BIOL 3051 Chapter Notes - Chapter 11.2: Kv1.1, Dendrotoxin, Sinus Rhythm
24 Apr 2020
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Typical k+ channels: k1. x expressed widely in nervous system, k1. 1 & 1. 2 control neural excitability, k1. 1 inhibited by dendrotoxin (dtx) produced by mamba snakes prolong duration of. Ap & increase ach release at nmj muscle hyperexcitability & convulsive symptoms number of ap increase. Kv1. 5 atrium specific k+ channel: kv1. 5 in atrial myocytes, not ventricular, selectively shortens atrial depolarization good drug target results in little dip. Faster repolarization of atria: vernakalant: open channel blocker of k1. 5. K1. 5 results in initial hyperpolarization faster repolarization of atria. It determines length of ventricular ap: ventricular ap terminated by increase k+ conductance at end of ap, activation of muscarinic receptor by acetyl, inhibits k+ (kcnq) channel. Blocking this channel will result in even slower conductance. K7. 1 modulator for cardiac fibrillation: azimilide is 7. 1/11. 1 inhibitor blocks channel so no repolaizaition slows ventricle contraction coordination of heart. It slows down repolarization to prolong contraction: prolongs duration of cardiac ap, reduce atrial & ventricle fibrillation,
