Brain glutamate decarboxylase and cholinergic enzyme activities in scrapie.

C57BL/6J mice, age 6-8 weeks were inoculated intracerebrally with brain homogenate from mice previously infected with the 139A strain of scrapie; control mice were identically treated with brain homogenate from non-infected normal mice. The activities of choline acetyltransferase (CAT), acetyl cholinesterase (AChE), and glutamic acid decarboxylase (GAD) were determined in the forebrain and hindbrain of these animals after 67, 126 and 151 days post-inoculation. There were no significant differences in the activities of CAT and GAD between scrapie and control mice at early, middle or late stages of the disease in the scrapie-infected animals; there was an about 20% decline in AChE activity in the scrapie brain.