Abstract
When aggressive mice induced by isolation were grouped with four normal mice, spontaneous motor activity (SMA), emotional behaviour, brain polyamines and monoamines were examined with the following results. 1) SMA by photo-cell counters method in mice returning from isolation to a group did not alter, but by open-field test markedly increased in comparison with that of normal mice on the 14th day under the new grouped circumstances. 2) In mice returning to a group, aggressive behaviour including attacking and biting was rarely observed. 3) Brain spermidine (SPD) in non-aggressive mice returning to groups was markedly decreased in comparison with that of aggressive mice on the 3rd day under the grouped circumstnces. 4) The ratio of brain spermine/ SPD in normal and non-aggressive mice isolated for 3 ?? 6 weeks was 1.16±0.07, 1.20±0.04, respectively, while in aggressive mice induced by isolation the ratio was 0.84±0.04. The ratio in nonaggressive mice by aggregation and by LiCl (12.5 ?? 50 mg/kg) twice a day for ten days was 1.18±0.03, 1.15±0.04, respectively.
