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

MicroRNAs (miRNAs) are a class of noncoding RNAs that regulates target gene expression at posttranscriptional level, leading to further biological functions. We have demonstrated that microvesicles (MVs) can deliver miRNAs into target cells as a novel way of intercellular communication. It is reported that in central nervous system, glial cells release MVs, which modulate neuronal function in normal condition. To elucidate the potential role of glial MVs in disease, we evaluated the effects of secreted astrocytic MVs on stress condition. Our results demonstrated that after Lipopolysaccharide (LPS) stimulation, astrocytes released shedding vesicles (SVs) that enhanced vulnerability of dopaminergic neurons to neurotoxin. Further investigation showed that increased astrocytic miR-34a in SVs was involved in this progress via targeting anti-apoptotic protein Bcl-2 in dopaminergic neurons. We also found that inhibition of astrocytic miR-34a after LPS stimulation can postpone dopaminergic neuron loss under neurotoxin stress. These data revealed a novel mechanism underlying astrocyte-neuron interaction in disease.
Animals ; Astrocytes ; cytology ; drug effects ; metabolism ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cell-Derived Microparticles ; metabolism ; Disease Models, Animal ; Dopaminergic Neurons ; drug effects ; pathology ; Down-Regulation ; drug effects ; Humans ; Lipopolysaccharides ; pharmacology ; MicroRNAs ; metabolism ; Neurotoxins ; toxicity ; Oxidopamine ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Stress, Physiological ; drug effects

Voltage-gated sodium channels (VGSCs), which are widely distributed in the excitable cells, are the primary mediators of electrical signal amplification and propagation. They play important roles in the excitative conduction of the neurons and cardiac muscle cells. The abnormalities of the structures and functions of VGSCs can change the excitability of the cells, resulting in a variety of diseases such as neuropathic pain, epilepsy and arrhythmia. At present, some voltage-gated sodium channel blockers are used for treating those diseases. In the recent years, several neurotoxins have been purified from the venom of the animals, which could inhibit the current of the voltage-gated sodium channels. Usually, these neurotoxins are compounds or small peptides that have been further designed and modified for targeted drugs of sodium channelopathies in the clinical treatment. In addition, a novel cysteine-rich secretory protein (CRBGP) has been isolated and purified from the buccal gland of the lampreys (Lampetra japonica), and it could inhibit the Na+ current of the hippocampus and dorsal root neurons for the first time. In the present study, the progress of the sodium channelopathies and the biological functions of voltage-gated sodium channel blockers are analyzed and summarized.
Animals ; Channelopathies ; physiopathology ; Hippocampus ; drug effects ; Neurons ; drug effects ; Neurotoxins ; pharmacology ; Venoms ; chemistry ; Voltage-Gated Sodium Channel Blockers ; pharmacology

Ligustrazine, one of the major effective components of the Chinese traditional medicinal herb Ligusticum Chuanxiong Hort, has been reported plenty of biological activities, such as protect cardiovascular and cerebrovascular, neuroprotection and anti-tumor, et al. Because of its remarkable effects, studies on structural modification of ligustrazine have attracted much attention. Ligustrazine synthetic derivatives reported in recent decades are mainly derived from four primary intermediates (TMP-COOH, TMP-OH, TMP-NH2, HO-TMP-OH). To explore the neuroprotection activitiy of ligustrazine intermediates, six ligustrazine intermediates (2, 5, 8, 11, 12, 13) were synthesized and their protective effects against CoCl2-induced neurotoxicity in differentiated PC12 cells were studied. The target compounds were prepared via different chemical methods, including oxidation, substitution, esterification and amidation without changing the structure nucleus of ligustrazine. Compared with TMP (EC50 = 56.03 micromol x L(-1)), four compounds (2, 5, 12 and 13) exhibited higher activity (EC50 < 50 micromol x L(-1)) respectively, of which, compound 2 displayed the highest protective effect against the damaged PC12 cells (EC50 = 32.86 micromol x L(-1)), but target compounds 8 and 11 appeared lower activity (EC50 > 70 micromol x L(-1)). By structure-activity relationships analysis, the introduction of carboxyl, amino to the side chain of ligustrazine and appropriately increase the proportion of ligustrazine may contribute to enhance its neuroprotective activity, which provides a reference for the design, synthesis and activity screening of relevant series of ligustrazine derivatives in the future.
Animals ; Cell Differentiation ; drug effects ; Chemistry Techniques, Synthetic ; Cobalt ; toxicity ; Drugs, Chinese Herbal ; chemistry ; Neuroprotective Agents ; chemical synthesis ; chemistry ; pharmacology ; Neurotoxins ; toxicity ; PC12 Cells ; Pyrazines ; chemical synthesis ; chemistry ; pharmacology ; Rats

