The Pain Function Of Toxin BmP01 From Scorpion Buthus Martensii Karsch

The intense pain induced by scorpion sting is a frequent clinical manifestation.To date, there is no established protocol with significant efficacy to alleviate the pain induced by scorpion envenomation. One of important reasons is that little information on pain-inducing compound of scorpion venoms is available. Here, a pain-inducing toxin BmP01, which has been previously reported as an inhibitor of voltage-gated potassium channel subtypes, has been identified and characterized from the venoms of scorpion Buthus martensii Karsch (BMK).Toxin BmP01 is a peptide which consists of 29 amino acid residues, and the sequence is:ATCEDCPEHCATQNARAKCDNDKCVCEPK. The disulfide bonds of toxin BmP01 is a typical ICK modle (inhibitor cystine knot),Cys1-Cys4, Cys2-Cys5, Cys3-Cys6, which built by 6 cysteines in the sequence.BmP01 induced pain by activating transient receptor potential vanilloid 1 ion channel (TRPV1), the well-known polymodal nociceptor. In an animal pain model by intraplantar injection in mouse hind paw, BmP01 induced significant acute pain in wild type but not in TRPV1 knock-out during 5 min recording. The patch clamp electrophysiological experiments indicated that BmP01 evoked currents in wild type dorsal root ganglion (DRG) neurons but had no effect on TRPV1 knock-out DRG neurons. This result suggests that 1):BmPO1 is one of pain-inducing agents in scorpion venoms; 2):BmP01 induces pain by acting on TRPV1. To our knowledge, this is the first report of pain-inducing compound in scorpion venom. The identification of pain-inducing compound may facilitate to treat pain induced by scorpion envenomation.