Journal
PSYCHOPHARMACOLOGY
Volume 196, Issue 3, Pages 441-450Publisher
SPRINGER
DOI: 10.1007/s00213-007-0978-6
Keywords
self-administration; incentive learning; titration; cocaine; remifentanil; food
Categories
Funding
- Intramural NIH HHS [Z99 DA999999, Z01 DA000001-23] Funding Source: Medline
Ask authors/readers for more resources
Rationale Patterns of drug self-administration are often highly regular, with a consistent pause after each self-injection. This pausing might occur because the animal has learned that additional injections are not reinforcing once the drug effect has reached a certain level, possibly due to the reinforcement system reaching full capacity. Thus, interoceptive effects of the drug might function as a discriminative stimulus, signaling when additional drug will be reinforcing and when it will not. Objective This hypothetical stimulus control aspect of drug self-administration was emulated using a schedule of food reinforcement. Materials and methods Rats' nose-poke responses produced food only when a cue light was present. No drug was administered at any time. However, the state of the light stimulus was determined by calculating what the whole-body drug level would have been if each response in the session had produced a drug injection. The light was only presented while this virtual drug level was below a specific threshold. A range of doses of cocaine and remifentanil were emulated using parameters based on previous self-administration experiments. Results Response patterns were highly regular, dose-dependent, and remarkably similar to actual drug self-administration. Conclusion This similarity suggests that the emulation schedule may provide a reasonable model of the contingencies inherent in drug reinforcement. Thus, these results support a stimulus control account of regulated drug intake in which rats learn to discriminate when the level of drug effect has fallen to a point where another self-injection will be reinforcing.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available