The effect of stereocilia bundle position on receptor potential characteristics of isolated outer hair cells in the guinea pig.

The receptor potential as a function of pre-stimulus position of the stereocilia was studied with the whole cell patch-clamp technique in isolated outer hair cells (OHC) during direct mechanical stimulation of the stereocilia (n = 6, cells ranging from 70-87 microm length). The amplitude and frequency of the stimulation was 1 microm and 100 Hz. Controlled pre-stimulus stereocilia displacements in the excitatory direction were followed by sustained membrane depolarization and a diminution of the DC component of the receptor potential. Spectral analysis has shown that recordings with most diminished DC components had a pronounced fundamental while the other harmonics were suppressed, indicating the linearization of the receptor potential. The observed non-lineararities depended on the resting position of the stereocilia and seemed to be determined by the operating range of the transduction process.