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Aims: Intermittent presentations of the ethanol sipper have been reported to induce more ethanol drinking in rats than when the ethanol sipper was continuously available during the session. This intermittent sipper effect was observed in a social drinking situation, in which subjects experienced intermittent opportunities to interact briefly with a conspecific rat. The objective of this study was to evaluate the effects of the intermittent sipper procedure in situations providing for intermittent presentations of food, and, in addition, in situations that do not provide for intermittent presentations of another rewarding event. Methods: Four groups of male Long-Evans hooded rats, arranged in a 2 × 2 factorial design with two levels of Sipper Procedure (Intermittent vs Continuous) and two levels of Food procedure (Food vs No Food), were trained in drinking chambers. During each daily session, Intermittent Sipper groups received access to the ethanol sipper during each of 25 trials of 10 s each, while Continuous Sipper groups had access to the ethanol sipper during the entire session (∼30 min). During each session, Food groups received 25 presentations of food pellets while No Food groups received no food pellets. Ethanol concentrations in the sipper [3, 4, 6, 8, and 10% (vol./vol.)] increased across sessions. Results: More rapid escalation of ethanol intake was observed in the Intermittent Sipper groups than in the Continuous Sipper groups, and this effect was observed in both the Food and No Food conditions ( P 's < 0.05), which did not differ from one another. Conclusions: Intermittent Sipper procedures provide less access to the ethanol sipper, yet induced more ethanol drinking than Continuous Sipper procedures. The intermittent sipper effect is not dependent on presentations of food. Implications for schedule-induced polydipsia and Pavlovian autoshaping are discussed. ( Received 19 August 2005; first review notified 31 October 2005; in revised form 31 December 2006; accepted 6 January 2006)

Aims: The present study evaluates the effects of pairing ethanol sipper conditioned stimulus (CS) with social opportunity unconditioned stimulus (US) on CS-directed ethanol drinking in rats. Subjects were Long-Evans male rats (n = 32) deprived of neither food nor water, and the concentration of unsweetened ethanol (3 to 16%) in the sipper CS was increased across sessions. Methods: Group Paired/Ethanol (n = 12) received the ethanol sipper CS for 10 s immediately prior to 15 s of social opportunity US. Control groups received water rather than ethanol in the sipper CS (Paired/Water), or ethanol sipper CS and US presentations randomly (Random/Ethanol), or ethanol sipper CS but no social opportunity US (Sipper Only). Results: Mean ethanol intake in the Paired/Ethanol and Random/Ethanol groups exceeded 1.0 g/kg when the sipper CS contained 12%, 14% and 16% ethanol, and higher fluid intakes were observed in the Paired/Ethanol and Random/Ethanol groups than in the Paired/Water and Sipper Only groups. Conclusions: Social opportunity increased ethanol drinking, and more so than water drinking; however, autoshaping did not induce additional ethanol drinking beyond that observed in random controls.

Aims: This study asks if repeated Pavlovian pairings of a sipper tube (conditioned stimulus, CS) with food (unconditioned stimulus, US) will induce Pavlovian autoshaping conditioned responses (CRs), consisting of drinking of either 6% ethanol or wat er from the sipper CS. This study also tests predictions derived from the autoshaping model by asking if sipper CS-directed drinking wi ll be retained, despite the absence of training for several weeks, and, in addition, if drinking rate is a negative function of sippe r CS duration. Methods: Autoshaping procedures, conducted in two daily sessions, consisted of the brief insertion of the sipper tube CS followed by the response-independent presentation of food US. For the Ethanol group ( n = 8), the sipper CS contained 6% ethanol, whereas for the Water group (n = 8), the sipper CS contained tap water. Saccharin fading procedures were employed, whereas for both groups, during days 1-19, the sipper CS contained 0.1% saccharin, and thereafter across training days the concentration of saccharin was gradu ally reduced (0.07, 0.035, 0.0%). Following elimination of saccharin, both groups were maintained in their home cages during a 27-da y retention interval, and then re-evaluated for autoshaping of drinking of unsweetened ethanol and water. Thereafter, across days , the duration of access to the sipper CS (5.0, 7.5, 10.0, 15.0 s) during each autoshaping trial was increased. Results: Both groups increased drinking across the first 19 days of training with sipper CS-food US pairings, and, at 0.0% saccharin, the Ethanol group consumed 14.76 ml of 6% ethanol per day, resulting in a daily ethanol consumption of 2.77 g/kg. For both groups, daily levels of drinkin g before and after the 27-day retention interval were comparable, attesting to the durability of the acquired drinking effects. At each CS duration, the Ethanol group consumed more millilitres of fluid per day than did the Water group, and for the Ethanol group, peak drinking of 24.0 ml of 6% ethanol per day was observed at the 10 s CS duration. For both groups, drinking rate (millilitres of fluid consum ed per second of CS duration), was a declining monotonic function of CS duration, resulting in a daily ethanol consumption of ~4.2 g/k g for the Ethanol group. Conclusions: These data reveal that these sipper CS-food US autoshaping procedures induce drinking in rats that is durable and negatively related to increasing CS duration. The effects of both variables are consistent with the hypothesis t hat drinking from the sipper CS is a Pavlovian autoshaping CR. Autoshaping of drinking in the Water group is observed despite the absence of water deprivation, and even more fluid is consumed by the Ethanol group than by the Water group. The high volumes of ethanol consumed during brief daily sessions suggest that Pavlovian autoshaping procedures may provide an animal learning model of binge drinkin g.