Kv2.1 channel currents in pancreatic beta-cells are thought to contribute to action potential repolarization and thereby modulate insulin secretion. Because of its central role in this important physiological process, Kv2.1 channel is a promising target for the treatment of type 2 diabetes. Jingzhaotoxin-XI (JZTX-XI) is a novel peptide neurotoxin isolated from the venom of the spider Chilobrachys jingzhao. Two-microelectrode voltage clamp experiments had showed that the toxin inhibited Kv2.1 potassium currents expressed in Xenopus Laevis oocytes. In order to investigate the structure-function relationship of JZTX-XI, the natural toxin and a mutant of JZTX-XI in which Arg3 was replaced by Ala, were synthesized by solid-phase chemistry method with Fmoc-protected amino acids on the PS3 automated peptide synthesizer. Reverse-phase high performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to monitor the oxidative refolding process of synthetic linear peptides to find the optimal renaturation conditions of these toxins. The experiments also proved that the relative molecular masses of refolded peptides were in accordance with their theoretical molecular masses. RP-HPLC chromatogram of co-injected native and refolded JZTX-XI was a single peak. Under the whole-cell patch-clamp mode, JZTX-XI could completely inhibit hKv2.1 and hNav1.5 channels currents expressed in HEK293T cells with IC50 values of 95.8 nmol/L and 437.1 nmol/L respectively. The mutant R3A-JZTX-XI could also inhibit hKv2.1 and hNav1.5 channel currents expressed in HEK293T cells with IC50 values of 1.22 micromol/L and 1.96 micromol/L respectively. However, the prohibitive levels of R3A-JZTX-XI on hKv2.1 and hNav1.5 channels were reduced by about 12.7 times and 4.5 times respectively, indicating that Arg3 was a key amino acid residue relative to the hKv2.1 channel activity of JZTX-XI, but it is also an amino acid residue correlated with the binding activity of JZTX-XI to hNav1.5 channel. Our findings should be helpful to develop JZTX-XI into a molecular probe and drug candidate targeting to Kv2.1 potassium channel in the pancreas.
Animals ; HEK293 Cells ; Humans ; Insulin-Secreting Cells ; metabolism ; Mutant Proteins ; genetics ; pharmacology ; NAV1.5 Voltage-Gated Sodium Channel ; metabolism ; Neurotoxins ; chemical synthesis ; genetics ; pharmacology ; Protein Refolding ; Shab Potassium Channels ; antagonists & inhibitors ; metabolism ; Sodium Channel Blockers ; pharmacology ; Spider Venoms ; genetics ; pharmacology ; Transfection

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

Kv4.3 channel is present in many mammalian tissues, predominantly in the heart and central nervous system. Its currents are transient, characterized by rapid activation and inactivation. In the hearts of most mammals, it is responsible for repolarization of the action potential of ventricular myocytes and is important in the regulation of the heart rate. Because of its central role in this important physiological process, Kv4.3 channel is a promising target for anti-arrhythmic drug development. Jingzhaotoxin-V (JZTX-V) is a novel peptide neurotoxin isolated from the venom of the spider Chilobrachys jingzhao. Whole-cell patch clamp recording showed that it partly blocked the transient outward potassium channels in dorsal root ganglion neurons of adult rats with an IC(50) value of 52.3 nmol/L. To investigate the effect of JZTX-V on Kv4.3 channel, JZTX-V was synthesized using the solid-phase chemical synthesis and separated by reverse phase high performance liquid chromatography (HPLC). The purity was tested by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MOLDI-TOF mass spectrometry). Two-electrode voltage-clamp technique was used to characterize the action of JZTX-V on Kv4.3 channels expressed in Xenopus laevis oocytes. As a result, JZTX-V displayed fast kinetics of inhibition and recovery from inactivation. Furthermore, it could inhibit Kv4.3 channel current in a time- and concentration-dependent manner with an IC(50) value of 425.1 nmol/L. The application of JZTX-V affected the activation and inactivation characteristics of Kv4.3 channel and caused a shift of the current-voltage relationship curve and the steady-state inactivation curve to depolarizing direction by approximately 29 mV and 10 mV, respectively. So we deduced that JZTX-V is a gating modifier toxin of Kv4.3 channel. Present findings should be helpful to develop JZTX-V into a molecular probe and drug candidate targeting to Kv4.3 channel in the myocardium.
Animals ; Ganglia, Spinal ; cytology ; Neurons ; drug effects ; Neurotoxins ; pharmacology ; Oocytes ; Patch-Clamp Techniques ; Peptides ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Rats ; Shal Potassium Channels ; metabolism ; Spider Venoms ; pharmacology ; Xenopus laevis

