Katz_1968_J.Physiol_199_729

1. Electrophoretic application of tetrodotoxin (TTX) was used to study the effect of localized blockage of impulses in motor nerve terminals.2. Under suitable conditions it can be shown that local production of end-plate potentials ceases distal to the site of TTX application, while it continues without diminution at proximal sites of the same terminal arborization.3. It is concluded that electrotonic spread of an action potential wave along a motor nerve terminal is insufficient to elicit transmitter release. Active propagation in the terminals is an essential requirement for neuromuscular transmission.