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Seck I, Ndoye SF, Kapchoup MVK, Nguemo F, Ciss I, Ba LA, Ba A, Sokhna S, Seck M. Effects of plant extracts and derivatives on cardiac K +, Nav, and Ca v channels: a review. Nat Prod Res 2024:1-28. [PMID: 38586947 DOI: 10.1080/14786419.2024.2337112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 03/24/2024] [Indexed: 04/09/2024]
Abstract
Natural products (NPs) are endless sources of compounds for fighting against several pathologies. Many dysfunctions, including cardiovascular disorders, such as cardiac arrhythmias have their modes of action regulation of the concentration of electrolytes inside and outside the cell targeting ion channels. Here, we highlight plant extracts and secondary metabolites' effects on the treatment of related cardiac pathologies on hERG, Nav, and Cav of cardiomyocytes. The natural product's pharmacology of expressed receptors like alpha-adrenergic receptors causes an influx of Ca2+ ions through receptor-operated Ca2+ ion channels. We also examine the NPs associated with cardiac contractions such as myocardial contractility by reducing the L-type calcium current and decreasing the intracellular calcium transient, inhibiting the K+ induced contractions, decreasing amplitude of myocyte shortening and showed negative ionotropic and chronotropic effects due to decreasing cytosolic Ca2+. We examine whether the NPs block potassium channels, particular the hERG channel and regulatory effects on Nav1.7.
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Affiliation(s)
- Insa Seck
- Laboratoire de Chimie de Coordination Organique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Samba Fama Ndoye
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | | | - Filomain Nguemo
- Institute of Neurophysiology, University of Cologne, Cologne, Germany
| | - Ismaila Ciss
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Lalla Aicha Ba
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Abda Ba
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Seynabou Sokhna
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Matar Seck
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
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Tiwari S, Acharya P, Solanki B, Sharma AK, Rawat S. A review on efforts for improvement in medicinally important chemical constituents in Aconitum through biotechnological interventions. 3 Biotech 2023; 13:190. [PMID: 37193333 PMCID: PMC10183062 DOI: 10.1007/s13205-023-03578-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 04/21/2023] [Indexed: 05/18/2023] Open
Abstract
The genus Aconitum belongs to the family Ranunculaceae, is endowed with more than 350 species on the earth. Medicinally important aconitine type of diterpenoid alkaloids are the characteristic compounds in most of the Aconitum species. The present review endeavored the major research carried out in the field of genetic resource characterization, pharmacological properties, phytochemistry, major factors influencing quantity, biosynthetic pathways and processing methods for recovery of active ingredients, variety improvement, propagation methods, and important metabolite production through cell/organ culture of various Aconitum species. More than 450 derivatives of aconitine-type C19 and C20-diterpenoid alkaloids along with a few other non-alkaloidal compounds, such as phenylpropanoids, flavonoids, terpenoids, and fatty acids, have been identified in the genus. A few Aconitum species and their common diterpenoid alkaloid compounds are also well characterized for analgesic, inflammatory and cytotoxic properties. However, the different isolated compound needs to be validated for supporting other traditional therapeutical uses of the plant species. Aconitine alkaloids shared common biosynthesis pathway, but their diversification mechanism remains unexplored in the genus. Furthermore, the process needs to be developed on secondary metabolite recovery, mass-scale propagation methods, and agro-technologies for maintaining the quality of products. Many species are losing their existence in nature due to over-exploitation or anthropogenic factors; thus, temporal monitoring of the population status in its habitat, and suitable management programs for ascertaining conservation needs to be developed.
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Affiliation(s)
- Sekhar Tiwari
- Department of Biotechnology, School of Sciences, P. P. Savani University, Surat, Gujarat India
| | - Puja Acharya
- Sikkim Regional Centre, G. B. Pant National Institute of Himalayan Environment, Pangthang, Gangtok, Sikkim India
| | - Bharat Solanki
- Department of Biochemistry, M. B. Patel Science College, Sardar Patel University, Anand, Gujarat India
| | - Anish Kumar Sharma
- Department of Biotechnology, School of Sciences, P. P. Savani University, Surat, Gujarat India
| | - Sandeep Rawat
- Sikkim Regional Centre, G. B. Pant National Institute of Himalayan Environment, Pangthang, Gangtok, Sikkim India
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Inhibitory Effectiveness in Delayed-Rectifier Potassium Current Caused by Vortioxetine, Known to Be a Novel Antidepressant. Biomedicines 2022; 10:biomedicines10061318. [PMID: 35740340 PMCID: PMC9220334 DOI: 10.3390/biomedicines10061318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 01/27/2023] Open
Abstract
Vortioxetine (VOR) is recognized to exert antidepressant actions. However, whether this drug modifies ionic currents in excitable cells remains unclear. The aim of this study was to explore the electrophysiological effects of VOR and other related compounds in pituitary GH3 cells and in Neuro-2a cells. VOR suppressed the delayed-rectifier K+ current (IK(DR)) in a concentration-, time-, and state-dependent manner. Effective IC50 values needed to inhibit peak and sustained IK(DR) were computed to be 31.2 and 8.5 μM, respectively, while the KD value estimated from minimal binding scheme was 7.9 μM. Cell exposure to serotonin (10 μM) alone failed to alter IK(DR), while fluoxetine (10 μM), a compound structurally similar to VOR, mildly suppressed current amplitude. In continued presence of VOR, neither further addition of propranolol nor risperidone reversed VOR-mediated inhibition of IK(DR). Increasing VOR concentration not only depressed IK(DR) conductance but also shifted toward the hyperpolarized potential. As the VOR concentration was raised, the recovery of IK(DR) block became slowed. The IK(DR) activated by a downsloping ramp was suppressed by its presence. The inhibition of IK(DR) by a train pulse was enhanced during exposure to VOR. In Neuro-2a cells, this drug decreased IK(DR). Overall, inhibitory effects of VOR on ionic currents might constitute another underlying mechanism of its actions.
