MECHANISMS OF DRUG/ION CHANNEL INTERACTIONS

心脏离子通道蛋白是抗心律失常药物的靶点 行动。该项目将整合功能分析(电压钳位 离子流)和分子生物学技术来识别阻塞 抗心律失常药物的作用机制及通道蛋白结合域 阻断钾离子通道。实验将利用这两个本机 心肌细胞内钾离子通道及其克隆 来自哺乳动物(包括人类)的心脏。钾电流将是 隔离测量，不受其他离子流污染 在外源表达系统中，非洲爪哇卵母细胞和小鼠成纤维细胞， 它将在这个项目中使用。相互作用的决定因素 具有开放通道的药物，包括通道门控、电压依赖 和离子渗透，并与失活的通道将进行测试 实验和用于改进药物抑制模型的结果 离子流。位点定向的通道蛋白修饰和 异构体通道的表达将被用于阐明分子 药物作用的决定因素，包括药物结合位点的确定 在离子通道上。在这里获得的信息将反馈给其他人 本计划中评估其他系统中的药物行为的项目。 这一项目将提高我们对这一机制的理解 抗心律失常药物的作用，并可能因此指向战略，将 有助于开发更新、更安全的化合物。

Cardiac ion channel proteins are the targets for antiarrhythmic drug action. This Project will integrate functional analysis (voltage clamp of ionic currents) and molecular biological techniques to identify blocking mechanisms and channel protein binding domains for antiarrhythmic agents which block potassium channels. Experiments will utilize both native potassium channels in isolated cardiac cells as well as channels cloned from mammalian (including human) heart. Potassium currents will be measured in isolation and without contamination from other ionic currents in the exogenous expression systems, Xenopus oocytes and mouse fibroblasts, which will be used in this Project. The determinants of the interactions of drugs with open channels, including channel gating, voltage-dependence and ion permeation, and with inactivated channels will be tested experimentally and the results used to refine models of drug inhibition of ion currents. Site-directed channel protein modifications and the expression of heteromeric channels will be used to elucidate the molecular determinants of drug action, including identification of drug binding loci on ion channels. The information gained here will feed back to other Projects in this Program which evaluate drug actions in other systems. This Project will improve our understanding of the mechanisms of antiarrhythmic drug action and may thereby point to strategies which will be useful in the development of newer and safer compounds.