Hormonally controlled chloride movement across Drosophila tubules is via ion channels in stellate cells

1998 ◽  
Vol 274 (4) ◽  
pp. R1039-R1049 ◽  
Author(s):  
Michael J. O’Donnell ◽  
Mark R. Rheault ◽  
Shireen A. Davies ◽  
Phillipe Rosay ◽  
Brian J. Harvey ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Chloride Channel ◽  
Chloride Channels ◽  
Stellate Cells ◽  
Fluid Secretion ◽  
Physiological Effect ◽  
Disulfonic Acid ◽  
Channel Blockers ◽  
Anion Conductance ◽  
Cation Conductance

Anion conductance across the Drosophila melanogaster Malpighian (renal) tubule was investigated by a combination of physiological and transgenic techniques. Patch-clamp recordings identified clusters of 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS)-sensitive “maxi-chloride” channels in a small domain of the apical membrane. Fluid secretion assays demonstrated sensitivity to the chloride channel blockers 5-nitro-2-(3-phenylpropylamino)benzoic acid, diphenylamine-2-carboxylate, anthracene-9-carboxylic acid, and niflumic acid. Electrophysiological analysis showed that the calcium-mediated increase in anion conductance was blocked by the same agents. Vibrating probe analysis revealed a small number of current density hot spots, coincident with “stellate” cells, that were abolished by low-chloride saline or the same chloride channel blockers. GAL-4-targeted expression of an aequorin transgene revealed that the neurohormone leucokinin elicits a rapid increase in intracellular calcium levels in stellate cells that precedes the fastest demonstrable physiological effect. Taken together, these data show that leucokinins act on stellate cells through intracellular calcium to increase transcellular chloride conductance through channels. As electrogenic cation conductance is confined to principal cells, the two pathways are spatially segregated in this tissue.

The Effects of Chloride Channel Blockers on Platelet Cytoplasmic Free Calcium Concentration and Platelet Aggregation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3879-3879
Author(s):  
Songmei Yin ◽  
Xiaolin Chen ◽  
Danian Nie ◽  
Shuangfeng Xie ◽  
Liping Ma ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Calcium Channel ◽  
Calcium Channel Blockers ◽  
Chloride Channel ◽  
Calcium Concentration ◽  
Disulfonic Acid ◽  
Free Calcium ◽  
Channel Blockers ◽  
Free Calcium Concentration ◽  
Cytoplasmic Free Calcium

Abstract Objective To explore the effects of chloride channels on the regulations of platelet cytoplasmic free calcium concentration ([Ca2+]i) and platelet aggregation (PAG). Methods Platelet were separated freshly and then activated by thrombin; The chloride channel blockers 4,4′-diisothiocyano-2, 2′-disulfonic acid stilbene (DIDS) or niflumic acid (NFA), and calcium channel blockers 1-{β-[3-(4-methoxyphenyl)propoxy]- 4-methoxyphenethyl}- 1H - imidazole hydrochloride (SK&F96365) or Nifedipine were added to react with the activated platelets. The effects of each agent on platelet [Ca2+]i and PAG were detected. The combine effects and the interactions among chloride channel blockers (DIDS, NFA) and calcium channel blockers (SK&F96365, Nifedipine) were also investigated. Results Both DIDS and NFA [the concentration were12.5, 25, 50, 100 and 200μmol•L−1 respectively] could inhibit the PAG induced by thrombin (1U/ml) and the effect was dose-dependent. Compared with the control, they had no significant effects on resting [Ca2+]i. Compare with the control group, DIDS (100μmol•L−1), SK&F96365 (100μmol•L−1) and Nifedipine (100μmol•L−1) could significantly reduce the PAG, Ca2+ release and Ca2+ influx activated by thrombin in platelet (P<0.05). DIDS (100μmol•L−1) and SK&F96365 (100μmol•L−1) could enhance each other’s effect on reducing the PAG, Ca2+ release and Ca2+ influx (P<0.05). DIDS (100μmol•L−1) and Nifedipine (100μmol•L−1) could enhance each other’s effect on reducing Ca2+ release (P<0.05). NFA (100μmol•L−1) and SK&F96365 (100μmol•L−1) could weaken each other’s effect on Ca2+ release (P<0.05). NFA (100μmol•L−1) and Nifedipine (100μmol•L−1) could weaken each other’s effect on PAG, Ca2+ release and Ca2+ influx activated by thrombin in platelet (P<0.05). Conclusion The chloride channel blockers DIDS and NFA have no effect on the resting [Ca2+]i and the leak calcium influx of platelet. DIDS can inhibit the Ca2+ release, Ca2+ influx and PAG of platelet induced by thrombin, while NFA can only inhibit the Ca2+ release of platelet induced by thrombin. There are interactions between chloride channel blockers and calcium channel blockers in resting [Ca2+]i and PAG of platelet. The opening of chloride channel can influence the cellular calcium movement of platelet.