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Effective Perturbations of the Amplitude, Gating, and Hysteresis of IK(DR) Caused by PT-2385, an HIF-2α Inhibitor. MEMBRANES 2021; 11:membranes11080636. [PMID: 34436399 PMCID: PMC8398179 DOI: 10.3390/membranes11080636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 01/30/2023]
Abstract
PT-2385 is currently regarded as a potent and selective inhibitor of hypoxia-inducible factor-2α (HIF-2α), with potential antineoplastic activity. However, the membrane ion channels changed by this compound are obscure, although it is reasonable to assume that the compound might act on surface membrane before entering the cell´s interior. In this study, we intended to explore whether it and related compounds make any adjustments to the plasmalemmal ionic currents of pituitary tumor (GH3) cells and human 13-06-MG glioma cells. Cell exposure to PT-2385 suppressed the peak or late amplitude of delayed-rectifier K+ current (IK(DR)) in a time- and concentration-dependent manner, with IC50 values of 8.1 or 2.2 µM, respectively, while the KD value in PT-2385-induced shortening in the slow component of IK(DR) inactivation was estimated to be 2.9 µM. The PT-2385-mediated block of IK(DR) in GH3 cells was little-affected by the further application of diazoxide, cilostazol, or sorafenib. Increasing PT-2385 concentrations shifted the steady-state inactivation curve of IK(DR) towards a more hyperpolarized potential, with no change in the gating charge of the current, and also prolonged the time-dependent recovery of the IK(DR) block. The hysteretic strength of IK(DR) elicited by upright or inverted isosceles-triangular ramp voltage was decreased during exposure to PT-2385; meanwhile, the activation energy involved in the gating of IK(DR) elicitation was noticeably raised in its presence. Alternatively, the presence of PT-2385 in human 13-06-MG glioma cells effectively decreased the amplitude of IK(DR). Considering all of the experimental results together, the effects of PT-2385 on ionic currents demonstrated herein could be non-canonical and tend to be upstream of the inhibition of HIF-2α. This action therefore probably contributes to down-streaming mechanisms through the changes that it or other structurally resemblant compounds lead to in the perturbations of the functional activities of pituitary cells or neoplastic astrocytes, in the case that in vivo observations occur.
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Midazolam's Effects on Delayed-Rectifier K + Current and Intermediate-Conductance Ca 2+-Activated K + Channel in Jurkat T-lymphocytes. Int J Mol Sci 2021; 22:ijms22137198. [PMID: 34281255 PMCID: PMC8267671 DOI: 10.3390/ijms22137198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 11/17/2022] Open
Abstract
Midazolam (MDZ) could affect lymphocyte immune functions. However, the influence of MDZ on cell’s K+ currents has never been investigated. Thus, in the present study, the effects of MDZ on Jurkat T lymphocytes were studied using the patch-clamp technique. Results showed that MDZ suppressed the amplitude of delayed-rectifier K+ current (IK(DR)) in concentration-, time-, and state-dependent manners. The IC50 for MDZ-mediated reduction of IK(DR) density was 5.87 μM. Increasing MDZ concentration raised the rate of current-density inactivation and its inhibitory action on IK(DR) density was estimated with a dissociation constant of 5.14 μM. In addition, the inactivation curve of IK(DR) associated with MDZ was shifted to a hyperpolarized potential with no change on the slope factor. MDZ-induced inhibition of IK(DR) was not reversed by flumazenil. In addition, the activity of intermediate-conductance Ca2+-activated K+ (IKCa) channels was suppressed by MDZ. Furthermore, inhibition by MDZ on both IK(DR) and IKCa-channel activity appeared to be independent from GABAA receptors and affected immune-regulating cytokine expression in LPS/PMA-treated human T lymphocytes. In conclusion, MDZ suppressed current density of IK(DR) in concentration-, time-, and state-dependent manners in Jurkat T-lymphocytes and affected immune-regulating cytokine expression in LPS/PMA-treated human T lymphocytes.
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Wang XC, Jia QZ, Yu YL, Wang HD, Guo HC, Ma XD, Liu CT, Chen XY, Miao QF, Guan BC, Su SW, Wei HM, Wang C. Inhibition of the I Na/K and the activation of peak I Na contribute to the arrhythmogenic effects of aconitine and mesaconitine in guinea pigs. Acta Pharmacol Sin 2021; 42:218-229. [PMID: 32747718 DOI: 10.1038/s41401-020-0467-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 06/23/2020] [Indexed: 12/22/2022] Open
Abstract
Aconitine (ACO), a main active ingredient of Aconitum, is well-known for its cardiotoxicity. However, the mechanisms of toxic action of ACO remain unclear. In the current study, we investigated the cardiac effects of ACO and mesaconitine (MACO), a structurally related analog of ACO identified in Aconitum with undocumented cardiotoxicity in guinea pigs. We showed that intravenous administration of ACO or MACO (25 μg/kg) to guinea pigs caused various types of arrhythmias in electrocardiogram (ECG) recording, including ventricular premature beats (VPB), atrioventricular blockade (AVB), ventricular tachycardia (VT), and ventricular fibrillation (VF). MACO displayed more potent arrhythmogenic effect than ACO. We conducted whole-cell patch-clamp recording in isolated guinea pig ventricular myocytes, and observed that treatment with ACO (0.3, 3 μM) or MACO (0.1, 0.3 μM) depolarized the resting membrane potential (RMP) and reduced the action potential amplitude (APA) and durations (APDs) in a concentration-dependent manner. The ACO- and MACO-induced AP remodeling was largely abolished by an INa blocker tetrodotoxin (2 μM) and partly abolished by a specific Na+/K+ pump (NKP) blocker ouabain (0.1 μM). Furthermore, we observed that treatment with ACO or MACO attenuated NKP current (INa/K) and increased peak INa by accelerating the sodium channel activation with the EC50 of 8.36 ± 1.89 and 1.33 ± 0.16 μM, respectively. Incubation of ventricular myocytes with ACO or MACO concentration-dependently increased intracellular Na+ and Ca2+ concentrations. In conclusion, the current study demonstrates strong arrhythmogenic effects of ACO and MACO resulted from increasing the peak INa via accelerating sodium channel activation and inhibiting the INa/K. These results may help to improve our understanding of cardiotoxic mechanisms of ACO and MACO, and identify potential novel therapeutic targets for Aconitum poisoning.
