Measuring methods of ion channel in the inner ear

Endolymph which fills the scala media is an unusual extracellular fluid in that its composition is reminiscent of intracellular fluid such as its high potassium concentration. This characteristic ion homeostasis is important for the production of the endocochlear DC potential which is the main driving force for sensory transduction. Imbalance of ion homeostasis in the inner ear is therefore closely-linked to the pathophysiological mechanism of hearing impairment and balance disorder. Moreover, it is very important to study the physiology of ion channels in the inner ear. Ion channel measuring methods have been established electro-physiologically and recently developed using molecular physiology and molecular genetics. The ion channel's function can be measured as the result of 'ion flux' by ion selective electrodes, a vibrating probe and the Ussing chamber. In this paper, ion transport models are introduced and useful ion measuring methods are explained.