scholarly journals Stilbene derivatives inhibit the activity of the inner mitochondrial membrane chloride channels

2007 ◽  
Vol 12 (4) ◽  
Author(s):  
Izabela Koszela-Piotrowska ◽  
Katarzyna Choma ◽  
Piotr Bednarczyk ◽  
Krzysztof Dołowy ◽  
Adam Szewczyk ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Chloride Channel ◽  
Chloride Channels ◽  
Mitochondrial Membrane ◽  
Disulfonic Acid ◽  
Mitochondrial Membranes ◽  
Rat Skeletal Muscle ◽  
Inner Mitochondrial Membrane ◽  
Stilbene Derivatives ◽  
Rat Heart Mitochondria

AbstractIon channels selective for chloride ions are present in all biological membranes, where they regulate the cell volume or membrane potential. Various chloride channels from mitochondrial membranes have been described in recent years. The aim of our study was to characterize the effect of stilbene derivatives on single-chloride channel activity in the inner mitochondrial membrane. The measurements were performed after the reconstitution into a planar lipid bilayer of the inner mitochondrial membranes from rat skeletal muscle (SMM), rat brain (BM) and heart (HM) mitochondria. After incorporation in a symmetric 450/450 mM KCl solution (cis/trans), the chloride channels were recorded with a mean conductance of 155 ± 5 pS (rat skeletal muscle) and 120 ± 16 pS (rat brain). The conductances of the chloride channels from the rat heart mitochondria in 250/50 mM KCl (cis/trans) gradient solutions were within the 70–130 pS range. The chloride channels were inhibited by these two stilbene derivatives: 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS) and 4-acetamido-4′-isothiocyanostilbene-2,2′-disulfonic acid (SITS). The skeletal muscle mitochondrial chloride channel was blocked after the addition of 1 mM DIDS or SITS, whereas the brain mitochondrial channel was blocked by 300 μM DIDS or SITS. The chloride channel from the rat heart mitochondria was inhibited by 50–100 μM DIDS. The inhibitory effect of DIDS was irreversible. Our results confirm the presence of chloride channels sensitive to stilbene derivatives in the inner mitochondrial membrane from rat skeletal muscle, brain and heart cells.

scholarly journals Chloride channel blockade relaxes airway smooth muscle and potentiates relaxation by β-agonists

2014 ◽  
Vol 307 (3) ◽  
pp. L273-L282 ◽  
Author(s):  
Jennifer Danielsson ◽  
Peter Yim ◽  
Alison Rinderspacher ◽  
Xiao Wen Fu ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Airway Smooth Muscle ◽  
Chloride Channel ◽  
Chloride Channels ◽  
Ex Vivo ◽  
Maintenance Phase ◽  
Channel Blockers ◽  
Asthmatic Patients ◽  
Inward Currents

