Motor nerve ending disorder in myasthenia gravis.

Mild myasthenia gravis patients were compared with normals with respect to the capacity of their motor nerve endings (MNEs) to generate a neostigmine-induced postactivation repetition (PAR). Dose-response analyses of PAR recorded from muscle electrically and by contractile measurement disclose a loss of this pharmacologic responsiveness in myasthenia. Since mild myasthenics transmitted nerve impulse trains of 20 to 200 Hz, as did normals, it was evident that PAR is transmitted insofar as it can be generated by MNEs. The dose-response analyses support this. These data indicate an MNE disorder in the disease.