||Fig. 4. Calnexin labels sustentacular supporting cells (SCs). (A–C) Image showing calnexin immunoreactivity (red fluorescence, A and C) of a biocytinbackfilled
⁄ avidin-stained (green fluorescence, B and C) slice of the olfactory epithelium (OE) of a Xenopus laevis tadpole. Note the localization of calnexin
immunoreactivity in the sustentacular cell layer and in cells in the basal cell layer (arrows). In the olfactory receptor cell layer only a few cells show positive calnexin
immunoreactivity (asterisks). The dashed lines in (A and B) indicate the border of the OE, the continuous line the approximate termination of the sustentacular cell
layer. (D) ATP-sensitive cells in an acute OE slice determined with fluo-4-calcium imaging. The dashed rectangle indicates one of the ATP-responding cells shown
at a higher magnification in (E). (F) Higher magnification of the dashed rectangle drawn in (C). The arrow marks an olfactory receptor neuron (ORN) dendrite.
The asterisk tags a typical calnexin-positive cell. (G) Typical sustentacular cell in the OE of Xenopus laevis tadpoles filled with biocytin through a patch pipette and
then stained with avidin. PC, principal cavity; SCL, sustentacular cell layer. Scale bars, 50 lm (A and D); 5 lm in (E–G).