Clostridial neurotoxins junctions

The extreme toxicity of clostridial neurotoxins (CNTs) derives from their absolute neurospecificity as well as from catalytic activity. TeTx and BoNTs bind specifically to the neuromuscular junction (NMJ) of motor neurons. The identity of the receptor(s) on the presynaptic membrane is unknown, but their extreme toxicity suggests that the binding affinity to the cognate receptor must be very high. The receptor-bound toxin is internalized at the presynaptic membrane of the NMJ and gains access to the neuronal cytosol. Here it blocks the release of acetylcholine (ACh), causing a flaccid paralysis (Simpson,... 

In general, sensitivity of a given preparation to clostridial neurotoxins depends on the type of neurotoxin. For instance, BoNT/A is particularly potent in poisoning peripheral cholinergic nerve terminals (i.e. neuromuscular junctions), whereas TeTx is most potent for CNS preparations. However, all eight neurotoxins are able to inhibit exocy-... 

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