Figure 3.

Dose-dependent inhibition of AgamORco function by identified antagonists. IC₅₀ values for all tested compounds except carvacrol (CRV) were determined using antagonist concentrations in the range of 1 μM to 1 mM. Because CRV was found to be toxic to the cells at concentrations above 250 μM, concentrations ranging from 1 to 200 μM were used for its dose–response evaluation. A, the IC₅₀ values determined for the two known repellents, CRV and cumin alcohol (CA), were 23.4 μM (pIC₅₀: 4.63179 ± 0.09524, R²: 0.9755) and 83 μM (pIC₅₀: 4.08243 ± 0.28481, R²: 0.99989), respectively, whereas that for the previously characterized ORco antagonist isopropyl cinnamate (IPC) was 41.7 μM (pIC₅₀: 4.37919 ± 0.061, R²: 0.9883; (34)). The EC₅₀ for the ORco agonist (OA) ORcoRAM2 from the curve that is shown in the inset is 91.9 μM (pEC₅₀: 4.03684 ± 0.11567, R²: 0.99998). B, the IC₅₀ values for the three new putative ORco antagonists, linalyl acetate (LA), (2E,4E)-2,4-octadienal (OCT), and (1S)-3-carene (CAR), were 67.7 μM (pIC₅₀: 4.16927 ± 0.15954, R²: 0.99999), 59.8 μM (pIC₅₀: 4.22309, R²: 0.99988), and 64.9 μM (pIC₅₀: 4.18725 ± 0.31571, R²: 0.99998), respectively. Error bars indicate mean ± SE. Data points were normalized to the maximum value and multiplied by 100.