Abnormalities in cerebellar Purkinje cells in the novel ataxic mutant mouse, pogo

The pogo mouse is a novel neurological mutant, which was discovered, in an inbred strain (KJR/MsKist) derived from a Korean wild mouse. The pathologic al manifestation include difficulty in maintaining normal posture, failures of interlimb coordination and the inability to walk straight. The ataxia i s first apparent from about 2 weeks of age and progresses throughout life. The mutation is inherited as an autosomal recessive trait. In this report, we describe abnormalities in the pogo/pogo cerebellum. Nissl staining shows that the pogo/pogo cerebellum is normal in size and lobulation. Similarly, immunocytochemical staining for a granule cell marker, 10B5, shows no diff erences in the thickness of the granular layer between pogo/pogo homozygote and pogo/+ heterozygote: littermate controls. By using anti-parvalbumin im munocytochemistry, the cells of molecular layer of the pogo/pogo cerebellum also appeared similar in distribution as compared to normal wild type mous e. In anti-neurofilament immunocytochemistry. the basket cells axons of the pogo/pogo cerebellum appeared normal. Purkinje cell abnormalities were ide ntified by using anti-calbindin D immunocytochemistry. In 120-day-old pogo/ pogo mutant mice there was a loss of Purkinje cells throughout the cerebell ar vermis. Furthermore, the somata and dendrites were extensively vacuolate d in the pogo/pogo Purkinje cells and the primary dendrites were frequently swollen. Focal axonal swellings were commonly observed in the Purkinje cel l axons of pogo/pogo mutant mice as they traversed the granular layer. Thes e data suggest that the progressive ataxia seen in pogo mice may be due to a failure of normal Purkinje cell activity. (C) 2000 Elsevier Science B.V. All rights reserved.