Acid-sensing ion channel 3 (ASIC3) is involved in acid nociception, but its possible role in neurosensory mechanotransduction is disputed. We report here the generation of Asic3-knockout/eGFPf-knockin mice and subsequent characterization of heterogeneous expression of ASIC3 in the dorsal root ganglion (DRG). ASIC3 is expressed in parvalbumin (Pv+) proprioceptor axons innervating muscle spindles. We further generate a floxed allele of Asic3 (Asic3f/f) and probe the role of ASIC3 in mechanotransduction in neurite-bearing Pv+ DRG neurons through localized elastic matrix movements and electrophysiology. Targeted knockout of Asic3 disrupts spindle afferent sensitivity to dynamic stimuli and impairs mechanotransduction in Pv+ DRG neurons due to substrate deformation-induced neurite stretching, but not to direct neurite indentation. In behavioral tasks, global knockout (Asic3-/-) and Pv-Cre::Asic3f/f mice produce similar deficits in grid and balance beam walking tasks. We conclude that, at least in mouse, ASIC3 is a molecular determinant contributing to dynamic mechanosensitivity in proprioceptors.
Lin, S-H., Cheng, Y-R., Banks, R. W., Min, M-Y., Bewick, G. S., & Chen, C-C. (2016). Evidence for the involvement of ASIC3 in sensory mechanotransduction in proprioceptors. Nature Communications, 7, 1-15. . https://doi.org/10.1038/NCOMMS11460