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Chang WT, Liu PY, Gao ZH, Lee SW, Lee WK, Wu SN. Evidence for the Effectiveness of Remdesivir (GS-5734), a Nucleoside-Analog Antiviral Drug in the Inhibition of I K(M) or I K(DR) and in the Stimulation of I MEP. Front Pharmacol 2020; 11:1091. [PMID: 32792942 PMCID: PMC7385287 DOI: 10.3389/fphar.2020.01091] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/06/2020] [Indexed: 12/13/2022] Open
Abstract
Remdesivir (RDV, GS-5734), a broad-spectrum antiviral drug in the class of nucleotide analogs, has been particularly tailored for treatment of coronavirus infections. However, to which extent RDV is able to modify various types of membrane ion currents remains largely uncertain. In this study, we hence intended to explore the possible perturbations of RDV on ionic currents endogenous in pituitary GH3 cells and Jurkat T-lymphocytes. The whole-cell current recordings of ours disclosed that upon membrane depolarization in GH3 cells the exposure to RDV concentration-dependently depressed the peak or late components of I K(DR) elicitation with effective IC50 values of 10.1 or 2.8 μM, respectively; meanwhile, the value of dissociation constant of RDV-induced blockage of I K(DR) on the basis of the first-order reaction was yielded to be 3.04 μM. Upon the existence of RDV, the steady-state inactivation curve of I K(DR) was established in the RDV presence; moreover, the recovery became slowed. However, RDV-induced blockage of I K(DR) failed to be overcome by further addition of either α,β-methylene ATP or cyclopentyl-1,3-dipropylxanthine. The RDV addition also lessened the strength of M-type K+ current with the IC50 value of 2.5 μM. The magnitude of voltage hysteresis of I K(M) elicited by long-lasting triangular ramp pulse was diminished by adding RDV. Membrane electroporation-induced current in response to large hyperpolarization was enhanced, with an EC50 value of 5.8 μM. Likewise, in Jurkat T-lymphocytes, adding RDV declined I K(DR) amplitude concomitantly with the raised rate of current inactivation applied by step depolarization. Therefore, in terms of the RDV molecule, there appears to be an unintended activity of the prodrug on ion channels. Its inhibition of both I K(DR) and I K(M) occurring in a non-genomic fashion might provide additional but important mechanisms through which in vivo cellular functions are seriously perturbed.
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Affiliation(s)
- Wei-Ting Chang
- College of Medicine, Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan
- Division of Cardiovascular Medicine, Chi-Mei Medical Center, Tainan, Taiwan
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Ping-Yen Liu
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Zi-Han Gao
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan
| | - Shih-Wei Lee
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan
| | - Wen-Kai Lee
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
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Chang WT, Lo YC, Gao ZH, Wu SN. Evidence for the Capability of Roxadustat (FG-4592), an Oral HIF Prolyl-Hydroxylase Inhibitor, to Perturb Membrane Ionic Currents: An Unidentified yet Important Action. Int J Mol Sci 2019; 20:ijms20236027. [PMID: 31795416 PMCID: PMC6928729 DOI: 10.3390/ijms20236027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/18/2019] [Accepted: 11/25/2019] [Indexed: 12/13/2022] Open
Abstract
Roxadustat (FG-4592), an analog of 2-oxoglutarate, is an orally-administered, heterocyclic small molecule known to be an inhibitor of hypoxia inducible factor (HIF) prolyl hydroxylase. However, none of the studies have thus far thoroughly investigated its possible perturbations on membrane ion currents in endocrine or heart cells. In our studies, the whole-cell current recordings of the patch-clamp technique showed that the presence of roxadustat effectively and differentially suppressed the peak and late components of IK(DR) amplitude in response to membrane depolarization in pituitary tumor (GH3) cells with an IC50 value of 5.71 and 1.32 μM, respectively. The current inactivation of IK(DR) elicited by 10-sec membrane depolarization became raised in the presence of roxadustatt. When cells were exposed to either CoCl2 or deferoxamine (DFO), the IK(DR) elicited by membrane depolarization was not modified; however, nonactin, a K+-selective ionophore, in continued presence of roxadustat, attenuated roxadustat-mediated inhibition of the amplitude. The steady-state inactivation of IK(DR) could be constructed in the presence of roxadustat. Recovery of IK(DR) block by roxadustat (3 and 10 μM) could be fitted by a single exponential with 382 and 523 msec, respectively. The roxadustat addition slightly suppressed erg-mediated K+ or hyperpolarization-activated cation currents. This drug also decreased the peak amplitude of voltage-gated Na+ current with a slowing in inactivation rate of the current. Likewise, in H9c2 heart-derived cells, the addition of roxadustat suppressed IK(DR) amplitude in combination with the shortening in inactivation time course of the current. In high glucose-treated H9c2 cells, roxadustat-mediated inhibition of IK(DR) remained unchanged. Collectively, despite its suppression of HIF prolyl hydroxylase, inhibitory actions of roxadustat on different types of ionic currents possibly in a non-genomic fashion might provide another yet unidentified mechanism through which cellular functions are seriously perturbed, if similar findings occur in vivo.
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Affiliation(s)
- Wei-Ting Chang
- Division of Cardiovascular Medicine, Chi-Mei Medical Center, Tainan 71004 Taiwan;
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 71004, Taiwan
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| | - Yi-Ching Lo
- Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Zi-Han Gao
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan;
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan;
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Department of Basic Medical Sciences, China Medical University Hospital, Taichung 40402, Taiwan
- Correspondence: ; Tel.: +886-6-2353535-5334/886-6-2362780
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So EC, Liu PY, Lee CC, Wu SN. High Effectiveness in Actions of Carfilzomib on Delayed-Rectifier K + Current and on Spontaneous Action Potentials. Front Pharmacol 2019; 10:1163. [PMID: 31649537 PMCID: PMC6791059 DOI: 10.3389/fphar.2019.01163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/10/2019] [Indexed: 12/27/2022] Open
Abstract
Carfilzomib (CFZ, Kyprolis®) is widely recognized as an irreversible inhibitor of proteasome activity; however, its actions on ion currents in electrically excitable cells are largely unresolved. The possible actions of CFZ on ionic currents and membrane potential in pituitary GH3, A7r5 vascular smooth muscle, and heart-derived H9c2 cells were extensively investigated in this study. The presence of CFZ suppressed the amplitude of delayed-rectifier K+ current (IK(DR)) in a time-, state-, and concentration-dependent manner in pituitary GH3 cells. Based on minimal reaction scheme, the value of dissociation constant for CFZ-induced open-channel block of IK(DR) in these cells was 0.33 µM, which is similar to the IC50 value (0.32 µM) used for its efficacy on inhibition of IK(DR) amplitude. Recovery from IK(DR) block by CFZ (0.3 µM and 1 µM) could be well fitted by single exponential with 447 and 645 ms, respectively. The M-type K+ current, another type of K+ current elicited by low-threshold potential, was slightly suppressed by CFZ (1 µM). Under current-clamp condition, addition of CFZ depolarized GH3 cells, broadened the duration of action potentials as well as raised the firing frequency. In A7r5 vascular smooth muscle cells or H9c2 cardiac cells, the CFZ-induced inhibition of IK(DR) remained efficacious. Therefore, our study led us to reflect that CFZ or other structurally similar compounds should somehow act on the activity of membrane KV channels through which they influence the functional activities in different types of electrically excitable cells such as endocrine, neuroendocrine cells, smooth muscle cells, or heart cells, if similar in vivo findings occur.
