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Wang YJ, Yeh CJ, Gao ZH, Hwang E, Chen HH, Wu SN. Inhibitory Perturbations of Fluvastatin on Afterhyperpolarization Current, Erg-mediated K + Current, and Hyperpolarization-activated Cation Current in Both Pituitary GH 3 Cells and Primary Embryonic Mouse Cortical Neurons. Neuroscience 2023; 531:12-23. [PMID: 37661016 DOI: 10.1016/j.neuroscience.2023.08.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
Fluvastatin (FLV), the first synthetically derived 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, is a potent inhibitor of cholesterol biosynthesis. While its primary mechanism of action is to reduce cholesterol levels, there is some evidence suggesting that it may also have effects on K+ channels. However, the overall effects of fluvastatin on ionic currents are not yet well understood. The whole-cell clamp recordings were applied to evaluate the ionic currents and action potentials of cells. Here, we have demonstrated that FLV can effectively inhibit the amplitude of erg-mediated K+ current (IK(erg)) in pituitary tumor (GH3) cells, with an IC50 of approximately 3.2 µM. In the presence of FLV, the midpoint in the activation curve of IK(erg) was distinctly shifted to a less negative potential by 10 mV, with minimal modification of the gating charge. However, the magnitude of hyperpolarization-activated cation current (Ih) elicited by long-lasting membrane hyperpolarization was progressively decreased, with an IC50 value of 8.7 µM, upon exposure to FLV. More interestingly, we also found that FLV (5 µM) could regulate the action potential and afterhyperpolarization properties in primary embryonic mouse cortical neurons. Our study presents compelling evidence indicating that FLV has the potential to impact both the amplitude and gating of the ion channels IK(erg) and Ih. We also provide credible evidence suggesting that this drug has the potential to modify the properties of action potentials and the afterhyperpolarization current in electrically excitable cells. However, the assumption that these findings translate to similar in-vivo results remains unclear.
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Affiliation(s)
- Ya-Jean Wang
- Department of Senior Services Industry Management, Minghsin University of Science and Technology, Hsinchu, Taiwan.
| | - Che-Jui Yeh
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Zi-Han Gao
- Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan
| | - Eric Hwang
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan; Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan; Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Hwei-Hisen Chen
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli, Taiwan; Institute of Neuroscience, National Chengchi University, Taipei, 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 and Education, An Nan Hostpial, China Medical University Hospital, China Medical University, Tainan, Taiwan.
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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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The Effectiveness of Isoplumbagin and Plumbagin in Regulating Amplitude, Gating Kinetics, and Voltage-Dependent Hysteresis of erg-mediated K+ Currents. Biomedicines 2022; 10:biomedicines10040780. [PMID: 35453530 PMCID: PMC9029050 DOI: 10.3390/biomedicines10040780] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/22/2022] [Accepted: 03/25/2022] [Indexed: 02/04/2023] Open
Abstract
Isoplumbagin (isoPLB, 5-hydroxy-3-methyl-1,4-naphthoquinone), a naturally occurring quinone, has been observed to exercise anti-inflammatory, antimicrobial, and antineoplastic activities. Notably, whether and how isoPLB, plumbagin (PLB), or other related compounds impact transmembrane ionic currents is not entirely clear. In this study, during GH3-cell exposure to isoPLB, the peak and sustained components of an erg (ether-à-go-go related gene)-mediated K+ current (IK(erg)) evoked with long-lasting-step hyperpolarization were concentration-dependently decreased, with a concomitant increase in the decaying time constant of the deactivating current. The presence of isoPLB led to a differential reduction in the peak and sustained components of deactivating IK(erg) with effective IC50 values of 18.3 and 2.4 μM, respectively, while the KD value according to the minimum binding scheme was estimated to be 2.58 μM. Inhibition by isoPLB of IK(erg) was not reversed by diazoxide; however, further addition of isoPLB, during the continued exposure to 4,4′-dithiopyridine, did not suppress IK(erg) further. The recovery of IK(erg) by a two-step voltage pulse with a geometric progression was slowed in the presence of isoPLB, and the decaying rate of IK(erg) activated by the envelope-of-tail method was increased in its presence. The strength of the IK(erg) hysteresis in response to an inverted isosceles-triangular ramp pulse was diminished by adding isoPLB. A mild inhibition of the delayed-rectifier K+ current (IK(DR)) produced by the presence of isoPLB was seen in GH3 cells, while minimal changes in the magnitude of the voltage-gated Na+ current were demonstrated in its presence. Moreover, the IK(erg) identified in MA-10 Leydig tumor cells was blocked by adding isoPLB. Therefore, the effects of isoPLB or PLB on ionic currents (e.g., IK(erg) and IK(DR)) demonstrated herein would be upstream of our previously reported perturbations on mitochondrial morphogenesis or respiration. Taken together, the perturbations of ionic currents by isoPLB or PLB demonstrated herein are likely to contribute to the underlying mechanism through which they, or other structurally similar compounds, result in adjustments in the functional activities of different neoplastic cells (e.g., GH3 and MA-10 cells), presuming that similar in vivo observations occur.
