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Sample records for basolateral chloride channels

  1. Basolateral potassium channels of rabbit colon epithelium: role in sodium absorption and chloride secretion.

    Science.gov (United States)

    Turnheim, Klaus; Plass, Herbert; Wyskovsky, Wolfgang

    2002-02-18

    In order to assess the role of different classes of K(+) channels in recirculation of K(+) across the basolateral membrane of rabbit distal colon epithelium, the effects of various K(+) channel inhibitors were tested on the activity of single K(+) channels from the basolateral membrane, on macroscopic basolateral K(+) conductance, and on the rate of Na(+) absorption and Cl(-) secretion. In single-channel measurements using the lipid bilayer reconstitution system, high-conductance (236 pS), Ca(2+)-activated K(+) (BK(Ca)) channels were most frequently detected; the second most abundant channel was a low-conductance K(+) channel (31 pS) that exhibited channel rundown. In addition to Ba(2+) and charybdotoxin (ChTX), the BK(Ca) channels were inhibited by quinidine, verapamil and tetraethylammonium (TEA), the latter only when present on the side of the channel from which K(+) flow originates. Macroscopic basolateral K(+) conductance, determined in amphotericin-permeabilised epithelia, was also markedly reduced by quinidine and verapamil, TEA inhibited only from the lumen side, and serosal ChTX was without effect. The chromanol 293B and the sulphonylurea tolbutamide did not affect BK(Ca) channels and had no or only a small inhibitory effect on macroscopic basolateral K(+) conductance. Transepithelial Na(+) absorption was partly inhibited by Ba(2+), quinidine and verapamil, suggesting that BK(Ca) channels are involved in basolateral recirculation of K(+) during Na(+) absorption in rabbit colon. The BK(Ca) channel inhibitors TEA and ChTX did not reduce Na(+) absorption, probably because TEA does not enter intact cells and ChTX is 'knocked off' its extracellular binding site by K(+) outflow from the cell interior. Transepithelial Cl(-) secretion was inhibited completely by Ba(2+) and 293B, partly by quinidine but not by the other K(+) channel blockers, indicating that the small (<3 pS) K(V)LQT1 channels are responsible for basolateral K(+) exit during Cl(-) secretion. Hence

  2. Berberine Reduces cAMP-Induced Chloride Secretion in T84 Human Colonic Carcinoma Cells through Inhibition of Basolateral KCNQ1 Channels.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2011-01-01

    Berberine is a plant alkaloid with multiple pharmacological actions, including antidiarrhoeal activity and has been shown to inhibit Cl(-) secretion in distal colon. The aims of this study were to determine the molecular signaling mechanisms of action of berberine on Cl(-) secretion and the ion transporter targets. Monolayers of T84 human colonic carcinoma cells grown in permeable supports were placed in Ussing chambers and short-circuit current measured in response to secretagogues and berberine. Whole-cell current recordings were performed in T84 cells using the patch-clamp technique. Berberine decreased forskolin-induced short-circuit current in a concentration-dependent manner (IC(50) 80 ± 8 μM). In apically permeabilized monolayers and whole-cell current recordings, berberine inhibited a cAMP-dependent and chromanol 293B-sensitive basolateral membrane K(+) current by 88%, suggesting inhibition of KCNQ1 K(+) channels. Berberine did not affect either apical Cl(-) conductance or basolateral Na(+)-K(+)-ATPase activity. Berberine stimulated p38 MAPK, PKCα and PKA, but had no effect on p42\\/p44 MAPK and PKCδ. However, berberine pre-treatment prevented stimulation of p42\\/p44 MAPK by epidermal growth factor. The inhibitory effect of berberine on Cl(-) secretion was partially blocked by HBDDE (∼65%), an inhibitor of PKCα and to a smaller extent by inhibition of p38 MAPK with SB202190 (∼15%). Berberine treatment induced an increase in association between PKCα and PKA with KCNQ1 and produced phosphorylation of the channel. We conclude that berberine exerts its inhibitory effect on colonic Cl(-) secretion through inhibition of basolateral KCNQ1 channels responsible for K(+) recycling via a PKCα-dependent pathway.

