Table 2.

Inhibition constants (Ki ± SEM, nM) obtained from competition binding assays at equilibrium for some cyclic imine toxins on various nAChRs, and comparisons with the nicotinic antagonists α-toxin, methyllycaconitine (MLA) and epibatidine.

Cyclic imine toxin	α12β1γδ (Torpedo)	α7-5HT3 (chick)	α3β2 (human)	α4β2 (human)	Reference
20-meSPX-Ga	0.028 ± 0.005i	0.11 ± 0.08	0.040 ± 0.001	3.6 ± 0.7	Couesnon et al. 2016
13,19-ddmeSPX-Cb	0.017 ± 0.003	0.22 ± 0.06	0.51± 0.14	53 ± 25	Aráoz et al. 2015
13-SPX-Cc	0.080 ± 0.002	0.53 ± 0.08	0.021 ± 0.005	0.58 ± 0.07	Bourne et al. 2010
GYM-Ad	0.23 ± 0.08	0.33 ± 0.08	0.24 ± 0.09	0.62 ± 0.07	Kharrat et al. 2008
PnTX-Ae	2.80 ± 0.03	0.35 ± 0.04	9.4 ± 1.9	15.6 ± 5.2	Aráoz et al. 2011
PnTX-Gf	0.11 ± 0.04	0.72 ± 0.03	64 ± 2	101 ± 30	Bourne et al. 2015
α-Toxing	0.011 ± 0.002				Couesnon et al. 2016
MLAh		0.83 ± 0.12			Couesnon et al. 2016
Epibatidine			0.034 ± 0.002	0.054 ± 0.011	Couesnon et al. 2016

^a20-methyl spirolide G;

^b13,19-didesmethyl spirolide C;

^c13-desmethyl spirolide C;

^dgymnodimine A;

^esynthetic pinnatoxin A;

^fsynthetic pinnatoxin G;

^gsynthetic peptidic α-toxin (Naja nigricollis);

^hmethyllycaconitine;

ⁱValues expressed as themean± SEM from 3–4 distinct experiments performed in duplicate.