The organ of Corti is composed of a variety of cell types including sensory, supporting and neural elements. Taken together, these cells comprise a functionally intricate and cohesive electrical unit that initiates the analysis of acoustic information within our environment. This electrical unit is extremely complex and nearly anatomically inaccessible, making an analysis of the whole quite a challenge. Fortunately, during the last several years the in vitro approach, including the isolated cochlea and cell preparations, has aided in the elucidation of cell function; the strategy is to understand the cells first on an individual basis, and finally to integrate this knowledge into a complete understanding of the organ of Corti. The overall aim of this project is to analyze the membrane properties of the outer hair cell (OHC), one of the major players in auditory function, principally using variations on the whole cell voltage clamp technique. Three areas of investigation are proposed. Specifically, we intend to 1) study in detail the mechanical sensitivity of the OHC lateral membrane as it relates to chloride flux, 2) study the effects of chloride and anions on the OHC motor activity, and 3) study mechanical coupling among OHCs in an explant organ of Corti preparation. The results that we will obtain will lead to a deeper understanding of inner ear function and aid in understanding auditory pathologies which may result from OHC insult and homeostatic imbalance, including sensorineural hearing loss and tinnitus.