Cue-induced reinstatement of ethanol seeking in Sardinian alcohol-preferring rats

The purpose of the present study was to characterize cue-induced reinstatement of ethanol seeking in selectively bred Sardinian alcohol-preferring (sP) rats trained to lever press for ethanol in 30-min self-administration sessions. Four responses on an "active" lever led to presentation of 0.1 ml of 15% (v/v) ethanol by a liquid dipper and concurrent activation of a set of discrete light and auditory cues. In a 70-min extinction/reinstatement session, responding was first extinguished for 60 min. Subsequently, different stimuli were delivered in a non-contingent manner and reinstatement of non-reinforced responding was assessed. Fifteen presentations of the ethanol-predictive stimulus complex, including the dipper cup containing 5% or 15% ethanol, potently reinstated responding on the previously active lever. The magnitude of reinstatement increased with the number of stimulus presentations and concentration of ethanol presented by the dipper cup. Fifteen presentations of the ethanol-predictive stimulus complex, including the dipper cup filled with water (0% ethanol), did not produce any reinstatement. These results indicate that: (i) non-contingent presentations of the ethanol-predictive stimulus complex may reinstate ethanol seeking in sP rats; (ii) the orosensory properties of ethanol may play an important role in reinstatement of ethanol seeking in sP rats. The latter finding concurs with clinical observations that odor and taste of alcoholic beverages elicits immediate craving responses in abstinent alcoholics.