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

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 g/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.