PHIL 2015 Lecture Notes - Lecture 50: Veratridine, Brevetoxin, Grayanotoxin
23 May 2020
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Document Summary
Window current for these channels is basically non-existent. These channels have no window current, they"re either on or off. This is a defining property of voltage gated sodium channels. This means we have sodium leak current through these channels, they just turn on depolarization. They mediate the rapid depolarization phase and shut them off. These toxins enhance activation of voltage gated sodium channels by hyperpolarizing the activation threshold of the channel. Similar to the effect of batrachatoxin (btx of vact) Binds the complex polyether toxins brevetoxin and ciguatoxin. We increase the channel open time, we reduce channel inactivation and we hyperpolarize the cell. Binds a family of lipid-soluble toxins including batrachotoxin, veratridine, aconitine, grayanotoxin. All of these compounds enhance activation of voltage gated sodium channels via hyperpolarization of activation threshold and elimination of channel inactivation. We shift the activation curve left (activating at more hyperpolarized potentials) site 3. Binds the alpha-scorpion toxins and sea anemone toxins.
