Pinocytosis in the Pillar Cells of the Organ of Corti

Abstract

Electron micrographs are presented showing openings in the head plates of the pillar cells of the organ of Corti. The possibility of fluid transport between the tunnel-spaces and the subtectorial space is inferred from these observations. The capabilities of the pillar cells for fluid transport were further examined through the use of the exogenous tracer, Thorotrast, which was not seen in the tunnel-spaces until at least 40 min after introduction into perilymph. After 2 hrs Thorotrast was found in vesicles in all parts of the pillar cells and closely applied to the external membrane. On the basis of a review of histochemical observations relating to the pillar cells, together with morphological findings and results of tracer experiments, it appears that these cells are implicated in active transport processes involving perilymph, cortilymph, and the fluid of the subtectorial space. They may help to maintain microhomeostasis in the cochlear transducer.