Neurochemical alterations in the cerebellum of a murine model of Niemann-Pick type C disease.

Niemann-Pick disease Type C (NPC) is a progressive neurovisceral metabolic disorder that is caused in most patients by a defect in a recently found gene, NPC-1. Neurological damage includes visual disorders such as vertical supranuclear gaze palsy, movement disorders such as dystonia and ataxia, dementia, and seizures. So far the biochemical deficit, most likely manifested by delayed intracellular cholesterol transport, has not been correlated with the progressive neurological damage. A mutant Balb/C mouse with a defect in the same gene is used as a model to study NPC. Pathological examination of brain tissue obtained by autopsy from NPC patients or brains of affected NPC mice of different ages, revealed signs of extensive damage throughout the brain, including neurofibrillary tangles and intracellular storage of various compounds. Loss of cerebellar Purkinje cells was the most significant specific damage. The present study examined whether the neurochemical changes present in the NPC mouse brain were related to the pathological changes. The results show major alterations in the levels of serotonin and its main metabolite, 5-hydroxyindoleacetic acid, in the cerebellum and cortex of NPC mice. The levels of the inhibitory amino acid glycine were threefold higher in the cerebellum of NPC mice and those of glutamate and GABA decreased in the cortex. Tyrosine hydroxylase immunoreactivity was present in Purkinje cells, and the levels of L-DOPA increased specifically in the vermis of the cerebellum. These results are the first to indicate changes in neurotransmitters in NPC and that these could be correlated with some of the neuropathology of this disease.