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Oliver R Goral - One of the best experts on this subject based on the ideXlab platform.
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cast elks proteins control voltage gated ca2 channel density and synaptic release probability at a mammalian central synapse
Cell Reports, 2018Co-Authors: Wei Dong, Akari Hagiwara, Yamato Hida, Tamara Radulovic, Oliver R Goral, Connon I Thomas, Monica Suarez Montesinos, Debbie Guerrerogiven, Travis Putzke, Kenji SakimuraAbstract:Summary In the presynaptic terminal, the magnitude and location of Ca2+ entry through voltage-gated Ca2+ channels (VGCCs) regulate the efficacy of neurotransmitter release. However, how presynaptic active zone proteins control mammalian VGCC levels and organization is unclear. To address this, we deleted the CAST/ELKS protein family at the calyx of Held, a Cav2.1 channel-exclusive presynaptic terminal. We found that loss of CAST/ELKS reduces the Cav2.1 current density with concomitant reductions in Cav2.1 channel numbers and clusters. Surprisingly, deletion of CAST/ELKS increases release probability while decreasing the readily releasable pool, with no change in active zone ultrastructure. In addition, Ca2+ channel coupling is unchanged, but spontaneous release rates are elevated. Thus, our data identify distinct roles for CAST/ELKS as positive regulators of Cav2.1 channel density and suggest that they regulate release probability through a post-priming step that controls synaptic vesicle fusogenicity.
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CAST/ELKS Proteins Control Voltage-Gated Ca2+ Channel Density and Synaptic Release Probability at a Mammalian Central Synapse
'Elsevier BV', 2018Co-Authors: Wei Dong, Akari Hagiwara, Yamato Hida, Tamara Radulovic, Oliver R Goral, Monica Suarez Montesinos, Travis Putzke, Connon Thomas, Debbie Guerrero-given, Manabu AbeAbstract:Summary: In the presynaptic terminal, the magnitude and location of Ca2+ entry through voltage-gated Ca2+ channels (VGCCs) regulate the efficacy of neurotransmitter release. However, how presynaptic active zone proteins control mammalian VGCC levels and organization is unclear. To address this, we deleted the CAST/ELKS protein family at the calyx of Held, a Cav2.1 channel-exclusive presynaptic terminal. We found that loss of CAST/ELKS reduces the Cav2.1 current density with concomitant reductions in Cav2.1 channel numbers and clusters. Surprisingly, deletion of CAST/ELKS increases release probability while decreasing the readily releasable pool, with no change in active zone ultrastructure. In addition, Ca2+ channel coupling is unchanged, but spontaneous release rates are elevated. Thus, our data identify distinct roles for CAST/ELKS as positive regulators of Cav2.1 channel density and suggest that they regulate release probability through a post-priming step that controls synaptic vesicle fusogenicity. : Dong et al. show that CAST/ELKS have multiple roles in presynaptic function. These proteins positively regulate Cav2.1 channel abundance and negatively regulate release probability. The authors propose that CAST/ELKS regulate release probability at a step in synaptic vesicle release that regulates the energy barrier for synaptic vesicle fusion. Keywords: calyx of Held, release probability, calcium channels, active zone, synaptic transmission, CAST/ELKS, exocytosis, auditory signalin
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a novel region in the Cav2.1 α1 subunit c terminus regulates fast synaptic vesicle fusion and vesicle docking at the mammalian presynaptic active zone
eLife, 2017Co-Authors: Matthias Lubbert, Oliver R Goral, Travis Putzke, Naomi Kamasawa, Arn M J M Van Den Maagdenberg, Rachel Satterfield, Samuel M YoungAbstract:In central nervous system (CNS) synapses, action potential-evoked neurotransmitter release is principally mediated by Cav2.1 calcium channels (Cav2.1) and is highly dependent on the physical distance between Cav2.1 and synaptic vesicles (coupling). Although various active zone proteins are proposed to control coupling and abundance of Cav2.1 through direct interactions with the Cav2.1 α1 subunit C-terminus at the active zone, the role of these interaction partners is controversial. To define the intrinsic motifs that regulate coupling, we expressed mutant Cav2.1 α1 subunits on a Cav2.1 null background at the calyx of Held presynaptic terminal. Our results identified a region that directly controlled fast synaptic vesicle release and vesicle docking at the active zone independent of Cav2.1 abundance. In addition, proposed individual direct interactions with active zone proteins are insufficient for Cav2.1 abundance and coupling. Therefore, our work advances our molecular understanding of Cav2.1 regulation of neurotransmitter release in mammalian CNS synapses.
