A Study of Striated Organelle in Vestibular End Organs

Using electron microscope tomography, vestibular hair cells from chinchilla were reconstructed to examine three-dimensional aspects of intracellular structures (the striated organelle and mitochondria).;The striated organelle was found to be particularly well developed in typed vestibular hair cells, shaped like an inverted conical cage that restricts a distinct set of mitochondria to the apical part of the hair cell. It is directly linked to some of the stereociliary actin rootlets and to the cell membrane, and it seems to anchor the cuticular plate. Based on ultrastructural findings, possible functional implications are discussed.;High resolution electron microscope tomography was used to examine mitochondria populations from apical regions of vestibular type-I and type-II hair cells. Apical mitochondria were larger in type-1 hair cells (both in surface areas and in volumes), and measurements of their internal structure (crista surface, crista junctions and crista junctions density) revealed configurations for high metabolic capacity. Such findings are important for understanding more about the functions of striated organelle and hair cells.;Immunohistochemistry methods showed that spectrin (i.e., a-II spectrin) was localized to the striated organelle of both type-I and type-II vestibular hair cells. Staining patterns were found to be different along lateral walls in type-I versus type-II hair cells, suggesting that the organelle may have a different configuration among these cells.