ABSTRACT
The effects of autoshaping procedures (paired vs. random) and sipper fluid (ethanol vs. water) on sipper-directed drinking were evaluated in male Long-Evans rats maintained with free access to food and water. For the paired/ethanol group (n=16), autoshaping procedures consisted of presenting the ethanol sipper (containing 0% to 28% unsweetened ethanol) conditioned stimulus (CS) followed by the response-independent presentation of food unconditioned stimulus (US). The random/ethanol group (n=8) received the sipper CS and food US randomly with respect to one another. The paired/water group (n=8) received only water in the sipper CS. The paired/ethanol group showed higher grams per kilogram ethanol intake than the random/ethanol group did at ethanol concentrations of 8% to 28%. The paired/ethanol group showed higher sipper CS-directed milliliter fluid consumption than the paired/water group did at ethanol concentrations of 1% to 6%, and 15%, 16%, 18%, and 20%. Following a 42-day retention interval, the paired/ethanol group showed superior retention of CS-directed drinking of 18% ethanol, relative to the random/ethanol group, and superior retention of CS-directed milliliter fluid drinking relative to the paired/water group. When tested for home cage ethanol preference using limited access two-bottle (28% ethanol vs. water) procedures, the paired/ethanol and random/ethanol groups did not differ on any drinking measures.
Subject(s)
Alcohol Drinking/psychology , Conditioning, Operant/drug effects , Ethanol/administration & dosage , Reinforcement Schedule , Retention, Psychology/drug effects , Animals , Conditioning, Operant/physiology , Dose-Response Relationship, Drug , Male , Rats , Rats, Long-Evans , Retention, Psychology/physiology , TimeABSTRACT
In two studies, we evaluated the effects of ethanol concentration and trial spacing on Pavlovian autoshaping of ethanol drinking in rats. In these studies, the brief insertion of an ethanol sipper conditioned stimulus (CS) was followed by the response-independent presentation of food unconditioned stimulus (US), inducing sipper CS-directed drinking conditioned responses (CRs) in all rats. In Experiment 1, the ethanol concentration in the sipper CS [0%-16% volume/volume (vol./vol.), in increments of 1%] was systematically increased within subjects across autoshaping sessions. Groups of rats received sipper CS-food US pairings (Paired/Ethanol), a CS-US random procedure (Random/Ethanol), or water sipper CS paired with food US (Paired/Water). In Experiment 2, saccharin-fading procedures were used to initiate, in the Ethanol group, drinking of 6% (vol./vol.) ethanol in 0.1% saccharin or, in the Water group, drinking of tap water in 0.1% saccharin. After elimination of saccharin, and across days, the duration of access to the sipper CS during each autoshaping trial was increased (5, 10, 12.5, 15, 17.5, and 20 s), and subsequently, across days, the duration of the mean intertrial interval (ITI) was increased (60, 90, 120, and 150 s). In Experiment 1, Paired/Ethanol and Random/Ethanol groups showed higher intake of ethanol, in terms of grams per kilogram of body weight, at higher ethanol concentrations, with more ethanol intake recorded in the Paired/Ethanol group. In Experiment 2, the Ethanol group drank more than was consumed by the Water group, and, for both groups, fluid intake increased with longer ITIs. Results support the suggestion that autoshaping contributes to sipper CS-directed ethanol drinking.
