EMBRYONIC DEVELOPMENT OF THE EFFERENT SYSTEM

传出系统的胚胎发育

• 批准号: 2340574
• 金额: $ 11.72万
• 依托单位: FATHER FLANAGAN'S BOYS' HOME
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2340574
• 关键词: Xenopus; acetylcholinesterase; afferent nerve; auditory pathways; chick embryo; cochlea; cochlear nerve; denervation; developmental neurobiology; ear hair cell; efferent nerve; embryo /fetus; epithelium; fluorescent dye /probe; histochemistry /cytochemistry; innervation; laboratory mouse; labyrinth; nervous system regeneration; neuroanatomy; neurogenesis; synapses; vertebrate embryology; vestibular nerve

The inner ear receives an afferent innervation from ganglion cells and an effernt or centrifugal innervation from cells in the brainstem. Much has been learned about the organization of adult afferent and efferent innervation and the embryonic development of the vertebrate ear, particularly the mammalian cochlea. In contrast, very little is known about the embryonic development or the regeneration of the efferent system. The available evidence for a prenatal arrival of efferents at the developing hair cells allows speculation that they may play some role in the maturation of the efferent system. The long term objective of this proposal is to further our understanding of the role played by the efferent system in normal maturation and pathological defects of the mammalian cochlea. The first major aim of is to provide a detailed neuroanatomical analysis of the spatiotemporal development of the inner ear efferent innervation in embryonic mice, chickens, and frogs to estimate their potential role in normal maturation. The second major aim is to explore the interactions between the ear primordia and ingrowing efferent fibers involved in establishing the patten of efferent innervation. This will be done experimentally by exploiting the accessibility of non-mammalian embryos. The specific aims are: to separately delineate the sequence of arrival of afferent an efferent fibers at the inner ear epithelia, to determine the temporal sequence of the segregation of vestibular and cochlear efferent neurons, to determine the number of efferent neurons at various stages of development, to compare the developmental sequence of inner ear innervation in mice with that of chickens and frogs, and to determine the role of the developing ear in the proper pattern formation of efferent innervation and to establish the accuracy of regeneration of inner ear efferents. The proposed experiments will employ the lipophilic dye, Dil, and use the histochemical demonstration of acetylcholinesterase (the degradative enzyme of the major efferent transmitter) to delineate fiber pathways to and from the developing ear at various embryonic stages. Exploration of the mechanisms governing efferent fiber patterns during development and regeneration will be initiated by manipulating the ear primordia or eighth cranial nerve in non-mammalian embryos. These data should provide insight into ontogenetic mechanisms that lead to the specific patterns of efferent innervation in mammals, birds and frogs.

内耳获得神经节细胞的传入神经和 从脑干中的细胞中产生的灭绝或离心神经。 有很多 已经了解了成人传入和传出的组织 神经和脊椎动物耳朵的胚胎发育， 特别是哺乳动物的耳蜗。 相比之下，很少知道 关于传出系统的胚胎发育或再生。 出现产前到达的可用证据 开发毛细胞可以猜测它们可能在 传出系统的成熟。 这个长期目标 提案是为了进一步理解侵蚀的作用 哺乳动物正常成熟和病理缺陷的系统 耳蜗。 第一个主要目的是提供详细的神经解剖学分析 内耳导致神经支配的时空发育 胚胎小鼠，鸡和青蛙，以估计它们在 正常成熟。 第二个主要目的是探索互动 在耳朵原始和涉及的发出纤维之间 建立传出神经的束缚。 这将完成 通过利用非哺乳动物胚胎的可及性来实验。 具体目的是：分别描述 在内耳上皮的传播纤维中传播纤维，以确定 前庭和人工耳蜗隔离的时间序列 神经元，确定在各个阶段的传出神经元的数量 开发，比较内耳神经的发展序列 在有鸡和青蛙的小鼠中，并确定 在适当形成的传出神经和 建立内耳侵蚀的再生的准确性。 提出的实验将采用亲脂性染料，DIL，并使用 乙酰胆碱酯酶的组织化学演示（降解酶 主要发射发射机）以描绘纤维通路 在各个胚胎阶段发育的耳朵。 探索 开发过程中管理传出纤维模式的机制和 再生将通过操纵耳朵原始或八分之一来启动 非哺乳动物胚胎中的颅神经。 这些数据应提供洞察力 进入构成机制，导致特定的传出模式 哺乳动物，鸟类和青蛙的神经。