Huwentoxin XVI, an analgesic, is a highly reversible and selective mammalian N-type calcium channel (IC50 of ~60 nM) antagonist from Chinese tarantula Ornithoctonus huwena. Huwentoxin XVI has no effect on voltagegated T-type calcium channels, potassium channels or sodium channels[1].
huwentoxin xvi(hwtx-xvi ) is composed of 39 amino acid residues including six cysteines. hwtx-xvi is a novel neurotoxin from the venom of chinese tarantula o. huwena. and specificially block n-type calcium channels. [1]n-type calcium channels are often highly expressed both in dorsal root ganglia cell bodies and in the synaptic terminals projecting to dorsal horn of the spinal cord n-type calcium channels play important roles in the control of neurotransmission release and transmission of pain signals to the central nervous system.[2]electrophysiological assay indicated that hwtx-xvi specifically inhibited n-type calcium channels in rat dorsal root ganglion cells. hwtx-xvi specifically inhibits gvia sensitive, n-type calcium channels in rat drg cells.[1]hwtx-xvi could almost completely block the twitch response of rat vas deferens to low-frequency electrical stimulation. hwtx-xvi ‘s analgesic effects, non-toxic and complete reversibility make it an interesting tool for developing novel drugs for the treatment of n-type calcium channel-related diseases.[1,2]
[1] deng m, luo x, xiao y etal. , huwentoxin-xvi, an analgesic, highly reversible mammalian n-type calcium channel antagonist from chinese tarantula ornithoctonus huwena. neuropharmacology. 2014 apr;79:657-67.
[2] liu z, dai j, dai l etal. , function and solution structure of huwentoxin-x, a specific blocker of n-type calcium channels, from the chinese bird spider ornithoctonus huwena. j biol chem. 2006 mar 31;281(13):8628-35.
