REGIONAL BRAIN VARIATIONS OF CYTOCHROME-OXIDASE ACTIVITY AND MOTOR COORDINATION IN HOT-FOOT MUTANT MICE

Hot-foot mutant mice are characterized by defective arborization of Pu rkinje cell dendrites, resulting in ataxia of gait and deficits of equ ilibrium. Regional brain variations of cytochrome oxidase (CO) activit y were analysed for the purpose of identifying those brain regions wit h abnormal metabolic activity as a secondary consequence to the cerebe llar alteration. In addition, the possible relation between CO activit y and motor deficits was evaluated. By comparison to normal littermate controls of the same background strain, hot-foot mutants had higher C O activity in the molecular layer of the cerebellum, the ventrolateral and midline thalamic nuclei, as well as in the frontal eye field. The re was no other alteration of CO activity in the hot-foot brain. No li near correlation was discerned between CO activity in the molecular la yer of the cerebellum and the ventrolateral and midline nuclei on one hand, and motor coordination performance on the other. These results i ndicate regionally selective abnormalities of metabolic activity in a cerebellar mutant with defective dendritic arborization of the Purkinj e cell.