Voltage-gated potassium channels (Kv4.1, Kv4.2 and Kv4.3) encoded by the members of the KCND/Kv4 (Shal) channel family mediate the native, fast inactivating (A-type) K(+) current (IA) described both in heart and neurons. This IA current is specifically blocked by short scorpion toxins that belong to the α-KTx15 subfamily and which act as pore blockers, a different mode of action by comparison to spider toxins known as gating modifiers. This review summarizes our present chemical and pharmacological knowledge on the α-KTx15 toxins.
Animals ; Potassium Channel Blockers ; chemistry ; Scorpion Venoms ; chemistry ; Scorpions ; Shal Potassium Channels ; antagonists & inhibitors

OBJECTIVETo set up a new analysis method of the traditional Chinese medicine Scorpio.

METHODSTen Scorpio samples were obtained from Hubei, Shaanxi, and Shandong provinces and analyzed with X-ray diffraction Fourier pattern technique to obtain the geometric topology and characteristic marked peak of Scorpio.

RESULTSThe geometric topologies of 9 samples were similar, excepting Sample 7#. Totally 11 characteristic marked peaks were observed among these 9 samples.

CONCLUSIONX-ray diffraction Fourier pattern is a useful tool for the identification and quality control of the Scorpio.

Animals ; Drugs, Chinese Herbal ; chemistry ; Fourier Analysis ; Powders ; Scorpions ; chemistry ; X-Ray Diffraction

Small conductance Ca(2+)-activated potassium channels (SK channels) distributing in the nervous system play an important role in learning, memory and synaptic plasticity. Most pharmacological properties of them are determined by short-chain scorpion toxins. Different from most voltage-gated potassium channels and large-conductance Ca(2+)-activated potassium channels, SK channels are only inhibited by a small quantity of scorpion toxins. Recently, a novel peptide screener in the extracellular pore entryway of SK channels was considered as the structural basis of toxin selective recognition. In this review, we summarized the unique interactions between scorpion toxins and SK channels, which is crucial not only in deep-researching for physiological function of SK channels, but also in developing drugs for SK channel-related diseases.
Animals ; Memory ; Neuronal Plasticity ; Scorpion Venoms ; chemistry ; Scorpions ; Small-Conductance Calcium-Activated Potassium Channels ; antagonists & inhibitors

The East Asian scorpion Buthus martensii Karsch (BmK) is one of the classical traditional Chinese medicines for treating epilepsy for over a thousand years. Neurotoxins purified from BmK venom are considered as the main active ingredients, acting on membrane ion channels. Voltage-gated sodium channels (VGSCs) play a crucial role in the occurrence of epilepsy, which make them become important drug targets for epilepsy. Long chain toxins of BmK, composed of 60-70 amino acid residues, could specifically recognize VGSCs. Among them, α-like neurotoxins, binding to the receptor site-3 of VGSC, induce epilepsy in rodents and can be used to establish seizure models. The β or β-like neurotoxins, binding to the receptor site-4 of VGSC, have significant anticonvulsant effects in epileptic models. This review aims to illuminate the anticonvulsant/convulsant effects of BmK polypeptides by acting on VGSCs, and provide potential frameworks for the anti-epileptic drug-design.
Animals ; Anticonvulsants/therapeutic use* ; Neurotoxins/pharmacology* ; Scorpion Venoms/pharmacology* ; Scorpions/chemistry* ; Voltage-Gated Sodium Channels

