Effect of Blood of Myasthenia Gravis Patients on Acetylcholine Sensitivity of Prostigminized Frog and Leech Muscle. *

Abstract

Summary

Attempts were made to experimentally demonstrate a circulating factor in the blood of normal people and of patients with myasthenia gravis before and after exercise to a fatigued state, which would depress the response of prostigminized frog and leech muscle to acetylcholine. Before the addition of acetylcholine to the perfusion fluid it was found that neither normal serum nor serum from myasthenic donors had any effect upon the prostigminized leech or frog muscle. Serum, whether from a normal or myasthenic donor, had no significant effect upon the acetylcholine sensitivity of either frog or leech muscle. Although hemolyzed blood from both normal and myasthenic donors increased the acetylcholine sensitivity of prostigminized leech and frog muscle, there was no quantitative difference in the effect of the two types of hemolyzed blood. A circulating factor depressing the acetylcholine sensitivity of frog and leech muscle could not be demonstrated with our methods in myasthenic patients. Some reasons for the non-detection of this hypothetical factor and some theories as to the etiology of myasthenia gravis were discussed.