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Evidence for Inhibitory Perturbations on the Amplitude, Gating, and Hysteresis of A-Type Potassium Current, Produced by Lacosamide, a Functionalized Amino Acid with Anticonvulsant Properties. Int J Mol Sci 2022; 23:ijms23031171. [PMID: 35163091 PMCID: PMC8835568 DOI: 10.3390/ijms23031171] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/11/2022] [Accepted: 01/19/2022] [Indexed: 02/05/2023] Open
Abstract
Lacosamide (Vimpat®, LCS) is widely known as a functionalized amino acid with promising anti-convulsant properties; however, adverse events during its use have gradually appeared. Despite its inhibitory effect on voltage-gated Na+ current (INa), the modifications on varying types of ionic currents caused by this drug remain largely unexplored. In pituitary tumor (GH3) cells, we found that the presence of LCS concentration-dependently decreased the amplitude of A-type K+ current (IK(A)) elicited in response to membrane depolarization. The IK(A) amplitude in these cells was sensitive to attenuation by the application of 4-aminopyridine, 4-aminopyridine-3-methanol, or capsaicin but not by that of tetraethylammonium chloride. The effective IC50 value required for its reduction in peak or sustained IK(A) was calculated to be 102 or 42 µM, respectively, while the value of the dissociation constant (KD) estimated from the slow component in IK(A) inactivation at varying LCS concentrations was 52 µM. By use of two-step voltage protocol, the presence of this drug resulted in a rightward shift in the steady-state inactivation curve of IK(A) as well as in a slowing in the recovery time course of the current block; however, no change in the gating charge of the inactivation curve was detected in its presence. Moreover, the LCS addition led to an attenuation in the degree of voltage-dependent hysteresis for IK(A) elicitation by long-duration triangular ramp voltage commands. Likewise, the IK(A) identified in mouse mHippoE-14 neurons was also sensitive to block by LCS, coincident with an elevation in the current inactivation rate. Collectively, apart from its canonical action on INa inhibition, LCS was effective at altering the amplitude, gating, and hysteresis of IK(A) in excitable cells. The modulatory actions on IK(A), caused by LCS, could interfere with the functional activities of electrically excitable cells (e.g., pituitary tumor cells or hippocampal neurons).
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Pérez PA, Toledo J, Picech F, Petiti JP, Mukdsi JH, Diaz-Torga G, Torres AI, De Paul AL, Gutiérrez S. Perinatal DEHP exposure modulates pituitary estrogen receptor α and β expression altering lactotroph and somatotroph cell growth in prepuberal and adult male rats. Food Chem Toxicol 2021; 158:112649. [PMID: 34728246 DOI: 10.1016/j.fct.2021.112649] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 10/05/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022]
Abstract
Phthalates are synthetic chemicals widely used to make polyvinylchloride (PVC) soft and flexible. Of these, Di-(2-ethylhexyl) phthalate (DEHP) is the most commonly used, with high human exposure occurring as early as the fetal developmental stage and affecting the endocrine system. We focused on the perinatal DEHP effects on pituitary estrogen receptor (ER) expression in male rats, explored their impact on lactotroph and somatotroph cell growth, and evaluated the direct effects of this phthalate on pituitary cell cultures. Our results showed that DEHP perinatal exposure was unable to modify the ERα+ pituitary cell number from prepuberal rats, but increased ERβ+ cells. In adulthood, the pituitary ERα+ cells underwent a slight decrease with ERβ showing the greatest changes, and with a significant increase observed in somatotroph cells. Also, in vitro, DEHP reduced the ERα+ cells, increased the percentage of ERβ+ pituitary cells and modified the Ki67 index, as well as decreasing the lactotrophs and increasing the somatotroph cells. In conclusion, the present study showed that DEHP induced ER expression changes in normal pituitary glands from male rats in in vivo and in vitro conditions, suggesting that DEHP could differentially modulate lactotroph and somatotroph cell growth, possibly as a consequence of ER imbalance.
