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乙酰胆碱(Ach)激活的钾离子通道(KAch)是内向整流钾通道家族中的一员,是由Kir3.1和Kir3.4蛋白以2∶2组成的异四聚体。在传导系统和心房肌细胞膜表达丰富,在心室组织中有少量表达,且沿心肌细胞T管分布。通道活性受Ach等配体激活的G蛋白、细胞外Na+、细胞内PH值等调节,Ach激活的钾电流(IKAch)在维持细胞膜静息电位和动作电位3期复极中起重要作用。IKAch的激活促使心肌细胞膜超极化、兴奋性降低、动作电位时程缩短、自律性降低,IKAch不仅与心房颤动等室上性心律失常密切相关,且其基因突变丧失电生理特性是长QT综合征的病因之一,是心律失常治疗的潜在靶点。
Acetylcholine (Ach) -activated potassium channel (KAch), a member of the inward rectifier potassium channel family, is a heterotetramer consisting of 2: 2 of Kir3.1 and Kir3.4 proteins. In the conduction system and atrial myocyte membrane expression is rich in a small amount of expression in ventricular tissue, and along the myocardial cells T-tube distribution. Channel activity is regulated by G proteins activated by ligands such as Ach, extracellular Na +, intracellular pH, and Ach-activated potassium currents (IKAch) play an important role in maintaining the resting and action potentials of stage 3 repolarization. Activation of IKAch promotes myocardial membrane hyperpolarization, decreased excitability, shortened action potential duration and decreased self-discipline. IKAch is not only closely related to supraventricular arrhythmias such as atrial fibrillation, but also has a loss of electrophysiological properties due to mutations in the long QT syndrome One of the etiologies of the syndrome is a potential target for the treatment of arrhythmias.