Changes in Movement and Ataxic Gait with Development in Genetically Ataxic Mice: A Comparison with the Level of Cerebellar Cyclic Nucleotide

Spontaneous movement and ataxic gait in ataxic mice showing various pathological changes in the cerebellum were investigated according to developmental stage by the open-field method of comparison with normal mice. As the cerebellum contains relatively high levels of cyclic nucleotide, its concentrations was measured by radioimmunoassay to elucidate the correlation between spontaneous movement and ataxic gait and the neurological changes. The movements of Rolling Mouse Nagoya (RMN), Weaver and Reeler mice without Purkinje Cell Degeneration (PCD) were found to decrease at 4 and 12 weeks of age. The degree of ataxic gait worsen in RMN, was unchanged in Reeler and improved in Weaver and PCD mice. The cerebellar c-GMP concentration of ataxic mice was decreased, while no significant changes in c-AMP concentration were found in comparison with normal mice. With development, the level of cerebellar c-GMP in Weaver mice increased, but this was not apparent in RMN, Reeler or PCD mice. The results of this investigation indicated that there may be some relation between the degree of ataxic gait and the level of cerebellar c-GMP in Weaver mice.