[Modes of appearance of giant spontaneous potentials induced by vinblastine on the isolated preparation of frog muscle].

Vinblastine induces reversible changes of the spontaneous release of ACh at the fro,neuromuscular junction characterized by the appearance of "giant" potentials. These large potentials occur soon after soaking the muscle in Vinblastine and are not consecutive to a large increase of the spontaneous release. They seem to serive from the release of big packets of ACh which could be elaborated from preexistent quantal units.