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Affiliation(s)
- Edmund Cheung So
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan, Taiwan.,Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan, Taiwan
| | - Ping-Yen Liu
- Division of Cardiovascular Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chien-Ching Lee
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan, Taiwan.,Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan.,Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan
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Liu YY, Hsiao HT, Wang JCF, Liu YC, Wu SN. Parecoxib, a selective blocker of cyclooxygenase-2, directly inhibits neuronal delayed-rectifier K + current, M-type K + current and Na + current. Eur J Pharmacol 2018; 844:95-101. [PMID: 30529469 DOI: 10.1016/j.ejphar.2018.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 11/29/2018] [Accepted: 12/05/2018] [Indexed: 11/24/2022]
Abstract
Parecoxib, a prodrug of valdecoxib, is a selective inhibitor of cyclooxygenase-2 and widely used for traumatic and postoperative patients to avoid opioid-induced side effects. It is a potent analgesic and has a role in multimodal analgesic and enhanced recovery after surgery. Whether parecoxib exerts any actions on these types of ionic currents remains unclear. In this study, we investigated whether it exerts any effects on ion currents in differentiated NG108-15 neuronal cells. Cell exposure to parecoxib (1-30 μM) caused a reversible reduction in the amplitude of IK(DR) with an IC50 value of 9.7 μM. The time course for the IK(DR) inactivation in response to a long-lasting pulse was changed to the biexponential process during cell exposure to 3 μM parecoxib. Other agents known to inhibit the cyclooxygenase activity have minimal effects on IK(DR). Parecoxib enhanced the degree of excessive accumulative inhibition of IK(DR) inactivation evoked by a train of brief repetitive stimuli. This compound suppressed the amplitude of M-type K+ current. It depressed the peak amplitude of voltage-gated Na+ current with no change in the current-voltage relationship of this current. However, it did not have any effect on hyperpolarization-activated cation current. No change in the expression level of KV3.1 mRNA was detected in the presence of parecoxib. The effects of parecoxib on ion currents are direct and unrelated to its inhibition of the enzymatic activity of cyclooxygenase-2. The inhibition of these ion channels by parecoxib may partly contribute to the underlying mechanisms by which it affects neuronal function in vivo.
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Affiliation(s)
- Yuan-Yuarn Liu
- Division of Trauma, Department of Emergency, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan
| | - Hung-Tsung Hsiao
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan
| | - Jeffrey Chi-Fei Wang
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan
| | - Yen-Chin Liu
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan
| | - Sheng-Nan Wu
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan City, Taiwan; Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan.
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11
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Gao X, Hu J, Zhang X, Zuo Y, Wang Y, Zhu S. Research progress of aconitine toxicity and forensic analysis of aconitine poisoning. Forensic Sci Res 2018; 5:25-31. [PMID: 32490307 PMCID: PMC7241456 DOI: 10.1080/20961790.2018.1452346] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/12/2018] [Indexed: 12/18/2022] Open
Abstract
Chinese herbal medicines have been extensively used in China and other countries for centuries. Aconitine, a diterpenoid alkaloid extracted from Aconitum plants, has anti-inflammatory and analgesic activities, but can also induce severe arrhythmia and neurotoxicity. Aconitine poisoning accidents caused by misuse, suicide, or homicide have been reported in recent years. In China, fatal aconitine poisoning can occasionally happen on account of accidental ingestion of some wild plants or consumption of herbal decoction made from the roots of Aconitum plants. However, it is rather difficult for forensic experts to find the specific results in present forensic autopsy of aconitine-induced death. To further clarify its potential risk following the widespread application of aconitine, toxicological characteristics and pharmacokinetics of aconitine are reviewed. Moreover, gastrointestinal, neurological, and cardiovascular symptoms were observed frequently in aconitine poisoning cases. In addition, the review also aims at providing some convincing evidences for forensic experts to identify unexplained death with postmortem examination.
