Hyperspiny Purkinje cell, a new neurological mutation in the mouse.

Hyperspiny Purkinje cell (hpc) is a new autosomal recessive mutation of the laboratory mouse. Homozygotes exhibit abnormal motor behavior, with predominance of cerebellar symptoms, about 10 days after birth. Morphological analysis disclosed a slightly reduced cerebellum with selective alteration of Purkinje cells. All these neurons have an atrophic dendritic tree. The proximal dendritic branches and the cell bodies, instead of being smooth, are studded with spines. Most of the axon terminals belonging to this neuronal population undergo progressive degenerative changes. Cell death is observed in only a small proportion of Purkinje cells. Electrophysiological study revealed that the synapses between climbing fibers and Purkinje cells are functional with no gross abnormality.