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Affiliation(s)
- Pablo A Pérez
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Jonathan Toledo
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Florencia Picech
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Juan P Petiti
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Jorge H Mukdsi
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Graciela Diaz-Torga
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Alicia I Torres
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Ana L De Paul
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Silvina Gutiérrez
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
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Effective Accentuation of Voltage-Gated Sodium Current Caused by Apocynin (4'-Hydroxy-3'-methoxyacetophenone), a Known NADPH-Oxidase Inhibitor. Biomedicines 2021; 9:biomedicines9091146. [PMID: 34572332 PMCID: PMC8464932 DOI: 10.3390/biomedicines9091146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/23/2021] [Accepted: 08/31/2021] [Indexed: 12/22/2022] Open
Abstract
Apocynin (aPO, 4'-Hydroxy-3'-methoxyacetophenone) is a cell-permeable, anti-inflammatory phenolic compound that acts as an inhibitor of NADPH-dependent oxidase (NOX). However, the mechanisms through which aPO can interact directly with plasmalemmal ionic channels to perturb the amplitude or gating of ionic currents in excitable cells remain incompletely understood. Herein, we aimed to investigate any modifications of aPO on ionic currents in pituitary GH3 cells or murine HL-1 cardiomyocytes. In whole-cell current recordings, GH3-cell exposure to aPO effectively stimulated the peak and late components of voltage-gated Na+ current (INa) with different potencies. The EC50 value of aPO required for its differential increase in peak or late INa in GH3 cells was estimated to be 13.2 or 2.8 μM, respectively, whereas the KD value required for its retardation in the slow component of current inactivation was 3.4 μM. The current-voltage relation of INa was shifted slightly to more negative potential during cell exposure to aPO (10 μM); however, the steady-state inactivation curve of the current was shifted in a rightward direction in its presence. Recovery of peak INa inactivation was increased in the presence of 10 μM aPO. In continued presence of aPO, further application of rufinamide or ranolazine attenuated aPO-stimulated INa. In methylglyoxal- or superoxide dismutase-treated cells, the stimulatory effect of aPO on peak INa remained effective. By using upright isosceles-triangular ramp pulse of varying duration, the amplitude of persistent INa measured at low or high threshold was enhanced by the aPO presence, along with increased hysteretic strength appearing at low or high threshold. The addition of aPO (10 μM) mildly inhibited the amplitude of erg-mediated K+ current. Likewise, in HL-1 murine cardiomyocytes, the aPO presence increased the peak amplitude of INa as well as decreased the inactivation or deactivation rate of the current, and further addition of ranolazine or esaxerenone attenuated aPO-accentuated INa. Altogether, this study provides a distinctive yet unidentified finding that, despite its effectiveness in suppressing NOX activity, aPO may directly and concertedly perturb the amplitude, gating and voltage-dependent hysteresis of INa in electrically excitable cells. The interaction of aPO with ionic currents may, at least in part, contribute to the underlying mechanisms through which it affects neuroendocrine, endocrine or cardiac function.
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Borgini M, Mondal P, Liu R, Wipf P. Chemical modulation of Kv7 potassium channels. RSC Med Chem 2021; 12:483-537. [PMID: 34046626 PMCID: PMC8128042 DOI: 10.1039/d0md00328j] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/01/2020] [Indexed: 01/10/2023] Open
Abstract
The rising interest in Kv7 modulators originates from their ability to evoke fundamental electrophysiological perturbations in a tissue-specific manner. A large number of therapeutic applications are, in part, based on the clinical experience with two broad-spectrum Kv7 agonists, flupirtine and retigabine. Since precise molecular structures of human Kv7 channel subtypes in closed and open states have only very recently started to emerge, computational studies have traditionally been used to analyze binding modes and direct the development of more potent and selective Kv7 modulators with improved safety profiles. Herein, the synthetic and medicinal chemistry of small molecule modulators and the representative biological properties are summarized. Furthermore, new therapeutic applications supported by in vitro and in vivo assay data are suggested.
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Affiliation(s)
- Matteo Borgini
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Pravat Mondal
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Ruiting Liu
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
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High Capability of Pentagalloylglucose (PGG) in Inhibiting Multiple Types of Membrane Ionic Currents. Int J Mol Sci 2020; 21:ijms21249369. [PMID: 33316951 PMCID: PMC7763472 DOI: 10.3390/ijms21249369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/13/2022] Open
Abstract
Pentagalloyglucose (PGG, penta-O-galloyl-β-d-glucose; 1,2,3,4,6-pentagalloyl glucose), a pentagallic acid ester of glucose, is recognized to possess anti-bacterial, anti-oxidative and anti-neoplastic activities. However, to what extent PGG or other polyphenolic compounds can perturb the magnitude and/or gating of different types of plasmalemmal ionic currents remains largely uncertain. In pituitary tumor (GH3) cells, we found out that PGG was effective at suppressing the density of delayed-rectifier K+ current (IK(DR)) concentration-dependently. The addition of PGG could suppress the density of proton-activated Cl− current (IPAC) observed in GH3 cells. The IC50 value required for the inhibitory action of PGG on IK(DR) or IPAC observed in GH3 cells was estimated to be 3.6 or 12.2 μM, respectively, while PGG (10 μM) mildly inhibited the density of the erg-mediated K+ current or voltage-gated Na+ current. The presence of neither chlorotoxin, hesperetin, kaempferol, morin nor iberiotoxin had any effects on IPAC density, whereas hydroxychloroquine or 4-[(2-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5yl)oxy] butanoic acid suppressed current density effectively. The application of PGG also led to a decrease in the area of voltage-dependent hysteresis of IPAC elicited by long-lasting isosceles-triangular ramp voltage command, suggesting that hysteretic strength was lessened in its presence. In human cardiac myocytes, the exposure to PGG also resulted in a reduction of ramp-induced IK(DR) density. Taken literally, PGG-perturbed adjustment of ionic currents could be direct and appears to be independent of its anti-oxidative property.
