Is an Imbalanced Calcium-Homeostasis Responsible for the Experimentally Induced Endolymphatic Hydrops?

The target of the investigations were the presumably ion-transporting cells of the vestibular organ, i.e. the area of 'dark cells' of the semicircular canal and utriculus. Those cells have been assayed for structural changes by LM and EM and for alterations of the ionic content (LAMMA) in coloured guinea pigs with unilaterally induced endolymphatic hydrops. Characteristically changed structures of the secretory epithelium and disordered pigmentation in the vestibular organ were noted. Those cellular alterations were accompanied by intracellular ionic changes, especially an increased level of Ca2+ in the light cells and melanocytes. Our investigations show that, at least for experimental hydrops, an imbalanced homeostasis of Ca exists that may be responsible for the enlargement of the endolymphatic space.