Effect of scorpion venom analgesic active peptide extracted from Buthus martensii Karsch on evoked potential in the thalamic posterior nucleus group in rats

BACKGROUND： Buthus martensii Karsch is a rare medicinal animal, and dried integral Buthus rnartensii Karsch is an important drug in traditional Chinese medicine. OBJECTIVE： To investigate the effects of scorpion venom analgesic active peptide （SAP） extracted from Buthus martensii Karsch on evoked unit discharge of the common peroneal nerve in the posterior nucleus group of the thalamus using a stereotaxic electrophysiological extracellular microelectrode recording. DESIGN, TIME AND SETTING： One-way designed study, performed in the Physiological Laboratory of Shenyang Medical College on September 15, 2006. MATERIALS： Fifty 3-4 months old Wistar rats （25 males and 25 females） were used. SAP was provided by Shenyang Pharmaceutical University. Morphine solution was made by the First Drug Manufactory, Northeastern Drug Manufacture Group （batch number： H20013351）. Naloxone solution was made by Hunan Pharmaceutical Co., Ltd. （batch number： H43021669）. Type ATAC-350 medical data processing equipment was made by the Photoelectricity Company, Japan. METHODS： Fifty rats were randomly divided into the SAP group （n=20）, saline group （n=10）, morphine group （n=10）, or naloxone group （n=10）. In the SAP group, the common peroneal nerve was separated and stimulated with a single square wave （17-19 V intensity; 0.2 ms width; 20 ms retardation time）. Subsequently, SAP （0.01%, 2 μL） was injected into the posterior nucleus group of the thalamus. Rats in the naloxone group were injected with naloxone （1.0 mg/kg i.v.） before SAP injection. Rats in the saline group and the morphine group were injected with saline （2 μL） or morphine （0.01%, 2μL）, respectively, before SAP injection. Other procedures were the same as those in the SAP group. MAIN OUTCOME MEASURES： Evoked discharge in the posterior nucleus group of the thalamus and effects of SAP alone and SAP in combination with saline, morphine, or naloxone on discharges in the posterior nucleus group of the thalamus as measured by TQ-19 medical data processing equipment. RESULTS： SAP group： At 1-3 minutes after SAP injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for （45.0±0.7） minutes. Saline group： Evoked discharges in the posterior nucleus group of the thalamus did not change after saline injection. Morphine group： At 1-3 minutes after morphine injection, evoked discharges in the posterior nucleus group of the thalamus were inhibited, and the inhibitory time lasted for （35.0±7.8） minutes. Naloxone group： SAP had no effects on evoked potentials in the posterior nucleus group of the thalamus. CONCLUSION： The inhibitory effect of SAP on evoked potentials was superior to that of morphine at the same concentration （2 μL of 0.01% solution）. Naloxone resupination demonstrated that the inhibitory effects of SAP on evoked discharges were influenced by the opioid receptor.

A Novel Peptide from Buthus martensii Karch

A novel peptide was purified and characterized from Buthus martensii Karch.The peptide,named BmK M6,is a single-chain polypeptide cross-linked by four intramolecular disulfide bridges.The molecular weight of the peptide was determined by MOLDI-TOF-MS as 7034 Da.The partial amino acid sequence of BmK M6 from N-terminal is VRDAYIAKPEN CVYECGITQDCNKLCTENG.

Polyclonal antibody against an insect excitatory toxin BmKIT from Buthus Martensii karsch and detection of BmKIT expressed in transgenic cotton

An insect excitatory toxin gene from Buthus martensii Karseh （BmKIT） was cloned into the expression vector, pET-28a. BmKIT was expressed as inclusion bodies in Eseherichia coli BL21 （DE3） host cells. The authenticity of in vitro expressed protein was confirmed by Western blot. The inclusion body protein band in SDS-PAGE was excised and the protein, BmKIT, was extracted. Polyelonal antibodies to the purified protein were raised in rabbits. The antibody reacted specifically with the expressed BmKIT and was used to quantify its presence in transgenic cotton.

Purification,Characterization and ~1H NMR Resonance Assignment of an α-Like Neurotoxin BmK 16 from the Venom of Chinese Scorpion Buthus martensii Karsch

A natural scorpion toxin BmK 16 was purified for the first time from the venom of the Chinese scorpion Buthus martensii Karsch (BmK) by using combined gel filtration, ion exchange and reversed phase chromatography. The sequence of the N terminal 8 amino acid residues was determined by Edman degradation. Using the N terminal sequence as a tag, the database searching revealed a hit in the scorpion cDNA Bank. The sequence for N terminal 8 amino acid residues, molecular weight and amino acid compositions of BmK 16 were identical with the calculated values according to the first 64 residues' sequence of the precursor peptide alpha neurotoxin TX16 derived from the sequence of the cDNA AF156597 (EMBL). The sequence specific resonance assignment of BmK 16 was achieved and the intact sequence of BmK 16 was determined as followings: VRDAY IAKPH NCVYE CARNE YCNDL CTKNG AKSGY CQWVG KYGNG CWCKE LPDNV PIRVP GKCH. Furthermore, the results from the sequence homology analysis and the toxicity assays indicated that BmK 16 was an α like scorpion neurotoxin.

Martentoxin, a large-conductance Ca^(2+)-activated K^+ channel inhibitor, attenuated TNF-α-induced nitric oxide release by human umbilical vein endothelial cells

Martentoxin, a 4,046 Da polypeptide toxin purified from the venom of the scorpion Buthus martensii Karsch, has been demonstrated to block large-conductance Ca2＋-activated K＋ （BKca） channels; however, its biological roles are still largely unknown. In the present study, we investigated the pharmacological effects of martentoxin on regulating the production of nitric oxide induced by TNF-a in human umbilical vein endothelial cells （HU- VECs）. We found that, 1, 10 and 100 ~tmol/L martentoxin decreased nitric oxide production by HUVECs ex- posed to 10 ng/mL TNF for 6, 12 and 24 hours. We further demonstrated that martentoxin inhibited the activity of iNOS and retarded the down-regulation of eNOS mRNA induced by TNF-a. Therefore, martentoxin could be a potential therapeutic agent for vascular diseases.