Molecular biology of hearing

The inner ear is our most sensitive sensory organ and can be subdivided into 3 functional units: organ of Corti, stria vascularis and spiral ganglion. The appropriate stimulus for the organ of hearing is sound which travels through the external auditory canal to the middle ear where it is transmitted to the inner ear. The inner ear habors the hair cells, the sensory cells of hearing. The inner hair cells are capable of mechanotransduction, the transformation of mechanical force into an electrical signal, which is the basic principle of hearing. The stria vascularis generates the endocochlear potential and maintains the ionic homeostasis of the endolymph. The dendrites of the spiral ganglion form synaptic contacts with the hair cells. The spiral ganglion is composed of neurons that transmit the electrical signals from the cochlea to the central nervous system. In the past years there was significant progress in research on the molecular basis of hearing. More and more genes and proteins which are related to hearing can be identified and characterized. The increasing knowledge on these genes contributes not only to a better understanding of the mechanism of hearing but also to a deeper understanding of the molecular basis of hereditary hearing loss. This basic research is a prerequisite for the development of molecular diagnostics and novel therapies for hearing loss.