Why does tetrodotoxin (TTX) poisoning disrupt nerve signal transmission at the synaptic cleft, rather than directly within the axon?

💡 Explanation

TTX selectively blocks voltage-gated sodium channels, preventing action potential propagation. This blockage reduces signal amplitude at the presynaptic terminal because action potentials fail to arrive; therefore, neurotransmitter release is inhibited, rather than TTX directly modifying the synapse itself.

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