Effect of elastase and BAPTA on hair-bundle morphology. A, An example of a single hair cell after the isolation procedure. Note the intact hair bundle at the apex of the cell (arrow). Scale bar, 10 μm. B, Detail of a stereociliary bundle from an isolated hair cell after incubation in HBSS alone. Note the presence of tip links on many of the stereocilia (arrows). C, A stereociliary bundle after elastase treatment (20 U/ml). Note the complete absence of tip links. D, A stereociliary bundle after 10 min of BAPTA treatment (5 mm). Tip links are completely absent. Scale bars: B–D, 750 nm.