Antibodies Indicate Acetylcholine Receptors in Limulus Neuromuscular Junctions

Binding of antibodies to Acetylcholine receptors (AChR) on skeletal muscle prevents or weakens contraction, as in the human autoimmune disease Myasthenia Gravis (MG), also inducible in rats. The horseshoe crab (Limulus polyphemus), an ancient arthropod, is an unlikely candidate for neuromuscular control by acetylcholine because most arthropods\u27\u27 muscles are innervated by glutamatergic (excitatory) and GABAergic (inhibitory) neurons. Nevertheless, monoclonal anti-human AChR antibody caused eserine-reversible paralysis in Limulus larvae and juveniles, and in severed legs