Reduced axonal transport of 10S acetylcholinesterase in dystrophic mice

Extracts of extensor digitorum longus muscle, atria, brain, and sciatic nerve from phenotypically normal and dystrophic ReJ/129 mice were subjected to sucrose density gradient ultracentrifugation, and the amounts of acetylcholinesterase (AChE) activity associated with each major enzyme form were determined. Normal muscle showed approximately equivalent amounts of the 4S, 10S, and 16S forms of AChE, while dystrophic muscle was relatively deficient in 10S AChE and relatively oversupplied with 4S AChE. This abnormality was not present in the other tissues examined. However, as measured by the 24-hour accumulation of enzyme activity proximal to a ligature on the sciatic nerve, the axonal transport of 10S AChE was only about one third as great in dystrophic as in normal nerve. This result is consistent with the view that the reduction in the amount of this enzyme form in dystrophic muscle could be related to disturbances in a transport-dependent trophic interaction between nerve and muscle.