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Affiliation(s)
- Xiangting Gao
- Department of Forensic Medicine, Soochow University, Suzhou, China
| | - Jun Hu
- Department of Forensic Medicine, Soochow University, Suzhou, China.,Laboratory of Biomedical Technology, Jiangsu Vocational College of Medicine, Yancheng, China
| | - Xincai Zhang
- Department of Forensic Medicine, Soochow University, Suzhou, China
| | - Yuanyi Zuo
- Department of Forensic Medicine, Soochow University, Suzhou, China.,Department of Forensic Sciences, Binhai People's Hospital, Yancheng, China
| | - Yun Wang
- Department of Forensic Medicine, Soochow University, Suzhou, China
| | - Shaohua Zhu
- Department of Forensic Medicine, Soochow University, Suzhou, China
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Kuo PC, Yang CJ, Lee YC, Chen PC, Liu YC, Wu SN. The comprehensive electrophysiological study of curcuminoids on delayed-rectifier K + currents in insulin-secreting cells. Eur J Pharmacol 2018; 819:233-241. [DOI: 10.1016/j.ejphar.2017.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 12/16/2022]
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Hsu HT, Lo YC, Huang YM, Tseng YT, Wu SN. Important modifications by sugammadex, a modified γ-cyclodextrin, of ion currents in differentiated NSC-34 neuronal cells. BMC Neurosci 2017; 18:6. [PMID: 28049438 PMCID: PMC5210182 DOI: 10.1186/s12868-016-0320-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 12/08/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Sugammadex (SGX) is a modified γ-cyclodextrin used for reversal of steroidal neuromuscular blocking agents during general anesthesia. Despite its application in clinical use, whether SGX treatment exerts any effects on membrane ion currents in neurons remains largely unclear. In this study, effects of SGX treatment on ion currents, particularly on delayed-rectifier K+ current [I K(DR)], were extensively investigated in differentiated NSC-34 neuronal cells. RESULTS After cells were exposed to SGX (30 μM), there was a reduction in the amplitude of I K(DR) followed by an apparent slowing in current activation in response to membrane depolarization. The challenge of cells with SGX produced a depolarized shift by 15 mV in the activation curve of I K(DR) accompanied by increased gating charge of this current. However, the inactivation curve of I K(DR) remained unchanged following SGX treatment, as compared with that in untreated cells. According to a minimal reaction scheme, the lengthening of activation time constant of I K(DR) caused by cell treatment with different SGX concentrations was quantitatively estimated with a dissociation constant of 17.5 μM, a value that is clinically achievable. Accumulative slowing in I K(DR) activation elicited by repetitive stimuli was enhanced in SGX-treated cells. SGX treatment did not alter the amplitude of voltage-gated Na+ currents. In SGX-treated cells, dexamethasone (30 μM), a synthetic glucocorticoid, produced little or no effect on L-type Ca2+ currents, although it effectively suppressed the amplitude of this current in untreated cells. CONCLUSIONS The treatment of SGX may influence the amplitude and gating of I K(DR) and its actions could potentially contribute to functional activities of motor neurons if similar results were found in vivo.
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Affiliation(s)
- Hung-Te Hsu
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung City, 80708, Taiwan.,Department of Anesthesia, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung City, 80145, Taiwan
| | - Yi-Ching Lo
- Department of Pharmacology, School of Medicine, Kaohsiung Medical University, Kaohsiung City, 80708, Taiwan.
| | - Yan-Ming Huang
- Department of Physiology, National Cheng Kung University Medical College, No. 1, University Road, Tainan City, 70101, Taiwan
| | - Yu-Ting Tseng
- Department of Pharmacology, School of Medicine, Kaohsiung Medical University, Kaohsiung City, 80708, Taiwan.,Graduate Institute of Natural Products, School of Pharmacy, Kaohsiung Medical University, Kaohsiung City, 80708, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, No. 1, University Road, Tainan City, 70101, Taiwan.
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Xin Y, Liu S. Quantitative Assessment of the Influence of Rhizoma Zingiberis on the Level of Aconitine in Rat Gut Sacs and Qualitative Analysis of the Major Influencing Components of Rhizoma Zingiberis on Aconitine Using UPLC/MS. PLoS One 2015; 10:e0124110. [PMID: 25978042 PMCID: PMC4433269 DOI: 10.1371/journal.pone.0124110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 02/25/2015] [Indexed: 11/19/2022] Open
Abstract
This study attempted to clarify the material basis for the detoxification of Rhizoma Zingiberis (RZ) on aconitine, an analgesic drug, by quantitatively assessing the influence of RZ on the in vitro intestinal concentration of aconitine using an everted gut sac model and by qualitatively identifying the components in the RZ extract. To quantify aconitine in rat everted gut sacs, both an accurate processing method and a sensitive detection method were required. We developed a three-step sample processing method to protect the components from decomposition and applied ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC/TQMS) to quantify aconitine, glucose and digoxin. In addition, ultra-performance liquid chromatography coupled with linear ion trap mass spectrometry (UPLC/ITMS) was applied to detect the potential antidotal components in the RZ extract. Finally, the RZ extract reduced the level of aconitine in everted gut sacs, and eleven gingerols were successfully identified, which could be considered potential antidotal components for aconitine. This study demonstrated the application of two UPLC/MS methods for analyzing the material basis for the reciprocity between Chinese medicine components in everted gut sacs.
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Affiliation(s)
- Yang Xin
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, 161006, China
- Changchun Center of Mass Spectrometry & Chemical Biology Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China
- Changchun University of Chinese Medicine, Changchun, 130117, China
| | - Shuying Liu
- Changchun Center of Mass Spectrometry & Chemical Biology Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China
- Changchun University of Chinese Medicine, Changchun, 130117, China
- * E-mail:
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Chan TYK. Aconitum alkaloid poisoning related to the culinary uses of aconite roots. Toxins (Basel) 2014; 6:2605-11. [PMID: 25184557 PMCID: PMC4179150 DOI: 10.3390/toxins6092605] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 08/11/2014] [Accepted: 08/21/2014] [Indexed: 12/27/2022] Open
Abstract
Aconite roots (roots or root tubers of the Aconitum species) are eaten as root vegetables and used to prepare herbal soups and meals, mainly for their purported health benefits. Aconite roots contain aconitine and other Aconitum alkaloids, which are well known cardiotoxins and neurotoxins. To better understand why Aconitum alkaloid poisoning related to the culinary uses of aconite roots can occur and characterize the risks posed by these “food supplements”, relevant published reports were reviewed. From 1995 to 2013, there were eight reports of aconite poisoning after consumption of these herbal soups and meals, including two reports of large clusters of cases (n = 19–45) and two reports of cases (n = 15–156) managed by two hospitals over a period of 4.5 to 5 years. The herbal formulae used did not adhere to the suggested guidelines, with regarding to the doses (50–500 g instead of 3–30 g per person) and types (raw instead of processed) of aconite roots used. The quantities of Aconitum alkaloids involved were huge, taking into consideration the doses of aconite roots used to prepare herbal soups/meals and the amounts of aconite roots and herbal soups/meals consumed. In a large cluster of cases, despite simmering raw “caowu” (the root tuber of A. kusnezoffii) in pork broth for 24 h, all 19 family members who consumed this soup and boiled “caowu” developed poisoning. Severe or even fatal aconite poisoning can occur after consumption of herbal soups and foods prepared from aconite roots. Even prolonged boiling may not be protective if raw preparations and large quantities of aconite roots are used. The public should be warned of the risk of severe poisoning related to the culinary and traditional medicinal uses of aconite roots.