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a novel region in the Cav2.1 α1 subunit c terminus regulates fast synaptic vesicle fusion and vesicle docking at the mammalian presynaptic active zone
eLife, 2017Co-Authors: Matthias Lubbert, Oliver R Goral, Travis Putzke, Naomi Kamasawa, Arn M J M Van Den Maagdenberg, Rachel Satterfield, Samuel M YoungAbstract:The points of contact between nerve cells are called synapses, and nerve cells communicate across synapses via chemicals known as neurotransmitters. These chemical messengers are initially stored within bubble-like packages called synaptic vesicles that are released after they fuse with the membrane of the nerve cell at a specialized site referred to as the “active zone”. Calcium ions are one of the major factors that lead to the release of synaptic vesicles. Ion channel proteins in the membrane of the nerve cell control the flow of calcium ions into the cell. There are often many different ion channels at a synapse, but one type called Cav2.1 most effectively triggers the release of synaptic vesicles when a nerve impulse reaches the synapse. Various proteins at the active zone can bind directly to parts of the Cav2.1 channel that are identified by a short sequence of amino acids – the building blocks of all proteins. Several researchers have proposed that the interactions with some of these short sequences, which are also known as motifs, control how much of this ion channel is in the synapse and how it interacts with synaptic vesicles to regulate the release of neurotransmitters. However, other researchers do not agree with this proposed explanation. Lubbert, Goral et al. set out to determine which parts in a specific part of the Cav2.1 channel (called the “α1 subunit C-terminus”) are critical for its interaction with synaptic vesicles. The experiments revealed a new motif that regulates how many synaptic vesicles could be released in response to electrical impulses travelling along nerve cells from mice. The same motif also regulates the total number of synaptic vesicles at the active zone. Lubbert, Goral et al. went on to show that binding to known active proteins at most played a minor role in controlling the abundance of the Cav2.1 channels and how close they were to the synaptic vesicles. As such, these findings counter prevailing views of the roles of certain motifs in the α1 subunit of the Cav2.1 channel. Thus, it may be necessary to re-think how the Cav2.1 channel regulates the release of synaptic vesicles. Ion channels are vital to the activity of all nerve cells, and working out how the numbers and organization of Cav2.1 and related ion channels are regulated will be fundamental to understanding how information is encoded in brain. In addition, problems with these kinds of ion channel may result in disorders such as migraines and epilepsy. Therefore, the new findings may help to guide further studies investigating possible ways to treat these disorders.
David J Adams - One of the best experts on this subject based on the ideXlab platform.
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spider venom peptide pn3a inhibition of primary afferent high voltage activated calcium channels
Frontiers in Pharmacology, 2021Co-Authors: Jeffrey R Mcarthur, Nehan R Munasinghe, Rocio K Finolurdaneta, David J Adams, Macdonald J. ChristieAbstract:Despite potently inhibiting the nociceptive voltage-gated sodium (Nav) channel, Nav1.7, µ-theraphotoxin Pn3a is antinociceptive only upon co-administration with sub-therapeutic opioid agonists, or by itself at doses >3,000-fold greater than its Nav1.7 IC50 by a yet undefined mechanism. Nav channels are structurally related to voltage-gated calcium (Cav) channels, Cav1 and Cav2. These channels mediate the high voltage-activated (HVA) calcium currents (ICa ) that orchestrate synaptic transmission in nociceptive dorsal root ganglion (DRG) neurons and are fine-tuned by opioid receptor (OR) activity. Using whole-cell patch clamp recording, we found that Pn3a (10 µM) inhibits ∼55% of rat DRG neuron HVA-ICa and 60-80% of Cav1.2, Cav1.3, Cav2.1, and Cav2.2 mediated currents in HEK293 cells, with no inhibition of Cav2.3. As a major DRG ICa component, Cav2.2 inhibition by Pn3a (IC50 = 3.71 ± 0.21 µM) arises from an 18 mV hyperpolarizing shift in the voltage dependence of inactivation. We observed that co-application of Pn3a and µ-OR agonist DAMGO results in enhanced HVA-ICa inhibition in DRG neurons whereas co-application of Pn3a with the OR antagonist naloxone does not, underscoring HVA channels as shared targets of Pn3a and opioids. We provide evidence that Pn3a inhibits native and recombinant HVA Cavs at previously reportedly antinociceptive concentrations in animal pain models. We show additive modulation of DRG HVA-ICa by sequential application of low Pn3a doses and sub-therapeutic opioids ligands. We propose Pn3a's antinociceptive effects result, at least in part, from direct inhibition of HVA-ICa at high Pn3a doses, or through additive inhibition by low Pn3a and mild OR activation.
