Fig. 4. Cells in a taste bud stained by stimulant and deterrent taste substances. Confocal micrographs showing cross sections of a taste bud taken at the taste bud pore (A), 20 µm below (B), and 40 µm below (C) that level. The oral cavity was first exposed for 5 min to glycine (gly), 100 mmol l^–1 + AM1-43, 1 µmol l^–1 (green, left column) and then for 5 min to L-cysteine (cys), 100 mmol l^–1 + FM4-64FX, 20 µmol l^–1 (red, middle column). The right column is the merged pictures. The yellow colour in some cells (arrows) indicates colocalization of green and red dye in the same cell. Note that two cells are yellow at all levels. Scale bar is for all images. See text for details.