Fig. 5.

Inhibition of one single odorant on another is PI3K-dependent. A: representative recording of the Ca²⁺ response from one of 13 dissociated rat ORNs activated by octanol (OOL, 50 μM) in which citral (CIT, 100 μM) evoked little or no Ca²⁺ response but substantially inhibited an almost saturating response to OOL. Preapplication of LY294002 (LY294, 10 μM) for 10 s completely relieved the CIT-dependent inhibition in all 13 cells. B: responses in each individual cell were normalized to the response induced by a common concentration of H100 (H-4, 10⁻⁴ dilution) and the data pooled. Note that citral was not an effective agonist for these ORNs, yet potently inhibited the response to octanol (t-test: ***P < 0.001; n, number of measurements). C: representative recording of the Ca²⁺ response from one of 78 other cells activated by OOL (50 μM), CIT (100 μM), and their mixture (OOL/CIT). CIT did not change the magnitude of the response to OOL, nor did LY294002 (LY294, 10 μM) change the response to OOL/CIT. Control responses to a higher concentration of H100 (H-4, 10⁻⁴ dilution) and 100 μM IBMX/10 μM forskolin (IF) denote the cell as canonical ORN. Arrowheads indicate time of odorant application.