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Bollinger WL, Sial N, Dawson-Scully K. BK channels and a cGMP-dependent protein kinase (PKG) function through independent mechanisms to regulate the tolerance of synaptic transmission to acute oxidative stress at the Drosophila larval neuromuscular junction. J Neurogenet 2018; 32:246-255. [DOI: 10.1080/01677063.2018.1500571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Wesley L. Bollinger
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
| | - Nadia Sial
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
- Brain Institute Research Scholars Program, Florida Atlantic University, Boca Raton, FL, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
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2
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Krutetskaya ZI, Milenina LS, Naumova AA, Butov SN, Antonov VG, Nozdrachev AD. The effect of chlorpromazine on intracellular Ca 2+ concentration in macrophages. DOKL BIOCHEM BIOPHYS 2017; 474:162-164. [PMID: 28726103 DOI: 10.1134/s1607672917030036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Indexed: 11/22/2022]
Abstract
Using Fura-2AM microfluorimetry, it was shown for the first time that neuroleptic chlorpromazine causes intracellular Ca2+ concentration increase in macrophages due to Ca2+ mobilization from intracellular Ca2+ stores and subsequent Ca2+ entry from the external medium. Chlorpromazine-induced Ca2+ entry is inhibited by La3+ and 2-aminoethoxydiphenyl borate and is associated with Ca2+ store depletion.
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Affiliation(s)
- Z I Krutetskaya
- St. Petersburg State University, St. Petersburg, 199034, Russia.
| | - L S Milenina
- St. Petersburg State University, St. Petersburg, 199034, Russia
| | - A A Naumova
- St. Petersburg State University, St. Petersburg, 199034, Russia
| | - S N Butov
- St. Petersburg State University, St. Petersburg, 199034, Russia
| | - V G Antonov
- St. Petersburg State University, St. Petersburg, 199034, Russia
| | - A D Nozdrachev
- St. Petersburg State University, St. Petersburg, 199034, Russia
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3
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Kikuta S, Endo H, Tomita N, Takada T, Morita C, Asaoka K, Sato R. Characterization of a ligand-gated cation channel based on an inositol receptor in the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 74:12-20. [PMID: 27132146 DOI: 10.1016/j.ibmb.2016.04.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 04/25/2016] [Accepted: 04/26/2016] [Indexed: 06/05/2023]
Abstract
Insect herbivores recognize non-volatile compounds in plants to direct their feeding behavior. Gustatory receptors (Gr) appear to be required for nutrient recognition by gustatory organs in the mouthparts of insects. Gr10 is expressed in Bombyx mori (BmGr10) mouthparts such as maxillary galea, maxillary palp, and labrum. BmGr10 is predicted to function in sugar recognition; however, the precise biochemical function remains obscure. Larvae of B. mori are monophagous feeders able to find and feed on mulberry leaves. Soluble mulberry leaf extract contains sucrose, glucose, fructose, and myo-inositol. In this study, we identified BmGr10 as an inositol receptor using electrophysiological analysis with the Xenopus oocyte expression system and Ca(2+) imaging techniques using mammalian cells. These results demonstrated that Xenopus oocytes or HEK293T cells expressing BmGr10 specifically respond to myo-inositol and epi-inositol but do not respond to any mono-, di-, or tri-saccharides or to some sugar alcohols. These inositols caused Ca(2+) and Na(+) influxes into the cytoplasm independently of a G protein-mediated signaling cascade, indicating that BmGr10 is a ligand-gated cation channel. Overall, BmGr10 plays an important role in the myo-inositol recognition required for B. mori larval feeding behavior.
