A trial to detect behavioral changes by swimming stress

We investigated behavioral changes in mice in a light/dark test after forced swimming stress in a streaming pool. Locomotion and rearing behavior in mice in a light/dark test was suppressed immediately after the swimming and gradually regained. Shuttle crossing between light and dark zones was also suppressed but time spent in a light zone was not. The suppression of locomotor activity by the swimming was not observed 20 min after it. Naloxone (10 mg/kg, i.p.) suppressed recovery of locomotor activity after the swimming while it did not affect a light/dark test in nonswimming mice. These results suggest that this model is useful for the study of behavioural and psychological changes after exercise, and that opioidergic systems may be involved in regaining spontaneous locomotor activity.