NASA Neurolab: Development of Vestibular Organs in Microgravity

检测重力的感受器在无脊椎动物中称为耳囊，在脊椎动物中称为耳石器。它们是含有被称为耳锥的钙化晶体的致密团块的袋子；重力对这些团块的作用覆盖着专门的机械感觉细胞，为确定正常的地球垂直方向提供了信号。在不同的动物中，耳石具有非常特殊的矿物化学和晶体结构，初步研究表明，这些特征在不同的重力条件下可能会有所不同。神经实验室的飞行提供了一个独特的机会，可以在没有正常重力的情况下检查这些重力传感附件的发展。使用电子显微镜和原子力显微镜的地面研究提供了正常发育期间耳锥的大小、重量和矿物组成的数据。研究结果对于了解前庭系统的发育、考虑钙稳态具有重要意义，并可能对生物材料的研究产生一定的影响。对该项目的贡献代表了NSF生物科学局参与了NASA/机构间神经实验室在航天飞机轨道上的活动，这反过来又是大脑活动十年的一部分。

Receptor organs for detecting gravity are called otocysts in invertebrates, and otolithic organs in vertebrates. They are pouches that contain dense masses of calcified crystals called otoconia; the action of gravity on these masses, overlying specialized mechanosensory cells, provides a signal for determining the normal earth-vertical direction. The otoconia have remarkably specific mineral chemistry and crystalline structure in different animals, and pilot studies suggest that these features may vary somewhat under different gravitational conditions. The flight of Neurolab provides a unique opportunity to examine the development of these gravitational sensing accessories in the absence of normal gravity. Ground-based studies using electron microscopy and atomic-force microscopy provide data on the sizes, weights, and mineral composition of the otoconia during normal development. Results will be important for understanding development of the vestibular system, for considering calcium homeostasis in general, and may have some impact on biomaterials studies. Contribution to this project represents the NSF Biological Sciences Directorate's participation in the NASA/Interagency Neurolab activity on the space shuttle orbiter, which in turn is part of Decade of the Brain activities.