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Affiliation(s)
- Shingo Kikuta
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Natsuo Tomita
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Tomoyuki Takada
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Chiharu Morita
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Kiyoshi Asaoka
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan
| | - Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
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4
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Li HJ, Zhang YJ, Zhou L, Han F, Wang MY, Xue MQ, Qi Z. Chlorpromazine confers neuroprotection against brain ischemia by activating BKCa channel. Eur J Pharmacol 2014; 735:38-43. [PMID: 24755143 DOI: 10.1016/j.ejphar.2014.04.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/09/2014] [Accepted: 04/10/2014] [Indexed: 01/13/2023]
Abstract
Chlorpromazine (CPZ) is a well-known antipsychotic drug, still widely being used to treat symptoms of schizophrenia, psychotic depression and organic psychoses. We have previously reported that CPZ activates the BKCa (KCa1.1) channel at whole cell level. In the present study, we demonstrated that CPZ increased the single channel open probability of the BKCa channels without changing its single channel amplitude. As BKCa channel is one of the molecular targets of brain ischemia, we explored a possible new use of this old drug on ischemic brain injury. In middle cerebral artery occlusion (MCAO) focal cerebral ischemia, a single intraperitoneal injection of CPZ at several dosages (5mg/kg, 10mg/kg and 20mg/kg) could exert a significant neuroprotective effect on the brain damage in a dose- and time-dependent manner. Furthermore, blockade of BKCa channels abolished the neuroprotective effect of CPZ on MCAO, suggesting that the effect of CPZ is mediated by activation of the BKCa channel. These results demonstrate that CPZ could reduce focal cerebral ischemic damage through activating BKCa channels and merits exploration as a potential therapeutic agent for treating ischemic stroke.
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Affiliation(s)
- Hua-Juan Li
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiang'an Nan Lu, Xiamen 361102, China
| | - Yu-Jiao Zhang
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiang'an Nan Lu, Xiamen 361102, China
| | - Li Zhou
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiang'an Nan Lu, Xiamen 361102, China
| | - Feng Han
- College of Pharmaceutical Sciences, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China
| | - Ming-Yan Wang
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiang'an Nan Lu, Xiamen 361102, China
| | - Mao-Qiang Xue
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiang'an Nan Lu, Xiamen 361102, China.
| | - Zhi Qi
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiang'an Nan Lu, Xiamen 361102, China.
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Sadek B, Ashoor A, Mansouri AA, Lorke DE, Nurulain SM, Petroianu G, Wainwright M, Oz M. N3,N7-diaminophenothiazinium derivatives as antagonists of α7-nicotinic acetylcholine receptors expressed in Xenopus oocytes. Pharmacol Res 2012; 66:213-8. [DOI: 10.1016/j.phrs.2012.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 05/28/2012] [Accepted: 05/28/2012] [Indexed: 10/28/2022]
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Effects of phenothiazine-class antipsychotics on the function of α7-nicotinic acetylcholine receptors. Eur J Pharmacol 2011; 673:25-32. [PMID: 22044918 DOI: 10.1016/j.ejphar.2011.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 10/03/2011] [Accepted: 10/11/2011] [Indexed: 11/22/2022]
Abstract
The effects of phenothiazine-class antipsychotics (chlorpromazine, fluphenazine, phenothiazine, promazine, thioridazine, and triflupromazine) upon the function of the cloned α₇ subunit of the human nicotinic acetylcholine receptor expressed in Xenopus oocytes were tested using the two-electrode voltage-clamp technique. Fluphenazine, thioridazine, triflupromazine, chlorpromazine, and promazine reversibly inhibited acetylcholine (100 μM)-induced currents with IC₅₀ values of 3.8; 5.8; 6.1; 10.6 and 18.3 μM, respectively. Unsubstituted phenothiazine did not have a significant effect up to a concentration of 30 μM. Inhibition was further characterized using fluphenazine, the strongest inhibitor. The effect of fluphenazine was not dependent on the membrane potential. Fluphenazine (10 μM) did not affect the activity of endogenous Ca²⁺-dependent Cl⁻ channels, since the extent of inhibition by fluphenazine was unaltered by intracellular injection of the Ca²⁺ chelator BAPTA and perfusion with Ca²⁺-free bathing solution containing 2 mM Ba²⁺. Inhibition by fluphenazine, but not by chlorpromazine was reversed by increasing acetylcholine concentrations. Furthermore, specific binding of [¹²⁵I] α-bungarotoxin, a radioligand selective for α₇-nicotinic acetylcholine receptor, was inhibited by fluphenazine (10 μM), but not by chlorpromazine in oocyte membranes. In hippocampal slices, epibatidine-evoked [³H] norepinephrine release was also inhibited by fluphenazine (10 μM) and chlorpromazine (10 μM). Our results indicate that phenothiazine-class typical antipsychotics inhibit, with varying potencies, the function of α₇-nicotinic acetylcholine receptor.
