association between tetrodotoxin resistant channels and lipid rafts regulates sensory neuron excitability河豚毒素抗性之间的联系渠道和脂质筏调节感觉神经元兴奋性.pdf

Association between Tetrodotoxin Resistant Channels and Lipid Rafts Regulates Sensory Neuron Excitability ` 1 2 1 Alessandro Pristera , Mark D. Baker , Kenji Okuse * 1 Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom, 2 Neuroscience and Trauma Centre, Blizard Institute, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, London, United Kingdom Abstract Voltage-gated sodium channels (VGSCs) play a key role in the initiation and propagation of action potentials in neurons. NaV 1.8 is a tetrodotoxin (TTX) resistant VGSC expressed in nociceptors, peripheral small-diameter neurons able to detect noxious stimuli. NaV 1.8 underlies the vast majority of sodium currents during action potentials. Many studies have highlighted a key role for NaV 1.8 in inflammatory and chronic pain models. Lipid rafts are microdomains of the plasma membrane highly enriched in cholesterol and sphingolipids. Lipid rafts tune the spatial and temporal organisation of proteins and lipids on the plasma membrane. They are thought to act as platforms on the membrane where proteins and lipids can be trafficked, compartmentalised and functionally clustered. In the present study we investigated NaV 1.8 sub- cellular localisation and explored the idea that it is associated with lipid rafts in nociceptors. We found that NaV 1.8 is distributed in clusters along the axons of DRG neurons in vitro and ex vivo. We also demonstrated, by biochemical and imaging studies, that NaV 1.8 is associated with lipid rafts along the sciatic nerve ex vivo and in DRG neurons in vitro. Moreover, treatments with methyl-b-cy