Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli.

TLDR

Hair cells transduce mechanical stimulation of their apical bundles into electrical signals in auditory, vestibular, and lateral‑line systems. The study used an in‑vitro bullfrog sacculus preparation with intracellular recordings to probe hair‑cell transduction. Graded depolarizing responses up to 15 mV (≈20 mV/µm) were elicited by bundle deflection, with depolarization toward the kinocilium linked to decreased membrane resistance, hyperpolarization to increased resistance, and occasional action potentials.

Abstract

Hair cells, the primary receptors of the auditory, vestibular, and lateral-line sensory systems, produce electrical signals in response to mechanical stimulation of their apical hair bundles. We employed an in vitro preparation and intracellular recording to investigate the transduction mechanism of hair cells in the sacculus from the inner ear of the bullfrog (Rana catesbeiana). When stimulated directly by mechanical deflection of their hair bundles, these cells gave graded responses up to 15 mV in amplitude; the peak sensitivity was about 20 mV/micron deflection. The depolarizing component of the receptor potential corresponding to stimuli directed towards the kinocilium. Depolarizing responses were associated with a membrane resistance decrease, and hyperpolarizing responses with a resistance increase. Action potentials, possibly calcium spikes, were occasionally evoked in hair cells by mechanical or electrical stimulation.