  3. Berberine Reduces cAMP-Induced Chloride Secretion in T84 Human Colonic Carcinoma Cells through Inhibition of Basolateral KCNQ1 Channels.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2012-02-01

    Berberine is a plant alkaloid with multiple pharmacological actions, including antidiarrhoeal activity and has been shown to inhibit Cl(-) secretion in distal colon. The aims of this study were to determine the molecular signaling mechanisms of action of berberine on Cl(-) secretion and the ion transporter targets. Monolayers of T84 human colonic carcinoma cells grown in permeable supports were placed in Ussing chambers and short-circuit current measured in response to secretagogues and berberine. Whole-cell current recordings were performed in T84 cells using the patch-clamp technique. Berberine decreased forskolin-induced short-circuit current in a concentration-dependent manner (IC(50) 80 +\\/- 8 muM). In apically permeabilized monolayers and whole-cell current recordings, berberine inhibited a cAMP-dependent and chromanol 293B-sensitive basolateral membrane K(+) current by 88%, suggesting inhibition of KCNQ1 K(+) channels. Berberine did not affect either apical Cl(-) conductance or basolateral Na(+)-K(+)-ATPase activity. Berberine stimulated p38 MAPK, PKCalpha and PKA, but had no effect on p42\\/p44 MAPK and PKCdelta. However, berberine pre-treatment prevented stimulation of p42\\/p44 MAPK by epidermal growth factor. The inhibitory effect of berberine on Cl(-) secretion was partially blocked by HBDDE ( approximately 65%), an inhibitor of PKCalpha and to a smaller extent by inhibition of p38 MAPK with SB202190 ( approximately 15%). Berberine treatment induced an increase in association between PKCalpha and PKA with KCNQ1 and produced phosphorylation of the channel. We conclude that berberine exerts its inhibitory effect on colonic Cl(-) secretion through inhibition of basolateral KCNQ1 channels responsible for K(+) recycling via a PKCalpha-dependent pathway.

  4. Berberine reduces cAMP-induced chloride secretion in T84 human colonic carcinoma cells through inhibition of basolateral KCNQ1 channels

    Directory of Open Access Journals (Sweden)

    Rodrigo eAlzamora

    2011-06-01

    Full Text Available Berberine is a plant alkaloid with multiple pharmacological actions, including antidiarrhoeal activity and has been shown to inhibit Cl- secretion in distal colon. The aims of this study were to determine the molecular signalling mechanisms of action of berberine on Cl- secretion and the ion transporter targets. Monolayers of T84 human colonic carcinoma cells grown in permeable supports were placed in Ussing chambers and short-circuit current measured in response to secretagogues and berberine. Whole-cell current recordings were performed in T84 cells using the patch-clamp technique. Berberine decreased forskolin-induced short-circuit current in a concentration-dependent manner (IC50 80  8 M. In apically permeabilized monolayers and whole-cell current recordings, berberine inhibited a cAMP-dependent and chromanol 293B-sensitive basolateral membrane K+ current by 88%, suggesting inhibition of KCNQ1 K+ channels. Berberine did not affect either apical Cl- conductance or basolateral Na+-K+-ATPase activity. Berberine stimulated p38 MAPK, PKC and PKA, but had no effect on p42/p44 MAPK and PKC. However, berberine pre-treatment prevented stimulation of p42/p44 MAPK by epidermal growth factor. The inhibitory effect of berberine on Cl- secretion was partially blocked by HBDDE (65 %, an inhibitor of PKC and to a smaller extent by inhibition of p38 MAPK with SB202190 (15 %. Berberine treatment induced an increase in association between PKC and PKA with KCNQ1 and produced phosphorylation of the channel. We conclude that berberine exerts its inhibitory effect on colonic Cl- secretion through inhibition of basolateral KCNQ1 channels responsible for K+ recycling via a PKC-dependent pathway.

