Figure 6.

Activation of specific purinergic receptor subtypes suppresses odor responses. A, C, Representative calcium transients in response to odor, 10 μM purinergic receptor (P2) agonists, or coapplication of odor + P2 agonists from individual mouse ORNs in fluo-4 AM-loaded OE slices. Filled triangles correspond to the time of loop injection of the odors or P2 agonists. Filled circles correspond to the predicted peak amplitude of coapplication (obtained by adding the control odor and P2 agonist values; refer to data analysis section for details). B, D, Responses to individual applications of P2 agonists and odor were normalized to the sum of each response and averaged (stacked columns). The responses to coapplication of P2 agonists and odor were normalized to the summed individual responses and averaged (black columns). The recoveries, obtained after coapplication, were also normalized to the initial summed response. Bar graphs depict normalized peak Ca²⁺ transient amplitudes (means + SEM). *p < 0.04, 0.001, respectively. A, B, Coapplication of P2X agonist (10 μM βγ-MeATP) and odor suppressed the calcium transient amplitude in 16 ORNs from six slices. C, D, Coapplication of P2Y agonist (10 μM ADPβS) and odor reduced the calcium transient amplitude in 15 ORNs from five slices.