PURKINJE-CELLS IN OLIVOPONTOCEREBELLAR ATROPHY AND GRANULE CELL-TYPE CEREBELLAR DEGENERATION - AN IMMUNOHISTOCHEMICAL STUDY

We carried out immunohistochemical studies on cerebellar Purkinje cell s in sporadic olivopontocerebellar atrophy (OPCA) and in granule cell- type cerebellar degeneration (gc-CD). The cell bodies, axons and dendr ites including spiny branchlets and dendritic spines of normal Purkinj e cells were intensely stained by the antibody against P-400 glycoprot ein/inositol 1,4,5-trisphosphate receptor protein (P-400/IP3R). The st aining pattern of OPCA Purkinje cells was heterogeneous: some were neg ative, while others were stained with various intensities. Although a small number of P-400/P3R-positive Purkinje cells in OPCA were similar to the normal ones, the immunoreaction products in OPCA Purkinje cell s disappeared from the dendritic spines and spiny branchlets toward th e cell bodies. Some of OPCA Purkinje cells were stained by the antibod ies to phosphorylated neurofilament proteins (pNFP), synaptophysin and alpha B-crystallin. Normal Purkinje cells did not express pNFP, synap tophysin or alpha B-crystallin. By contrast, the staining pattern of t he Purkinje cells of gc-CD case was uniform: almost all the Purkinje c ells expressed P-400/IP3R in cell bodies, axons and dendrites, but not in the dendritic spines and spiny branchlets. Our data suggest that t he function of OPCA Purkinje cells is impaired from the peripheral den drites toward the cell bodies, and that the presence of aberrant phosp horylation of neurofilament proteins, synaptophysin and alpha B-crysta llin may be related to the degeneration of Purkinje cells in OPCA. In the gc-CD, our results suggest that the lack of P-400/P3R immunoreacti vity in dendritic spines and spiny branchlets of the Purkinje cells is related to the loss of inputs from the granule cells as well as the r esult of maldevelopment of the Purkinje cells.