Аннотация:Neurotoxins are among the main components of scorpion and snake venoms.Scorpion neurotoxins affect voltage-gated ion channels, while most snake neu-rotoxins target ligand-gated ion channels, mainly nicotinic acetylcholinereceptors (nAChRs). We report that scorpion venoms inhibita-bungarotoxinbinding to both muscle-type nAChR fromTorpedo californicaand neuronalhumana7 nAChR. Toxins inhibiting nAChRs were identified as OSK-1 (a-KTx family) fromOrthochirus scrobiculosusand HelaTx1 (j-KTx family)fromHeterometrus laoticus, both being blockers of voltage-gated potassiumchannels. With an IC50of 1.6lM, OSK1 inhibits acetylcholine-induced cur-rent through mouse muscle-type nAChR heterologously expressed inXenopusoocytes. Other well-characterized scorpion toxins from these families alsobind toTorpedonAChR with micromolar affinities. Our results indicate thatscorpion neurotoxins present target promiscuity.