Fluoxetine's effects on ethanol's rewarding, aversive and stimulus properties

Abstract

These experiments examined the influence of fluoxetine on ethanol-induced conditioned place preference, ethanol-induced conditioned taste aversion, and ethanol discrimination. In the place conditioning experiment, male Swiss-Webster mice received 4 pairings of a distinctive floor cue with 2 g kg ethanol, 10 mg kg fluoxetine + ethanol, or fluoxetine alone. A different floor was paired with saline. During conditioning ethanol produced locomotor stimulation. Fluoxetine + ethanol resulted in greater levels of locomotor activity during conditioning trials 2–4. Fluoxetine alone also caused increases in activity. Floor preference testing revealed conditioned place preference in groups receiving ethanol. Fluoxetine did not change the magnitude of ethanol-induced conditioned place preference nor produced place conditioning alone. In the taste conditioning procedure, mice received 1-h access to 0.2 M NaCl solution followed by injections of 0, 5 or 10 mg kg fluoxetine and 0 or 2.5 mg kg ethanol. Ethanol produced reductions in NaCl intake. Fluoxetine (10 mg kg ) enhanced the development of ethanol-conditioned taste aversion but did not cause taste aversion alone. In the ethanol discrimination experiment, mice were trained to respond for 10% sucrose on an FR20 schedule following injections of either 1 g kg ethanol or saline. Following acquisition, 10 mg kg fluoxetine pretreatment enhanced ethanol-appropriate responding at a dose of ethanol (0.5 g kg ) below the training dose. These results indicate enhancement of serotonergic activity influences ethanol aversion and discrimination but not ethanol reward.