Figure 7. Bipolar cells from C-terminal-binding protein 1(CtBP1)-knockout retina loaded normally with FM4-64. A: The images show a single confocal optical section of FM4-64 fluorescence in a live mouse bipolar cell terminal from wild-type (WT) or CtBP1-knockout (KO) retina. Cells were loaded with FM4–64 in the presence of high external [K⁺] to activate calcium channels and trigger synaptic vesicle cycling, followed by washing with Advasep-7 to rapidly remove plasma-membrane dye. B: Each data point represents results from a single WT terminal (open circles; n=11 cells in three animals) or KO terminal (filled circles; n=16 cells in three animals). The arrows indicate the average FM4–64 fluorescence for each genotype.