(±)-Epibatidine (hydrochloride) (Synonyms: CMI 545 dihydrochloride)

(±)-Epibatidine is an alkaloid that has been found in Ecuadoran poison frog (E. tricolor) skin extracts and an agonist of α4β2 subunit-containing nicotinic acetylcholine receptors (nAChRs; K_i = 43 pM).^1,2 It is selective for α4β2 subunit-containing nAChRs over α7 nAChRs (K_i = 230 nM).¹ (±)-Epibatidine enhances ⁸⁶Rb⁺ flux in IMR-32 cells (EC₅₀ = 7 nM) and induces dopamine release from rat striatal slices (EC₅₀ = 0.4 nM), effects that can be reduced by the nAChR antagonist mecamylamine . In vivo, (±)-epibatidine induces analgesia in the hot plate test and the Straub-tail response in mice (ED₅₀s = 0.005 and 0.02 mg/kg, respectively).²

1.Sullivan, J.P., Decker, M.W., Brioni, J.D., et al.(+/-)-Epibatidine elicits a diversity of in vitro and in vivo effects mediated by nicotinic acetylcholine receptorsJ. Pharmacol. Exp. Ther.271(2)624-631(1994) 2.Spande, T.F., Garraffo, H.M., Edwards, M.W., et al.Epibatidine: A novel (chloropyridyl)azabicycloheptane with potent analgesic activity from an Ecuadoran poison frogJ. Am. Chem. Soc.114(9)3475-3478(1992)