Nerve stimulation test in murine experimental autoimmune myasthenia gravis.

Use of the mouse model of myasthenia gravis (murine EAMG), ideally suited for immunological study, has been hampered by the relatively mild character of the disease and by the extended time and effort required for inducing severe disease. Electromyographic measurement of the compound action potential after repetitive stimuli, the nerve stimulation test, was evaluated for its ability to diagnose neuromuscular transmission defects in mice immunized with Torpedo acetylcholine receptor. With the combination of provocative maneuvers and raising of the body temperature, EAMG could be diagnosed in nearly all immunized animals a few weeks after immunization, whereas clinical evaluation of muscle weakness was positive in less than half of immunized mice months after the first immunization. Thus, EMG provides a means of objective evaluation of the disease and attempts at its experimental modification.