Severe bronchospasm refractory to β-agonists continues to cause significant morbidity and mortality in asthmatic patients. We questioned whether chloride channels/transporters are novel targets for the relaxation of airway smooth muscle (ASM). We have screened a library of compounds, derivatives of anthranilic and indanyloxyacetic acid, that were originally developed to antagonize chloride channels in the kidney. We hypothesized that members of this library would be novel calcium-activated chloride channel blockers for the airway. The initial screen of this compound library identified 4 of 20 compounds that relaxed a tetraethylammonium chloride-induced contraction in guinea pig tracheal rings. The two most effective compounds, compounds 1 and 13, were further studied for their potential to either prevent the initiation of or relax the maintenance phase of an acetylcholine (ACh)-induced contraction or to potentiate β-agonist-mediated relaxation. Both relaxed an established ACh-induced contraction in human and guinea pig ex vivo ASM. In contrast, the prevention of an ACh-induced contraction required copretreatment with the sodium-potassium-chloride cotransporter blocker bumetanide. The combination of compound 13 and bumetanide also potentiated relaxation by the β-agonist isoproterenol in guinea pig tracheal rings. Compounds 1 and 13 hyperpolarized the plasma cell membrane of human ASM cells and blocked spontaneous transient inward currents, a measure of chloride currents in these cells. These functional and electrophysiological data suggest that modulating ASM chloride flux is a novel therapeutic target in asthma and other bronchoconstrictive diseases.

ClC-3 is a candidate of the channel proteins mediating acid-activated chloride currents in nasopharyngeal carcinoma cells

2012 ◽  
Vol 303 (1) ◽  
pp. C14-C23 ◽  
Author(s):  
Liwei Wang ◽  
Wenbo Ma ◽  
Linyan Zhu ◽  
Dong Ye ◽  
Yuan Li ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Chloride Channel ◽  
Cell Function ◽  
Extracellular Ph ◽  
Carcinoma Cells ◽  
Chloride Current ◽  
Disulfonic Acid ◽  
Channel Blockers ◽  
Chloride Currents ◽  
Channel Proteins

Acid-activated chloride currents have been reported in several cell types and may play important roles in regulation of cell function. However, the molecular identities of the channels that mediate the currents are not defined. In this study, activation of the acid-induced chloride current and the possible candidates of the acid-activated chloride channel were investigated in human nasopharyngeal carcinoma cells (CNE-2Z). A chloride current was activated when extracellular pH was reduced to 6.6 from 7.4. However, a further decrease of extracellular pH to 5.8 inhibited the current. The current was weakly outward-rectified and was suppressed by hypertonicity-induced cell shrinkage and by the chloride channel blockers 5-nitro-2–3-phenylpropylamino benzoic acid (NPPB), tamoxifen, and 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid disodium salt hydrate (DIDS). The permeability sequence of the channel to anions was I− > Br− > Cl− > gluconate−. Among the ClC chloride channels, ClC-3 and ClC-7 were strongly expressed in CNE-2Z cells. Knockdown of ClC-3 expression with ClC-3 small interfering (si)RNA prevented the activation of the acid-induced current, but silence of ClC-7 expression with ClC-7 siRNA did not significantly affect the current. The results suggest that the chloride channel mediating the acid-induced chloride current was volume sensitive. ClC-3 is a candidate of the channel proteins that mediate or regulate the acid-activated chloride current in nasopharyngeal carcinoma cells.

Production of superoxide and TNF-α from alveolar macrophages is blunted by glycine

1999 ◽  
Vol 277 (5) ◽  
pp. L952-L959 ◽  
Author(s):  
Michael D. Wheeler ◽  
Ronald G. Thurman
Keyword(s):  
Intracellular Calcium ◽  
Kupffer Cells ◽  
Alveolar Macrophages ◽  
Chloride Channel ◽  
Chloride Channels ◽  
Dependent Manner ◽  
Tnf Α ◽  
The Central Nervous System ◽  
Factor Α ◽  
Dose Dependent

