TABLE 1.

Activation of avian Tas2rs by bitter substances.

No.	Receptor substance	tgTas2r1	tgTas2r5	tgTas2r6	tgTas2r7	ggTas2r1	ggTas2r2	ggTas2r7	mgTas2r3	mgTas2r4
1	Absinthin
2	Amarogentin
3	Andrographolide
4	Azathioprine
5	Caffeine
6	Camphor
7	Carisoprodol
8	Chloramphenicol
9	Chloroquine
10	Chlorpheniramine
11	Colchicine
12	Coumarin
13	Cucurbitacin I
14	Cycloheximide
15	Denatoniumbenzoate
16	Diphenhydramin
17	Diphenidol
18	Erythromycin
19	Gingkolide A
20	Limonin
21	Nicotin
22	Parthenolide
23	Picrotoxinin
24	PTC
25	Quassin
26	Quinine sulphate
27	Saccharin
28	(−)-α-Thujone
29	Yohimbine

The bitter compounds shown to activate zebra finch (tgTas2r), chicken (ggTas2r), and turkey (mgTas2r) bitter taste receptors are listed. The signal amplitudes are divided in 3 categories, weak (, ΔF/F < 0.2), medium (, ΔF/F 0.2–0.4), and high (, ΔF/F > 0.4).