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Bianchi MT. Promiscuous modulation of ion channels by anti-psychotic and anti-dementia medications. Med Hypotheses 2010; 74:297-300. [DOI: 10.1016/j.mehy.2009.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Accepted: 09/06/2009] [Indexed: 10/20/2022]
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Qu YJ, Bondarenko VE, Xie C, Wang S, Awayda MS, Strauss HC, Morales MJ. W-7 modulates Kv4.3: pore block and Ca2+-calmodulin inhibition. Am J Physiol Heart Circ Physiol 2007; 292:H2364-77. [PMID: 17220193 DOI: 10.1152/ajpheart.00409.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca(+)-calmodulin (Ca(2+)-CaM)-dependent protein kinase II (Ca(2+)/CaMKII) is an important regulator of cardiac ion channels, and its inhibition may be an approach for treatment of ventricular arrhythmias. Using the two-electrode voltage-clamp technique, we investigated the role of W-7, an inhibitor of Ca(2+)-occupied CaM, and KN-93, an inhibitor of Ca(2+)/CaMKII, on the K(v)4.3 channel in Xenopus laevis oocytes. W-7 caused a voltage- and concentration-dependent decrease in peak current, with IC(50) of 92.4 muM. The block was voltage dependent, with an effective electrical distance of 0.18 +/- 0.05, and use dependence was observed, suggesting that a component of W-7 inhibition of K(v)4.3 current was due to open-channel block. W-7 made recovery from open-state inactivation a biexponential process, also suggesting open-channel block. We compared the effects of W-7 with those of KN-93 after washout of 500 muM BAPTA-AM. KN-93 reduced peak current without evidence of voltage or use dependence. Both W-7 and KN-93 accelerated all components of inactivation. We used wild-type and mutated K(v)4.3 channels with mutant CaMKII consensus phosphorylation sites to examine the effects of W-7 and KN-93. In contrast to W-7, KN-93 at 35 muM selectively accelerated open-state inactivation in the wild-type vs. the mutant channel. W-7 had a significantly greater effect on recovery from inactivation in wild-type than in mutant channels. We conclude that, at certain concentrations, KN-93 selectively inhibits Ca(2+)/CaMKII activity in Xenopus oocytes and that the effects of W-7 are mediated by direct interaction with the channel pore and inhibition of Ca(2+)-CaM, as well as a change in activity of Ca(2+)-CaM-dependent enzymes, including Ca(2+)/CaMKII.
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Affiliation(s)
- Yu-Jie Qu
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo-State University of New York, 3435 Main Street, Buffalo, NY 14214, USA
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Goytain A, Quamme GA. Identification and characterization of a novel mammalian Mg2+ transporter with channel-like properties. BMC Genomics 2005; 6:48. [PMID: 15804357 PMCID: PMC1129089 DOI: 10.1186/1471-2164-6-48] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 04/01/2005] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Intracellular magnesium is abundant, highly regulated and plays an important role in biochemical functions. Despite the extensive evidence for unique mammalian Mg2+ transporters, few proteins have been biochemically identified to date that fulfill this role. We have shown that epithelial magnesium conservation is controlled, in part, by differential gene expression leading to regulation of Mg2+ transport. We used this knowledge to identify a novel gene that is regulated by magnesium. RESULTS Oligonucleotide microarray analysis was used to identify a novel human gene that encodes a protein involved with Mg2+-evoked transport. We have designated this magnesium transporter (MagT1) protein. MagT1 is a novel protein with no amino acid sequence identity to other known transporters. The corresponding cDNA comprises an open reading frame of 1005 base pairs encoding a protein of 335 amino acids. It possesses five putative transmembrane (TM) regions with a cleavage site, a N-glycosylation site, and a number of phosphorylation sites. Based on Northern analysis of mouse tissues, a 2.4 kilobase transcript is present in many tissues. When expressed in Xenopus laevis oocytes, MagT1 mediates saturable Mg2+ uptake with a Michaelis constant of 0.23 mM. Transport of Mg2+ by MagT1 is rheogenic, voltage-dependent, does not display any time-dependent inactivation. Transport is very specific to Mg2+ as other divalent cations did not evoke currents. Large external concentrations of some cations inhibited Mg2+ transport (Ni2+, Zn2+, Mn2+) in MagT1-expressing oocytes. Ca2+and Fe2+ were without effect. Real-time reverse transcription polymerase chain reaction and Western blot analysis using a specific antibody demonstrated that MagT1 mRNA and protein is increased by about 2.1-fold and 32%, respectively, in kidney epithelial cells cultured in low magnesium media relative to normal media and in kidney cortex of mice maintained on low magnesium diets compared to those animals consuming normal diets. Accordingly, it is apparent that an increase in mRNA levels is translated into higher protein expression. CONCLUSION These studies suggest that MagT1 may provide a selective and regulated pathway for Mg2+ transport in epithelial cells.
