. Author manuscript; available in PMC: 2011 Nov 1.

Published in final edited form as: Drug Dev Res. 2010 Nov 1;71(7):404–411. doi: 10.1002/ddr.20388

TABLE 3.

K_i Values for Binding SR141716A Analogues to the CB1 Receptors With Mutations in Positions 268–271 in EC2


	K_i (nM)
Receptor	SR141716A^a	O-1302	O-1690	O-1255
WT	5.2 (3.4–8.1)	1.7 (1.2–2.3)	1.3 (0.8–2.0)	83.4 (49.7–139.9)
F268W	7.3 (6.4–8.3)	26.2 (20.2–34.1)^*	23.3 (16.9–32.0)^*	310.2 (242.8–396.2)^*
[WT:F268W]^b	[1:1]	[1:15]	[1:18]	[1:4]
P269A	5.3 (3.8–7.3)	1.1 (0.82–1.5)	0.96 (0.71–1.3)	74.7 (28.5–195.8)
[WT:P269A]^b	[1:1]	[1:1]	[1:1]	[1:1]
H270A	3.5 (2.5–5.0)	2.6 (1.6–4.2)	2.0 (1.4–2.8)	113 (87.0–147)
[WT:H270A]^b	[1:1]	[1:1]	[1:1]	[1:1]
I271A	2.4 (1.9–2.9)	38.4 (33.2–44.6)^*	77.3 (72.0–82.9)^*	460 (361–587)^*
[WT:I271A]^b	[2:1]	[1:23]	[1:59]	[1:6]

Data are the median and corresponding 95% confidence limits of three independent experiments performed in duplicate. K_i values for each ligand were determined using 4 nM [³H]SR141716A.

Statistically significant differences from wild-type (P<0.05) using analysis of variance followed by Dunn's post hoc test.

K_i values from Ahn et al. [2009], except for H270A, which was obtained here.

Values represent the K_i ratio for WT to EC2 mutant receptors for the specified compound.