a The left time series of green fluorescence shows how Alexa-488 conjugated antibodies diffuse from the targeted IHC (delineated in red, C1) to the coupled IHC (delineated in green, C2). Two of the surrounding uncoupled IHCs (highlighted by white lines) have previously been loaded with the antibodies. After retracting the pipette, CBX (250 µM) was added to the bath solution five minutes prior to the loading of Alexa-568 conjugated antibodies via patching C2. The right time series of red fluorescence (same length scale as in a) shows that the spread of Alexa-568 conjugated antibodies to C1 is not blocked by CBX. Surrounding SCs, especially inner pillar cells, exhibit auto-fluorescence. b–e Ca2+-current voltage (IV) curves were obtained by depolarizing IHCs from the holding voltage (−60 mV) with 5 mV steps before and during bath application of CBX. The presence of CBX is marked with gray in the membrane capacitance (Cm)-time and maximal ICa (ICaMax)-time plots. The recording time points of the presented IV curves are marked with t1 (for black curve) and t2 (for red curve) in the ICaMax-time plots. The experiments were stopped when the patched IHC was lost. CBX inhibits ICa of coupled IHCs without changing Cm, as seen in with single IHCs. CBX carbenoxolone, Vm membrane voltage. Scale bar: a = 5 µm.