Passive and active deflections of ampullary kinocilia correlated with changes in transepithelial voltage.

Deflections of individual ampullary kinocilia were optically recorded in the undissected vestibular system of young eels. At mechanical stimulation, transepithelial receptor potentials and nerve activity were recorded. Saturating responses occurred at ciliary deflections of +6 degrees and -3 degrees. Kinocilia occasionally oscillate spontaneously in a snaking or pointer-like mode as the preparation deteriorates. In nearly all kinocilia of fresh preparations exogenous transepithelial voltage change induces active pointer-like deflection in a graded and tonic manner. A voltage change of a given sign induces a deflection that counteracts mechanical stimuli producing a voltage change of the same sign.