ISCI 1A24 Lecture Notes - Lecture 15: Lipid Bilayer, Tetrodotoxin, Resting Potential
29 Sep 2016
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Document Summary
Chemical structure: the tetrodotoxin molecule contains 4 different elements: c (carbon), n (nitrogen), O (oxygen), and h (hydrogen): the bonds in tetrodotoxin molecules are covalent, and involve the sharing of electrons. Some, such as carbon-oxygen bonds, are slightly polar. Carbon-carbon and carbon-hydrogen bonds are nonpolar: we would expect this molecule to bind to intercellular structures, because it blocks sodium ion channels in the cell membranes. Its charge would likely not allow it to pass through the nonpolar phospholipid bilayer. Receptor proteins would interact to bind it to the outside of the cell. Cellular communication: a voltage-gated sodium ion channel allows sodium to pass through when a certain voltage is detected (action-potential or stimulus). It creates new voltage, activates potassium ion channels, and eventually brings back to resting potential. It sends signals from cell to cell (intercellular communication), and an action potential is only generated if a threshold is met.
