Figure 4. Dye coupling through gap junction channels in the developing cochlea of Cx26^loxP/loxP and Cx26^Sox10Cre mice.

(a) Scheme of the sensory epithelium (midmodiolar section) in the developing cochlea (middle turn, P6); red arrowheads indicate the approximate position of laser foci in the receding greater epithelial ridge (GER) and in the lesser epithelial ridge (LER); AD, afferent dendrites of type I spiral ganglion neurons; BM, basilar membrane; Cap, capillary; CC, cuboidal cells; DC, Deiters' cells; EA, efferent axons; IC, interdental cells; IHC, inner hair cell; IS, inner sulcus; OHC, outer hair cells; OS, outer sulcus; OSL, osseous spiral lamina; PC, pillar cells; R, root cells; SL, spiral ligament; SLi, spiral limbus; SP, spiral prominence; TCC, tall columnar cells; V, vas spiralis. (b) Plots of f_b/f_u (bleached over unbleached fluorescence intensity) versus time in P5 organotypic cultures from the basal, middle and apical turns of the cochlea (see Materials and Methods). Solid lines are averages of n = 3 independent experiments, dashed lines indicate standard error of the mean. Downward arrows mark the time of laser pulse delivery. Carbenoxolone (CBX) is a non–specific inhibitor of gap junction channels [32].