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Antagonism of botulinum toxin type A‐induced cleavage of SNAP‐25 in rat cerebral synaptosome by toosendanin
Author(s) -
Zhou Jian-Ying,
Wang Zhong-Feng,
Ren Xiao-Mei,
Tang Mian-Zhi,
Shi Yu-Liang
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01291-2
Subject(s) - synaptosome , synaptobrevin , chemistry , cleavage (geology) , botulism , synaptic vesicle , toxin , neurotoxin , biochemistry , incubation , biophysics , vesicle , membrane , biology , paleontology , genetics , fracture (geology)
Toosendanin (TSN), a triterpenoid derivative extracted from Chinese traditional medicine, has been demonstrated to be an effective cure for experimental botulism. This study is designed to explore its antibotulismic mechanism by Western blotting. The results showed that TSN incubation did not change the electrophoresis pattern and the amounts of synaptosomal‐associated protein of 25 kDa (SNAP‐25), syntaxin and synaptobrevin/vesicle‐associated membrane protein in rat cerebral synaptosomes, but made the synaptosomes completely resistant to botulinum neurotoxin A (BoNT/A)‐mediated cleavage of SNAP‐25. After binding of BoNT/A to synaptosomes, TSN still partially antagonized the toxin‐mediated cleavage of SNAP‐25. However, TSN‐incubated synaptosomal membrane fraction did not resist the cleavage of SNAP‐25 by the light chain of BoNT/A. It is suggested that the antibotulismic effect of TSN results from blocking the toxin's approach to its enzymatic substrate.