IMMUNOHISTOCHEMICAL STUDY OF UTROPHIN AND DYSTROPHIN AT THE MOTOR END-PLATE IN MYASTHENIA-GRAVIS

We studied the densities of utrophin and dystrophin at the motor end-p lates of patients with myasthenia gravis (MG) using immunohistochemica l analysis. The densities were compared with those found in patients w ith amyotrophic lateral sclerosis, Lambert-Eaton myasthenic syndrome a nd normal controls. Utrophin was reduced at the motor end-plates of MG patients, in association with a reduction of alpha-bungarotoxin bindi ng sites. In contrast, the density of dystrophin at the motor end-plat e of MG patients was not significantly different from that found in th e controls. We conclude that, at the motor end-plate, utrophin may be more closely associated than dystrophin with the acetylcholine recepto r, and that it plays a different role.