(±)-Anatoxin A is a bicyclic amine isolated from the blue-green alga A. aquae that displays high affinity for nicotinic acetylcholine receptors (Kd = 0.1-0.2 μM). It binds α4β2- and α7-type nicotinic receptors with Ki values of 1.3 nM and 1.8 μM, respectively, and stimulates [3H]-dopamine release from striatal synaptosomes with an EC50 value of 134 nM.