• cerebellum;
  • medulla;
  • calbindin;
  • immunocytochemistry


The mutant mouse ‘hyperspiny Purkinje cells’(hpc) has morphologically abnormal Purkinje cells and below normal intracerebellar calbindin-D28k, a calcium-binding protein that, in the cerebellum, is found only in the Purkinje cells. We counted the Purkinje cells on serial sections stained with thionin or labelled with anti-calbindin-D28k antibodies to investigate whether the depletion of the cerebellar content of calbindin-D28k was correlated with a reduced number of Purkinje cells. We also counted the inferior olivary neurons, as they are one of the major afferents of the Purkinje cells and also contain calbindin-D28k. The hpc mutant mice had 27% fewer cerebellar Purkinje cells and 12% fewer inferior olivary neurons than did controls. Their Purkinje cells were evenly immunostained but slightly atrophic. These data suggest that the depleted cerebellar calbindin-D28k content could be explained both by the loss of some Purkinje cells and the reduced size of the remaining ones.