Table 1

Comparison of K values for competition of LY320135 and selected cannabinoid ligands for 0.5 nM 3H-CP 55,940 binding to the CB1 and CB2 receptors

L-CB1CHO-CB2Ki Ratio (CB2/CB1)
nM nM
Antagonists
 LY320135141  ± 414,900  ± 403106
 SR141716A11.8  ± 2.013,200  ± 7001119
Agonists
 HU2100.0608  ± 0.00700.524  ± 0.0458.6
 CP559403.72  ± 0.0902.55  ± 0.190.7
 (−) Δ°-THC53.3  ± 8.375.3  ± 8.41.4
 WIN55212-262.3  ± 313.3  ± 0.400.1
 Anandamide543  ± 831940  ± 2403.6

The Ki values for LY320135 and SR141716A are presented in the top of the table. Cannabinoid agonists are ranked according to their Ki value at the CB1 receptor.Ki values for the agonists are provided for comparison purposes and were evaluated under the identical conditions used for the antagonists [reprinted with permission from Felderet al. (1995)]. Data are the mean ± S.E.M. of at least three experiments, each performed in triplicate. (Radioligand binding data: L-CB1: Kd = 3.3 ± 0.7 nM,Bmax = 7.0 ± 0.5 pmol/mg; CHO-CB2:Kd = 7.5 ± 0.9 nM, Bmax = 1.21 ± 0.1 pmol/mg; CP55,940 was used as the labeled ligand.)