Structurally based new functional interpretations of the subsurface cisternal network in human outer hair cells

Abstract

The system of subsurface cisterns (SSC) in human outer hair cells (OHC) was studied by high-resolution transmission electron microscopy (TEM). The SSC consist of only a single layer of cisterns, either flattened or tubular. The subsynaptic cisterns of efferent synapses are an integral part of the SSC. The outer leaflet of the SSC facing the cell membrane is connected to the OHC wall by pillars arranged in a highly regular and geometric pattern. The inner leaflet facing the cytoplasm displays an identical pattern of particles arranged in a star-like configuration so that pores are formed centrally. Pores are also identified at the outer leaflet and at the insertion of the pillars into the cell membrane. It is hypothesized that this highly specific organization of SSC, so far described only in the human OHC wall, is controlled by the efferent acetylcholine-mediated innervation.

Key Words:

• outer hair cell
• subsurface cisterns
• morphology
• function
• human