Absence of [125I] alpha-bungarotoxin binding to motor nerve terminals of frog, lizard and mouse muscle

摘要: The existence of nicotinic acetylcholine receptors (AChRs) on the motor nerve terminals vertebrates has long been controversial. We have re- examined this issue by electron microscope autoradiography with [125I] alpha-bungarotoxin, following separation from muscle fibers collagenase and protease treatment. found no label over terminal membranes other than that due to background, we calculate upper limits less 0.1% postsynaptic AChR density for in frogs, lizards, mice. conclude there are essentially presynaptic bind alpha-bungarotoxin at vertebrate neuromuscular junctions.