The depressant scorpion neurotoxin LqqIT2 selectively modulates the insect voltage-gated sodium channel.
LqqIT2 is a depressant neurotoxin present in the venom of the Leiurus quinquestriatus quinquestriatus scorpion, one of the world's most dangerous scorpions endemic to dry habitats in Africa and Asia. In order to determine its efficacy, potency and selectivity, LqqIT2 was subjected for the first time to an electrophysiological and pharmacological comparison between two different cloned sodium channels expressed in Xenopus laevis oocytes. Aside from typical beta-toxin effects, LqqIT2 also affected the inactivation process and ion selectivity of the insect voltage-gated sodium channel. The most interesting feature of LqqIT2 is its total insect-selectivity. At a concentration of 1 microM, the insect-voltage-gated sodium channel, para, was profoundly modulated while its mammalian counterpart, the rat brain Na(v)1.2 channel, was not affected. This trait offers excellent prospects for the development of novel insecticides.
Bosmans
Frank
F
Laboratory of Toxicology, Faculty of Pharmacy, University of Leuven, E. Van Evenstraat 4, B-3000 Leuven, Belgium.
Martin-Eauclaire
Marie-France
MF
Tytgat
Jan
J
D000595:Amino Acid Sequence; D000818:Animals; D029721:Drosophila Proteins / Q000187:drug effects / Q000378:metabolism; D004594:Electrophysiology; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D062551:NAV1.2 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D051381:Rats; D012604:Scorpion Venoms / Q000235:genetics / Q000494:pharmacology*; D012605:Scorpions / Q000737:chemistry*; D016415:Sequence Alignment; D015222:Sodium Channels / Q000187:drug effects* / Q000378:metabolism; D013045:Species Specificity; D014982:Xenopus laevis
D029721:Drosophila Proteins; C063417:Lqq IT2; D008565:Membrane Proteins; D062551:NAV1.2 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568253:Scn2A protein, rat; D012604:Scorpion Venoms; D015222:Sodium Channels; C095833:TipE protein, Drosophila; C469950:para protein, Drosophila