ABSTRACT
The induction of experimental autoimmune myasthenia gravis (EAMG) has long been shown to result in inefficient function of the acetylcholine receptor (AChR) and concomitant impairment of AChR-dependent neuromuscular communication. As an animal model of human myasthenia gravis, AChR-immunized rats demonstrate symptoms of MG very similar to those observed in human patients resulting from the presence of circulating anti-AChR antibodies which interfere with the normal function of the receptor. In addition to antibody antagonists of neuromuscular function, a variety of drugs have been observed to be associated with possible exacerbations of impaired neuromuscular function leading to myasthenic crisis in some MG patients. One drug, the cardiac anti-arrhythmic agent, procainamide, has been reported to cause both pre-synaptic and post-synaptic electrophysiologic effects at the neuromuscular junction. The study described below extends these observations to include the demonstration of perturbed AChR-dependent contractile muscle function in a rat model of MG.