  5. Characterization of basolateral chloride/bicarbonate exchange in macula densa cells.

    Science.gov (United States)

    Komlosi, Peter; Frische, Sebastian; Fuson, Amanda L; Fintha, Attila; Zsembery, Akos; Peti-Peterdi, Janos; Bell, P Darwin

    2005-02-01

    Functional and immunohistological studies were performed to identify basolateral chloride/bicarbonate exchange in macula densa cells. Using the isolated, perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney, macula densa intracellular pH (pH(i)) was measured with fluorescence microscopy and BCECF. For these experiments, basolateral chloride was reduced, resulting in reversible macula densa cell alkalinization. Anion exchange activity was assessed by measuring the maximal net base efflux on readdition of bath chloride. Anion exchange activity required the presence of bicarbonate, was independent of changes in membrane potential, did not require the presence of sodium, and was inhibited by high concentrations of DIDS. Inhibition of macula densa anion exchange activity by basolateral DIDS increased luminal NaCl concentration-induced elevations in pH(i). Immunohistochemical studies using antibodies against AE2 demonstrated expression of AE2 along the basolateral membrane of macula densa cells of rabbit kidney. These results suggest that macula densa cells functionally and immunologically express a chloride/bicarbonate exchanger at the basolateral membrane. This transporter likely participates in the regulation of pH(i) and might be involved in macula densa signaling.

  6. Chloride channels in stroke

    Institute of Scientific and Technical Information of China (English)

    Ya-ping ZHANG; Hao ZHANG; Dayue Darrel DUAN

    2013-01-01

    Vascular remodeling of cerebral arterioles,including proliferation,migration,and apoptosis of vascular smooth muscle cells (VSMCs),is the major cause of changes in the cross-sectional area and diameter of the arteries and sudden interruption of blood flow or hemorrhage in the brain,ie,stroke.Accumulating evidence strongly supports an important role for chloride (Clˉ) channels in vascular remodeling and stroke.At least three Clˉ channel genes are expressed in VSMCs:1) the TMEM16A (or Ano1),which may encode the calcium-activated Clˉ channels (CACCs); 2) the CLC-3 Clˉ channel and Clˉ/H+ antiporter,which is closely related to the volume-regulated Clˉ channels (VRCCs); and 3) the cystic fibrosis transmembrane conductance regulator (CFTR),which encodes the PKA-and PKC-activated Clˉ channels.Activation of the CACCs by agonist-induced increase in intracellular Ca2+ causes membrane depolarization,vasoconstriction,and inhibition of VSMC proliferation.Activation of VRCCs by cell volume increase or membrane stretch promotes the production of reactive oxygen species,induces proliferation and inhibits apoptosis of VSMCs.Activation of CFTR inhibits oxidative stress and may prevent the development of hypertension.In addition,Clˉ current mediated by gammaaminobutyric acid (GABA) receptor has also been implicated a role in ischemic neuron death.This review focuses on the functional roles of Clˉ channels in the development of stroke and provides a perspective on the future directions for research and the potential to develop Clˉ channels as new targets for the prevention and treatment of stroke.

  7. Lubiprostone: a chloride channel activator.

    Science.gov (United States)

    Lacy, Brian E; Levy, L Campbell

    2007-04-01

    In January 2006 the Food and Drug Administration approved lubiprostone for the treatment of chronic constipation in men and women aged 18 and over. Lubiprostone is categorized as a prostone, a bicyclic fatty acid metabolite of prostaglandin E1. Lubiprostone activates a specific chloride channel (ClC-2) in the gastrointestinal (GI) tract to enhance intestinal fluid secretion, which increases GI transit and improves symptoms of constipation. This article reviews the role of chloride channels in the GI tract, describes the structure, function, and pharmacokinetics of lubiprostone, and discusses clinically important data on this new medication.