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less is more design of a highly stable disulfide deleted mutant of analgesic cyclic α conotoxin vc1 1
Scientific Reports, 2015Co-Authors: Victoria A L Seymour, David J Adams, Geza Berecki, Xinying Jia, Muharrem Akcan, Quentin Kaas, David J CraikAbstract:Cyclic α-conotoxin Vc1.1 (cVc1.1) is an orally active peptide with analgesic activity in rat models of neuropathic pain. It has two disulfide bonds, which can have three different connectivities, one of which is the native and active form. In this study we used computational modeling and nuclear magnetic resonance to design a disulfide-deleted mutant of cVc1.1, [C2H,C8F]cVc1.1, which has a larger hydrophobic core than cVc1.1 and, potentially, additional surface salt bridge interactions. The new variant, hcVc1.1, has similar structure and serum stability to cVc1.1 and is highly stable at a wide range of pH and temperatures. Remarkably, hcVc1.1 also has similar selectivity to cVc1.1, as it inhibited recombinant human α9α10 nicotinic acetylcholine receptor-mediated currents with an IC50 of 13 μM and rat N-type (Cav2.2) and recombinant human Cav2.3 calcium channels via GABAB receptor activation, with an IC50 of ~900 pM. Compared to cVc1.1, the potency of hcVc1.1 is reduced three-fold at both analgesic targets, whereas previous attempts to replace Vc1.1 disulfide bonds by non-reducible dicarba linkages resulted in at least 30-fold decreased activity. Because it has only one disulfide bond, hcVc1.1 is not subject to disulfide bond shuffling and does not form multiple isomers during peptide synthesis.
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Differential Cav2.1 and Cav2.3 channel inhibition by baclofen and α-conotoxin Vc1.1 via GABAB receptor activation
Journal of General Physiology, 2014Co-Authors: Geza Berecki, Jeffrey R Mcarthur, Hartmut Cuny, Richard J. Clark, David J AdamsAbstract:Neuronal Cav2.1 (P/Q-type), Cav2.2 (N-type), and Cav2.3 (R-type) calcium channels contribute to synaptic transmission and are modulated through G protein–coupled receptor pathways. The analgesic α-conotoxin Vc1.1 acts through γ-aminobutyric acid type B (GABAB) receptors (GABABRs) to inhibit Cav2.2 channels. We investigated GABABR-mediated modulation by Vc1.1, a cyclized form of Vc1.1 (c-Vc1.1), and the GABABR agonist baclofen of human Cav2.1 or Cav2.3 channels heterologously expressed in human embryonic kidney cells. 50 µM baclofen inhibited Cav2.1 and Cav2.3 channel Ba2+ currents by ∼40%, whereas c-Vc1.1 did not affect Cav2.1 but potently inhibited Cav2.3, with a half-maximal inhibitory concentration of ∼300 pM. Depolarizing paired pulses revealed that ∼75% of the baclofen inhibition of Cav2.1 was voltage dependent and could be relieved by strong depolarization. In contrast, baclofen or Vc1.1 inhibition of Cav2.3 channels was solely mediated through voltage-independent pathways that could be disrupted by pertussis toxin, guanosine 5′-[β-thio]diphosphate trilithium salt, or the GABABR antagonist CGP55845. Overexpression of the kinase c-Src significantly increased inhibition of Cav2.3 by c-Vc1.1. Conversely, coexpression of a catalytically inactive double mutant form of c-Src or pretreatment with a phosphorylated pp60c-Src peptide abolished the effect of c-Vc1.1. Site-directed mutational analyses of Cav2.3 demonstrated that tyrosines 1761 and 1765 within exon 37 are critical for inhibition of Cav2.3 by c-Vc1.1 and are involved in baclofen inhibition of these channels. Remarkably, point mutations introducing specific c-Src phosphorylation sites into human Cav2.1 channels conferred c-Vc1.1 sensitivity. Our findings show that Vc1.1 inhibition of Cav2.3, which defines Cav2.3 channels as potential targets for analgesic α-conotoxins, is caused by specific c-Src phosphorylation sites in the C terminus.
