Voltage-gated sodium channels （VGSCs） in primary sensory neurons play a key role in transmitting pain signals to the central nervous system. BmK I, a site-3 sodium channel-specific toxin from scorpion Buthus martens...Voltage-gated sodium channels （VGSCs） in primary sensory neurons play a key role in transmitting pain signals to the central nervous system. BmK I, a site-3 sodium channel-specific toxin from scorpion Buthus martensi Karsch, induces pain behaviors in rats. How- ever, the subtypes of VGSCs targeted by BmK I were not entirely clear. We therefore investigated the effects of BmK I on the current amplitude, gating and kinetic properties of Nav1.8, which is associated with neuronal hyperexcitability in DRG neurons. It was found that BmK I dose-dependently increased Nav1.8 current in small- sized （〈25 μm） acutely dissociated DRG neurons, which correlated with its inhibition on both fast and slow in- activation. Moreover, voltage-dependent activation and steady-state inactivation curves of Nay1.8 were shifted in a hyperpolarized direction. Thus, BmK I reduced the threshold of neuronal excitability and increased action potential firing in DRG neurons. In conclusion, our data clearly demonstrated that BmK I modulated Nav1.8 re- markably, suggesting BmK I as a valuable probe for studying Nay1.8. And Navl.8 is an important target re- lated to BmK I-evoked pain.展开更多
Previous work has demonstrated that the sensitization of spinal neurons and microglia is important in the development of pain behaviors induced by BmK I,a Na^+ channel activator and a major peptide component of the ve...Previous work has demonstrated that the sensitization of spinal neurons and microglia is important in the development of pain behaviors induced by BmK I,a Na^+ channel activator and a major peptide component of the venom of the scorpion Buthus martensi Karsch(BmK).We found that the expression of P2X7 receptors(P2X7Rs)was up-regulated in the ipsilateral spinal dorsal horn after BmK I injection in rats.P2X7R was selectively localized in microglia but not astrocytes or neurons.Similarly,interleukin 1β(IL-1β)was selectively up-regulated in microglia in the spinal dorsal horn after BmK I injection.Intrathecal injection of P2X7R antagonists largely reduced BmK I-induced spontaneous and evoked pain behaviors,and the up-regulation of P2X7R and IL-1β in the spinal cord.These data suggested that the up-regulation of P2X7Rs mediates microglial activation in the spinal dorsal horn,and therefore contributes to the development of BmK I-induced pain.展开更多
An Buthus martensii Karsch Insect Toxin (BmK IT ) gene was inserted into the genome of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) to construct a recombinant baculovirus, AcMNPV-BmK IT. The expres...An Buthus martensii Karsch Insect Toxin (BmK IT ) gene was inserted into the genome of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) to construct a recombinant baculovirus, AcMNPV-BmK IT. The expression of BmK IT was confirmed using RT-PCR, dot blot and SDS-PAGE analysis. Dose-lethal time responses to Spodoptera exigua larvae were compared between wild-type baculovirus AcMNPV and recombinant virus AcMNPV-BmK IT. At the concentration of 1×107 PIBs/mL, the median lethal time of recombinant baculovirus (LT50 = 73.6h) on third instar S. exigua larvae showed an improvement of 13.2% over the efficacy of wild type virus (LT50 = 84.8h) during a 192h in-fection.展开更多
The mammalian target of rapamycin （mTOR） pathway is essential for maintenance of the sensitivity of certain adult sensory neurons. Here, we investigated whether the mTOR cascade is involved in scorpion envenomation-...The mammalian target of rapamycin （mTOR） pathway is essential for maintenance of the sensitivity of certain adult sensory neurons. Here, we investigated whether the mTOR cascade is involved in scorpion envenomation-induced pain hypersensitivity in rats. The results showed that intraplantar injection of a neurotoxin from Buthus martensii Karsch, BmK I （10 pg）, induced the activation of mTOR, as well as its downstream molecules p70 ribosomal S6 protein kinase （p70 S6K） and eukaryotic initiation factor 4E-binding protein 1 （4E-BP1）, in lumbar 5-6 dorsal root ganglia neurons on both sides in rats. The activation peaked at 2 h and recovered 1 day after injection. Compared with the control group, the ratios of p-mTOR/p-p70 S6K/p-4E- BP1 in three types of neurons changed significantly. The cell typology of p-mTOR/p-p70 S6K/p-4E-BP1 immuno-reactive neurons also changed. Intrathecal administration of deforolimus, a specific inhibitor of mTOR, attenuated BmK I-induced pain responses （spontaneous flinching, paroxysmal pain-like behavior, and mechanical hypersensitivity）. Together, these results imply that the mTOR signaling pathway is mobilized by and contributes to experimental scorpion sting-induced pain.展开更多
Dear Editor,As the key contributor to the rising phase of action potentials in dorsal root ganglion（DRG）neurons,voltagegated sodium channels（VGSCs）are important in physiological and pathological pain conditions.Fo...Dear Editor,As the key contributor to the rising phase of action potentials in dorsal root ganglion（DRG）neurons,voltagegated sodium channels（VGSCs）are important in physiological and pathological pain conditions.For instance,abnormal expression of VGSCs in DRG neurons is the展开更多
基金J.Y.H was supported by the National Basic Research Program （973 Program） （No. 2010CB529806）, partially by grants from National Nat- ural Science Foundation of China （Grant Nos. 31171064 and 81402903） and Key Research Program of Science and Technology Commissions of Shanghai Municipality （11JC1404300, 13DJ 1400300）. L.T. was supported by grants from National Natural Science Foundation of China （Grant Nos. 31371179 and 81300968） and A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Voltage-gated sodium channels （VGSCs） in primary sensory neurons play a key role in transmitting pain signals to the central nervous system. BmK I, a site-3 sodium channel-specific toxin from scorpion Buthus martensi Karsch, induces pain behaviors in rats. How- ever, the subtypes of VGSCs targeted by BmK I were not entirely clear. We therefore investigated the effects of BmK I on the current amplitude, gating and kinetic properties of Nav1.8, which is associated with neuronal hyperexcitability in DRG neurons. It was found that BmK I dose-dependently increased Nav1.8 current in small- sized （〈25 μm） acutely dissociated DRG neurons, which correlated with its inhibition on both fast and slow in- activation. Moreover, voltage-dependent activation and steady-state inactivation curves of Nay1.8 were shifted in a hyperpolarized direction. Thus, BmK I reduced the threshold of neuronal excitability and increased action potential firing in DRG neurons. In conclusion, our data clearly demonstrated that BmK I modulated Nav1.8 re- markably, suggesting BmK I as a valuable probe for studying Nay1.8. And Navl.8 is an important target re- lated to BmK I-evoked pain.