  8. Mercury toxicity in the shark (Squalus acanthias) rectal gland: apical CFTR chloride channels are inhibited by mercuric chloride.

    Science.gov (United States)

    Ratner, Martha A; Decker, Sarah E; Aller, Stephen G; Weber, Gerhard; Forrest, John N

    2006-03-01

    In the shark rectal gland, basolateral membrane proteins have been suggested as targets for mercury. To examine the membrane polarity of mercury toxicity, we performed experiments in three preparations: isolated perfused rectal glands, primary monolayer cultures of rectal gland epithelial cells, and Xenopus oocytes expressing the shark cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. In perfused rectal glands we observed: (1) a dose-dependent inhibition by mercury of forskolin/3-isobutyl-1-methylxanthine (IBMX)-stimulated chloride secretion; (2) inhibition was maximal when mercury was added before stimulation with forskolin/IBMX; (3) dithiothrietol (DTT) and glutathione (GSH) completely prevented inhibition of chloride secretion. Short-circuit current (Isc) measurements in monolayers of rectal gland epithelial cells were performed to examine the membrane polarity of this effect. Mercuric chloride inhibited Isc more potently when applied to the solution bathing the apical vs. the basolateral membrane (23 +/- 5% and 68 +/- 5% inhibition at 1 and 10 microM HgCl2 in the apical solution vs. 2 +/- 0.9% and 14 +/- 5% in the basolateral solution). This inhibition was prevented by pre-treatment with apical DTT or GSH; however, only the permeant reducing agent DTT reversed mercury inhibition when added after exposure. When the shark rectal gland CFTR channel was expressed in Xenopus oocytes and chloride conductance was measured by two-electrode voltage clamping, we found that 1 microM HgCl2 inhibited forskolin/IBMX conductance by 69.2 +/- 2.0%. We conclude that in the shark rectal gland, mercury inhibits chloride secretion by interacting with the apical membrane and that CFTR is the likely site of this action.

  9. Basolateral localisation of KCNQ1 potassium channels in MDCK cells: molecular identification of an N-terminal targeting motif

    DEFF Research Database (Denmark)

    Jespersen, Thomas; Rasmussen, Hanne B; Grunnet, Morten;

    2004-01-01

    KCNQ1 potassium channels are expressed in many epithelial tissues as well as in the heart. In epithelia KCNQ1 channels play an important role in salt and water transport and the channel has been reported to be located apically in some cell types and basolaterally in others. Here we show that KCNQ...

  10. Regulated trafficking of the CFTR chloride channel

    NARCIS (Netherlands)

    Braakman, L.J.; Kleizen, B.; Jonge, H.R. de

    2000-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR), the ABC transporter encoded by the cystic fibrosis gene, is localized in the apical membrane of epithelial cells where it functions as a cyclic AMP-regulated chloride channel and as a regulator of other ion channels and transporters. Wh

  11. Shikonin inhibits intestinal calcium-activated chloride channels and prevents rotaviral diarrhea

    Directory of Open Access Journals (Sweden)

    Yu Jiang

    2016-08-01

    Full Text Available Secretory diarrhea remains a global health burden and causes major mortality in children. There have been some focuses on antidiarrheal therapies that may reduce fluid losses and intestinal motility in diarrheal diseases. In the present study, we identified shikonin as an inhibitor of TMEM16A chloride channel activity using cell-based fluorescent-quenching assay. The IC50 value of shikonin was 6.5 μM. Short-circuit current measurements demonstrated that shikonin inhibited Eact-induced Cl current in a dose-dependent manner, with IC50 value of 1.5 μM. Short-circuit current measurement showed that shikonin exhibited inhibitory effect against CCh-induced Cl currents in mouse colonic epithelia but did not affect cytoplasmic Ca2+ concentration as well as the other major enterocyte chloride channel CFTR. Characterization study found that shikonin inhibited basolateral K+ channel activity without affecting Na+/K+-ATPase activities. In-vivo studies revealed that shikonin significantly delayed intestinal motility in mice and reduced stool water content in a neonatal mice model of rotaviral diarrhea without affecting the viral infection process in-vivo. Taken together, the results suggested that shikonin inhibited enterocyte CaCCs, the inhibitory effect was partially through inhbition of basolateral K+ channel acitivty, and shikonin could be a lead compound in the treatment of rotaviral secretory diarrhea.