Glycine blunts lipopolysaccharide (LPS)-induced increases in intracellular calcium concentration ([Ca2+]i) and tumor necrosis factor-α (TNF-α) production by Kupffer cells through a glycine-gated chloride channel. Alveolar macrophages, which have a similar origin as Kupffer cells, play a significant role in the pathogenesis of several lung diseases including asthma, endotoxemia, and acute inflammation due to inhaled bacterial particles and dusts. Therefore, studies were designed here to test the hypothesis that alveolar macrophages could be inactivated by glycine via a glycine-gated chloride channel. The ability of glycine to prevent endotoxin [lipopolysaccharide (LPS)]-induced increases in [Ca2+]iand subsequent production of superoxide and TNF-α in alveolar macrophages was examined. LPS caused a transient increase in intracellular calcium to nearly 200 nM, with EC50values slightly greater than 25 ng/ml. Glycine, in a dose-dependent manner, blunted the increase in [Ca2+]i, with an IC50less than 100 μM. Like the glycine-gated chloride channel in the central nervous system, the effects of glycine on [Ca2+]iwere both strychnine sensitive and chloride dependent. Glycine also caused a dose-dependent influx of radiolabeled chloride with EC50values near 10 μM, a phenomenon which was also inhibited by strychnine (1 μM). LPS-induced superoxide production was also blunted in a dose-dependent manner by glycine and was reduced ∼50% with 10 μM glycine. Moreover, TNF-α production was also inhibited by glycine and also required nearly 10 μM glycine for half-inhibition. These data provide strong pharmacological evidence that alveolar macrophages contain glycine-gated chloride channels and that their activation is protective against the LPS-induced increase in [Ca2+]iand subsequent production of toxic radicals and cytokines.

A capacitative Ca2+ influx is required for sustained fluid secretion in sublingual mucous acini

1991 ◽  
Vol 261 (6) ◽  
pp. G1043-G1050 ◽  
Author(s):  
J. E. Melvin ◽  
L. Koek ◽  
G. H. Zhang
Keyword(s):  
Anion Exchange ◽  
Fluid Secretion ◽  
Mucous Gland ◽  
Disulfonic Acid ◽  
Channel Blockers ◽  
Free Medium ◽  
Fura 2 ◽  
Entry Pathway ◽  
Electrolyte Secretion ◽  
Induced Changes

The Ca2+ dependence of muscarinic-induced fluid and electrolyte secretion was studied using rat sublingual mucous gland preparations. During stimulation, secretions from vascularly perfused glands were totally inhibited when perfused with a Ca(2+)-free medium. Fluid secretion correlated with sustained losses of 42K+ and 36Cl- content and sustained increases in 22Na+ content and the intracellular free Ca2+ concentration ([Ca2+]i) in fura-2-loaded acini. The magnitudes of the initial agonist-induced changes in Na+, K+, and Cl- content and [Ca2+]i were unaltered in a Ca(2+)-free medium, whereas extracellular Ca2+ removal resulted in the recovery of these ions during the sustained phase to pre-stimulation levels. The recovery of Cl- content induced by Ca2+ depletion was totally blocked in the presence of bumetanide, an inhibitor of Na(+)-K(+)-2Cl- cotransport, while 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), an inhibitor of anion exchange, did not influence Cl- recovery in a HCO(3-)-containing solution (25 mM NaHCO3, 5% CO2). The stimulated increase in [Ca2+]i was not inhibited by the addition of voltage-activated Ca2+ channel blockers (D 888, nifedipine, and diltiazem) or in a Na(+)-free medium. Studies using the quench of fura-2 by Mn2+ as an index of Ca2+ influx and thapsigargin, an inhibitor of microsomal Ca(2+)-ATPase, indicate that a capacitative Ca2+ entry pathway mediates Ca2+ entry during stimulation. The above data demonstrate that Ca2+ uptake, which is dependent on the refill status of the agonist-sensitive intracellular Ca2+ pool, is a prerequisite for sustained muscarinic-induced fluid and electrolyte secretion in the rat sublingual mucous gland.

scholarly journals Estradiol activates chloride channels via estrogen receptor-α in the cell membranes of osteoblasts

