The transformation of acoustic and vestibular stimuli into neural responses depends largely upon the energy producing metabolism of the respective receptors. Accordingly, knowledge about the biochemical processes serving this purpose is indispensable for the understanding of physiology and pathology of hearing and equilibrium. It is the purpose of this project to study the sources and main sites of the energy producing metabolism important for the transformation process in the normal and pathologic inner ear. The research techniques used cover electrophysiology, morphology, and quantitative microchemistry. The specific methods developed allow a precise correlation of short term experimental changes, monitored by electrophysiologic recordings with the underlying chemical changes. The experimental animals are guinea pig and chinchilla. Microdissection techniques have been developed which allow the isolation of tissues and cells of the inner ear without changes in their in vivo patterns for purposes of chemical analysis. Analogous techniques are used for the sampling and analysis and minute volumes of inner ear fluids. Vascular and perilymphatic perfusion methods used allow to control experimental parameters with great precision. The detection of potential chemical effects of hypoxia, acoustic trauma and ototoxic drugs are specific long term goals of this project.