Mu-conotoxins block voltage-gated sodium channels (Nav) (By similarity). In vitro, this synthetic peptide displays a low blocking effect in mouse extensor digitorum longus muscles (IC(50)=616 nM). Expressed by the venom duct. The cysteine framework is III (CC-C-C-CC). Classified in the M-4 branch, since 4 residues stand between the fourth and the fifth cysteine residues. Belongs to the conotoxin M superfamily.