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Differential Cav2.1 and CaV2.3 Channel Inhibition by Baclofen and α-Conotoxin Vc1.1 via GABAB Receptor Activation
Biophysical Journal, 2014Co-Authors: Geza Berecki, Jeffrey R Mcarthur, Hartmut Cuny, Richard J. Clark, David J AdamsAbstract:In the nervous system, Cav2.1 (P/Q-type), Cav2.2 (N-type) and Cav2.3 (R-type) calcium channels contribute to synaptic transmission and are modulated via G protein-coupled receptor pathways. The analgesic α-conotoxin Vc1.1 has been identified as a selective inhibitor of Cav2.2 channels acting via GABAB receptors. We investigated baclofen and Vc1.1 modulation of human Cav2.1 or Cav2.3 channels via human GABAB receptor activation in HEK cells. Baclofen (50 µM) inhibited Cav2.1 and Cav2.3 channel Ba2+ currents by ∼ 40%, whereas Vc1.1 did not affect Cav2.1, but potently inhibited Cav2.3, with a half-maximal inhibitory concentration of ∼ 300 pM. Depolarizing paired-pulses revealed that ∼ 75% of the baclofen inhibition of Cav2.1 was voltage-dependent, and could be relieved by strong depolarization. In contrast, baclofen or Vc1.1 inhibition of Cav2.3 channels was solely mediated via voltage-independent pathways that could be disrupted by pertussis toxin, GDP-β-S or the GABAB receptor antagonist, CGP55845. Over-expression of c-Src kinase significantly increased inhibition of Cav2.3 by Vc1.1. Conversely, co-expression of a double mutant c-Src or pre-treatment with a phosphorylated pp60c-Src peptide abolished the effect of Vc1.1. Site-directed mutational analyses of Cav2.3 demonstrated that tyrosines 1761 and 1765 within exon 37 are critical for mediating the inhibition by Vc1.1 and are involved in baclofen inhibition of these channels. Remarkably, point mutations introducing specific c-Src phosphorylation sites into human Cav2.1 channels conveyed Vc1.1 sensitivity. Our findings demonstrate that Vc1.1 inhibition of Cav2.3 is due to specific c-Src phosphorylation sites in the C-teminus, which defines Cav2.3 channels as potential targets for analgesic α-conotoxins.
Pierre Charnet - One of the best experts on this subject based on the ideXlab platform.
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introduction into ca v 2 1 of the homologous mutation of ca v 1 2 causing the timothy syndrome questions the role of v421 in the phenotypic definition of p type ca 2 channel
Pflügers Archiv: European Journal of Physiology, 2008Co-Authors: Thierry Cens, Jeanphilippe Leyris, Pierre CharnetAbstract:The Timothy syndrome is a multisystem disorder associated with the mutation of a Gly residue (G402 or G406) in the Cav1.2 Ca2+ channel. G406 is localized at the end of the IS6 segment and just before the intracellular I–II loop, which is important for the regulation of channel inactivation and the binding of the Cavβ subunit. This Gly residue is conserved in all Cav1 and Cav2 channels, and the G to R exchange produces a strong decrease of inactivation not only in Cav1.2 but also in Cav2.3. Here, we show that the mutation into Arg or Glu of the homologous Gly residue in Cav2.1 (G363) produces also a slowing of inactivation. However, the G-to-A exchange that decreases the inactivation rate in Cav1.2 and Cav2.3 increases inactivation in Cav2.1. Each mutation affects specifically the gating properties of Cav2.1 that remain nevertheless modulated by the co-expressed β subunit as with wild-type channel. The strong decrease of inactivation produced by the G363R or G363E mutations was reminiscent to that previously described for a specific splice variant of Cav2.1 that contains a single Val residue inserted in the I–II loop (V421). We unexpectedly found that the V421 insertion does not affect the inactivation rate of Cav2.1 and that the effects previously attributed to this insertion, including those on G-protein regulation, can be reproduced by the G363E mutation. Altogether, our results highlight the role of G363 in gating properties, inactivation kinetics, and G-protein regulation of Cav2.1 and the lack of effect of V421 insertion on inactivation.
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down regulation of voltage gated ca2 channels by neuronal calcium sensor 1 is β subunit specific
Journal of Biological Chemistry, 2003Co-Authors: Matthieu Rousset, Thierry Cens, Sophie Gavarini, Andreas Jeromin, Pierre CharnetAbstract:Abstract Neuronal Ca2+sensor protein-1 (NCS-1) is a member of the Ca2+ binding protein family, with three functional Ca2+ binding EF-hands and an N-terminal myristoylation site. NCS-1 is expressed in brain and heart during embryonic and postnatal development. In neurons, NCS-1 facilitates neurotransmitter release, but both inhibition and facilitation of the Ca2+ current amplitude have been reported. In heart, NCS-1 co-immunoprecipitates with K+channels and modulates their activity, but the potential effects of NCS-1 on cardiac Ca2+ channels have not been investigated. To directly assess the effect of NCS-1 on the various types of Ca2+ channels we have co-expressed NCS-1 inXenopus oocytes, with CaV1.2, Cav2.1, and CaV2.2 Ca2+ channels, using various subunit combinations. The major effect of NCS-1 was to decrease Ca2+ current amplitude, recorded with the three different types of α1 subunit. When expressed with Cav2.1, the depression of Ca2+ current amplitude induced by NCS-1 was dependent upon the identity of the β subunit expressed, with no block recorded without β subunit or with the β3 subunit. Current-voltage and inactivation curves were also slightly modified and displayed a different specificity toward the β subunits. Taken together, these data suggest that NCS-1 is able to modulate cardiac and neuronal voltage-gated Ca2+ channels in a β subunit specific manner.