基金supported by grants from the National Natural Science Foundation of China (31571032 and 31771191)supported by an Indiana Spinal Cord and Brain Injury Research Fund grant from Indiana State Department of Health, USA (2017)
文摘Previous work has demonstrated that the sensitization of spinal neurons and microglia is important in the development of pain behaviors induced by BmK I,a Na^+ channel activator and a major peptide component of the venom of the scorpion Buthus martensi Karsch(BmK).We found that the expression of P2X7 receptors(P2X7Rs)was up-regulated in the ipsilateral spinal dorsal horn after BmK I injection in rats.P2X7R was selectively localized in microglia but not astrocytes or neurons.Similarly,interleukin 1β(IL-1β)was selectively up-regulated in microglia in the spinal dorsal horn after BmK I injection.Intrathecal injection of P2X7R antagonists largely reduced BmK I-induced spontaneous and evoked pain behaviors,and the up-regulation of P2X7R and IL-1β in the spinal cord.These data suggested that the up-regulation of P2X7Rs mediates microglial activation in the spinal dorsal horn,and therefore contributes to the development of BmK I-induced pain.
基金the National Natural Science Foundation of China (Grant Nos.30670282 and 30700534)the Department of Science and Technology of Shanxi Province
文摘An Buthus martensii Karsch Insect Toxin (BmK IT ) gene was inserted into the genome of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) to construct a recombinant baculovirus, AcMNPV-BmK IT. The expression of BmK IT was confirmed using RT-PCR, dot blot and SDS-PAGE analysis. Dose-lethal time responses to Spodoptera exigua larvae were compared between wild-type baculovirus AcMNPV and recombinant virus AcMNPV-BmK IT. At the concentration of 1×107 PIBs/mL, the median lethal time of recombinant baculovirus (LT50 = 73.6h) on third instar S. exigua larvae showed an improvement of 13.2% over the efficacy of wild type virus (LT50 = 84.8h) during a 192h in-fection.
基金supported by grants from the National Basic Research Development Program of China(2010CB529806)the National Natural Science Foundation of China(31171064)+2 种基金the Shanghai Science and Technology CommissionChina(11JC140430010411956700 and 124119b0600)
文摘The mammalian target of rapamycin （mTOR） pathway is essential for maintenance of the sensitivity of certain adult sensory neurons. Here, we investigated whether the mTOR cascade is involved in scorpion envenomation-induced pain hypersensitivity in rats. The results showed that intraplantar injection of a neurotoxin from Buthus martensii Karsch, BmK I （10 pg）, induced the activation of mTOR, as well as its downstream molecules p70 ribosomal S6 protein kinase （p70 S6K） and eukaryotic initiation factor 4E-binding protein 1 （4E-BP1）, in lumbar 5-6 dorsal root ganglia neurons on both sides in rats. The activation peaked at 2 h and recovered 1 day after injection. Compared with the control group, the ratios of p-mTOR/p-p70 S6K/p-4E- BP1 in three types of neurons changed significantly. The cell typology of p-mTOR/p-p70 S6K/p-4E-BP1 immuno-reactive neurons also changed. Intrathecal administration of deforolimus, a specific inhibitor of mTOR, attenuated BmK I-induced pain responses （spontaneous flinching, paroxysmal pain-like behavior, and mechanical hypersensitivity）. Together, these results imply that the mTOR signaling pathway is mobilized by and contributes to experimental scorpion sting-induced pain.
基金This work was supported by National Basic Research Priorities Program of China (1999054001), partially grants from National Nature Sciences Foundation of China (39625010).
基金supported by grants from the National Natural Science Foundation of China(No.31272100,31372199)the Natural Science Foundation of Shanxi Province,China(No.2014011038-1)+1 种基金the National High Technology Research and Development Program of China(863 Program,No.2012AA020809)the Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi Province,China
基金supported by the National Basic Research Development Program of China(No.2010CB529806)National Natural Science Foundation of China(No.31171064 and 30772554)+2 种基金Leading Academic Discipline Project of Shanghai Municipal Education Commission“Molecular Physiology”(No.J50108)Innovation Program of Shanghai Municipal Education Commission(No.15ZZ063)Research Project of Putuo Hospital,Shanghai University of Traditional Chinese Medicine,China(No.2014YJ002)
基金supported by grants from the National Natural Science Foundation of China (31571032, 31771191, and 81402903)supported by an Indiana Spinal Cord and Brain Injury Research Fund grant (ISCBIRF2017)
文摘Dear Editor,As the key contributor to the rising phase of action potentials in dorsal root ganglion（DRG）neurons,voltagegated sodium channels（VGSCs）are important in physiological and pathological pain conditions.For instance,abnormal expression of VGSCs in DRG neurons is the