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Pérez PA, Toledo J, Sosa LDV, Peinetti N, Torres AI, De Paul AL, Gutiérrez S. The phthalate DEHP modulates the estrogen receptors α and β increasing lactotroph cell population in female pituitary glands. CHEMOSPHERE 2020; 258:127304. [PMID: 32559490 DOI: 10.1016/j.chemosphere.2020.127304] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/24/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
Humans are exposed to numerous endocrine disruptors on a daily basis, which may interfere with endogenous estrogens, with Di-(2-ethylhexyl) phthalate (DEHP) being one of the most employed. The anterior pituitary gland is a target of 17β-estradiol (E2) through the specific estrogen receptors (ERs) α and β, whose expression levels fluctuate in the gland under different contexts, and the ERα/β index is responsible for the final E2 effect. The aim of the present study was to evaluate in vivo and in vitro the DEHP effects on ERα and β expression in the pituitary cell population, and also its impact on lactotroph and somatotroph cell growth. Our results revealed that perinatal exposure to DEHP altered the ERα and β expression pattern in pituitary glands from prepubertal and adult female rats and increased the percentage of lactotroph cells in adulthood. In the in vitro system, DEHP down-regulated ERα and β expression, and as a result increased the ERα/β ratio and decreased the percentages of lactotrophs and somatotrophs expressing ERα and β. In addition, DEHP increased the S + G2M phases, Ki67 index and cyclin D1 in vitro, leading to a rise in the lactotroph and somatotroph cell populations. These results showed that DEHP modified the pituitary ERα and β expression in lactotrophs and somatotrophs from female rats and had an impact on the pituitary cell growth. These changes in ER expression may be a mechanism underlying DEHP exposure in the pituitary gland, leading to cell growth deregulation.
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Affiliation(s)
- Pablo A Pérez
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Jonathan Toledo
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Liliana Del Valle Sosa
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Nahuel Peinetti
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Alicia I Torres
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Ana L De Paul
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Silvina Gutiérrez
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-CONICET), Córdoba, Argentina; Centro de Microscopia Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
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Liu PY, Chang WT, Wu SN. Characterization of the Synergistic Inhibition of IK(erg) and IK(DR) by Ribociclib, a Cyclin-Dependent Kinase 4/6 Inhibitor. Int J Mol Sci 2020; 21:ijms21218078. [PMID: 33138174 PMCID: PMC7663338 DOI: 10.3390/ijms21218078] [Citation(s) in RCA: 7] [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: 09/25/2020] [Revised: 10/21/2020] [Accepted: 10/28/2020] [Indexed: 12/13/2022] Open
Abstract
Ribociclib (RIB, LE011, Kisqali®), an orally administered inhibitor of cyclin-dependent kinase-4/6 (CDK-4/6) complex, is clinically effective for the treatment of several malignancies, including advanced breast cancer. However, information regarding the effects of RIB on membrane ion currents is limited. In this study, the addition of RIB to pituitary tumor (GH3) cells decreased the peak amplitude of erg-mediated K+ current (IK(erg)), which was accompanied by a slowed deactivation rate of the current. The IC50 value for RIB-perturbed inhibition of deactivating IK(erg) in these cells was 2.7 μM. In continued presence of μM RIB, neither the subsequent addition of 17β-estradiol (30 μM), phorbol 12-myristate 13-acetate (10 μM), or transforming growth factor-β (1 μM) counteracted the inhibition of deactivating IK(erg). Its presence affected the decrease in the degree of voltage-dependent hysteresis for IK(erg) elicitation by long-duration triangular ramp voltage commands. The presence of RIB differentially inhibited the peak or sustained component of delayed rectifier K+ current (IK(DR)) with an effective IC50 of 28.7 or 11.4 μM, respectively, while it concentration-dependently decreased the amplitude of M-type K+ current with IC50 of 13.3 μM. Upon 10-s long membrane depolarization, RIB elicited a decrease in the IK(DR) amplitude, which was concomitant with an accelerated inactivation time course. However, the inability of RIB (10 μM) to modify the magnitude of the hyperpolarization-activated cation current was disclosed. The mean current–voltage relationship of IK(erg) present in HL-1 atrial cardiomyocytes was inhibited in the presence of RIB (10 μM). Collectively, the hyperpolarization-activated cation current was observed. RIB-mediated perturbations in ionic currents presented herein are upstream of its suppressive action on cytosolic CDK-4/6 activities and partly participates in its modulatory effects on the functional activities of pituitary tumor cells (e.g., GH3 cells) or cardiac myocytes (e.g., HL-1 cells).
