Potent inhibitor of hNav1.8/SCN10A (IC(50)=141-380 nM) (PubMed:30804211). Is highly selective for this channel and acts in a reversible manner (PubMed:30804211). Shows a depolarizing shift of activation and hyperpolarizing shift of inactivation (PubMed:30804211). In contrast to the very similar cytotoxin A5 (AC P62375), does not seem to bind integrin alpha-V/beta-3, since it does not promote or inhibit the proliferation of HUVECs and C-PAE cells (PubMed:30804211). In vivo, in rodent models of inflammatory and neuropathic pain, it alleviates nociceptive behaviors more potently than does morphine (PubMed:30804211). It displays no evident cytotoxic, hemolytic and cardiotoxic activities and produces no obvious adverse responses in mice even at a dose 30-fold higher than that producing a significant analgesic effect (PubMed:30804211). Expressed by the venom gland. Is classified as a P-type cytotoxin, since a proline residue stands at position 52 (Pro-31 in standard classification). Shows no or very weak inhibition of rNav1.1/SCN1A, hNav1.2/SCN2A, hNav1.3/SCN3A, hNav1.4/SCN4A (IC(50)>10 uM), hNav1.5/SCN5A (IC(50)=8.51 uM), hNav1.6/SCN8A, hNav1.7/SCN9A, and Nav1.9/SCN11A (PubMed:30804211). Has no effect on transient receptor potential cation channels TRPV1, TRPV2, TRPV3, TRPV4, TRPA1, TRPM8, TRPC3, TRPC4, TRPC5, and TRPC6 (PubMed:30804211). Belongs to the snake three-finger toxin family. Short-chain subfamily. Orphan group XV sub-subfamily.