[Endocrine cells of the internal ear in the normal state and in specific labyrinthine lesion in rabbits].

Using light and electron microscopes, apudocytes of internal ear in normal and syphilis-infected rabbits were examined. Temporal bone blocks were dissected from 16 healthy (control) and 32 infected (experimental) animals. Some of the preparations were hematoxylin and eosin stained for histological examinations; some were silver stained according to Griemelius for histochemical examinations; and others were used to prepare ultrathin sections for electron microscopy. It was demonstrated that apudocytes were normally found in different labyrinthine structures and consistently seen in the vascular stripe. Electron microscopy showed that the vascular stripe included endocrine cells containing secretory granules which are characteristic of serotonin-, melatonin- and catecholamine-producing cells. Apudocytes from the syphilis-infected labyrinth were in the state of hyperfunction: the preparations stained according to Griemelius had lowered quantities of apudocytes and contained light cells with the hormone utilized completely; electron microscopy preparations showed granules in the capillary lumen that were transferred there by exocytosis. These observations give evidence that endocrine cells are involved in processes that develop in internal ear both in the norm and pathology.