Conditioned taste aversion induced by wheel running: further evidence on wheel running duration.

Rats given access to a running wheel after drinking a flavored solution subsequently drink less of that liquid. It has been suggested that suppression of intake is the result of conditioned taste aversion (CTA). This study explored whether the magnitude of CTA is related to time in the wheel (i.e., amount of wheel running). During 4 days of conditioning, rats drank an orange liquid for 60 min. Immediately after drinking, experimental rats were transferred to running wheels for either 20 or 60 min. Control animals remained in their home cages. Following the conditioning phase, all rats received a preference test composed of the paired flavored liquid (i.e., orange solution) and water. Rats in both experimental groups (20 and 60 min) decreased their consumption of the orange flavored liquid, but no difference in CTA was found between these groups. Wheel running, whether for 20 or 60 min, suppresses the consumption of a liquid consumed immediately before wheel access. These findings are discussed in terms of discrepancies between CTA induced by wheel running and CTA induced by emetic agents.