Gating-spring stiffness increases outer-hair-cell bundle stiffness, damping, and receptor current

Autor: Zenghao Zhu, Wisam Reid, Dáibhid Ó Maoiléidigh
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Scientific Reports, Vol 14, Iss 1, Pp 1-11 (2024)
Druh dokumentu: article
ISSN: 2045-2322
DOI: 10.1038/s41598-024-81355-5
Popis: Abstract In our ears, outer-hair-cell bundles (OHBs) convert sound-induced forces into receptor currents that drive cochlear amplification, the process responsible for the micropascal-scale threshold and million-fold dynamic range of hearing. OHBs rely on gating springs to open mechanoelectrical-transduction (MET) ion channels, through which the receptor current flows. OHBs have larger gating-spring stiffnesses than other types of hair bundles, but we have a poor understanding of how gating-spring stiffness contributes to OHB mechanics and receptor-current regulation. Using experimentally-constrained mathematical models of the OHB, we show that the increased gating-spring stiffness in an OHB increases its stiffness and damping. The OHB’s 3D morphology reduces the contribution of gating-spring stiffness to OHB stiffness, reduces the contribution of MET-channel gating to OHB stiffness and damping, but causes additional OHB damping that rises with gating-spring stiffness. Gating-spring stiffness increases the OHB’s receptor current but decreases its displacement-current dynamic range. Strikingly, the OHB’s 3D morphology causes its force-current dynamic range to decrease with gating-spring stiffness. Our results suggest a trade-off between threshold and dynamic range regulated by OHB gating-spring stiffness.
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