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Drug effects on multiple and concurrent schedules of ethanol‐ and food‐maintained behaviour: context‐dependent selectivity
Author(s) -
Ginsburg B C,
Lamb R J
Publication year - 2014
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.12707
Subject(s) - naltrexone , context (archaeology) , pharmacology , fluvoxamine , chlordiazepoxide , ethanol , drug , chemistry , psychology , opioid , medicine , serotonin , biochemistry , biology , paleontology , receptor , diazepam , fluoxetine
Background and Purpose Drugs that more potently or effectively reduce ethanol‐maintained behaviour versus an alternative are considered selective and are considered promising pharmacotherapies for alcoholism. Such results are often obtained using separate groups or multiple schedules where ethanol and the alternative are available alone or sequentially. Recently, we observed that when ethanol and food were available sequentially under a multiple schedule, fluvoxamine and varenicline were selective; yet this selectivity disappeared when ethanol and food were concurrently available. Experimental Approach We examined the generality of these findings by comparing doses of several drugs required to decrease ethanol‐ and food‐maintained responding under a multiple schedule and under a concurrent schedule. Effects were determined for chlordiazepoxide, 2,5‐dimethoxy‐4‐iodoamphetamine ( DOI ), meta‐chlorophenylpiperazine ( mCPP ), morphine, naltrexone and d‐amphetamine. Key Results Under the multiple schedule, ED 50 values for decreases in ethanol‐maintained responding were significantly different and lower than ED 50 s for decreases in food‐maintained responding (demonstrating selectivity) for each drug except for chlordiazepoxide (which was equipotent) and naltrexone (which did not affect responding). However, this selectivity vanished or even inverted under the concurrent schedule, such that ED 50 values for decreasing ethanol‐ and food‐maintained responding were not different (or, following DOI , the ED 50 for food‐maintained responding was lower than for ethanol‐maintained responding). Conclusions and Implications Results are consistent with those seen following fluvoxamine and varenicline administration, and suggest that selectivity is assay‐dependent. These results indicate the need for careful interpretation of selective drug effects, especially when obtained in situations where ethanol or the alternative is the only programmed reinforcement available.