Neural stem cells (NSCs) have mainly been applied to neurodegeneration in some medically intractable neurologic diseases. In this study, we established a novel NSC line and investigated the cytotoxic responses of NSCs to exogenous neurotoxicants, glutamates and reactive oxygen species (ROS). A multipotent NSC line, B2A1 cells, was established from long-term primary cultures of oligodendrocyte-enriched cells from an adult BALB/c mouse brain. B2A1 cells could be differentiated into neuronal, astrocytic and oligodendroglial lineages. The cells also expressed genotypic mRNA messages for both neural progenitor cells and differentiated neuronoglial cells. B2A1 cells treated with hydrogen peroxide and L-buthionine-(S,R)-sulfoximine underwent 30-40% cell death, while B2A1 cells treated with glutamate and kainate showed 25-35% cell death. Cytopathologic changes consisting of swollen cell bodies, loss of cytoplasmic processes, and nuclear chromatin disintegration, developed after exposure to both ROS and excitotoxic chemicals. These results suggest that B2A1 cells may be useful in the study of NSC biology and may constitute an effective neurotoxicity screening system for ROS and excitotoxic chemicals.
Animals ; Brain/*cytology ; Buthionine Sulfoximine/pharmacology ; Cell Differentiation ; Cell Line ; Cell Lineage ; Cytokines/pharmacology ; Enzyme Inhibitors/pharmacology ; Excitatory Amino Acid Agonists/pharmacology ; Glutamic Acid/pharmacology ; Humans ; Hydrogen Peroxide/pharmacology ; Intercellular Signaling Peptides and Proteins/pharmacology ; Kainic Acid/pharmacology ; Mice ; Mice, Inbred BALB C ; Multipotent Stem Cells/cytology/*drug effects/physiology ; Neuroglia/cytology/drug effects/physiology ; Neurons/cytology/*drug effects/physiology ; Neurotoxins/*pharmacology ; Oxidants/pharmacology ; Phenotype ; Reactive Oxygen Species/metabolism

OBJECTIVETo observe the protective effect of serum with Tongqiao Huoxue decoction (TQHXD) on PC12 cells damaged by glutamate(Glu) and provide clinical proof of the formulae.

METHODSprague Dawley rats underwent intragastric administration of Tongqiao Huoxue decoction twice a day for five days, the administration dose for rats was 4 g x kg(-1). Thus the serum containing TQHXD was prepared. The model of neurocytes damaged by Glu had been established by adding 12.5 mmol x L(-1) Glu to culture medium of PC12 cells. Photic microscope had been used to observe the morphologic changes of cells, the proliferation and activity of PC12 cells had been detected by MTT. Cell membrane permeability had been investigated by the methods of the coloration of trypan blue and AO/EB, the activities of LDH and the contents of NO in the supernatant of PC12 cells had been detected after 5%, 10%, 20% TQHXD being added to the culture medium of PC12 cells damaged by Glu.

RESULTThe morphologic changes in cells were observed under the inverted microscope. Normal PC12 cells in control group were full and bright, but the cells exposed to Glu were shrank; moreover, some cells were disrupted, configuration of the cells in the TQHXD group was closed to that of normal group. Compared with model group, the ratio of living cells in the group being treated by TQHXD after trypan blue staining had a significant increase. After AO/EB staining, cells in TQHXD groups were less being stained by EB. The absorbance (A) values of TQHXD group increased largely. LDH and NO in cell culture supernatant had decreased, it had shown the marked difference.

CONCLUSIONTQHXD showed an apparent protective effect on neurocytes damaged by Glu on proliferation activity and membrane permeability.

Animals ; Cells, Cultured ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Glutamic Acid ; toxicity ; Male ; Neurons ; drug effects ; Neuroprotective Agents ; administration & dosage ; pharmacology ; Neurotoxins ; toxicity ; PC12 Cells ; Rats ; Rats, Sprague-Dawley ; Serum ; chemistry

OBJECTIVETo investigate the neuroprotective effects of the constituents in Herba Erigerontis on neuroblastoma SH-SY5Y cells, and find out its possible material foundation in treating Alzheimer's disease (AD).

METHODDifferent combinations of the three constituents in Herba Erigerontis were prepared according to the orthogonality experiment, and the indexes (MTT reduction assay, lipid peroxidation and expressions of nAChR alpha7 protein)were observed upon the SH-SY5Y cells followed by treatment of these combinations and beta-amyloid peptide (AP). The pharmacology data thus obtained and peak data in UPLC fingerprint were analyzed through ANOVA and correlationship by SPSS to give the information of active possible material foundation.

RESULTConstituents B and C showed clear activity and peaks of 4, 7-12 did positive correlationship according to the correlation of fingerprints and pharmacology.

CONCLUSIONThis study makes a valid approach for deducing the active constituents even the exact compounds against neurotoxicity induced by Abeta by correlation of fingerprints and pharmacology.

Alzheimer Disease ; drug therapy ; Amyloid beta-Peptides ; toxicity ; Analysis of Variance ; Animals ; Cell Line, Tumor ; Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; therapeutic use ; Erigeron ; chemistry ; Humans ; Nervous System ; drug effects ; Neurotoxins ; toxicity