Distribution and Functional Characteristics of Voltage-Gated Sodium Channels in Immature Cochlear Hair Cells

更新时间:2023-05-28

【摘要】Voltage-gated sodium channels（VGSCs） are transiently expressed in cochlear hair cells before hearing onset and play an indispensable role in shaping spontaneous activity.In this study,we showed that Na+ currents shaped the spontaneous action potentials in developing mouse inner hair cells（IHCs） by decreasing the time required for the membrane potential to reach the actionpotential threshold.In immature IHCs,we identified 9 known VGSC subtypes（Nav1.1α-1.9α）,among which Nav1.7α was the most highly expressed subtype and the main contributor to Na+ currents in developing hair cells.Elec trophy siological recordings of two cochlea-specific Nav1.7 variants（CbmNav1.7a and CbmNav1.7b） revealed a novel loss-of-function mutation（C934R） at the extracellular linker between segments 5 and 6 of domain Ⅱ.In addition,post-transcriptional modification events,such as alternative splicing and RNA editing,amended the gating properties and kinetic features of CbmNav1.7a（C934）.These results provide molecular and functional characteristics of VGSCs in mammalian IHCs and their contributions to spontaneous physiological activity during cochlear maturation.

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