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Affiliation(s)
- Pin-Yen Liu
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, National Cheng Kung University Hospital, Tainan 704, Taiwan;
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
| | - Wei-Ting Chang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
- Division of Cardiovascular Medicine, Chi-Mei Medical Center, Tainan 710, Taiwan
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 704, Taiwan
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 704, Taiwan
- Correspondence: ; Tel.: +886-6-2353535-5334; Fax: +886-6-2362780
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Lai MC, Wu SN, Huang CW. Telmisartan, an Antagonist of Angiotensin II Receptors, Accentuates Voltage-Gated Na + Currents and Hippocampal Neuronal Excitability. Front Neurosci 2020; 14:902. [PMID: 33013297 PMCID: PMC7499822 DOI: 10.3389/fnins.2020.00902] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/03/2020] [Indexed: 12/19/2022] Open
Abstract
Telmisartan (TEL), a non-peptide blocker of the angiotensin II type 1 receptor, is a widely used antihypertensive agent. Nevertheless, its neuronal ionic effects and how they potentially affect neuronal network excitability remain largely unclear. With the aid of patch-clamp technology, the effects of TEL on membrane ion currents present in hippocampal neurons (mHippoE-14 cells) were investigated. For additional characterization of the effects of TEL on hippocampal neuronal excitability, we undertook in vivo studies on Sprague Dawley (SD) rats using pilocarpine-induced seizure modeling, a hippocampal histopathological analysis, and inhibitory avoidance testing. In these hippocampal neurons, TEL increased the peak amplitude of INa, with a concomitant decline in the current inactivation rate. The TEL concentration dependently enhanced the peak amplitude of depolarization-elicited INa and lessened the inactivation rate of INa. By comparison, TEL was more efficacious in stimulating the peak INa and in prolonging the inactivation time course of this current than tefluthrin or (-)-epicatechin-3-gallate. In the continued presence of pioglitazone, the TEL-perturbed stimulation of INa remained effective. In addition, cell exposure to TEL shifted the steady-state inactivation INa curve to fewer negative potentials with no perturbations of the slope factor. Unlike chlorotoxin, either ranolazine, eugenol, or KMUP-1 reversed TEL-mediated increases in the strength of non-inactivating INa. In the cell-attached voltage-clamp recordings, TEL shortened the latency in the generation of action currents. Meanwhile, TEL increased the peak INa, with a concurrent decrease in current inactivation in HEKT293T cells expressing SCN5A. Furthermore, although TEL did not aggravate pilocarpine-induced chronic seizures and tended to preserve cognitive performance, it significantly accentuated hippocampal mossy fiber sprouting. Collectively, TEL stimulation of peak INa in combination with an apparent retardation in current inactivation could be an important mechanism through which hippocampal neuronal excitability is increased, and hippocampal network excitability is accentuated following status epilepticus, suggesting further attention to this finding.
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Affiliation(s)
- Ming-Chi Lai
- Department of Pediatrics, Chi-Mei Medical Center, Tainan, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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12
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Ramadan M, Cooper B, Posnack NG. Bisphenols and phthalates: Plastic chemical exposures can contribute to adverse cardiovascular health outcomes. Birth Defects Res 2020; 112:1362-1385. [PMID: 32691967 DOI: 10.1002/bdr2.1752] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 12/18/2022]
Abstract
Phthalates and bisphenols are high production volume chemicals that are used in the manufacturing of consumer and medical products. Given the ubiquity of bisphenol and phthalate chemicals in the environment, biomonitoring studies routinely detect these chemicals in 75-90% of the general population. Accumulating evidence suggests that such chemical exposures may influence human health outcomes, including cardiovascular health. These associations are particularly worrisome for sensitive populations, including fetal, infant and pediatric groups-with underdeveloped metabolic capabilities and developing organ systems. In the presented article, we aimed to review the literature on environmental and clinical exposures to bisphenols and phthalates, highlight experimental work that suggests that these chemicals may exert a negative influence on cardiovascular health, and emphasize areas of concern that relate to vulnerable pediatric groups. Gaps in our current knowledge are also discussed, so that future endeavors may resolve the relationship between chemical exposures and the impact on pediatric cardiovascular physiology.
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Affiliation(s)
- Manelle Ramadan
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia, USA.,Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia, USA
| | - Blake Cooper
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia, USA
| | - Nikki Gillum Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia, USA.,Children's National Heart Institute, Children's National Hospital, Washington, District of Columbia, USA.,Department of Pediatrics, George Washington University, School of Medicine, Washington, District of Columbia, USA.,Department of Pharmacology & Physiology, George Washington University, School of Medicine, Washington, District of Columbia, USA
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13
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Characterization of Convergent Suppression by UCL-2077 (3-(Triphenylmethylaminomethyl)pyridine), Known to Inhibit Slow Afterhyperpolarization, of erg-Mediated Potassium Currents and Intermediate-Conductance Calcium-Activated Potassium Channels. Int J Mol Sci 2020; 21:ijms21041441. [PMID: 32093314 PMCID: PMC7073080 DOI: 10.3390/ijms21041441] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 01/06/2023] Open
Abstract
UCL-2077 (triphenylmethylaminomethyl)pyridine) was previously reported to suppress slow afterhyperpolarization in neurons. However, the information with respect to the effects of UCL-2077 on ionic currents is quite scarce. The addition of UCL-2077 decreased the amplitude of erg-mediated K+ current (IK(erg)) together with an increased deactivation rate of the current in pituitary GH3 cells. The IC50 and KD values of UCL-2077-induced inhibition of IK(erg) were 4.7 and 5.1 μM, respectively. UCL-2077 (10 μM) distinctly shifted the midpoint in the activation curve of IK(erg) to less hyperpolarizing potentials by 17 mV. Its presence decreased the degree of voltage hysteresis for IK(erg) elicitation by long-lasting triangular ramp pulse. It also diminished the probability of the opening of intermediate-conductance Ca2+-activated K+ channels. In cell-attached current recordings, UCL-2077 raised the frequency of action currents. When KCNH2 mRNA was knocked down, a UCL-2077-mediated increase in AC firing was attenuated. Collectively, the actions elaborated herein conceivably contribute to the perturbating effects of this compound on electrical behaviors of excitable cells.