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Affiliation(s)
- Thomas Y K Chan
- Division of Clinical Pharmacology and Drug and Poisons Information Bureau, Department of Medicine and Therapeutics, Faculty of Medicine, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China.
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So EC, Wu KC, Kao FC, Wu SN. Effects of midazolam on ion currents and membrane potential in differentiated motor neuron-like NSC-34 and NG108-15 cells. Eur J Pharmacol 2013; 724:152-60. [PMID: 24374009 DOI: 10.1016/j.ejphar.2013.12.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 11/22/2013] [Accepted: 12/16/2013] [Indexed: 11/25/2022]
Abstract
Midazolam (MDL) was known to act through stimulation of benzodiazepine receptors (GABA). Whether midazolam affects ion currents and membrane potential in neurons remains largely unclear. Electrophysiological studies of midazolam actions were performed in differentiated motor neuron-like (NSC-34 and NG108-15) cells. Midazolam suppressed the amplitude of delayed rectifier K(+) current (IK(DR)) in a time- and concentration-dependent manner with an IC50 value of 10.4 µM. Addition of midazolam was noted to enhance the rate of IK(DR) inactivation. On the basis of minimal binding scheme, midazolam-induced block of IK(DR) was quantitatively provided with a dissociation constant of 9.8 µM. Recovery of IK(DR) from inactivation in the presence of midazolam was fitted by a single exponential. midazolam had no effect on M-type or erg-mediated K(+) current in these cells. Midazaolam (30 µM) suppressed the peak amplitude of voltage-gated Na(+) current (INa) with no change in the current-voltage relationships of this current. Inactivation kinetics of INa remained unaltered in the presence of this agent. In current-clamp configuration, midazolam (30 µM) prolonged the duration of action potentials (APs) and reduce AP amplitude. Similarly, in differentiated NG108-15 cells, the exposure to midazolam also suppressed IK(DR) with a concomitant increase in current inactivation. Midazolam can act as an open-channel blocker of delayed-rectifier K(+) channels in these cells. The synergistic blocking effects on IK(DR) and INa may contribute to the underlying mechanisms through which midazolam affects neuronal function in vivo.
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Affiliation(s)
- Edmund Cheung So
- Department of Anesthesia, Tainan Municipal An-Nan Hospital, China Medical University, 66# Cheung Ho Road, An-Nan District, Tainan, Taiwan; Department of Anesthesia, China Medical University, 91# Hsueh-Shih Road, Taichung, Taiwan; Department of Cell Biology and Anatomy, Cheng Kung University, 1# University Road, Tainan City, Taiwan; Department of Anesthesia, Taishan Medical University, 619 Chang Cheng Road, Taian 271016, Shandong Province, PR China; Department of Anesthesia, Nan Shan branch of Gilu Hospital, Shandong University, Shandong Province, PR China.
| | - King Chuen Wu
- Department of Anesthesiology, Eda-Hospital/I-Shou University, 1# Yida Road, Jiaosu Village, Yanchao District, Kaohsiung, Taiwan.
| | - Feng Chen Kao
- Department of Orthopedic Surgery, E-Da Hospital/I-Shou University, 1# Yida Road, Jiaosu Village, Yanchao District, Kaohsiung, Taiwan.
| | - Sheng Nan Wu
- Department of Physiology, National Cheng Kung University, 1# University Road, Tainan City, Taiwan.
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Wu SN, Yeh CC, Huang HC, So EC, Lo YC. Electrophysiological characterization of sodium-activated potassium channels in NG108-15 and NSC-34 motor neuron-like cells. Acta Physiol (Oxf) 2012; 206:120-34. [PMID: 22533628 DOI: 10.1111/j.1748-1716.2012.02438.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/09/2011] [Accepted: 03/19/2012] [Indexed: 12/13/2022]
Abstract
AIMS The electrical properties of Na(+) -activated K(+) current (I(K(Na)) ) and its contribution to spike firing has not been characterized in motor neurons. METHODS We evaluated how activation of voltage-gated K(+) current (I(K) ) at the cellular level could be coupled to Na(+) influx through voltage-gated Na(+) current (I(N) (a) ) in two motor neuron-like cells (NG108-15 and NSC-34 cells). RESULTS Increasing stimulation frequency altered the amplitudes of both I(Na) and I(K) simultaneously. With changes in stimulation frequency, the kinetics of both I(Na) inactivation and I(K) activation were well correlated at the same cell. Addition of tetrodotoxin or ranolazine reduced the amplitudes of both I(Na) and I(K) simultaneously. Tefluthrin (Tef) increased the amplitudes of both I(Na) and I(K) throughout the voltages ranging from -30 to + 10 mV. In cell-attached recordings, single-channel conductance from a linear current-voltage relation was 94 ± 3 pS (n = 7). Tef (10 μm) enhanced channel activity with no change in single-channel conductance. Tef increased spike firing accompanied by enhanced facilitation of spike-frequency adaptation. Riluzole (10 μm) reversed Tef-stimulated activity of K(Na) channels. In motor neuron-like NSC-34 cells, increasing stimulation frequency altered the kinetics of both I(Na) and I(K) . Modelling studies of motor neurons were simulated to demonstrate that the magnitude of I(K(Na)) modulates AP firing. CONCLUSIONS There is a direct association of Na(+) and K(Na) channels which can provide the rapid activation of K(Na) channels required to regulate AP firing occurring in motor neurons.
