Aspartate-taurine imbalance in dominantly inherited olivopontocerebellar atrophy.

Amino acids were measured in autopsied brain from two patients who died with a dominantly inherited form of olivopontocerebellar atrophy. Neuropathologic changes found in the brain of these patients suggested a loss of cerebellar climbing fibers. The contents of aspartic acid, gamma-aminobutyric acid, and homocarnosine were reduced in the cerebellar cortex and the dentate nucleus, while taurine content was markedly elevated in the same brain regions. These findings are compatible with the possibility that aspartic acid is the excitatory synaptic transmitter of the climbing fibers and taurine is the inhibitory neurotransmitter of one or more types of interneurons in the cerebellum.