Mu-conotoxins block voltage-gated sodium channels (Nav). This toxin specifically inhibits mammalian Nav1.8/SCN10A sodium currents (IC(50)=2.11 uM) without inducing a shift in the current-voltage relationship of this channel (PubMed:32758497). In vivo, shows potent analgesic activity in a mice hotplate analgesic assay (PubMed:28219625). In addition, this toxin has better analgesic effects than Ziconotide, an analgesic drug (PubMed:28219625). Expressed by the venom duct. The cysteine framework is III (CC-C-C-CC). Classified in the M-4 branch, since 5 residues stand between the fourth and the fifth cysteine residues. Has no effects (10 uM tested) on the human tetrodotoxin-sensitive Nav1.1/SCN1A, Nav1.2/SCN2A, Nav1.3/SCN3A, Nav1.4/SCN4A, Nav1.6/SCN8A and Nav1.7/SCN9A, as well as human tetrodotoxin-resistant Nav1.5/SCN7A. Belongs to the conotoxin M superfamily.