Different mechanisms of inhibition of nerve terminals by botulinum and snake presynaptic neurotoxins.
The different mode of action on peripheral nerve terminals of the botulinum neurotoxins and of the snake presynaptic phospholipase A2 neurotoxins is reviewed here. These two groups of toxins are highly toxic because they are neurospecific and at the same time are enzymes that can modify many substrate molecules before being inactivated. The similarity of symptoms they cause in humans derives from the fact that both botulinum neurotoxins (seven serotypes named A-G) and snake presynaptic PLA2 neurotoxins block the nerve terminals and that peripheral cholinergic terminals are major targets. Given this general similarity of targets and clinical symptoms, the specific molecular and cellular mechanisms at the basis of their action are very different. This difference appears evident from the beginning of intoxication, i.e. neurotoxins binding to peripheral nerve terminals and proceeds with the different site of actions and molecular targets.
Montecucco
Cesare
C
Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Viale G. Colombo 3, 35131 Padova, Italy. cesare.montecucco@unipd.it
Rossetto
Ornella
O
Caccin
Paola
P
Rigoni
Michela
M
Carli
Luca
L
Morbiato
Laura
L
Muraro
Lucia
L
Paoli
Marco
M
D000818:Animals; D001905:Botulinum Toxins / Q000378:metabolism* / Q000494:pharmacology; D002799:Cholinergic Fibers / Q000187:drug effects; D006801:Humans; D009433:Neural Inhibition / Q000187:drug effects*; D009498:Neurotoxins / Q000378:metabolism / Q000494:pharmacology; D017933:Peripheral Nervous System / Q000187:drug effects; D054467:Phospholipases A2 / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000187:drug effects*; D011485:Protein Binding; D012910:Snake Venoms / Q000201:enzymology* / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism; D022161:Transport Vesicles / Q000378:metabolism
D009498:Neurotoxins; D012910:Snake Venoms; D054467:Phospholipases A2; D001905:Botulinum Toxins