A, TIRF image of the footprint of a chromaffin cell, which had been transfected with a otoferlin-eGFP fusion construct. Individual fluorescent spots most probably represent otoferlin-eGFP-tagged chromaffin granules, scale bar: 1 µm.
B, average ΔCm in response to the first flash in control (n = 20; black) and otoferlin-expressing (n = 20; red) bovine chromaffin cells. The first flash was delivered 120–180 s after establishment of the whole-cell configuration.
C, exocytic responses of a wild-type non-transfected mouse chromaffin cell (black) and mean response of 5 Syt1 deficient chromaffin cells that had been transfected to express the otoferline-GFP fusion construct: lack of the fast component of the exocytic burst. Insert: representative exocytotic response from wild-type (black, postflash [Ca2+]i: 16.31 µM) and Syt1 knock-out (red, postflash [Ca2+]i: 15.5 µM).