[Experimental studies on ischemia of the cochlea. 2. Pathobiochemistry]

Biochemical analyses of organic substances (protein, glucose, amino acids) as well as inorganic substances (potassium and sodium) in inner ear fluids were performed for the first time under local ischemic conditions. The perilymph of the thrombosed right ear was collected from various animals after different durations of ischemia. The normal left cochlea served as control. The concentrations of potassium and sodium and the total protein content remain unchanged in the perilymph of the guinea pig during the first two hours of ischemia. The decrease in the glucose concentration in the perilymph shortly after the thrombosis is a new finding. It points to the possible existence of a reservoir of energy carriers in the fluid of the inner ear that become available to cochlear tissues during ischemia. The increase in the amino acid concentration during ischemia suggests metabolic processes in the cochlea. The biochemical analysis of the perilymph during ischemia of the cochlea provides evidence of two possible mechanisms that secure the survival of the organ of Corti. The glucose reserves of the perilymph are utilized by the cochlear tissues and the concentration of certain amino acids secure the supply.