Diminishing Purkinje cell populations in the cerebella of aging heterozygous Purkinje cell degeneration but not heterozygous nervous mice.

Mice homozygous for the recessive, cerebellar affected mutations nervous and Purkinje cell degeneration display an almost complete loss of Purkinje cells during their first two postnatal months. We have recently shown a progressive and age-related loss of Purkinje cells in mutant mice heterozygous for mutations apparently recessive, such as staggerer and reeler, and have thus chosen to investigate whether a similar Purkinje cell loss occurred with aging in +/nr and +/pcd heterozygous mice. Purkinje cells were counted on serial sections stained with thionin obtained from 17-month-old male and female heterozygous mice and their respective wild-type controls. In the case of the +/nr and wild-type mice, no difference in cell counts was observed. However, +/pcd mice had significantly fewer (-18%) Purkinje cells (143.700+/-5.400) than control wild-types (175.100+/-2.300); p<0.0001) at 17 months. These results extend our previous findings and further support the idea that apparently recessive neurological mutations may exert, at the heterozygous state, a deleterious effect upon Purkinje cells during the aging process.