Open AccessBlock of transmitter release by botulinum C1 action on syntaxin at the squid giant synapse
Author(s) -
Jordi Marsal,
Bonaventura Ruiz-Montasell,
Juan Blasi,
Jorge E. Moreira,
Diego Contreras,
Mutsuyuki Sugimori,
Rodolfó R. Llinás
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.26.14871
Subject(s) - syntaxin , synaptic vesicle , synapse , biophysics , microbiology and biotechnology , biology , neurotransmission , vesicle , neuroscience , chemistry , biochemistry , membrane , receptor
Electrophysiological, morphological, and biochemical approaches were combined to study the effect of the presynaptic injection of the light chain of botulinum toxin C1 into the squid giant synapse. Presynaptic injection was accompanied by synaptic block that occurred progressively as the toxin filled the presynaptic terminal. Neither the presynaptic action potential nor the Ca2+ currents in the presynaptic terminal were affected by the toxin. Biochemical analysis of syntaxin moiety in squid indicates that the light chain of botulinum toxin C1 lyses syntaxinin vitro , suggesting that this was the mechanism responsible for synaptic block. Ultrastructure of the injected synapses demonstrates an enormous increase in the number of presynaptic vesicles, suggesting that the release rather than the docking of vesicles is affected by biochemical lysing of the syntaxin molecule.