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Affiliation(s)
- Angela Goytain
- Department of Medicine University of British Columbia Vancouver, B.C. Canada
| | - Gary A Quamme
- Department of Medicine University of British Columbia Vancouver, B.C. Canada
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10
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Goytain A, Quamme GA. Functional characterization of human SLC41A1, a Mg2+ transporter with similarity to prokaryotic MgtE Mg2+ transporters. Physiol Genomics 2005; 21:337-42. [PMID: 15713785 DOI: 10.1152/physiolgenomics.00261.2004] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We have begun to identify and characterize genes that are differentially expressed with low magnesium. One of these sequences conformed to the solute carrier SLC41A1. Real-time RT-PCR of RNA isolated from renal distal tubule epithelial [mouse distal convoluted tubule (MDCT)] cells cultured in low-magnesium media relative to normal media and in the kidney cortex of mice maintained on low-magnesium diets compared with those animals consuming normal diets confirmed that the SLC41A1 transcript is responsive to magnesium. Mouse SLC41A1 was cloned from MDCT cells, expressed in Xenopus laevis oocytes, and studied with two-electrode voltage-clamp studies. When expressed in oocytes, SLC41A1 mediates saturable Mg2+ uptake with a Michaelis constant of 0.67 mM. Transport of Mg2+ by SLC41A1 is rheogenic, voltage dependent, and not coupled to Na+ or Cl-. Expressed SLC41A1 transports a range of other divalent cations: Mg2+, Sr2+, Zn2+, Cu2+, Fe2+, Co2+, Ba2+, and Cd2+. The divalent cations Ca2+, Mn2+, and Ni2+ and the trivalent ion Gd3+ did not induce currents nor did they inhibit Mg2+ transport. The nonselective cation La3+ abolished Mg2+ uptake. The SLC41A1 transcript is present in many tissues, notably renal epithelial cells, and is upregulated in some tissues with magnesium deficiency. These studies suggest that SLC41A1 is a regulated Mg2+ transporter that might be involved in magnesium homeostasis in epithelial cells.
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Affiliation(s)
- Angela Goytain
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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11
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Thomas D, Wu K, Kathöfer S, Katus HA, Schoels W, Kiehn J, Karle CA. The antipsychotic drug chlorpromazine inhibits HERG potassium channels. Br J Pharmacol 2003; 139:567-74. [PMID: 12788816 PMCID: PMC1573882 DOI: 10.1038/sj.bjp.0705283] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
(1) Acquired long QT syndrome (aLQTS) is caused by prolongation of the cardiac action potential because of blockade of cardiac ion channels and delayed repolarization of the heart. Patients with aLQTS carry an increased risk for torsade de pointes arrhythmias and sudden cardiac death. Several antipsychotic drugs may cause aLQTS. Recently, cases of QTc prolongation and torsade de pointes associated with chlorpromazine treatment have been reported. Blockade of human ether-a-go-go-related gene (HERG) potassium channels, which plays a central role in arrhythmogenesis, has previously been reported to occur with chlorpromazine, but information on the mechanism of block is currently not available. We investigated the effects of chlorpromazine on cloned HERG potassium channels to determine the biophysical mechanism of block. (2) HERG channels were heterologously expressed in Xenopus laevis oocytes, and ion currents were measured using the two-microelectrode voltage-clamp technique. (3) Chlorpromazine blocked HERG potassium channels with an IC(50) value of 21.6 micro M and a Hill coefficient of 1.11. (4) Analysis of the voltage dependence of block revealed a reduction of inhibition at positive membrane potentials. (5) Inhibition of HERG channels by chlorpromazine displayed reverse frequency dependence, that is, the amount of block was lower at higher stimulation rates. No marked changes in electrophysiological parameters such as voltage dependence of activation or inactivation, or changes of the inactivation time constant were observed. (6) In conclusion, HERG channels were blocked in the closed and activated states, and unblocking occurred very slowly.
