Decreased number of cells in the inferior olivary nucleus of the adult mouse (+/sg) heterozygous for the staggerer gene.
Light microscopic study and cell counts of the inferior olivary nucleus were performed in adult mouse (+/sg), i.e. heterozygous for the staggerer gene. Two, six, and twelve-month-old animals were studied and compared to (+/+) C57BL6J mice of the same age. The number of cells and their repartition within the four subnuclei of the inferior olivary nucleus were normal in 2-month-old (+/sg) mice but a cell loss appears afterwards and mostly between 6 and 12 months so that about 30% of the olivary cells are missing in (+/sg) mice aged 12 months. The deficit affects the four inferior olivary nucleus subnuclei but predominates in the dorsal accessory olive. This cell loss is the first described expression of the mutation in the (+/sg) mouse, and it is not yet known if the inferior olivary nucleus represents a primary site of gene action or if the deficit is secondary to a hitherto unnoticed abnormality in the heterozygous (+/sg) mouse.
D000367:Age Factors; D000818:Animals; D001931:Brain Mapping; D002452:Cell Count; D006579:Heterozygote; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants / Q000033:anatomy & histology*; D009847:Olivary Nucleus / Q000166:cytology*