Figure 1.

ACh evokes global Ca²⁺ transients in OHCs. A, Illustration of a recorded OHCs within the intact organ of Corti preparation, with synaptic connections (green MOC terminal, red Type II afferent), and a scheme of the imaging focal plane (dashed lines). B, Sequence of wide-field microscopy images of an OHC (loaded with Fluo-4) during ACh 1 mm perfusion. Dotted white lines represent the outer margin of the OHC's fluorescence signal. First image shows ROI design scheme in which the cell's cytoplasm was divided in 24 radial ROIs (see Materials and Methods). Scale bar: 5 μm. C, Black trace corresponds to the whole-cell current recorded during ACh perfusion (Vhold = –100 mV) and red trace to the ΔF/F₀ signal measured at the ROI depicted in red on panel B. Arrows indicate the time points of images shown on panel B. D–F, Peak current (D), charge (E), and maximal ΔF/F₀ (F) during ACh perfusion. Bar plots are mean ± SEM.