Fig. 5: Propagation of TRPA1-initiated Ca2+ responses across the organ of Corti. | Nature Communications

Fig. 5: Propagation of TRPA1-initiated Ca2+ responses across the organ of Corti.

From: TRPA1 activation in non-sensory supporting cells contributes to regulation of cochlear sensitivity after acoustic trauma

Fig. 5: Propagation of TRPA1-initiated Ca2+ responses across the organ of Corti.The alternative text for this image may have been generated using AI.

a Ca2+ responses to the local application of 400 µM of 4-HNE in a cochlear explant from a neonatal (P1) wild-type mouse. 4-HNE was locally applied first to the Hensen’s cells (top) and then to the cells of the Kolliker’s organ (bottom) in the same specimen. The direction of Ca2+ response propagation and its speed are indicated by the white arrows and numbers. b PPADS (50 µM), an inhibitor of ATP receptors, attenuates Ca2+ responses in the Kolliker’s organ but not in the Hensen’s cells. 4-HNE (400 µM) was applied to a neonatal (P2) wild-type explant. c, e In an experiment when fura-2 was able to permeate into Deiters’ cells, Ca2+ responses were observed also in these cells after several puff applications of 200 µM of 4-HNE in the absence (c) or presence (e) of 50 µM PPADS in the bath solution. Gray and white arrowheads point to the Hensen’s and Deiters’ cells that were measured in panels (d) and (f). d, f [Ca2+]i changes in Deiters’ (black) and Hensen’s (gray) cells in the absence (d) or presence (f) of PPADS. The x-axis arrows indicate the timing of frames in (c) and (e). g–i Representative current-voltage relationships of TRPA1 conductances activated by CA (100 µM) in wild-type (black and gray) and Trpa1–/– (red) Hensen’s (g), Deiters’ (h), and pillar (i) cells. Usually, the whole-cell patch-clamp recordings were obtained in the presence of FFA (100 µM) to electrically uncouple the supporting cells, but some Hensen’s cells were recorded in the presence of another gap junction blocker, octanol (1 mM) (gray in (g)). Insets show whole-cell current responses to CA at holding potential of −80 mV. j Average TRPA1-mediated current at −86 mV holding potential in Hensen’s (HeC), Deiters’ (DC), and pillar (PC) cells in wild-type (black) and Trpa1–/– (red) mice. The data are shown as Mean ± SE. Asterisks indicate statistical significance (P = 0.030, HeC; P = 0.016, DC; two-sided Student’s t test). Source data are provided as a Source Data file.

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