Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This toxin acts as a competitive inhibitor and is 3-fold more potent on alpha-7/CHRNA7 nAChRs (IC(50)=6 nM) than on alpha-3-beta-2/CHRNA3-CHRNB2 nAChR (IC(50)=18 nM). Acts as a competitive inhibitor and is 33-fold more potent on alpha-7/CHRNA7 nAChRs (IC(50)=1.8 nM) than on alpha-3-beta-2/CHRNA3-CHRNB2 nAChR (IC(50)=60.1 nM). Expressed by the venom duct. The cysteine framework is I (CC-C-C). Alpha4/7 pattern. The mutant ArIB[V30L,V35D] is a potent and selective competitive antagonist of rat and human alpha-7/CHRNA7 nAChRs, making it an attractive probe for this receptor subtype. Belongs to the conotoxin A superfamily.