Characteristics of depressive behavior induced by feeding thiamine-deficient diet in mice

We produced thiamine-deficient (TD) mice by TD diet treatment. The growth c urve of mice on TD feeding was sharply increased until on the 10th day and subsequently the body weight gradually deZD creased. The mortality rate in mice was about 67% on the 30th day after the start of TD feeding. We perfor med the forced swimming test on the 10th and 20th day after the start of TD feeding. The duration of immobility in the forced swimming test was increa sed on the 20th day of TD feeding. Locomotor activity and motor co-ordinati on between the pair-fed control group and TD group on the 20th day of TD fe eding, were not significantly changed. Only a single injection of thiamine HCl (50 mg/kg, s.c.) on the 10th day after the start of a TD diet shortened the increased duration of immobility in the forced swimming test on the 20 th day after the start of TD feeding. Whereas these reversal effects of thi amine treatment on the 20th day were not found when the treatment was given on the 19th day after the start of a TD diet. On the 20th day after the st art of TD feeding, the increased duration of immobility time induced by TD was shortened by chronic administration of the tricyclic antidepressant imi pramine (10 mg/kg, i. p.). These results suggested that behavioral changes in the forced swimming test might be involved in the degeneration of seroto nergic and noradrenergic neurons. (C) 2001 Elsevier Science Inc. All rights reserved.