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Affiliation(s)
| | - C.-C. Yeh
- Department of Physiology; National Cheng Kung University Medical College; Tainan City; Taiwan
| | - H.-C. Huang
- Department of Physiology; National Cheng Kung University Medical College; Tainan City; Taiwan
| | - E. C. So
- Department of Anesthesia; Chi Mei Medical Center; Tainan City; Taiwan
| | - Y.-C. Lo
- Department of Pharmacology; Kaohsiung Medical University; Kaohsiung City; Taiwan
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Evidence for inhibitory effects of flupirtine, a centrally acting analgesic, on delayed rectifier k(+) currents in motor neuron-like cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:148403. [PMID: 22888361 PMCID: PMC3408763 DOI: 10.1155/2012/148403] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 06/18/2012] [Indexed: 12/25/2022]
Abstract
Flupirtine (Flu), a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K+ currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K+ current (IK(DR)) with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of IK(DR) inactivation rate was about 9.8 μM. Neither linopirdine (10 μM), NMDA (30 μM), nor gabazine (10 μM) reversed Flu-induced changes in IK(DR) inactivation. Addition of Flu shifted the inactivation curve of IK(DR) to a hyperpolarized potential. Cumulative inactivation for IK(DR) was elevated in the presence of this compound. Flu increased the amplitude of M-type K+ current (IK(M)) and produced a leftward shift in the activation curve of IK(M). In another neuronal cells (NG108-15), Flu reduced IK(DR) amplitude and enhanced the inactivation rate of IK(DR). The results suggest that Flu acts as an open-channel blocker of delayed-rectifier K+ channels in motor neurons. Flu-induced block of IK(DR) is unlinked to binding to NMDA or GABA receptors and the effects of this agent on K+ channels are not limited to its action on M-type K+ channels.
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Characterizing the effects of Eugenol on neuronal ionic currents and hyperexcitability. Psychopharmacology (Berl) 2012; 221:575-87. [PMID: 22160139 DOI: 10.1007/s00213-011-2603-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 11/26/2011] [Indexed: 01/24/2023]
Abstract
RATIONALE Eugenol (EUG, 4-allyl-2-methoxyphenol), the main component of essential oil extracted from cloves, has various uses in medicine because of its potential to modulate neuronal excitability. However, its effects on the ionic mechanisms remains incompletely understood. OBJECTIVES We aimed to investigate EUG's effects on neuronal ionic currents and excitability, especially on voltage-gated ion currents, and to verify the effects on a hyperexcitability-temporal lobe seizure model. METHODS With the aid of patch-clamp technology, we first investigated the effects of EUG on ionic currents in NG108-15 neuronal cells differentiated with cyclic AMP. We then used modified Pinsky-Rinzel simulation modeling to evaluate its effects on spontaneous action potentials (APs). Finally, we investigated its effects on pilocarpine-induced seizures in rats. RESULTS EUG depressed the transient and late components of I(Na) in the neurons. It not only increased the degree of I(Na) inactivation, but specifically suppressed the non-inactivating I(Na) (I(Na(NI))). Its inhibition of I (Na(NI)) was reversed by tefluthrin. In addition, EUG diminished L-type Ca(2+) current and delayed rectifier K(+) current only at higher concentrations. EUG's effects on APs frequency reduction was verified by the simulation modeling. In pilocarpine-induced seizures, the EUG-treated rats showed no shorter seizure latency but a lower seizure severity and mortality than the control rats. The EUG's effect on seizure severity was occluded by the I(Na(NI)) antagonist riluzole. CONCLUSION The synergistic blocking effects of I (Na) and I(Na(NI)) contributes to the main mechanism through which EUG affects the firing of neuronal APs and modulate neuronal hyperexcitability such as pilocarpine-induced temporal lobe seizures.
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Xin Y, Pi Z, Song F, Liu Z, Liu S. Study on the Metabolic Characteristics of Aconite Alkaloids in the Extract of Radix aconiti under Intestinal Bacteria of Rat by UPLC/MSn Technique. CHINESE J CHEM 2012. [DOI: 10.1002/cjoc.201100228] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wu SN, Chen BS, Lo YC. Evidence for aconitine-induced inhibition of delayed rectifier K(+) current in Jurkat T-lymphocytes. Toxicology 2011; 289:11-8. [PMID: 21782880 DOI: 10.1016/j.tox.2011.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 07/04/2011] [Accepted: 07/06/2011] [Indexed: 02/07/2023]
Abstract
Aconitine (ACO) is a highly toxic diterpenoid alkaloid and known to exert the immunomodulatory action. However, whether it has any effects on ion currents in immune cells remains unknown. The effects of ACO and other related compounds on ion currents in Jurkat T-lymphocytes were investigated in this study. ACO suppressed the amplitude of delayed-rectifier K(+) current (I(K(DR))) in a time- and concentration-dependent manner. Margatoxin (100 nM), a specific blocker of K(V)1.3-encoded current, decreased the I(K(DR)) amplitude in these cells and the ACO-induced inhibition of I(K(DR)) was not reversed by 1-ethyl-2-benzimidazolinone (30 μM) or nicotine (10 μM). The IC(50) value for ACO-mediated inhibition of I(K(DR)) was 5.6 μM. ACO accelerated the inactivation of I(K(DR)) with no change in the activation rate of this current. Increasing the ACO concentration not only reduced the I(K(DR)) amplitude, but also accelerated the inactivation time course of the current. With the aid of minimal binding scheme, the inhibitory action of ACO on I(K(DR)) was estimated with a dissociation constant of 6.8 μM. ACO also shifted the inactivation curve of I(K(DR)) to a hyperpolarized potential with no change in the slope factor. Cumulative inactivation for I(K(DR)) was enhanced in the presence of ACO. In Jurkat cells incubated with amiloride (30 μM), the ACO-induced inhibition of I(K(DR)) remained unaltered. In RAW 264.7 murine macrophages, ACO did not modify the kinetics of I(K(DR)), although it suppressed I(K(DR)) amplitude. Taken together, these effects can significantly contribute to its action on functional activity of immune cells if similar results are found in vivo.
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Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan.
