Non‐linearities in the responses of turtle hair cells

作者：Andrew Charles Crawford, Robert Fettiplace · 发表于：The Journal of Physiology · 年份：1981 · DOI：10.1113/jphysiol.1981.sp013750 · 被引用次数：102 · 研究领域：Marine animal studies overview、Hearing, Cochlea, Tinnitus, Genetics、Acoustic Wave Resonator Technologies

1. Intracellular recordings were made from single cochlear hair cells in the isolated half-head of the turtle. Receptor potentials were recorded while the ear was stimulated with high-intensity tones in order to examine the cochlear non-linearities which shape the hair cell responses.2. The size of a hair cell's voltage response to a tone burst was reduced, abolished and then reversed by steady depolarizing currents of increasing strength. The average current needed to produce reversal was about 0.3 nA, the reversal potential being close to zero with respect to the scala tympani.3. Short current pulses injected on the peaks and dips of the receptor potential showed that the membrane resistance and time constant were decreased on the depolarizing phase of the receptor potential. These changes were not due to non-linearity in the hair cell's current-voltage curve in the absence of acoustic stimulation. The results are consistent with the idea that the transducer causes the cell to depolarize by increasing the membrane conductance to ions with an equilibrium potential close to zero.4. Saturated receptor potentials from poorly tuned cells exhibited a pronounced asymmetry, with the maximum depolarizing excursion being several times the maximum hyperpolarizing excursion. This asymmetry was not seen in sharply tuned cells. It is proposed that the asymmetry is present in the transducer conductance change and in sharply tuned cells is reduced in the receptor potential by subsequent fi...