Store-Operated Ca2+Channels Contribute to the Generation of Ca2+Waves in Interdental Cells in the Cochleae

Cochlear calcium (Ca2+) waves are vital regulators of the cochlear development and establishment of hearing function. Inner supporting cells are believed to be the main region generating Ca2+ waves that work as internal stimuli to coordinate the development of hair cells and the mapping of neurons in the cochlea. However, Ca2+ 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 Ca2+ wave formation and propagation by developing a single-cell Ca2+ excitation technology, which can easily be accomplished using a two-photon microscope for simultaneous microscopy and femtosecond laser Ca2+ excitation in any target individual cell in fresh cochlear tissues. We demonstrated that the store-operated Ca2+ channels in IDCs are responsible for Ca2+ wave formation in these cells. The specific architecture of the IDCs determines the propagation of Ca2+ waves. Our results provide the mechanism of Ca2+ formation in IDCs and a controllable, precise, and noninvasive technology to excite local Ca2+ waves in the cochlea, with good potential for research on cochlear Ca2+ and hearing functions.

Automated summary

This research reports the vital role of cochlear calcium (Ca2+) waves in cochlear development and hearing function. Inner supporting cells are believed to be the main region generating Ca2+ waves that coordinate the development of hair cells and the mapping of neurons in the cochlea. However, the Ca2+ waves in interdental cells (IDCs) that connect to inner supporting cells and spiral ganglion neurons are rarely observed and poorly understood. By developing a single-cell Ca2+ excitation technology, the authors demonstrate the mechanism of IDC Ca2+ wave formation and propagation, providing new insights into cochlear Ca2+ and hearing functions.