EXPRESSION OF ION CHANNELS IN THE AUDITORY SYSTEM

听觉系统中离子通道的表达

• 批准号: 3218498
• 负责人: LEONARD K KACZMAREK
• 金额: $ 25.83万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3218498
• 关键词: Xenopus oocyte; acoustic nerve; antisense nucleic acid; auditory deprivation; auditory nuclei; auditory stimulus; gene expression; genetic regulation; growth factor; immunocytochemistry; in situ hybridization; laboratory rat; messenger RNA; molecular cloning; neurogenesis; neurons; northern blottings; polymerase chain reaction; potassium channel; protein structure; second messengers; tissue /cell culture; voltage /patch clamp

The ability of the auditory system to encode the frequency, localization and intensity of sounds, and to discriminate between small differences in these parameters, depends on the precise timing and frequency of action potentials in neurons within central auditory pathways. These, in turn, depend on the number and characteristics of plasma membrane ion channels in these neurons, particularly potassium channels, which control factors such as threshold, latency to action potential accommodation, and pattern of firing in response to a maintained stimulus. In preliminary experiments, we have found that a recently cloned potassium channel gene, Kv3.1, is expressed at very high levels in neurons of central auditory pathways. Using in situ hybridization, the polymerase chain reaction, immunohistochemistry and other molecular biological approaches, we plan to identify other channels that are expressed in these pathways and to localize the channels to specific auditory nuclei and neuronal subtypes. Because the response properties of auditory neurons change during development, we shall determine the stages in development at which each channel species appears. We shall then measure the influence of auditory stimulation or deprivation on the level of expression of the channels. To determine which component of potassium current each gene corresponds to, we shall, using patch clamp recording, compare the electrical characteristics of the channels expressed in cell lines of Xenopus oocytes with those found in auditory neurons. This will be tested further by electrophysiological experiments that use immunological techniques and antisense oligonucleotide approaches to selectively alter the channel within auditory neurons. Finally, using brain slices and primary cultures of auditory neurons, we shall determine whether the expression of the genes for these channels are regulated by factors such as depolarization, ongoing electrical activity, growth factors and second messengers. An understanding of the molecular basis for the electrical characteristics of different neurons in the auditory system is likely to lead to an understanding od deficits in certain forms of deafness and in the genesis of abnormal firing patterns such as occur in audiogenic seizures.

听觉系统编码频率的能力， 声音的本地化和强度，并区分小 这些参数的差异取决于精确的时机和 中央听觉中神经元的动作电位频率 途径。 这些反过来取决于 这些神经元中的质膜离子通道，尤其是钾 渠道，控制阈值等因素，行动延迟 潜在的住宿和对响应的射击方式 保持刺激。 在初步实验中，我们发现 最近克隆的钾通道基因Kv3.1在非常表达 中央听觉途径神经元的高水平。 使用原位 杂交，聚合酶链反应，免疫组织化学和 其他分子生物学方法，我们计划识别其他 在这些途径中表达的渠道并定位 特定听觉核和神经元亚型的通道。 因为 在开发过程中，听觉神经元的响应特性会改变， 我们将确定每个渠道的开发阶段 物种出现。 然后，我们将衡量听觉的影响 刺激或剥夺通道的表达水平。 为了确定钾电流的哪个成分，每个基因对应 为了使用贴片夹记录，比较电气 在爪蟾细胞系中表达的通道的特征 卵母细胞与听觉神经元中发现的卵母细胞。 这将进行测试 进一步通过使用免疫学的电生理实验 技术和反义寡核苷酸方法有选择地 更改听觉神经元内的通道。 最后，使用大脑切片 和听觉神经元的主要培养物，我们将确定是否是否 这些通道的基因的表达受因素的调节 例如去极化，持续的电活动，生长因子和 第二使者。 对分子基础的理解 听觉系统中不同神经元的电气特征 可能导致某些形式的OD缺陷 耳聋和异常发射模式的起源（例如 在听力发作中。