Alterations in cerebellar glutamic acid decarboxylase (GAD) activity in a genetic model of torsion dystonia (rat).

Glutamic acid decarboxylase (GAD) activity was studied in specific brain regions of a newly identified genetic (rat) model of human torsion dystonia. GAD activity was found to be significantly increased in the deep cerebellar nuclei of dystonic rats at 16, 20, and 24 days of age. GAD activity in the other regions examined (vermis, cerebellar hemispheres, caudate nucleus, and globus pallidus) did not differ from that of age-matched normal littermate controls. Diazepam treatment significantly reduced the frequency of dystonic movements in the mutant.