An investigation of the interaction between the reinforcing properties of food and ethanol using the place preference paradigm

• 1.

  1. For three groups of rats, intraperitoneal injections of either 250, 500, or 1000 mg/kg ethanol were paired with a distinctive environment and later a choice was offered between that environment and one that had previously been associated with saline injections.

• 2.

  2. For a second set of three groups of animals the identical procedure was followed except that food was available in both the environment paired with ethanol and the one paired with saline.

• 3.

  3. The rats showed no preference or aversion for the environment paired with the 250 mg/kg dose either when the drug was given alone or when combined with the availability of food. No preference or aversion for the 500 mg/kg dose was indicated when the drug was given alone, but the same dose combined with food was preferred to food plus saline. The 1000 mg/kg dose was found to be aversive when given by itself, yet the same dose was neither aversive nor preferred when combined with the availability of food.

• 4.

  4. These findings suggest that ethanol can interact with food, a positive reinforcer, in ways that cannot be predicted from the effect of the drug when presented alone.