Action of Botulinum Toxin on Artificial Models for Acetylcholine Transport
Two artificial models for acetylcholine secretion have been used in order to study if they are sensitive to the action of Botulinum toxin type A. We have used the electric organ of Torpedo as the source to obtain subcellular components of the cholinergie nerve terminals. Giant proteoliposomes which have incorporated presynaptic plasma membrane proteins are able to translocate acetylcholine in a calcium dependent manner, in the presence of A23187 calcium ionophore. This transport is sensitive to BoNT/A. In addition the fluidity of such artificial membrane is also sensitive to BoNT/A, suggesting that BoNT/A may inhibit ACh release by making synaptic membranes more rigid. The second model utilized is Xenopus oocytes injected with cholinergie synaptic vesicles and presynaptic plasma membrane. These injected cells are able to release ACh under potassium depolarization or by A23187 ionophore. BoNT/A is capable to inhibit such depolarization-induced release.
KeywordsBotulinum Toxin Synaptic Vesicle Xenopus Oocyte Electric Organ Botulinum Toxin Type
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