Fig. 9.

Exocytosis was induced by depolarization and Ca²⁺ influx. A bipolar cell was superfused with an extracellular saline containing 100 nmCa²⁺. The lower timing traceindicates the application of 20 μm FM4–64. Theupper timing trace indicates 4 sec applications of a high Ca²⁺ and K⁺ saline (4 mm Ca²⁺ and 40 mmK⁺). v_x is the intensity increase produced by vesicle exocytosis. Transient exocytosisT_x was measured asT_x = ρv_x/s. For the two applications of high Ca²⁺ and K⁺saline, T_x was 0.13 and 0.08 MEq.