Effect of clonazepam on brain development of mice

Twenty-seven Kun-Ming white mice were divided randomly into three groups of 9 animals. One of these groups served as a control group. Clonazepam (CZP), 0.1 or 0.5 mg/kg/day, was administered by oral gavage for 22 days. The water-maze test was performed before giving CZP and 10 and 22 days later. The step-down test was performed on the 1st and the 2nd day after discontinuing CZP treatment to determine toxic effects on brain development and learning-memory function. Body weights and brain weight were also recorded. Brain development and learning-memory function, evaluated by water-maze and step-down tests, were not impaired by CZP. Although there was a trend toward lower weights in the higher-dose group, CZP treatment did not significantly affect either body weight or total or regional brain weight. The results of this study indicate that 4 weeks of treatment with CZP does not impair brain development and learning-memory function in baby mice.