Anatoxin-a is a secondary, bicyclic amine alkaloid and cyanotoxin with acute neurotoxicity. Symptoms of anatoxin exposure include loss of coordination, muscular fasciculations, convulsions and death by respiratory paralysis. Its mode of action is through the nicotinic acetylcholine receptor (nAchR) where it acts as an agonist of acetylcholine. As such, anatoxin-a has been used for medicinal purposes to investigate diseases characterized by low acetylcholine levels. Due to its high toxicity and potential presence in drinking water, anatoxin-a poses a threat to humans and animals. While methods for detection and water treatment exist, scientists have called for more research to improve reliability and efficacy. Anatoxin-a is not to be confused with anatoxin-a(S), another potent cyanotoxin that has a similar mechanism of action to that of anatoxin-a and is produced by many of the same cyanobacteria genera, but is structurally unrelated.