药理学课件23.利尿药是.ppt

第二十一章 利尿药及脱水药 朱海扬 嘉应学院医学院药理教研室 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 定义：作用于肾脏，增加电解质及水排泄，使尿量增加的药物。 一、利尿药作用的生理学基础 肾小球的滤过 肾小管和集合管的重吸收及分泌。 第一节┃利尿药 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. （一）肾小球的滤过 （二）肾小管和集合管的重吸收 1.近曲小管：65–70%Na+被重吸收. 2.髓袢升支粗段：30–35% Na+被重吸收,水的再吸收↓，NaCl的再吸收依赖管腔膜K+-Na+-2Cl-共同转运系统。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 3. 远曲小管和集合管:5–10%Na+被重吸收。 远曲小管近端在管腔膜K+-Na+2Cl-共同转运系统介导下重吸收原尿中10%Na+。因此抑制该段Na+吸收的药可产生中效利尿作用。同时该段存在Na+-Ca2+交换。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 二、常用利尿药的分类、作用部位及机制 低效利尿药 留K+利尿药 排K+利尿药 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 65–70% Na+被重吸收 30–35% Na+被重吸收 5–10%Na+被重吸收 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (一)高效利尿药(袢利尿药) 药物：呋噻咪、依他尼酸（利尿酸）、布美他尼 呋噻咪（Furosemide，速尿） 【药理作用】 1.使肾小管对Na+的重吸收由原来的99.4%下降为70％～80％，利尿作用强、快、短。 ●作用部位：髓袢升枝粗段髓质部和皮质部 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 抑制髓袢升枝粗段Na+-2Cl-- K+共同转运载体（与Cl-共同竞争该载体的Cl-结合部位），使Na+、Cl-重吸收↓，从而影响肾脏的稀释和浓缩功能。 ◆作用机理： 增加K+排泄 Na+排出增加，促进K+-Na+交换。同时因利尿使体液减少，促进肾素和醛固酮分泌增多，K+排泄 。易引起低血钾 、低盐综合征。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2.扩张血管： （1）扩张肾血管，降低肾血管阻力，增加肾血流量。 （2）扩张小静脉，降低左心室充盈压