Longitudinal and radial differences in the subsurface cisternal system in the gerbil cochlea

Many features of cochlear anatomy vary systematically radially and longitudinally within the organ of Corti. There is limited evidence that along the longitudinal axis of the cochlea the thickness of the subsurface cisternal system in the outer hair cells (OHCs) changes. Similarly a radial gradient may exist. The thickness of the subsurface cisternal system in OHCs was measured in gerbils to determine if there are differences between the three rows of OHCs and in OHCs in different locations along the length of the organ of Corti. The results suggest that there is a longitudinal as well as a radial gradient of subsurface cisternal system thickness. These gradients are the inverse to those for efferent innervation of OHCs. It is possible that these differences may contribute to the increased susceptibility to trauma and ototoxic compounds characteristic of the innermost and basalmost OHCs.