Inhibition of insect calcium channels by huwentoxin-V, a neurotoxin from Chinese tarantula Ornithoctonus huwena venom

The effects of huwentoxin-V, an insect neurotoxic peptide from Chinese tarantula Ornithoctonus huwena venom, were studied on neuronal voltage-gated ion channels. Whole-cell patch-clamp configuration indicated that huwentoxin-V specifically inhibited high-voltage-activated calcium channels in adult cockroach dorsal unpaired median neurons (IC(50) approximately 219 nM) while having no evident effect on voltage-gated potassium and sodium channels. Omega-conotoxin GVIA is a well-known neuronal N-type calcium channel blocker from the venom of the sea snail Conus geographus and it also can partially block calcium currents in cockroach dorsal unpaired median neurons. In our study, huwentoxin-V inhibited omega-conotoxin GVIA-sensitive, diltiazem-sensitive and partial omega-conotoxin GVIA and diltiazem-resistant calcium currents elicited from insect neurons. Based on the sensitivity of calcium currents to these toxins, insect neuronal HVA calcium channels might be classified into four types: Type I, omega-conotoxin GVIA-sensitive and huwentoxin-V-sensitive; type II, diltiazem-sensitive and huwentoxin-V-sensitive; type III, huwentoxin-V-sensitive but omega-conotoxin GVIA and diltiazem-resistant; type IV, omega-conotoxin GVIA and diltiazem-resistant and huwentoxin-V-resistant. Its specificity, incomplete inhibition and insect-toxic effects make it an interesting tool for investigating insect voltage-gated calcium channels and development of new insecticidal compounds

Keywords : Adult,Amino Acid Sequence,Animals,Calcium,Calcium Channel Blockers,Calcium Channels,Cells,Cultured,chemistry,China,cytology,drug effects,Ganglia,Spinal,In Vitro Techniques,Ion Channel Gating,Ion Channels,Molecular Sequence Data,Neurons,Neurotoxins,Patch-Clamp Techniques,Periplaneta,pharmacology,physiology,Potassium Channels,Rats,Rats,Sprague-Dawley,Sequence Homology,Amino Acid,Sodium Channels,Spider Venoms,Spiders,, Insect,Calcium,Channels,By, bearable pain

Date of Publication : 2008 Mar 17

Authors : Deng M;Luo X;Meng E;Xiao Y;Liang S;

Organisation : College of Life Sciences, Hunan Normal University, Changsha 410081, China

Journal of Publication : Eur J Pharmacol

Pubmed Link : https://www.ncbi.nlm.nih.gov/pubmed/18234186

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