior Vol. 82; no. 3; pp. 293 - 310
• Main Authors: Pinkston, Jonathan W., Branch, Marc N.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2004; Society for the Experimental Analysis of Behavior
• Subjects: Animal Behavior; Animals; Behavior, Animal - drug effects; Behavioral Science Research; Birds; Cocaine; Cocaine - administration & dosage; Cocaine - pharmacology; Columbidae; Dopamine Uptake Inhibitors - administration & dosage; Dopamine Uptake Inhibitors - pharmacology; Dose-Response Relationship, Drug; Drug Use; fixed-interval schedules; Intervals; key peck; log-survivor functions; pigeons; Psychomotor Performance - drug effects; Reinforcement; Reinforcement Schedule; Schedules; tandem fixed-interval fixed-ratio schedules; tolerance; Tolerance intervals
• ISSN: 0022-5002; 1938-3711
• DOI: 10.1901/jeab.2004.82-293

Daily administration of cocaine often results in the development of tolerance to its effects on responding maintained by fixed‐ratio schedules. Such effects have been observed to be greater when the ratio value is small, whereas less or no tolerance has been observed at large ratio values. Similar schedule‐parameter‐dependent tolerance, however, has not been observed with fixed‐interval schedules arranging comparable interreinforcement intervals. This experiment examined the possibility that differences in rate and temporal patterning between the two types of schedule are responsible for the differences in observed patterns of tolerance. Five pigeons were trained to key peck on a three‐component multiple (tandem fixed‐interval fixed‐ratio) schedule. The interval values were 10, 30, and 120 s; the tandem ratio was held constant at five responses. Performance appeared more like that observed under fixed‐ratio schedules than fixed‐interval schedules. Effects of various doses of cocaine given weekly were then determined for each pigeon. A dose that reduced responding was administered prior to each session for 50 days. A reassessment of effects of the range of doses revealed tolerance. The degree of tolerance was similar across components of the multiple schedule. Next, the saline vehicle was administered prior to each session for 50 days to assess the persistence of tolerance. Tolerance diminished in all subjects. Overall, the results suggested that schedule‐parameter‐dependent tolerance does not depend on the temporal pattern of responding engendered by fixed‐ratio schedules.