Affinity values (K_i, nM) of selected chromenones at the human σ (hσ₁) and rat σ₂ (rσ₂) receptors.

Compd	R	n	hσ1	rσ2	Selectivity hσ1//rσ2
1		1	2870	12 500	4.4
2		2	499	23 900	48
3		3	227	3110	14
4		4	87.0	1450	17
5		1	825 ± 146	9070	11
6		2	65.5 ± 4.5	2890	44
7		3	309 ± 45	1970 ± 1400	6.4
8		4	213	490	2.3
9		1	>10 000	>10 000	n.d.
10		2	245	22 500	92
11		3	23.9 ± 9.7	14 600	610
12		4	19.6 ± 3.2	2630 ± 1200	130
13		1	604	14 200	24
14		2	809	17 100	21
15		4	82.5	4100	50
16		1	12 100	30 000	2.5
17		2	1220	8360	6.9
18		4	218	2500	11
19		1	113 ± 28	1620	14
20		2	27.2 ± 6.8	750 ± 250	28
21		3	104	1090	10
22		4	134	583	4.4
Haloperidol			3.53 ± 0.47	20.5 ± 1.0	5.8
SA4503			3.77 ± 0.11	n.d.a	n.d.
S1RA b			17.0	9300	550

^aNot determined.

^bData from ref. 21.