Fig. 3.
Odorant responses at the level of the main olfactory epithelium. a Acute slice preparation of the whole MOE stained with Fluo-4 (image acquired at rest). The red ovals indicate somata of individual ORNs that responded to the mixture of amino acids (100 μM). Quantitative evaluation (right panel) shows more amino acid-responsive cells in the lateral third of the MOE compared to intermediate and medial segments (n = 116 ORNs from 13 acute slices of the MOE). The blue ovals indicate somata of forskolin-responsive cells (50 μM) of the same slice preparation. Significantly more forskolin-responsive cells were located in the medial and intermediate third of the MOE compared to its lateral third (n = 600 ORNs from 14 acute slices of the olfactory epithelium). Statistical analysis was performed using a t test; *p < 0.05, **p < 0.01; error bars show SEM. b Acute slice preparation of the MOE stained with Fluo-4 (image acquired at rest). Field of view does not cover the whole MOE. The colored ovals indicate somata of individual ORNs that responded to the mixture of alcohols, aldehydes, and ketones (yellow), amines (green), bile acids (magenta), amino acids (red) or to forskolin (blue). All odorants were applied at a final concentration of 200 μM, forskolin at a final concentration of 50 μM. c Time courses of [Ca2+]i transients of four responsive ORNs of this slice. d Out of 340 ORNs tested (n = 17 acute slices), 314 responded to only one odorant group whereas 23 responded to two odorant groups and three to three odorant groups (upper left panel). The exact odorant profile of multiresponsive cells is shown in the upper right panel. The histogram in the lower left-hand panel gives the frequencies of correlated responses to the tested odorant groups. The lower right-hand panel gives the correlation of odorant- and forskolin-sensitivity of individual ORNs. L lateral, M medial, AA amino acids, AL alcohols, ketones, and aldehydes, AM mixture of amines, BA mixture of bile acids, FO forskolin, control application of bath solution