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Updated: Aug 11, 2026

Historical View and Physiology Demonstration at the NMJ of the Crayfish Opener Muscle
Published on: November 9, 2009
Quantal secretion and loss of vesicles induced by veratridine at the crayfish neuromuscular junction
Abstract:
Experiments were conducted in nerve-muscle preparations of small young crayfish (Austropotamobius torrentium, Astacus astacus). Application of veratridine in the superfusate induced strong quantal release of transmitter. After about 5 min when quantal release had declined to a low level preparations were fixed for electron microscopy. Unlike control preparations, veratridine-treated preparations revealed nerve terminals which were largely depleted of their synaptic vesicles. Our findings suggest that in the presence of veratridine the decline of quantal secretion results from the loss of vesicles caused by tonic nerve terminal depolarization. Moreover, our results indicate that during or after excessive quantal release triggered by veratridine synaptic vesicles may fuse with both the presynaptic membrane and each other.
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