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Mechano-electric transduction and dynamics of cytoskeletons in mechanoreceptor cells

机械感受器细胞中的机械电转导和细胞骨架动力学

基本信息

批准号：
06454028
负责人：
TOH Yoshihiro
金额：
$ 4.8万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

It is widely known that there are three types of mechanoreceptors in insects, which structurally and morphologically differ from each other. In the present study morphological basis of mechano-electric transduction has been examined in the three types of insect mechanoreceptors by means of rapid freezing techniques for electron microscopy.1) The structure of the chordotonal organ was examined in cockroach antennae, Drosophila halteres, and locust femurs. Their sensory cilia show some similarity to motile cilia, being thin and long and possessing axoneme with dyenin arms. Morphological comparison between mechanically stimulated cilia and un-stimulated ones suggests that active stroke or passive waving of the sensory cilia may be involved in the mechano-electric transduction.2) The structure of the campaniform sensillum was examined in cockroach antennae and Drosophila halteres. Their sensory cilia are characterized by the tubular body in the distal tip, which is known as a bundle of microtubules. The observation of rapid frozen specimens revealed that actin filaments occur among microtubules in the tubular body. Regular arrangement of the two types of filaments may comprise morphological basis of mechano-electric transduction in the campaniform sensilla. Depolymerization of such cytoskeleton resulted in reduction of receptor sensitivity.3) The structure of the stretch receptor was examined in locust wings. The cell body of the stretch receptors is large (up to 50 mum) and extends many dendrites, which must be receptor sites. Actin filaments were densely localized in the dendritic regions.4) The data obtained in the present study suggest that three types of the insect mechanoreceptors possess their specific primary processes of the mechano-electric transduction, which is closely related to specific organization of cytoskeleton in the receptor region.

众所周知，昆虫存在三种类型的机械感受器，它们在结构和形态上各不相同。在本研究中，通过电子显微镜快速冷冻技术，研究了三种昆虫机械感受器的机械电传导的形态学基础。1）研究了蟑螂触角、果蝇和蝗虫股骨的脊索器官结构。它们的感觉纤毛与运动纤毛有一些相似之处，又细又长，并具有带有染料臂的轴丝。机械刺激纤毛与未刺激纤毛的形态学比较表明，感觉纤毛的主动行程或被动挥动可能参与了机电传导。2)对蟑螂触角和果蝇的钟形感器结构进行了研究。它们的感觉纤毛的特征是远端的管状体，被称为微管束。对快速冷冻标本的观察表明，肌动蛋白丝存在于管状体内的微管之间。两种类型的细丝的规则排列可能构成钟状感器中机械电传导的形态学基础。这种细胞骨架的解聚导致受体敏感性降低。3)在蝗虫翅膀中检查了拉伸受体的结构。牵张感受器的细胞体很大（可达50μm），并延伸出许多树突，这些树突必定是感受器位点。肌动蛋白丝密集地分布在树突区域。4)本研究获得的数据表明，三种类型的昆虫机械感受器具有其特定的机械电传导初级过程，这与受体区域细胞骨架的特定组织密切相关。