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Affiliation(s)
- Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
| | - Kezhong Wu
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
| | - Sven Kathöfer
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
| | - Wolfgang Schoels
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
| | - Johann Kiehn
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
| | - Christoph A Karle
- Department of Cardiology, Medical University Hospital Heidelberg, Bergheimerstrasse 58, D-69115 Heidelberg, Germany
- Author for correspondence:
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Chernova MN, Stewart AK, Jiang L, Friedman DJ, Kunes YZ, Alper SL. Structure-function relationships of AE2 regulation by Ca(i)(2+)-sensitive stimulators NH(4+) and hypertonicity. Am J Physiol Cell Physiol 2003; 284:C1235-46. [PMID: 12529246 DOI: 10.1152/ajpcell.00522.2002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We showed previously that the nonerythroid anion exchanger AE2 and the erythroid anion exchanger AE1 differ greatly in their regulation by acute changes in intracellular pH (pH(i)) and extracellular pH (pH(o)). We have now examined how AE2, but not AE1, is activated by two stimuli with opposing effects on oocyte pH(i): an alkalinizing stimulus, hypertonicity, and an acidifying stimulus, NH(4)(+). We find that both NH(2)-terminal cytoplasmic and COOH-terminal transmembrane domains of AE2 are required for activation by either stimulus. Directed by initial deletion mutagenesis studies of the NH(2)-terminal cytoplasmic domain, an alanine scan of AE2 amino acids 336-347 identified residues whose individual mutation abolished or severely attenuated sensitivity to both or only one activating stimulus. Chelation of cytoplasmic Ca(2+) (Ca(i)(2+)) diminished or abolished AE2 stimulation by NH(4)(+) and by hypertonicity. Calmidazolium inhibited AE2 activity, but not that of AE1. AE2 was insensitive to many other modifiers of Ca(2+) signaling. Unlike AE2 stimulation by NH(4)(+) and by hypertonicity, AE2 inhibition by calmidazolium required only AE2's COOH-terminal transmembrane domain.
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Affiliation(s)
- Marina N Chernova
- Molecular Medicine and Renal Units, Beth Israel Deaconess Medical Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
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Karmakar P, Natarajan AT, Poddar RK, Dasgupta UB. Induction of apoptosis by Phenothiazine derivatives in V79 cells. Toxicol Lett 2001; 125:19-28. [PMID: 11701219 DOI: 10.1016/s0378-4274(01)00411-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Phenothiazine derivatives chlorpromazine (cpz) and trifluoperazine (tfp) were found to induce apoptosis, abnormal cell cycle and expression of p53 in Chinese hamster lung fibroblast V79 cells. Both the drugs can induce apoptosis when cells are treated with drug at a concentration of 10 microg/ml within 4 h, as detected by propidium iodide staining and DNA fragmentation analysis. Flow cytometric analysis revealed that the apoptotic response is mediated by a loss of G(1) population of cells. In Western blot analysis, p21 is induced and p53 is accompanied by additional bands. Also indirect immunolabeling of single cells revealed that p21 is accumulated from cytoplasm into nucleus after the drug treatment and the intensities of p53 increased. Our findings demonstrate for the first time that phenothiazine derivatives, in addition to their cytotoxic effects, could induce apoptosis, an observation that has important clinical implications.
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Affiliation(s)
- P Karmakar
- Department of Biophysics, Molecular Biology & Genetics, 92, A.P.C. Road, 700 009, Calcutta, India.
