Metabolic Pathways in the Vestibular Labyrinth as Revealed by Histochemical Technics

Abstract

Tissues of the vestibular system were studied for the activity of a number of oxidative enzymes by using histochemical methods. In general, striking activity was found in the sensory epithelium of the crista ampullaris and macula sacculi, while other parts of the membranous labyrinth showed varying degrees of enzyme activity. A detailed description of the observations is presented. The results indicate a marked capacity of the sensory epithelium for anaerobic glycolysis, the presence of a citric acid cycle and active hexose monophosphate shunt, the existence of the cytochrome oxidation system and the capacity of oxidative decarboxylation of alphaketo acids to energy-rich acyl coenzyme A. The significance and possible relation of these metabolic avenues to the function of the cells is discussed briefly. It is presumed that physiological stimuli and toxic agents affect the sensory epithelium by interfering with its complex metabolism.