Odor and purinergic receptor (P2R) agonists evoke increases in [Ca2+]i. See also supplementary information (available at http://medstat.med.utah.edu/physio/hegg/). A1-D4, Confocal images from a fluo-4-AM-loaded mouse OE slice during application of odors (10 μmn-amyl acetate + 10 μm r-carvone) (A), 10 μm ATP (B), 10 μm βγ-methylene ATP (βγ-MeATP) (C), or 10 μm UTP (D). Scale bar, 10 μm. A5-D5, Time course of odor- and P2R-agonist-evoked Ca2+ transients. Time points indicated by black triangles correspond to frame numbers in A1-D4. Representative odor-responsive ORNs are indicated by filled triangles (A1-A4; 6/11 ORNs marked) and as solid lines in A5. One odor-responsive ORN (filled triangle in B1-D4) and one SC (open triangle in B1-D4) are shown in the time course (B5-D5).