EFFECT OF BLOOD SERUM FROM PATIENTS WITH MYASTHENIA GRAVIS ON THE SYNTHESIS OF ACETYLCHOLINE IN VITRO1

Abstract

Using frog brain-serum and frog brain-Ringer''s soln. mixtures as preps. for studying rate of acetylcholine synthesis, and the sensitized rectus abdominis muscle of frog for bioassay of acetylcholine content of the mixtures, the effect of control sera and sera from patients with myasthenia gravis on the synthesis of acetylcholine was investigated. Acetylcholine synthesis in mixtures of frog brain-control serum mixtures or in frog brain-dialysate of control serum mixtures exceeded that from frog brain-Ringer''s soln. mixtures. Acetylcholine synthesis in mixtures of frog brain and serum from patients with myasthenia gravis was significantly less than that in frog brain-control serum mixtures. The more severe the myasthenia gravis, the less the acetylcholine synthesis. In mixtures of frog brain and dialysate of serum from patients with myasthenia gravis acetylcholine synthesis was less than in mixtures of frog brain-Ringer''s soln. These results suggest that there is a defect in acetylcholine synthesis in patients with myasthenia gravis which can explain the fatigability and weakness of these patients.