Sandbox Reserved 466: Difference between revisions
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== Mechanism of Action == | == Mechanism of Action == | ||
The tetanus toxin acts in the [ | The tetanus toxin acts in the [http://thebrain.mcgill.ca/flash/i/i_01/i_01_m/i_01_m_ana/i_01_m_ana_1a.jpg synaptic cleft] of neuronal cells. Neurotransmitters are released from the presynaptic terminal of a neuron into the synaptic cleft and received by endocytosis by the postsynaptic terminal of the next neuron. Nerve terminals are filled with vesicles, which are specialized storage components that contain neurotransmitters, and are released from the terminal into the synaptic cleft by exocytosis. The surface of the postsynaptic terminal has many specialized receptors, which bind with specific vesicles. The neurotransmitters are then endocytized into the postsynaptic neuron for transmission of the synapse to facilitate a response to the nerve stimuli. | ||
Tetanus toxin enters the bloodstream or directly binds with a neuronal cell after entering the body from a cut or abrasion. It binds to the neural cells through gangliosides and a protein receptor. Once bound, they enter the cytosol of the synaptic cleft of muscle fiber neurons via a vesicle membrane. Here, they attack and cleave the proteins that form the synaptic vesicle fusion apparatus, particularly [http://en.wikipedia.org/wiki/Synaptobrevin synaptobrevin] [Krishnamurthy et al., 2005]. Synaptobrevin is a protein that forms [http://en.wikipedia.org/wiki/SNARE_proteins SNARE proteins], which mediate the fusion of synaptic vesicles to the presynaptic terminal. The clostridial neurotoxins each have unique binding sites and substrate cleavage specificity. Tetanus toxin cleaves vesicle-associated membrane proteins of synaptobrevin. The VAMP protein is cleaved at the peptide bond Gln76-Phe77 requiring a amino-terminal extension of 22 residues and a peptide of 33-97 residues in length [Kirshnamurthy et al., 2005]. | Tetanus toxin enters the bloodstream or directly binds with a neuronal cell after entering the body from a cut or abrasion. It binds to the neural cells through gangliosides and a protein receptor. Once bound, they enter the cytosol of the synaptic cleft of muscle fiber neurons via a vesicle membrane. Here, they attack and cleave the proteins that form the synaptic vesicle fusion apparatus, particularly [http://en.wikipedia.org/wiki/Synaptobrevin synaptobrevin] [Krishnamurthy et al., 2005]. Synaptobrevin is a protein that forms [http://en.wikipedia.org/wiki/SNARE_proteins SNARE proteins], which mediate the fusion of synaptic vesicles to the presynaptic terminal. The clostridial neurotoxins each have unique binding sites and substrate cleavage specificity. Tetanus toxin cleaves vesicle-associated membrane proteins of synaptobrevin. The VAMP protein is cleaved at the peptide bond Gln76-Phe77 requiring a amino-terminal extension of 22 residues and a peptide of 33-97 residues in length [Kirshnamurthy et al., 2005]. | ||
