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

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

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

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 observe effect of oral scorpio and scolopendra powder on T-cell subsets in peripheral blood and intestine from rats with collagen induced arthritis (CIA).

METHOD60 rats were randomly divided into 6 groups: normal control group, model control group, low-dose scorpio and scolopendra group, middle-dose scorpio and scolopendra group, high-dose scorpio and scolopendra group, and type II collagen group. Rat's rheumatoid arthritis was induced by collagen II (C II). Level of T-cell subsets from peripheral blood and intestine was measured by flow cytometry.

RESULTCD4+ T cellular level was obviously increased (P < 0.05 or P < 0.01) or kept increased tendency in peripheral blood and intestine from the model group compared with that of the normal group, while the ratio of CD4+/CD8+ in intestine was obviously descent but the contrary in peripheral blood (P < 0.05 or P < 0.01). CD4+, CD8+ T cellular level in intestine were obviously descent and the ratio of CD4+ /CD8+ increased in all treated groups when compared with in the model group (P < 0.05 or P < 0.01). However, CD4+ T cellular level and the ratio of CD4+/CD8+ in peripheral blood were remarkablely decreased.

CONCLUSIONThe mechanism that scorpio and scolopendra could treat rat's rheumatoid arthritis may be regulating balance of T-lymphocyte subsets in peripheral blood and intestine.

Animals ; Anti-Inflammatory Agents ; pharmacology ; Arthritis, Experimental ; immunology ; Arthritis, Rheumatoid ; immunology ; CD4 Lymphocyte Count ; CD4-Positive T-Lymphocytes ; CD8-Positive T-Lymphocytes ; Female ; Intestinal Mucosa ; immunology ; Medicine, Chinese Traditional ; Rats ; Rats, Wistar ; Scorpions ; chemistry ; T-Lymphocyte Subsets ; drug effects ; immunology

OBJECTIVETo study the expression of HIF-1alpha and SDF-1/CXCR4 in repopulating H22 tumor tissue and the mechanism of angiogenesis of polypeptide extract from scorpion venom (PESV) during chemotherapy treatment.

METHODThe expression of HIF-1alpha and SDF-1/CXCR4 in H22 tumor tissue was monitored by immunohistochemistry, and the expression level was determined by Qwin V3 image analyzing software. The correlation between HIF-1alpha and SDF-1 was analyzed. SDF-1 content was detected by ELISA.

RESULTHIF-1alpha expression was found no difference in model group between 14 d and 21 d, and up-regulated in 28 d. There was no change of HIF-1alpha expression was observed in low-dose PESV group. In high-dose PESV group, the level of HIF-1alpha expression was high in 14 d and low in 21 d. ELISA detecting showed SDF-1 content increased slowly from 14 d to 21 d, highly from 21 d to 28 d. But in high-dose PESV groups, the content increased slowly all the time. The immunohitochemistry method got the same result with ELISA. Correlation analysis showed r = 0.805. CXCR4 expression down-regulated in two PESV treated groups, and no difference was found between these two groups.

CONCLUSIONHIF-1alpha and SDF-1 participated in VEGF expression and angiogenesis in tumor tissue during chemotherapy, while PESV could inhibit the expression of HIF-1alpha and SDF-I.

Animals ; Cell Line, Tumor ; Chemokine CXCL12 ; drug effects ; metabolism ; Down-Regulation ; drug effects ; Hypoxia-Inducible Factor 1, alpha Subunit ; drug effects ; metabolism ; Mice ; Peptides ; pharmacology ; Receptors, CXCR4 ; drug effects ; metabolism ; Scorpion Venoms ; chemistry ; pharmacology ; Scorpions ; chemistry ; Time Factors

Diverse subtypes of voltage-gated sodium channels (VGSCs) have been found throughout tissues of the brain, muscles and the heart. Neurotoxins extracted from the venom of the Asian scorpion Buthus martensi Karsch (BmK) act as sodium channel-specific modulators and have therefore been widely used to study VGSCs. α-type neurotoxins, named BmK I, BmK αIV and BmK abT, bind to receptor site-3 on VGSCs and can strongly prolong the inactivation phase of VGSCs. In contrast, β-type neurotoxins, named BmK AS, BmK AS-1, BmK IT and BmK IT2, occupy receptor site-4 on VGSCs and can suppress peak currents and hyperpolarize the activation kinetics of sodium channels. Accumulating evidence from binding assays of scorpion neurotoxins on VGSCs, however, indicate that pharmacological sensitivity of VGSC subtypes to different modulators is much more complex than that suggested by the simple α-type and β-type neurotoxin distinction. Exploring the mechanisms of possible dynamic interactions between site 3-/4-specific modulators and region- and/or species-specific subtypes of VGSCs would therefore greatly expand our understanding of the physiological and pharmacological properties of diverse VGSCs. In this review, we discuss the pharmacological and structural diversity of VGSCs as revealed by studies exploring the binding properties and cross-competitive binding of site 3- or site 4-specific modulators in VGSC subtypes in synaptosomes from distinct tissues of diverse species.
Animals ; Binding Sites ; Binding, Competitive ; Brain ; metabolism ; Heart ; physiology ; Humans ; Insect Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Insecta ; Ion Channel Gating ; drug effects ; physiology ; Kinetics ; Mammals ; Muscles ; metabolism ; Neurotoxins ; chemistry ; classification ; pharmacology ; Protein Binding ; Scorpions ; chemistry ; Sodium ; metabolism ; Sodium Channel Blockers ; pharmacology ; Sodium Channels ; classification ; genetics ; metabolism ; Synaptosomes ; drug effects ; metabolism

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