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14
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Characterization of Inhibitory Effectiveness in Hyperpolarization-Activated Cation Currents by a Group of ent-Kaurane-Type Diterpenoids from Croton tonkinensis. Int J Mol Sci 2020; 21:ijms21041268. [PMID: 32070065 PMCID: PMC7072998 DOI: 10.3390/ijms21041268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/07/2020] [Accepted: 02/09/2020] [Indexed: 12/24/2022] Open
Abstract
Croton is an extensive flowering plant genus in the spurge family, Euphorbiaceae. Three croton compounds with the common ent-kaurane skeleton have been purified from Croton tonkinensis. Methods: We examined any modifications of croton components (i.e., croton-01 [ent-18-acetoxy-7α-hydroxykaur-16-en-15-one], croton-02 [ent-7α,14β-dihydroxykaur-16-en-15-one] and croton-03 [ent-1β-acetoxy-7α,14β-dihydroxykaur-16-en-15-one] on either hyperpolarization-activated cation current (Ih) or erg-mediated K+ current identified in pituitary tumor (GH3) cells and in rat insulin-secreting (INS-1) cells via patch-clamp methods. Results: Addition of croton-01, croton-02, or croton-03 effectively and differentially depressed Ih amplitude. Croton-03 (3 μM) shifted the activation curve of Ih to a more negative potential by approximately 11 mV. The voltage-dependent hysteresis of Ih was also diminished by croton-03 administration. Croton-03-induced depression of Ih could not be attenuated by SQ-22536 (10 μM), an inhibitor of adenylate cyclase, but indeed reversed by oxaliplatin (10 μM). The Ih in INS-1 cells was also depressed effectively by croton-03. Conclusion: Our study highlights the evidence that these ent-kaurane diterpenoids might conceivably perturb these ionic currents through which they have high influence on the functional activities of endocrine or neuroendocrine cells.
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15
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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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Liu Y, Hsiao H, Wang JC, Liu Y, Wu S. Effectiveness of nalbuphine, a κ‐opioid receptor agonist and μ‐opioid receptor antagonist, in the inhibition ofINa,IK(M), andIK(erg)unlinked to interaction with opioid receptors. Drug Dev Res 2019; 80:846-856. [DOI: 10.1002/ddr.21568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/25/2019] [Accepted: 06/30/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Yuan‐Yuarn Liu
- Division of Trauma, Department of EmergencyKaohsiung Veterans General Hospital Kaohsiung City Taiwan
| | - Hung‐Tsung Hsiao
- Department of Anesthesiology, National Cheng Kung University Hospital, College of MedicineNational Cheng Kung University Tainan City Taiwan
| | - Jeffery C.‐F. Wang
- Department of Anesthesiology, National Cheng Kung University Hospital, College of MedicineNational Cheng Kung University Tainan City Taiwan
| | - Yen‐Chin Liu
- Department of Anesthesiology, National Cheng Kung University Hospital, College of MedicineNational Cheng Kung University Tainan City Taiwan
| | - Sheng‐Nan Wu
- Institute of Basic Medical SciencesNational Cheng Kung University Medical College Tainan City Taiwan
- Department of PhysiologyNational Cheng Kung University Medical College Tainan City Taiwan
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17
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Hsiao HT, Liu YC, Liu PY, Wu SN. Concerted suppression of I h and activation of I K(M) by ivabradine, an HCN-channel inhibitor, in pituitary cells and hippocampal neurons. Brain Res Bull 2019; 149:11-20. [PMID: 30951796 DOI: 10.1016/j.brainresbull.2019.03.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 11/24/2022]
Abstract
Ivabradine (IVA), a heart-rate reducing agent, is recognized as an inhibitor of hyperpolarization-activated cation current (Ih) and also reported to ameliorate inflammatory or neuropathic pain. However, to what extent this agent can perturb another types of membrane ion currents in neurons or endocrine cells remains to be largely unknown. Therefore, the Ih or other types of ionic currents in pituitary tumor (GH3) cells and in hippocampal mHippoE-14 neurons was studied with or without the presence of IVA or other related compounds. The IVA addition caused a time- and concentration-dependent reduction in the amplitude of Ih with an IC50 value of 0.64 μM and a KD value of 0.68 μM. IVA (0.3 μM) shifted the Ih activation curve to a more negative potential by approximately 8 mV, despite no concomitant change in the gating charge. Additionally, IVA was found to increase M-type K+ current (IK(M)) together with a rightward shift in the activation curve. In cell-attached current recordings, IVA (3 μM) applied to the bath increased the open probability of M-type K+ channels; however, it did not modify single-channel conductance of the channel. In current-clamp voltage recordings, IVA suppressed the firing of spontaneous action potentials in GH3 cells; and, further addition of linopirdine attenuated its suppression of firing. In hippocampal mHippoE-14 neurons, IVA also effectively increased IK(M) amplitude. In summary, both inhibition of Ih and activation of IK(M) caused by IVA can synergistically combine to influence electrical behaviors in different types of electrically excitable cells occurring in vivo.
