title: Inhibition of insect calcium channels by huwentoxin-V, a neurotoxin from Chinese tarantula Ornithoctonus huwena venom.
abstract: 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.
authors.affiliation: College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Meichun
authors.initials: M
authors.lastname: Deng
authors.forename: Xuan
authors.initials: X
authors.lastname: Luo
authors.forename: Er
authors.initials: E
authors.lastname: Meng
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Xiao
authors.forename: Songping
authors.initials: S
authors.lastname: Liang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000166:cytology; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D009498:Neurotoxins / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D010526:Periplaneta; D015221:Potassium Channels / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000502:physiology; D013111:Spider Venoms / Q000737:chemistry* / Q000494:pharmacology; D013112:Spiders / Q000737:chemistry*
chemical_list: D002121:Calcium Channel Blockers; D009498:Neurotoxins; D015221:Potassium Channels; D015222:Sodium Channels; D013111:Spider Venoms; C529312:huwentoxin-V, Ornithoctonus huwena