Taste aversion learning induced by delayed swimming activity.

The experiment reported here demonstrated that forced swimming endows rats with aversion to a taste solution consumed 30 min before the swimming. The experimental rats were allowed to drink 0.2% sodium saccharin solution, which was followed by a 30-min empty interval, and then a 20-min swimming opportunity in water. Compared with the control rats, which were returned to their home cages after drinking the saccharin, the experimental rats drank a small amount of saccharin solution both in the later sessions of one-bottle training and in the subsequent two-bottle choice (saccharin versus tap water) testing. The delayed swimming procedure was as effective as an immediate swimming procedure, extending the generality of the swimming-induced taste aversion, which we recently discovered with the immediate swimming procedure.