Store-Operated Ca 2+ Channels Contribute to the Generation of Ca 2+ Waves in Interdental Cells in the Cochleae.

Cochlear calcium (Ca ²⁺ ) waves are vital regulators of the cochlear development and establishment of hearing function. Inner supporting cells are believed to be the main region generating Ca ²⁺ waves that work as internal stimuli to coordinate the development of hair cells and the mapping of neurons in the cochlea. However, Ca ²⁺ waves in interdental cells (IDCs) that connect to inner supporting cells and spiral ganglion neurons are rarely observed and poorly understood. Herein, we reported the mechanism of IDC Ca ²⁺ wave formation and propagation by developing a single-cell Ca ²⁺ excitation technology, which can easily be accomplished using a two-photon microscope for simultaneous microscopy and femtosecond laser Ca ²⁺ excitation in any target individual cell in fresh cochlear tissues. We demonstrated that the store-operated Ca ²⁺ channels in IDCs are responsible for Ca ²⁺ wave formation in these cells. The specific architecture of the IDCs determines the propagation of Ca ²⁺ waves. Our results provide the mechanism of Ca ²⁺ formation in IDCs and a controllable, precise, and noninvasive technology to excite local Ca ²⁺ waves in the cochlea, with good potential for research on cochlear Ca ²⁺ and hearing functions.