Effect of α-Bungarotoxin on Acetylcholinesterase bound to Mouse Diaphragm Endplates

IT has been shown that α-bungarotoxin (α-Bgt) irreversibly blocks cholinoreceptors 1–10 , and that D -(+)tubocurarine (TC) protects these receptors from the toxin 4–7 . On the other hand, it has been emphasized that α-Bgt has no effect on the catalytic activity of acetylcholinesterase (AChE) 4,6,9 , and it was concluded that the cholinoreceptor and AChE must be two different macromolecules 8,9 . Because typical cholinolytics, including TC and gallamine, characteristically influence the kinetics of a membrane-bound AChE 11,12 , it seemed justified to reinvestigate whether α-Bgt really is an exception in this respect.