PHGY 214 Lecture Notes - Lecture 26: Kvlqt1, Cardiac Muscle, Antiarrhythmic Agent
8 Dec 2017
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Ion chan: cell memb proteins which selectively premeate specific ions. Patch clamp: instrument that can analyze and test ion conduction. Na chans are heterotetramers meaning each domain is distinct but everything else is same: inactivation occurs in domain 3-4. S4 controls open/close of chan, it is +vely charged w/n, during depol pushes s4 seg upwards (attracted to ve) opening pore, baseline= closed and s4 seg not up or down. In cardiac muscle cells na chan inactivation underlies refractory period. Length of ap is det by l type ca chan. Qt interval is long can be due to genetic (lqt1) or acquired (external stim like drug withdrawl) Can lead to torsades to pointes: irregular ap open ca chan leading to non synchronous contraction fibrillation: forms: Natural occurring mutation in kvlqt1 decreases iks causing lqt1. Natural occurring mutation in herg decreases ikr causing lqt2. Natural occurring mutations in scnsa gene increases persistent ina causing lqt3.
