Glutamic acid decarboxylase activity in micropunches of the deep cerebellar nuclei of the genetically dystonic (dt) rat.

Glutamic acid decarboxylase (GAD) activity was measured in specific divisions of the deep cerebellar nuclei of rats with an inherited dystonia. In 16-day-old dystonic rats there was a significant increase in GAD activity only in the nucleus interpositus (+26%). In 20-day-old dystonic rats GAD activity in all 3 cerebellar nuclei (fastigial, interpositus, dentate) was significantly increased compared to normal controls. The results indicate a spread of the anatomical locus of the neurochemical abnormality with time. During this period (postnatal days 16-20) there is a progressive worsening of the motor disorder in the affected animals.