Figure 6.
The coupling between Ca2+ entry and exocytosis differs as a function of IHC position along the mature cochlea. (A–C) The kinetics of RRP vesicle pool release in mature gerbil IHCs from apical (A), middle (B), and basal (C) cochlear regions in the presence of 0.1 mm EGTA (black circles) and 10 mm EGTA (gray circles). Average ΔCm points were obtained in response to voltage steps from 2 to 50 msec (to −11 mV) that elicit the release of the RRP. The x-axis time refers to the voltage step duration. Note that 10 mm EGTA blocks RRP release in the basal coil IHCs, reduces it significantly in the middle coil, but only slightly in the apex. (From Fig. 2 in Johnson et al. 2017b; reprinted, with permission, from the Journal of Neuroscience © 2017.)