PATCH CLAMP STUDY OF HEPATOCYTE K CHANNEL REGULATION

候选人：科恩博士将从事学术医学工作 基础研究与临床教学相结合。在博士后期间 耶鲁大学生理学研究员何格哈德博士 获得了上皮运输生理学方面的广泛背景 丰富的电气技术经验，有助于学习这些 包括膜片钳方法在内的运输过程允许直接 单离子通道的记录。科恩博士致力于开发一种 将这项技术应用于肾上皮细胞的合适准备(见 附录)和中国人脑底外侧钾通道的微电极研究。 两栖类近端小管。这里提出的研究是合乎逻辑的 继续这项工作。 2.研究：肝细胞含有一种钾电导， 对阿尔法和贝塔肾上腺素能药以及多种激素。它 也对细胞内钙离子和环磷酸腺苷和这两个 物质似乎介导了荷尔蒙和 神经递质。这种导电性被认为在 将荷尔蒙信号转化为代谢事件。电导 也已知与Na+K+ATPase的转运速率直接相关。 这似乎是许多上皮性K+电导的特性。 使用膜片钳技术的初步工作证明 肝细胞中存在K+通道。在建议的研究中， 我们将探讨该通道的钙敏感性以及钙通道的性质。 钙与环磷酸腺苷的相互作用。耦合的机理 泵和活性之间的关系将被研究，特别是假说 钙敏感性的改变是这种耦合的基础，这一点将得到测试。 进一步的研究将探索新陈代谢和 通道，再次强调对钙敏感性的调制。这些 后一项研究与膜的变化是否 K+通透性在细胞损伤的病理生理学中发挥作用 缺氧。 3.环境：马萨诸塞州总医院肾科成员 医院积极参与了与此相关的几个领域的研究 应用包括环AMP作用的生物化学。赞助商， 亚历山大·利夫博士一直是上皮细胞转运学的领导者之一 多年来和最近几年一直将努力集中在 缺氧的后果。

1. The candidate: Dr. Cohen will be pursuing a career in academic medicine combining basic research with clinical teaching. During a postdoctoral fellowship in physiology at Yale University under Dr. Gerhard Giebisch he obtained a broad background in the physiology of epithelial transport and extensive experience in electrical techniques useful in studying these transport processes including the patch-clamp method which allows direct recording of single ionic channels. Dr. Cohen worked on developing a suitable preparation for applying this technique to renal epithelia (see appendix) and on microelectrode studies of the basolateral K+ channel in an amphibian proximal tubule. The studies proposed here are a logical continuation of that work. 2. The research: Hepatocytes contain a potassium conductance that responds to Alpha and Beta adrenergic agents as well as a variety of hormones. It is also responsive to intracellular Ca++ and cyclic AMP and these two substances appear to mediate the action of the hormones and neurotransmitters. This conductance is thought to play a role in the translation of the hormonal signals into metabolic events. The conductance is also known to vary directly with transport rate of the Na+ K+ ATPase. This seems to be a property of many epithelial K+ conductances. Preliminary work using the patch-clamp technique has demonstrated the presence of a K+ channel in hepatocytes. In the proposed studies, the calcium sensitivity of the channel will be explored as will the nature of the interaction between calcium and cyclic AMP. The mechanism of coupling between pump and activity will be studied and in particular the hypothesis that altered calcium sensitivity underlies this coupling will be tested. Further studies will explore the interaction between metabolism and the channel, again, with emphasis on modulation of calcium sensitivity. These latter studies are relevant to the question of whether changes in membrane K+ permeability play a role in the pathophysiology of cell damage during anoxia. 3. The environment: Members of the Renal Unit at the Massachusetts General Hospital are actively engaged in several areas of research relevant to this application including the biochemistry of cyclic AMP action. The sponsor, Dr. Alexander Leaf, has been one of the leaders in epithelial transport for many years and in recent years has been focusing his efforts on the consequences of anoxia.