2017 ◽  
Vol 313 (2) ◽  
pp. C162-C172 ◽  
Author(s):  
Zhiqin Deng ◽  
Shuang Peng ◽  
Yanfang Zheng ◽  
Xiaoya Yang ◽  
Haifeng Zhang ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Cell Membrane ◽  
Chloride Channels ◽  
Estrogen Receptor Α ◽  
Disulfonic Acid ◽  
Equilibrium Potential ◽  
Channel Blockers ◽  
Osteoblast Activity ◽  
Osteoblast Cell Line ◽  
17Β Estradiol

Estrogen plays important roles in regulation of bone formation. Cl− channels in the ClC family are expressed in osteoblasts and are associated with bone physiology and pathology, but the relationship between Cl− channels and estrogen is not clear. In this study the action of estrogen on Cl− channels was investigated in the MC3T3-E1 osteoblast cell line. Our results show that 17β-estradiol could activate a current that reversed at a potential close to the Cl− equilibrium potential, with a sequence of anion selectivity of I− > Br− > Cl− > gluconate, and was inhibited by the Cl− channel blockers 5-nitro-2-(3-phenylpropylamino)-benzoate and 4,4′-diisothiocyano-2,2′-stilbene disulfonic acid. Knockdown of ClC-3 Cl− channel expression by a specific small interfering RNA to ClC-3 attenuated activation of the 17β-estradiol-induced Cl− current. Extracellular application of membrane-impermeable 17β-estradiol-albumin conjugates activated a similar current. The estrogen-activated Cl− current could be inhibited by the estrogen receptor (ER) antagonist fulvestrant (ICI 182780). The selective ERα agonist, but not ERβ agonist, activated a Cl− current similar to that induced by 17β-estradiol. Silencing ERα expression prevented activation of estrogen-induced currents. Immunofluorescence and coimmunoprecipitation experiments demonstrated that ClC-3 Cl− channels and ERα were colocalized and closely related in cells. Estrogen promoted translocation of ClC-3 and ERα to the cell membrane from the nucleus. In conclusion, our findings show that Cl− channels can be activated by estrogen via ERα on the cell membrane and suggest that the ClC-3 Cl− channel may be one of the targets of estrogen in the regulation of osteoblast activity.

A synthetic peptide derived from glycine-gated Cl- channel induces transepithelial Cl- and fluid secretion

1997 ◽  
Vol 272 (5) ◽  
pp. C1672-C1679 ◽  
Author(s):  
D. P. Wallace ◽  
J. M. Tomich ◽  
T. Iwamoto ◽  
K. Henderson ◽  
J. J. Grantham ◽  
...  
Keyword(s):  
Synthetic Peptide ◽  
Apical Membrane ◽  
Mdck Cells ◽  
Short Circuit ◽  
Fluid Secretion ◽  
Disulfonic Acid ◽  
Intracellular Camp ◽  
Channel Blockers ◽  
Apical Surface ◽  
Cl Channel

M2GlyR is a synthetic 23-amino acid peptide that mimics the second membrane-spanning region of the alpha-subunit of the postsynaptic glycine receptor. This peptide has been shown to form an anion-selective channel in phospholipid bilayers. We have investigated the possibility that the peptide may incorporate into the apical membrane of secretory epithelia and induce the secretion of Cl- and water. We improved the solubility of this peptide by adding four lysine residues to the carboxy terminus, C-K4-M2GlyR, and assayed its channel-forming activity using a subculture of Madin-Darby canine kidney (MDCK) cells. The addition of 100 microM C-K4-M2GlyR to the apical surface of MDCK monolayers significantly increased short-circuit current (Ise), hyperpolarized transepithelial potential difference, and induced fluid secretion. The increase in Ise was inhibited by 100 microM bumetanide and by Cl- channel inhibitors. The effectiveness of the channel blockers followed the sequence niflumic acid > or = 5-nitro-2-(3-phenylpropylamino)benzoate > diphenylamine-2-carboxylate (DPC) > glibenclamide. The effect of the peptide was not inhibited by 4.4'-diisothiocyanostilbene-2-2'-disulfonic acid. Removing Cl from the bathing solutions also inhibited the effect of the peptide. The Cl- efflux pathway induced by C-K4-M2GlyR differs from the native pathway activated by the adenosine 3',5'-cyclic monophosphate (cAMP) agonist, forskolin. First, intracellular cAMP levels were unaffected. Second, the concentration of DPC required to inhibit the effect of the peptide was much lower than that needed to block the forskolin response (100 microM vs. 3 mM). These results support the hypothesis that the synthetic peptide C-K4-M2GlyR can from Cl -selective channels in the apical membrane of secretory epithelial cells and can induce sustained transepithelial secretion of Cl- and fluid.

