Reduced axonal transport of dopamine-β-hydroxylase activity in dystrophic mice: Evidence for abnormality of adrenergic nerve cells

Abstract

Axonal transport in sympathetic nerves of normal and dystrophic mice (strain 129/ReJ) was studied by measuring the accumulation of activity of a marker-enzyme, dopamine-β-hydroxylase, above a ligature on the sciatic nerve. Although the enzyme activity of unligated sciatic nerve was similar in all mice, the rate of accumulation of DBH activity proximal to a ligature on this nerve was reduced by one-third in 5 to 6-week-old dystrophic mice as compared with their normal littermates ( P < 0.001). This effect was not an artifact of lowered hindlimb temperature, and it was confined to homozygotes for the recessive allele. Reduced transport of dopamine-β-hydroxylase activity in dystrophic mice was not associated with any apparent changes in the tubulin content of the sciatic nerve. We conclude that there is some abnormality in the sympathetic neurons of dystrophic mice, which may reflect a general alteration of synthesis or transport of neural proteins in murine dystrophy.