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14
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McNaughton NC, Green PJ, Randall AD. Inhibition of human alpha1E subunit-mediated ca2+ channels by the antipsychotic agent chlorpromazine. ACTA PHYSIOLOGICA SCANDINAVICA 2001; 173:401-8. [PMID: 11903132 DOI: 10.1046/j.1365-201x.2001.00914.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chlorpromazine is a neuroleptic antipsychotic agent with a long history of clinical use. Its primary mode of action is thought to be through modulation of monoaminergic inter-neuronal communication; however, its side-effect profile indicates substantial activities in other systems. Recent work has begun to uncover actions of this compound on ion channels. In this light we have investigated the actions of chlorpromazine on the recombinant alpha1E subunit-encoded voltage-sensitive Ca2+ channel (VSCC) that is believed to encode drug-resistant R-type currents found in neurones and other cells. Chlorpromazine produced a dose-dependent antagonism of these channels that was reversed on drug removal. The mean IC50 was close to 10 microM. At this concentration, the level of antagonism observed was dependent on the membrane potential, with greater inhibition being observed at more negative test potentials. Furthermore, chlorpromazine induced substantial changes in the steady-state inactivation properties of alpha1Ebeta3-mediated currents, although it was not seen to elicit a corresponding change in inactivation kinetics. These results are discussed with regard to the possible clinical mechanisms of chlorpromazine actions.
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Affiliation(s)
- N C McNaughton
- Neuroscience Research, GlaxoSmithKline Pharmaceuticals, Harlow, UK
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15
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Abstract
K(+) channel effectors are widely used in the treatment of various diseases, including diabetes mellitus type II, hypertension, and cardiac arrhythmia. In addition, a constantly growing body of literature reveals that some of these substances, despite their direct effect on K(+) channels, may influence cellular lipid metabolism. As a result, membrane lipid content and cellular concentrations of lipid messengers are changed. Due to the dependence of K(+) channel activity on membrane lipids, these observations seem to be of particular importance not only to characterize secondary effects of K(+) channel effectors but also to understand the long-term effects of these agents on K(+) channel activity.
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Affiliation(s)
- A Szewczyk
- Laboratories of *Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland.
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16
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Weber W. Ion currents of Xenopus laevis oocytes: state of the art. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1421:213-33. [PMID: 10518693 DOI: 10.1016/s0005-2736(99)00135-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- W Weber
- Laboratory of Physiology, K.U. Leuven, Campus Gasthuisberg, B-3000, Leuven, Belgium.
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17
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Rogalski SL, Cyr C, Chavkin C. Activation of the endothelin receptor inhibits the G protein-coupled inwardly rectifying potassium channel by a phospholipase A2-mediated mechanism. J Neurochem 1999; 72:1409-16. [PMID: 10098843 DOI: 10.1046/j.1471-4159.1999.721409.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To develop a malleable system to model the well-described, physiological interactions between Gq/11 - coupled receptor and Gi/o-coupled receptor signaling, we coexpressed the endothelin A receptor, the mu-opioid receptor, and the G protein-coupled inwardly rectifying potassium channel (Kir 3) heteromultimers in Xenopus laevis oocytes. Activation of the Gi/o-coupled mu-opioid receptor strongly increased Kir 3 channel current, whereas activation of the Gq/11-coupled endothelin A receptor inhibited the Kir 3 response evoked by mu-opioid receptor activation. The magnitude of the inhibition of Kir 3 was channel subtype specific; heteromultimers composed of Kir 3.1 and Kir 3.2 or Kir 3.1 and Kir 3.4 were significantly more sensitive to the effects of endothelin-1 than heteromultimers composed of Kir 3.1 and Kir 3.5. The difference in sensitivity of the heteromultimers suggests that the endothelin-induced inhibition of the opioid- activated current was caused by an effect at the channel rather than at the opioid receptor. The endothelin-1-mediated inhibition was mimicked by arachidonic acid and blocked by the phospholipase A2 inhibitor arachidonoyl trifluoromethyl ketone. Consistent with a possible phospholipase A2-mediated mechanism, the endothelin-1 effect was blocked by calcium chelation with BAPTA-AM and was not affected by kinase inhibition by either staurosporine or genistein. The data suggest the hypothesis that Gq/11-coupled receptor activation may interfere with Gi/o-coupled receptor signaling by the activation of phospholipase A2 and subsequent inhibition of effector function by a direct effect of an eicosanoid on the channel.
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Affiliation(s)
- S L Rogalski
- Department of Pharmacology, University of Washington, Seattle 98195-7280, USA
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