Block of Lens and Neuronal Gap Junctions by Quinine

奎宁阻断晶状体和神经元间隙连接

• 批准号: 7122353
• 负责人: Miduturu Srinivas
• 金额: $ 28.21万
• 依托单位: STATE COLLEGE OF OPTOMETRY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7122353
• 关键词: Xenopus oocyte; aminoacid; analog; binding sites; biophysics; chemical structure function; computer data analysis; electrophysiology; eye circulation; eye pharmacology; gap junctions; gene targeting; genetically modified animals; histogenesis; immunofluorescence technique; ion channel blocker; laboratory mouse; lens; membrane channels; neurons; organ culture; quinine; western blottings

DESCRIPTION: The lens is an avascular organ and therefore relies on a unique microcirculatory system to transport nutrients and metabolites to its core. Gap junction channels are important components of this microcirculation and thus maintenance of homeostasis and transparency of the lens is critically dependent on their presence. Three gap junction proteins (connexins) are expressed in the lens. They are Cx43, Cx46 and Cx50. Mice lacking Cx50 or Cx46 develop nuclear cataracts. In addition, the lenses of Cx50 knockout mice are smaller than normal, implying an early developmental defect. We have developed an additional tool to discriminate between the different connexins. A potent and specific blocker of Cx50 gap junction channels was identified. This drug blocks Cx50 channels with an IC50 value of ~ 1 uM; block of the other two gap junctions expressed in the lens, Cx43 and Cx46, occurs only at 15- and 75-fold higher concentrations respectively. This observation forms the basis of this proposal. The overall goals of this project is to use a pharmacological approach to provide an understanding of the role of Cx50 gap junctions and hemichannels in maintaining transparency of the lens and in controlling lens growth. Such a pharmacological approach will also serve to complement studies on genetically engineered mice.

晶状体是一个无血管器官，因此依靠独特的微循环系统将营养物质和代谢物输送到晶状体的核心。间隙连接通道是这种微循环的重要组成部分，因此维持体内平衡和晶状体的透明度关键取决于它们的存在。晶状体中表达三种间隙连接蛋白（连接蛋白）。它们是Cx43、Cx46和Cx50。缺乏Cx50或Cx46的小鼠会发生核性白内障。此外，Cx50基因敲除小鼠的晶状体比正常小鼠小，这意味着早期发育缺陷。我们已经开发了一个额外的工具来区分不同的连接。发现了一种有效的特异性Cx50间隙连接通道阻滞剂。该药物阻断Cx50通道，IC50值为~ 1 uM；在晶状体中表达的另外两个间隙连接Cx43和Cx46的阻滞分别只发生在浓度高15倍和75倍的情况下。这一看法构成了本建议的基础。该项目的总体目标是使用药理学方法来了解Cx50间隙连接和半通道在维持晶状体透明度和控制晶状体生长中的作用。这种药理学方法也将有助于补充基因工程小鼠的研究。