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Affiliation(s)
- Hung-Tsung Hsiao
- 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
| | - Ping-Yen Liu
- Division of Cardiovascular Medicine, National Cheng Kung University Medical College, Tainan City, 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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18
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Lu TL, Chang WT, Chan CH, Wu SN. Evidence for Effective Multiple K +-Current Inhibitions by Tolvaptan, a Non-peptide Antagonist of Vasopressin V 2 Receptor. Front Pharmacol 2019; 10:76. [PMID: 30873020 PMCID: PMC6401633 DOI: 10.3389/fphar.2019.00076] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/21/2019] [Indexed: 12/28/2022] Open
Abstract
Tolvaptan (TLV), an oral non-peptide antagonist of vasopressin V2 receptor, has been increasingly used for managements in patients with hyponatremia and/or syndrome of inappropriate antidiuretic hormone secretion. However, none of the studies have thus far been investigated with regard to its possible perturbations on membrane ion currents in endocrine or neuroendocrine cells. In our electrophysiological study, the whole-cell current recordings showed that the presence of TLV effectively and differentially suppressed the amplitude of delayed rectifier K+ (IK(DR)) and M-type K+ current (IK(M)) in pituitary GH3 cells with an IC50 value of 6.42 and 1.91 μM, respectively. This compound was also capable of shifting the steady-state activation curve of IK(M) to less depolarized potential without any appreciable change in the gating charge of this current. TLV at a concentration greater than 10 μM also suppressed the amplitude of erg-mediated K+ current or the activity of large-conductance Ca2+-activated K+ channels; however, this compound failed to alter the amplitude of hyperpolarization-activated cation current in GH3 cells. In vasopressin-preincubated GH3 cells, TLV-mediated suppression of IK(M) remained little altered. Under current-clamp condition, we also observed that addition of TLV increased the firing of spontaneous action potentials in GH3 cells and further addition of flupirtine could reverse TLV-mediated elevation of the firing. In Madin-Darby canine kidney (MDCK) cells, the K+ current elicited by long ramp pulse was also effectively subject to inhibition by this compound. Findings from the present study were thus stated as saying that the suppression by TLV of multiple type K+ currents could be direct and independent of its antagonism of vasopressin V2 receptors. Our study also reveals an important aspect that should be considered when assessing aquaretic effect of TLV or its structurally similar compounds.
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Affiliation(s)
- Te-Ling Lu
- School of Pharmacy, China Medical University, Taichung, Taiwan
| | - Wei-Ting Chang
- Division of Cardiovascular Medicine, Chi-Mei Medical Center, Tainan, Taiwan
| | - Chee-Hong Chan
- Department of Nephrology, Chang Bing Show Chwan Memorial Hospital, Changhua, 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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So EC, Foo NP, Ko SY, Wu SN. Bisoprolol, Known to Be a Selective β₁-Receptor Antagonist, Differentially but Directly Suppresses I K(M) and I K(erg) in Pituitary Cells and Hippocampal Neurons. Int J Mol Sci 2019; 20:E657. [PMID: 30717422 PMCID: PMC6386942 DOI: 10.3390/ijms20030657] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 01/27/2019] [Accepted: 01/30/2019] [Indexed: 12/27/2022] Open
Abstract
Bisoprolol (BIS) is a selective antagonist of β₁ adrenergic receptors. We examined the effects of BIS on M-type K⁺ currents (IK(M)) or erg-mediated K⁺ currents (IK(erg)) in pituitary GH3, R1220 cells, and hippocampal mHippoE-14 cells. As GH₃ cells were exposed to BIS, amplitude of IK(M) was suppressed with an IC50 value of 1.21 μM. The BIS-induced suppression of IK(M) amplitude was not affected by addition of isoproterenol or ractopamine, but attenuated by flupirtine or ivabradine. In cell-attached current, BIS decreased the open probability of M-type K⁺ (KM) channels, along with decreased mean opening time of the channel. BIS decreased IK(erg) amplitude with an IC50 value of 6.42 μM. Further addition of PD-118057 attenuated BIS-mediated inhibition of IK(erg). Under current-clamp conditions, BIS depolarization increased the firing of spontaneous action potentials in GH₃ cells; addition of flupirtine, but not ractopamine, reversed BIS-induced firing rate. In R1220 cells, BIS suppressed IK(M); subsequent application of ML-213(Kv7.2 channel activator) reversed BIS-induced suppression of the current. In hippocampal mHippoE-14 neurons, BIS inhibited IK(M) to a greater extent compared to its depressant effect on IK(erg). This demonstrated that in pituitary cells and hippocampal neurons the presence of BIS is capable of directly and differentially suppressing IK(M) and IK(erg), despite its antagonism of β₁-adrenergic receptors.
