Table 6.

Receptor binding affinity of selected α-amino acids antagonists at native and recombinant homomeric iGluRs, determined in radioligand binding assays (all values in μM).

cmpd	IC50/Ki [μM]		Ki [μM]
	Native iGluRs		Recombinant Homomeric iGluRs
	AMPA [3H]AMPA	KA [3H]KA	GluK1	GluK2	GluK3	GluA2
35	16 ± 1 (IC50) a	>100 (IC50) a	2.2 ± 0.5 b 2.9 ± 0.3 c 2.6 ± 0.4 d	>100 c,d	>100 c >1000 d	60 ± 5 d
36 e	3.4 ± 0.3 (IC50)	nd	3.0 ± 0.8	nd	14 ± 3	nd
(S)-36 e	nd	nd	1.5 ± 0.2	nd	8.0 ± 1.1	nd
37 c	>100 (IC50)	>100 (IC50)	2.8 ± 0.8	>100	>100	nd
38	4.6 ± 0.2 (IC50) c	>100 (IC50) c	92 ± 2 f	78 ± 10 f	52 ± 3 f	5.0 ± 0.4 f
39 g	51 ± 10 (IC50)	22 ± 2 (IC50)	4.3 ± 0.4	>100	8.1 ± 0.6	67 ± 16
40 d	2.0 (IC50)	1.4 (IC50)	4.8 ± 1.5	10–100	0.87 ± 0.09	nd
41 d	48 (IC50)	22 (IC50)	0.62 ± 0.10	81 ± 8	2.2 ± 0.4	nd
42 h	>100 (Ki)	>100 (Ki)	4.0	>100	>100	nd
43	nd	nd	0.13 ± 0.02 i	>100 i	>100 i	>100 j
44	nd	nd	2.4 j 0.56 k	7.7 j 6.7 k	>100 k	>100 j >30 k
45 l	nd	nd	0.16 ± 0.02	99 ± 22	7.5 ± 0.3	73 ± 15
46 m	>100 (Ki)	>100 (Ki)	177 ± 4	>5000	6.4 ± 0.7	>1000

^a ref. [129]; radioligands: [³H]AMPA, [³H]KA; ^b ref. [130], affinity given for (R,S)-ATPO, radioligand: [³H]SYM2081; ^c ref. [133], radioligand: GluK1-3, [³H]SYM2081; ^d ref. [111], radioligands: GluA2, [³H]AMPA, GluK1-3, [³H]SYM2081; ^e ref. [132], radioligand: GluK1,3, [³H]SYM2081; ^f ref. [134], radioligands: GluA2, [³H]AMPA, GluK1-3, [³H]SYM2081; ^g ref. [136], radioligands: GluA2, [³H]AMPA, GluK1-3, [³H]SYM2081; ^h ref. [137], radioligands: GluK1, [³H]-(S)-NF608, GluK2-3, [³H]KA; ⁱ ref. [140], radioligand: GluK1-3, [³H]KA; ^j ref. [145], radioligands: GluA2, [³H]AMPA, GluK1-2, [³H]KA; ^k ref. [144], radioligands: GluA2, [³H]AMPA, GluK1-2, [³H]KA; ^l ref. [147], radioligands: GluA2, [³H]AMPA, GluK1-3, [³H]SYM2081; ^m ref. [148], radioligands: GluA2, [³H]AMPA, GluK1, [³H]KA or [³H]-(S)-NF608, GluK2-3, [³H]KA; nd—not determined.