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Relative Potency of Varenicline or Fluvoxamine to Reduce Responding for Ethanol Versus Food Depends on the Presence or Absence of Concurrently Earned Food
Author(s) -
Ginsburg Brett C.,
Lamb Richard J.
Publication year - 2014
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/acer.12285
Subject(s) - varenicline , fluvoxamine , chemistry , pharmacology , agonist , potency , partial agonist , psychology , nicotine , medicine , biochemistry , in vitro , serotonin , receptor , fluoxetine
Background Varenicline, a nicotinic partial agonist, selectively reduces ethanol ( E t OH )‐ versus sucrose‐maintained behavior when tested in separate groups, yet like the indirect agonist fluvoxamine, this selectivity inverts when E t OH and food are concurrently available. Methods Here, we extend these findings by examining varenicline and fluvoxamine effects under a multiple concurrent schedule where food and E t OH are concurrently available in different components: Component 1 where the food fixed‐ratio was 25 and Component 2 where the food fixed‐ratio was 75. The EtOH fixed‐ratio was always 5. Food‐maintained responding predominated in Component 1, while E t OH ‐maintained responding predominated in Component 2. In a second experiment, varenicline effects were assessed under a multiple schedule where food, then E t OH , then again food were available in separate 5‐minute components with fixed‐ratios of 5 for each reinforcement. Results In the multiple concurrent schedule, varenicline was more potent at reducing food‐ versus E t OH ‐maintained responding in both components and reduced E t OH ‐maintained responding more potently during Component 1 (when food was almost never earned) than in Component 2 (where food was often earned). Fluvoxamine was similarly potent at reducing food‐ and E t OH ‐maintained responding. Under the multiple schedule, varenicline, like fluvoxamine, more potently decreases E t OH ‐ versus food‐maintained responding when only food or E t OH is available in separate components. Conclusions These results demonstrate that selective effects on drug‐ versus alternative‐maintained behavior depend on the schedule arrangement, and assays in which E t OH or an alternative is the only programmed reinforcement may overestimate the selectivity of treatments to decrease E t OH self‐administration. Thus selective effects obtained under one assay may not generalize to another. Better understanding the behavioral mechanisms responsible for these results may help to guide pharmacotherapeutic development for substance use disorders.