TABLE 2.

ED₅₀ values (with 95% confidence intervals; 95% CL) and potencies of nicotinic agonists relative to the d-MA-like effects produced by (−)-nicotine in rats trained to discriminate intraperitoneal injections of 0.3 mg/kg d-MA from saline

The in vitro affinity of nicotinic agonists in inhibiting (−)-[³H]nicotine binding at the (α4β2) nicotinic ACh receptors and inhibiting ¹²⁵I-α- bungarotoxin binding for the α₇ nicotinic receptors represents the average of values taken from the references cited. In vitro binding affinity values at nicotinic receptor subtypes represent the average of values taken from experiments conducted in rat brain using [³H]nicotine binding for the α4β2 subtype and ¹²⁵I-α-bungarotoxin binding for the α7 nicotinic receptor subtype.

Drug	Doses	ED50 (95% CL)	Relative Behavior Potency	In Vitro Affinity (Ki Values) at α4β2	Relative Affinity at α4β2 Receptors	In Vitro Affinity (Ki Values) at α7	Relative Affinity at α7 Receptors
	mg/kg (μmol/kg)	mg/kg (μmol/kg)		nM		nM
(−)-Nicotine	0.01–0.1 (0.06–0.62)	0.03 (0.02–0.04)	1	3.4a–e	1	4895c	1
		0.18 (0.12–0.25)
(+) Epibatidine	0.0001–0.001 (0.00048–0.0048)	0.00024 (0.00002–0.00077)	0.007	0.05b,d	0.015	255f	0.052
		0.0012 (0.000096–0.0037)
(−) Epibatidine	0.0001–0.001 (0.00048–0.0048)	0.00032 (0.00006–0.0017)	0.008	0.06b,d	0.018	109f	0.022
		0.0015 (0.00029–0.0081)
Isoarecolone	1.0–10 (6.88–68.75)	2.49 (0.18–9.48)	95.1	611c	179.7	>100,000c	20.43
		17.12 (1.24–65.18)
Anabaseine	0.3–3.0 (1.87–18.72)	0.54 (2.10–75.15)g	18.7	32h	9.41	58h	0.012
		3.37 (13.11–469.0)
Varenicline	0.01–3.0 (0.05–14.20)	N.C.		0.17e,i	0.05	620i	0.127

N.C., not conducted.

^a Jensen et al., 2003; Anderson and Arenric, 1994; Xiao and Kellar, 2004; Marks et al., 1986, 1996; Decker et al., 1995.

^b Baido and Daly, 1994.

^c Hahn et al., 2003.

^d Damaj et al., 1994.

^e Rollema et al., 2010.

^f Sullivan et al., 1994.

^g Estimate because of a nonsignificant regression.

^h Kem et al., 1997.

ⁱ Rollema et al., 2007.