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Affiliation(s)
- Edmund Cheung So
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan 70965, Taiwan.
- Department of Anesthesia, China Medical University, Taichung 40402, Taiwan.
- Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan 71101, Taiwan.
| | - Ning-Ping Foo
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan 70965, Taiwan.
- Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan 71101, Taiwan.
- Department of Emergency Medicine, An Nan Hospital, China Medical University, Tainan 70965, Taiwan.
| | - Shun Yao Ko
- Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan 71101, Taiwan.
| | - Sheng-Nan Wu
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 70101, Taiwan.
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan.
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20
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Chiang NJ, Wu SN, Kao CA, Huang YM, Chen LT. Stimulation of electroporation-induced inward currents in glioblastoma cell lines by the heat shock protein inhibitor AUY922. Clin Exp Pharmacol Physiol 2015; 41:830-7. [PMID: 24909268 DOI: 10.1111/1440-1681.12273] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 05/28/2014] [Accepted: 05/28/2014] [Indexed: 02/06/2023]
Abstract
Membrane electroporation (MEP) increases the electrical conductivity of the plasma membrane by addition of an external electrical field. Combining MEP-induced current (IMEP ) with antineoplastic agents has been increasingly considered as a new therapeutic manoeuvre, especially in the treatment of malignant gliomas. Thus, the aim of the present study was to evaluate the effect of AUY922 (AUY), a potent inhibitor of heat-shock protein 90 (HSP90), on IMEP in glioblastoma cells. The IMEP in glioblastoma cells (U373) was generated by repetitive hyperpolarization from -80 to -200 mV. The amplitude of IMEP was increased by AUY in a concentration-dependent manner, with an EC50 of 0.32 μmol/L. In addition AUY shortened the latency to IMEP generation. Before depolarization to +50 mV, hyperpolarization to -200 mV for 50 msec produced Ca(2+) influx and subsequently increased the amplitude of the Ca(2+) -activated K(+) current (IK(Ca) ). The amplitude of IK(Ca) and Ca(2+) influx was further increased by AUY through its ability to activate IMEP . Other HSP90 inhibitors, namely 17-(allylamino)-17-demethoxygeldanamycin (17-AAG; 1 μmol/L) and 6-chloro-9-[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]-9H-purin-2-amine (BIIB021; 1 μmol/L), only slightly (albeit significantly) increased the amplitude of IMEP in glioblastoma cells. A 50 msec depolarizing step elevated Ca(2+) influx and subsequently increased the amplitude of IK(Ca) in the presence of these three inhibitors. These data indicate that the AUY-mediated stimulation of IMEP and IK(Ca) in glioblastoma cells is independent of HSP90 inhibition. Moreover, these results indicate that AUY-stimulated IMEP and the subsequent activation of IK(Ca) may create important signalling events in glioblastoma cells. Thus, AUY is a drug that could potentially be used to augment the effectiveness of electrochemotherapy.
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Affiliation(s)
- Nai-Jung Chiang
- National Institute of Cancer Research, National Health Research Institutes, Tainan City, Taiwan; Division of Hematology/Oncology, Department of Internal Medicine, Tainan City, Taiwan
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Martín JMP, Freire PF, Daimiel L, Martínez-Botas J, Sánchez CM, Lasunción MÁ, Peropadre A, Hazen MJ. The antioxidant butylated hydroxyanisole potentiates the toxic effects of propylparaben in cultured mammalian cells. Food Chem Toxicol 2014; 72:195-203. [DOI: 10.1016/j.fct.2014.07.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 02/06/2023]
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22
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Zhang Y, Wang L, Du N, Ma G, Yang A, Zhang H, Wang Z, Song Q. Effects of diethylphthalate and di-(2-ethyl)hexylphthalate on the physiology and ultrastructure of cucumber seedlings. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:1020-1028. [PMID: 23860597 DOI: 10.1007/s11356-013-1884-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 05/29/2013] [Indexed: 06/02/2023]
Abstract
Phthalic acid esters (PAEs) are one kind of persistent organic pollutants. This study was conducted to investigate the effects of diethylphthalate (DEP) and di(2-ethyl)hexylphthalate (DEHP) with different concentrations (0, 30, 50, 100, and 200 mg L(-1)) on early seedling growth of Cucumis sativus L. Physiological, biochemical, and ultrastructure of seedling leaves were examined for 7-day exposure. The three antioxidant enzymes' activities was stimulated at low-DEP treatments and decreased under higher levels (>200 mg L(-1)) compared to the controls. Furthermore, MDA and H2O2 gradually enhanced with the elevation of DEP and DEHP concentration. Significant impact on the chloroplast and mitochondrion was visible, possibly as a consequence of free radical generation. DEP induced bigger and more starch grains in chloroplasts than DEHP. This study concluded that the effects of DEP and DEHP on cucumber seedlings represented the adverse impacts of DEP and DEHP on the ecosystem and agricultural production. The environmental harm caused by DEP was severer than DEHP.
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Affiliation(s)
- Ying Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin, 150030, People's Republic of China,
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