Saidel W M, Crowder J A
Department of Biology, Rutgers University, Camden, NJ 08102, USA.
Hear Res. 1997 Jul;109(1-2):63-77. doi: 10.1016/s0378-5955(97)00042-7.
Ultrastructural variation in some cytoplasmic organelles and synaptic structures is one characteristic distinguishing the types of hair cells in the teleost ear. In this study, we explored differences in mitochondria by analyzing mitochondrial reactivity for cytochrome oxidase (COX) in hair cells of the teleost utricle. The reactivity for COX within mitochondria in the subcuticular compartment directly beneath the cuticular plate differentiated among hair cells in utricles of three teleost species, Carassius auratus, Pantodon buchholzi, and Astronotus ocellatus. Mitochondria in the subcuticular region of hair cells in the striola reacted intensely. Within juxtastriola and extrastriolar hair cells near the striola, mitochondria reacted at a lowered intensity than in striolar hair cells. Subcuticular mitochondria of extrastriolar hair cells located distant from the striola reacted negligibly. The reactivity of mitochondria in other cytoplasmic compartments did not provide similar evidence for distinguishing among teleost hair cells. Mitochondria within intraepithelial branches of the eighth nerve terminals in the different utricular regions reacted to COX histochemistry commensurate with their respective presynaptic hair cells. Branches of sensory afferent neurons innervating striolar hair cells displayed a dense COX reaction. Sensory afferents innervating the extrastriolar hair cells did not display many mitochondria at synapses nor, when present, was the staining as dense. The presynaptic side of the hair cell-afferent nerve synapse usually, but not always, contained reactive mitochondria. The presynaptic side of the efferent nerve-hair cell synapse did not necessarily contain mitochondria. Mitochondria filling the cytoplasm in a type of juxtamacula cell revealed uniformly dense COX reactivity.
一些细胞质细胞器和突触结构的超微结构变化是硬骨鱼内耳毛细胞类型的一个显著特征。在本研究中，我们通过分析硬骨鱼椭圆囊毛细胞中细胞色素氧化酶（COX）的线粒体反应性，探究了线粒体的差异。在三种硬骨鱼（鲫鱼、蝴蝶鱼和眼斑星丽鱼）椭圆囊的毛细胞中，位于角质板正下方的皮下隔室内线粒体的COX反应性存在差异。纹状区内毛细胞皮下区域的线粒体反应强烈。在纹状区附近的近纹状区和纹状区外毛细胞中，线粒体的反应强度低于纹状区内毛细胞。远离纹状区的纹状区外毛细胞的皮下线粒体反应微弱。其他细胞质隔室内线粒体的反应性并未提供区分硬骨鱼毛细胞的类似证据。不同椭圆囊区域第八神经末梢上皮内分支中的线粒体对COX组织化学的反应与其各自的突触前毛细胞一致。支配纹状区内毛细胞的感觉传入神经元分支显示出密集的COX反应。支配纹状区外毛细胞的感觉传入神经在突触处没有显示出许多线粒体，即使有，染色也不密集。毛细胞 - 传入神经突触的突触前侧通常（但并非总是）含有反应性线粒体。传出神经 - 毛细胞突触的突触前侧不一定含有线粒体。一种近黄斑细胞中充满细胞质的线粒体显示出均匀密集的COX反应性。
