Figure 1.

Fluorescent peptide with affinity for RIBEYE labels synaptic ribbons in live mouse bipolar cells. A, Bright-field image of an isolated mouse bipolar cell. B, Confocal image of a different cell loaded with Rpep. Bright spots (e.g., arrow) mark the positions of synaptic ribbons. C, Rpep-labeled bipolar cell terminal at higher magnification. The top panel shows a projection of a series of z-axis confocal optical sections through the depth of the terminal. Spots varied in size, suggesting that they might represent clusters with multiple ribbons. The bottom panel shows a single optical section of the same cell. D, A stereo pair showing a three-dimensional reconstruction from optical sections through a bipolar cell synaptic terminal loaded with Rpep.