Table 2.

Sigma-1 Receptor Affinity (K_D) and One-Site Linear Regression (R²) of N-Alkyl-N′-aralkyl Derivatives. K_D and R² values of these compounds were calculated using GraphPad Prism software. (A) Competitive displacement curves against 10 nM (+)-[³H]pentazocine were generated, and data points were fit to a one-site nonlinear regression curve. R² values are reported to examine the “goodness of fit”. Haloperidol (5 μM) was used to determine nonspecific binding. (B) Structures of the N-alkyl-N′-aralkyl derivatives used in competitive displacement assays

A
Ligand	Sigma-1R KD (μM) (± SEM, n=3), R2	Sigma-2R KD (μM) (± SEM, n=3), R2	Ratio Sigma2/Sigma1
11	a	12.45 (±8.1, 0.88)	Ndb
14	28.9 (±8.4, 0.97)	42.0 (±34, 0.86)	0.689
15	7.24 (±2.03, 0.98)	1.29 (±3.4, 0.96)	0.178
13	2.59 (±0.63, 0.96)	0.12 (±0.045, 0.91)	0.046

B

^aDoes not compete with [³H]-DTG

^bNd - not determined