It is hypothesized that protease inhibitors play an essential role in survival of venomous animals through protecting peptide/protein toxins from degradation by proteases in their prey or predators. However, the biological function of protease inhibitors in scorpion venoms remains unknown. In the present study, a trypsin inhibitor was purified and characterized from the venom of scorpion Mesobuthus eupeus, which enhanced the biological activities of crude venom components in mice when injected in combination with crude venom. This protease inhibitor, named MeKTT-1, belonged to Kunitz-type toxins subfamily. Native MeKTT-1 selectively inhibited trypsin with a Kivalue of 130 nmol·L(-1). Furthermore, MeKTT-1 was shown to be a thermo-stable peptide. In animal behavioral tests, MeKTT-1 prolonged the pain behavior induced by scorpion crude venom, suggesting that protease inhibitors in scorpion venom inhibited proteases and protect the functionally important peptide/protein toxins from degradation, consequently keeping them active longer. In conclusion, this was the first experimental evidence about the natural existence of serine protease inhibitor in the venom of scorpion Mesobuthus eupeus, which preserved the activity of venom components, suggests that scorpions may use protease inhibitors for survival.
Amino Acid Sequence ; Animals ; Base Sequence ; Female ; Kinetics ; Male ; Mice ; Molecular Sequence Data ; Protease Inhibitors ; chemistry ; toxicity ; Scorpion Venoms ; chemistry ; genetics ; toxicity ; Scorpions ; chemistry ; genetics ; Trypsin ; chemistry

In the present study, a 'novel' toxin, called Am IT from the venom of scorpion Androctonus mauretanicus is isolated and characterized. A detailed analysis of the action of Am IT on insect axonal sodium currents is reported. Am IT was purified through gel filtration followed by C18 reversed-phase HPLC. Toxicity of Am IT in vivo was assessed on male German cockroach (Blattella germanica) larvae and C57/BL6 mice. Cross-reactivity of Am IT with two β-toxins was evidenced using (125)I-iodinated toxin-based radioimmunoassays with synaptosomal preparations from rat brain. The complete amino acid sequence of Am IT was finally determined by Edman sequencing. Am IT was observed to compete with AaH IT4 purified from the venom of scorpion Androctonus australis in binding assays. It was recognized by an antibody raised against a β-type toxin, which indicated some structural similarity with β-toxins (or related toxin family). The 'novel' toxin exhibited dual activity since it competed with anti-mammal toxins in binding assays as well as showed contracting activity to insect. The toxin competed with radio-labeled β-toxin Css IV by binding to Na(+) channels of rat brain synaptosomes. Analysis of toxin amino acid sequences showed that Am IT shares high structural identity (92%) with AaH IT4. In conclusion, Am IT not only reveals an anti-insect compound properties secreted by 'Old World' scorpions, paralyzing insect larvae by binding to Na(+) channels on larvae's nerve-cell membranes, but also exerts toxic activity in mice, which is similar to anti-mammal toxins from 'New World' scorpions (North and South Americas). Therefore, Am IT appears to be structurally and functionally similar to AaH IT4.
Amino Acid Sequence ; Animals ; Chromatography, High Pressure Liquid ; Insecta ; Male ; Mice ; Neuropeptides ; Rats ; Scorpion Venoms ; chemistry ; Scorpions

According to the reported sequence of Buthus martensii Karsch scorpion toxin gene (BmK IT3), we synthesized two primers, which were complementary in a region. By the means of PCR, we got the gene. The gene was fused in expression vector pET-28a, which gave rise to a recombinant plasmid pET(IT3R). Then it was transformed into E. coli BL21 (DE3). With IPTG induction, the gene was efficiently expressed. And the fusion product was soluble.
Animals ; Cloning, Molecular ; Escherichia coli ; genetics ; Gene Expression ; drug effects ; Isopropyl Thiogalactoside ; pharmacology ; Recombinant Proteins ; biosynthesis ; genetics ; Scorpion Venoms ; biosynthesis ; chemistry ; genetics ; Scorpions ; chemistry ; genetics