Fawu Dong - One of the best experts on this subject based on the ideXlab platform.
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valepotriates from the roots and rhizomes of valeriana jatamansi jones as novel n type calcium channel antagonists
Frontiers in Pharmacology, 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of V. jatamansi have long been used as folk medicine in Asia and usually named as ″Zhizhuxiang″ in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibiting the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analysis after the fraction was identified active and got seventeen compounds (1-17). All isolates were then sent further for bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compounds 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 μM and 4.8 μM respectively and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists
Frontiers Media S.A., 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan YangAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics
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Data_Sheet_1_Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists.pdf
2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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cav2 2 and cav3 1 calcium channel inhibitors from valeriana jatamansi jones
RSC Advances, 2017Co-Authors: Fawu Dong, Hehai Jiang, Jian Yang, Jun Zhou, Yin NianAbstract:In China, the roots and rhizomes of Valeriana jatamansi Jones are traditionally used to treat gastrointestinal and rheumatic pain. Small molecule inhibitors of N-type (Cav2.2) and T-type (Cav3.1–3.3) calcium channels have become attractive resources in analgesic drug development. Therefore, in the present study, the isolated compounds (1–13) from V. jatamansi, including three new valepotriates (1–3), were initially evaluated on Cav2.2 and Cav3.1. As a result, compounds 1–12 showed weak to potent inhibition on Cav2.2 peak currents at 30 μM. Among them, compounds 1, 6, 7, 11 and 12 exhibited significant antagonistic effects, with EC50 values of 4.33, 2.18, 1.13, 2.70 and 7.8 μM, respectively. Meanwhile, the aforementioned compounds exhibited 18.2 ± 2.5% to 49.2 ± 7.1% peak current inhibition on Cav3.1 at 30 μM. In addition, they also exhibited noticeable specificity against Cav1.2, Cav2.1, and KCNH2 (hERG) channels.
Hehai Jiang - One of the best experts on this subject based on the ideXlab platform.
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valepotriates from the roots and rhizomes of valeriana jatamansi jones as novel n type calcium channel antagonists
Frontiers in Pharmacology, 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of V. jatamansi have long been used as folk medicine in Asia and usually named as ″Zhizhuxiang″ in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibiting the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analysis after the fraction was identified active and got seventeen compounds (1-17). All isolates were then sent further for bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compounds 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 μM and 4.8 μM respectively and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists
Frontiers Media S.A., 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan YangAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics
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Data_Sheet_1_Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists.pdf
2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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cav2 2 and cav3 1 calcium channel inhibitors from valeriana jatamansi jones
RSC Advances, 2017Co-Authors: Fawu Dong, Hehai Jiang, Jian Yang, Jun Zhou, Yin NianAbstract:In China, the roots and rhizomes of Valeriana jatamansi Jones are traditionally used to treat gastrointestinal and rheumatic pain. Small molecule inhibitors of N-type (Cav2.2) and T-type (Cav3.1–3.3) calcium channels have become attractive resources in analgesic drug development. Therefore, in the present study, the isolated compounds (1–13) from V. jatamansi, including three new valepotriates (1–3), were initially evaluated on Cav2.2 and Cav3.1. As a result, compounds 1–12 showed weak to potent inhibition on Cav2.2 peak currents at 30 μM. Among them, compounds 1, 6, 7, 11 and 12 exhibited significant antagonistic effects, with EC50 values of 4.33, 2.18, 1.13, 2.70 and 7.8 μM, respectively. Meanwhile, the aforementioned compounds exhibited 18.2 ± 2.5% to 49.2 ± 7.1% peak current inhibition on Cav3.1 at 30 μM. In addition, they also exhibited noticeable specificity against Cav1.2, Cav2.1, and KCNH2 (hERG) channels.