Contribution of chloride channels to volume regulation of cortical astrocytes

2003 ◽  
Vol 284 (6) ◽  
pp. C1460-C1467 ◽  
Author(s):  
Kimberly A. Parkerson ◽  
Harald Sontheimer
Keyword(s):  
Volume Regulation ◽  
Chloride Channels ◽  
Brain Regions ◽  
Niflumic Acid ◽  
Cell Swelling ◽  
Disulfonic Acid ◽  
Channel Blockers ◽  
Relative Contribution ◽  
Cortical Astrocytes ◽  
Hippocampal Astrocytes

The objective of this study was to determine the relative contribution of Cl− channels to volume regulation of cultured rat cortical astrocytes after hypotonic cell swelling. Using a Coulter counter, we showed that cortical astrocytes regulate their cell volume by ∼60% within 45 min after hypotonic challenge. This volume regulation was supported when Cl− was replaced with Br−, NO[Formula: see text], methanesulfonate−, or acetate− but was inhibited when Cl− was replaced with isethionate− or gluconate−. Additionally, substitution of Cl− with I−completely blocked volume regulation. Volume regulation was unaffected by furosemide or bumetanide, blockers of KCl transport, but was inhibited by Cl− channel blockers, including 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), and niflumic acid. Surprisingly, the combination of Cd2+ with NPPB, DIDS, or niflumic acid inhibited regulation to a greater extent than any of these drugs alone. Volume regulation did not differ among astrocytes cultured from different brain regions, as cerebellar and hippocampal astrocytes exhibited behavior identical to that of cortical astrocytes. These data suggest that Cl− flux through ion channels rather than transporters is essential for volume regulation of cultured astrocytes in response to hypotonic challenge.

scholarly journals Gambogenic Acid Triggers Apoptosis of Human Nasopharyngeal Carcinoma CNE-2Z Cells through Activating Volume-Sensitive Outwardly Rectifying Chloride Channels

2018 ◽  
Author(s):  
Jingjing Su ◽  
Ting Xu ◽  
Genling Jiang ◽  
Mengru Liang ◽  
Hui Cheng ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Cell Membrane ◽  
Patch Clamp ◽  
Er Stress ◽  
Chloride Channel ◽  
Cell Apoptosis ◽  
Chloride Channels ◽  
Channel Blockers ◽  
Human Nasopharyngeal Carcinoma ◽  
Patch Clamp Method

Nasopharyngeal carcinoma (NPC) has not been thoroughly studied, and the pathogenesis of NPC is unclear. Scientists have neither discovered effective therapies nor achieved a desirable prognosis. Some studies have found that the regulation of intra- and extracellular ion channels hinges directly on cell apoptosis, and treatment with Gambogenic acid (GNA) brings changes to the volume-sensitive outwardly rectifying chloride (VSOR Cl-) current of CNE-2Z cells recorded by the patch clamp method. Nevertheless, rarely have any researchers probed into the relevance between this variation and the anti-tumor mechanism of GNA. This paper is suggested that GNA activates the VSOR Cl- current on the CNE-2Z cell membrane, and the activation of VSOR Cl- currents by GNA in CNE-2Z cells is blocked by the chloride channel blockers DIDS and DCPIB. GNA induces the down-regulation of GRP78 and up-regulation of ATF4 as well as chop proteins, which is evidence for the induction of CNE-2Z cell apoptosis, and this correlates with ER stress. GNA can activate the VSOR Cl- channel and lead to the occurrence of ER stress, thus inducing the apoptosis of CNE-2Z cells and inhibiting the proliferation of CNE-2Z cells.

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