MOLECULAR BIOLOGY OF COCHLEAR EFFERENT RECEPTORS

耳蜗传出受体的分子生物学

• 批准号: 6055835
• 负责人: ANNE E LUEBKE
• 金额: $ 10.79万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-30 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6055835
• 关键词: calcitonin gene related peptide; cholinergic receptors; cochlear nerve; complementary DNA; efferent nerve; guinea pigs; immunocytochemistry; in situ hybridization; molecular cloning; neuropeptide receptor; organ of Corti; protein structure function; western blottings

DESCRIPTION: The objective of this proposal is to study the molecular mechanisms by which neurotransmitters released by olivocochlear efferents influence outer hair cells (OHCs) of the cochlea. One theory about the contributions that cochlear efferents make to hearing is that they protect the cochlea from high frequency acoustic over-stimulation, whereas another theory is that they enhance sound recognition in the presence of background noise. The primary neurotransmitters of the efferents projecting on high frequency OHCs are acetylcholine (ACh) and calcitonin gene-related peptide (CGRP). The proposed experiments will test the hypothesis that CGRP exerts its effects by initiating a cascade of events resulting in desensitization of the cholinergic receptors present on OHCs. The first specific aim is to clone full-length cDNAs for ACh and CGRP receptor subtypes from the guinea pig cochlea using as probes partial cDNAs encoding the guinea pig a9 ACh and CGRP receptors. In situ hybridization techniques will be used to establish which cells in the guinea pig organ of Corti express these receptors. The second specific aim will use immunohistochemical and Western blotting techniques to verify the presence and distribution of proteins for the cochlear ACh a9 and CGRP efferent receptors. The third specific aim employs electrophysiological techniques to investigate whether the cloned CGRP and Ach receptors are able to interact functionally, such that CGRP preincubation causes second messenger effects, which leads to Ach receptor desensitization. Information gained from these studies may contribute to future drug therapies that target the cochlear efferents system, and thus, help decrease the occurrence of, and improve the treatment for patients with high-frequency hearing loss.

描述：本提案的目的是研究分子 橄榄耳蜗传出神经释放神经递质的机制 影响耳蜗的外毛细胞 (OHC)。 一种理论关于 耳蜗传出神经对听力的贡献是保护 耳蜗免受高频声过度刺激，而另一个 理论上来说，它们可以增强背景下的声音识别能力 噪音。 传出神经的主要神经递质投射到高位 频率 OHC 是乙酰胆碱 (ACh) 和降钙素基因相关肽 （CGRP）。 所提出的实验将检验 CGRP 发挥作用的假设 通过引发一系列事件导致脱敏来产生其影响 OHC 上存在的胆碱能受体。 第一个具体目标是克隆 ACh 和 CGRP 的全长 cDNA 使用部分 cDNA 作为探针从豚鼠耳蜗中提取受体亚型 编码豚鼠 a9 ACh 和 CGRP 受体。 原位杂交 技术将用于确定豚鼠器官中的哪些细胞 Corti 表达这些受体。 第二个具体目标将使用 免疫组织化学和蛋白质印迹技术来验证其存在 耳蜗 ACh a9 和 CGRP 传出蛋白的分布 受体。 第三个具体目标采用电生理学技术 研究克隆的 CGRP 和 Ach 受体是否能够 功能上相互作用，使 CGRP 预孵化产生第二信使 作用，导致 Ach 受体脱敏。 从这些研究中获得的信息可能有助于未来的药物开发 针对耳蜗传出系统的疗法，从而有助于减少 的发生，并改善患者的治疗 高频听力损失。