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Huang MH, Shen AY, Wang TS, Wu HM, Kang YF, Chen CT, Hsu TI, Chen BS, Wu SN. Inhibitory action of methadone and its metabolites on erg-mediated K+ current in GH₃ pituitary tumor cells. Toxicology 2010; 280:1-9. [PMID: 21094671 DOI: 10.1016/j.tox.2010.10.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 10/20/2010] [Accepted: 10/21/2010] [Indexed: 01/05/2023]
Abstract
Methadone (Mtd) is a widely used opioid drug associated with the side effect of hyperprolactinemia. The mechanism of how Mtd induces prolactin secretion remains unclear. The effects of Mtd and its two main metabolites (EDDP: (±)-2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium percholarate and EMDP: 2-ethyl-5-methyl-3,3-dipnehyl-1-pyrroline) on ion currents were investigated in GH₃ pituitary tumor cells. Hyperpolarization-elicited K+ currents in GH₃ cells bathed in a high-K(+), Ca(2+)-free solution were studied to evaluate the effects of Mtd and other related compounds on the ether-à-go-go-related-gene (erg) K(+) current (I(K(erg))). Mtd suppressed the amplitude of I(K(erg)) in a concentration-dependent manner with an IC(50) value of 10.4 μM. With the aid of a minimal binding scheme, the inhibitory action of Mtd on I(K(erg)) was estimated with a dissociation constant of 8.2 μM. Mtd tended to increase the rate of I(K(erg)) deactivation in a voltage-dependent fashion. EDDP (10 μM) had no effect on I(K(erg)), while EMDP (10μM) slightly suppressed it. In GH₃ cells incubated with naloxone (30 μM), the Mtd-induced inhibition of I(K(erg)) remained unaltered. Under cell-attached voltage-clamp recordings, Mtd increased the frequency of spontaneous action currents with no change in current amplitude. Similarly, Mtd can suppress I(K(erg)) in differentiated NG108-15 cells; dynorphin A(1-13) did not reverse Mtd-induced inhibition of I(K(erg)). This study shows that Mtd has a depressant effect on I(K(erg)), and suggests its ability to affect membrane excitability and prolactin secretion. The cyclization of Mtd, in which EDDP and EMDP are formed, tends to be critical in removal of the Mtd binding to erg K+ channel.
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Affiliation(s)
- Mei-Han Huang
- College of Medical and Health Sciences, Fooyin University, Ta-Liao, Kaohsiung County, Taiwan
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Chen BS, Peng H, Wu SN. Dexmedetomidine, an α2-adrenergic agonist, inhibits neuronal delayed-rectifier potassium current and sodium current. Br J Anaesth 2009; 103:244-54. [DOI: 10.1093/bja/aep107] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Wu SN, Chen BS, Hsu TI, Peng H, Wu YH, Lo YC. Analytical studies of rapidly inactivating and noninactivating sodium currents in differentiated NG108-15 neuronal cells. J Theor Biol 2009; 259:828-36. [PMID: 19446569 DOI: 10.1016/j.jtbi.2009.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 04/07/2009] [Accepted: 05/06/2009] [Indexed: 11/16/2022]
Abstract
The rapidly inactivating (I(Naf)) and noninactivating Na(+) currents (I(Na)(()(NI)())) were characterized in NG108-15 neuronal cells differentiated with dibutyryl cyclic AMP in this study. Standard activation and inactivation protocols were used to evaluate the steady-state and kinetic properties of the I(Naf) present in these cells. The voltage protocols with a slowly depolarizing ramp were implemented to examine the properties of I(Na)(()(NI)()). Based on experimental data and computer simulations, a window component of the rapidly inactivating sodium current (I(Naf)(()(W)())) was also generated in response to the slowly depolarizing ramp. The I(Naf)(()(W)()) was subtracted from I(Na)(()(NI)()) to yield the persistent Na(+) current (I(Na)(()(P)())). Our results demonstrate the presence of I(Na)(()(P)()) in these cells. In addition to modifying the steady-state inactivation of I(Naf), ranolazine or riluzloe could be effective in blocking I(Naf)(()(W)()) and I(Na)(()(P)()). The ability of ranolazine and riluzole to suppress I(Na)(()(P)()) was greater than their ability to inhibit I(Naf)(()(W)()). In current-clamp recordings, current-induced voltage oscillations were applied to elicit action potentials (APs) through a gradual transition between spontaneous depolarization and upstroke. Ranolazine or riluzole at a concentration of 3 microM then effectively suppressed the AP firing generated by oscillatory changes in membrane current. The data suggest that a small rise in I(Na)(()(NI)()) facilitates neuronal hyper-excitability due the decreased threshold of AP initiation. The underlying mechanism of the inhibitory actions of ranolazine or riluzole on membrane potential in neurons or neuroendocrine cells in vivo may thus be associated with their blocking of I(Na)(()(NI)()).
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Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan.
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Wu SN, Wu YH, Chen BS, Lo YC, Liu YC. Underlying mechanism of actions of tefluthrin, a pyrethroid insecticide, on voltage-gated ion currents and on action currents in pituitary tumor (GH3) cells and GnRH-secreting (GT1-7) neurons. Toxicology 2009; 258:70-7. [PMID: 19378468 DOI: 10.1016/j.tox.2009.01.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tefluthrin is a synthetic pyrethroid and involved in acute neurotoxic effects. How this compound affects ion currents in endocrine or neuroendocrine cells remains unclear. Its effects on membrane ion currents in pituitary tumor (GH3) cells and in hypothalamic (GT1-7) neurons were investigated. Application of Tef (10 microM) increased the amplitude of voltage-gated Na+ current (INa), along with a slowing in current inactivation and deactivation in GH3 cells. The current-voltage relationship of INa was shifted to more negative potentials in the presence of this compound. Tef increased INa with an EC50 value of 3.2 +/- 0.8 microM. It also increased the amplitude of persistent INa. Tef reduced the amplitude of L-type Ca2+ current. This agent slightly inhibited K+ outward current; however, it had no effect on the activity of large-conductance Ca2+-activated K+ channels. Under cell-attached voltage-clamp recordings, Tef (10 microM) increased amplitude and frequency of spontaneous action currents, along with appearance of oscillatory inward currents. Tef-induced inward currents were suppressed after further application of tetrodotoxin, riluzole or ranolazine. In GT1-7 cells, Tef also increased the amplitude and frequency of action currents. Taken together, the effects of Tef and its structural related pyrethroids on ion currents can contribute to the underlying mechanisms through which they affect endocrine or neuroendocrine function in vivo.
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Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan.
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Wang YJ, Chen BS, Lin MW, Lin AA, Peng H, Sung RJ, Wu SN. Time-Dependent Block of Ultrarapid-Delayed Rectifier K+ Currents by Aconitine, a Potent Cardiotoxin, in Heart-Derived H9c2 Myoblasts and in Neonatal Rat Ventricular Myocytes. Toxicol Sci 2008; 106:454-63. [DOI: 10.1093/toxsci/kfn189] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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