The Rockefeller University - Laboratory of Sensory Neuroscience

Hair Cells of the Inner Ear

Screening for Zebrafish Mutations Affecting
Hearing and Balance

Mutation of the Zebrafish's choroideremia Gene
Causes Hair-Cell Degeneration

Paravalbumin 3, A Potent Ca²⁺ Buffer in Hair Cells

Spontaneous Oscillation by Hair Bundles

Electrical Stimulation of Hair-Bundle Movement

Electron-Microscopic Tomographic Analysis of
the Transduction Element

Radixin in the hair bundle

Dynamical instability and the ear's active process

Friday, September 05, 2008

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Hair Cells of the Inner Ear

A hair cell is an epithelial cell derived from the embryonic ectoderm. Its apical surface is characterized by the hair bundle, a cluster of 20-300 mechanoreceptive "feelers" termed stereocilia. At the tall edge of the beveled hair bundle stands a single kinocilium, a microtubule-containing true cilium. When the cell experiences an auditory or accelerational stimulus, deflection of the hair bundle is transduced into an electrical response, the receptor potential, across the cell's plasma membrane. Our earlier experiments have shown that transduction involves the direct opening of cation-selective ion channels as a result of mechanical stimuli applied to the hair bundle. A positive stimulus, which moves the bundle towards its kinocilum-bearing tall edge, depolarizes the membrane. This response is then transmitted to an afferent fiber of the eighth cranial nerve by synapses that stud the cell's basolateral membrane surface. The resultant signal travels to the brain, where it is interpreted as a sound or an acceleration.