Codon bias is an important factor which influences heterologous gene expression. Optimizing codon sequence could improve expression level of heterologous gene. In order to improve the expression level of BmK AngM1 gene encoding the analgesic peptide from Buthus martensii Karsch in Pichia pastoris, the codon-optimized BmK AngM1 gene according to its cDNA sequence and the preference codon usage of P. pastoris were cloned into expression vector pPIC9K and then transformed into P. pastoris. The expersion of recombinant BmK AngM1 (rBmK AngM1) was inducced by methanol in the medium, and the expression level of the optimized BmK AngM1 gene was 3.7 times of the native one. These results suggested that the expression of BmK AngM1 in P. pastoris could be successfully improved by codon optimization.
Amino Acid Sequence ; Animals ; Codon ; genetics ; Gene Expression ; Pichia ; genetics ; metabolism ; Plasmids ; Recombinant Proteins ; genetics ; metabolism ; Scorpion Venoms ; genetics ; isolation & purification ; metabolism ; Scorpions ; chemistry ; Transformation, Genetic

OBJECTIVETo study the anticonvulsive action of scorpion alcoholic extraction (SAE) on phenytoin-resistant convulsive rats made by direct cortical electrical stimulation in order to investigate the mechanism of antagonizing drug-resistance of SAE.

METHODUsing the method of implanting microelectrodes in the cortical motor area of the brains of rats where the brain tissue was stimulated frequently by electricity through microelectrodes until igniting and then PHT (0.154 g x kg(-1) x d(-1)) ig for 7 days, We established phenytoin-resistant convulsive rat model. Total 6 groups were set up in the experiment: Normal control group, convulsion model control group (CMCG), phenytoin-resistant convulsion control group (PRCG), verapamil positive control group (VPCG, 0.0385 g x kg(-1)), scorpion alcohol extraction (SAE1, 6.5 g x kg(-1)) and scorpion alcohol extraction (SAE2, 13.0 g x kg(-1)). After ig both doses of SAE (6.5, 13.0 g x kg(-1)), the effects of SAE on the changes of convulsion threshold of phenytoin-resistant convulsive rats were observed. The method of RT-polymerase chain reaction (RT-PCR) was used to detect the changes of mdrl gene expression and the method of immunohistochemistry (SABC) was adopted to determine the changes of P-gp expression.

RESULTBoth doses of SAE and verapamil (Ver) ig all raised the convulsant threshold of phenytoin-resistant rats (480.38 +/- 18.48) microA, there were statistical differences (P < 0.05) compared to themselves before drugs-treated. PHT was administrated, and mdrl mRNA and P-gp expression in PRCG was much higher than that in CMCG, with significantly statistical difference (P < 0.01); ig both doses of SAE and Ver all decreased mdrl mRNA and P-gp expression compared to PRCG respectively (P < 0.01).

CONCLUSIONSAE and Ver ig all produce antagonizing action on phenytoin-resistant convulsive rat model. The machanism is related with inhabiting the mdrl mRNA expression and further decreasing the product P-gp.

ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Animals ; Brain ; drug effects ; metabolism ; Disease Models, Animal ; Ethanol ; chemistry ; Female ; Gene Expression ; drug effects ; Humans ; Phenytoin ; pharmacology ; Rats ; Rats, Wistar ; Scorpions ; chemistry ; Seizures ; drug therapy ; genetics ; metabolism

OBJECTIVEExtracting the total protein from scorpii tegument, investigating its effect on immune system by transformation of T/B cell.

METHODWater-soluble protein(ST1) was extracted by distilled water method and salting-out method, while keratin(ST2) by deoxidization method. Sephadex G-50 was used to isolate the protein. The effects of components isolated by sephadex G-50 on T/B and NK cell were investigated.

RESULTThe protein from scorpii tegument could increase the transformation of T/B cell distinctly in vitro, while no apparent effect on NK cell.

CONCLUSIONProtein from scorpii tegument could modulate the immune system, which may offer a new way for people to find protein drugs.

Animals ; B-Lymphocytes ; drug effects ; Female ; Keratins ; isolation & purification ; pharmacology ; Killer Cells, Natural ; drug effects ; Lymphocyte Activation ; drug effects ; Mice ; Mice, Inbred BALB C ; Proteins ; isolation & purification ; pharmacology ; Scorpions ; chemistry ; Skin ; chemistry ; T-Lymphocytes ; drug effects