  12. Src family protein tyrosine kinase regulates the basolateral K channel in the distal convoluted tubule (DCT) by phosphorylation of KCNJ10 protein.

    Science.gov (United States)

    Zhang, Chengbiao; Wang, Lijun; Thomas, Sherin; Wang, Kemeng; Lin, Dao-Hong; Rinehart, Jesse; Wang, Wen-Hui

    2013-09-01

    The loss of function of the basolateral K channels in the distal nephron causes electrolyte imbalance. The aim of this study is to examine the role of Src family protein tyrosine kinase (SFK) in regulating K channels in the basolateral membrane of the mouse initial distal convoluted tubule (DCT1). Single-channel recordings confirmed that the 40-picosiemen (pS) K channel was the only type of K channel in the basolateral membrane of DCT1. The suppression of SFK reversibly inhibited the basolateral 40-pS K channel activity in cell-attached patches and decreased the Ba(2+)-sensitive whole-cell K currents in DCT1. Inhibition of SFK also shifted the K reversal potential from -65 to -43 mV, suggesting a role of SFK in determining the membrane potential in DCT1. Western blot analysis showed that KCNJ10 (Kir4.1), a key component of the basolateral 40-pS K channel in DCT1, was a tyrosine-phosphorylated protein. LC/MS analysis further confirmed that SFK phosphorylated KCNJ10 at Tyr(8) and Tyr(9). The single-channel recording detected the activity of a 19-pS K channel in KCNJ10-transfected HEK293T cells and a 40-pS K channel in the cells transfected with KCNJ10+KCNJ16 (Kir.5.1) that form a heterotetramer in the basolateral membrane of the DCT. Mutation of Tyr(9) did not alter the channel conductance of the homotetramer and heterotetramer. However, it decreased the whole-cell K currents, the probability of finding K channels, and surface expression of KCNJ10 in comparison to WT KCNJ10. We conclude that SFK stimulates the basolateral K channel activity in DCT1, at least partially, by phosphorylating Tyr(9) on KCNJ10. We speculate that the modulation of tyrosine phosphorylation of KCNJ10 should play a role in regulating membrane transport function in DCT1.

  13. Regulated trafficking of the CFTR chloride channel.

    Science.gov (United States)

    Kleizen, B; Braakman, I; de Jonge, H R

    2000-08-01

    The cystic fibrosis transmembrane conductance regulator (CFTR), the ABC transporter encoded by the cystic fibrosis gene, is localized in the apical membrane of epithelial cells where it functions as a cyclic AMP-regulated chloride channel and as a regulator of other ion channels and transporters. Whereas a key role of cAMP-dependent phosphorylation in CFTR-channel gating has been firmly established, more recent studies have provided clear evidence for the existence of a second level of cAMP regulation, i.e. the exocytotic recruitment of CFFR to the plasma membrane and its endocytotic retrieval. Regulated trafficking of the CFTR Cl- channel has sofar been demonstrated only in a subset of CFTR-expressing cell types. However, with the introduction of more sensitive methods to measure CFTR cycling and submembrane localization, it might turn out to be a more general phenomenon that could contribute importantly to both the regulation of CFTR-mediated chloride transport itself and to the regulation of other transporters and CFTR-modulated cellular functions. This review aims to summarize the present state of knowledge regarding polarized and regulated CFTR trafficking and endosomal recycling in epithelial cells, to discuss present gaps in our understanding of these processes at the cellular and molecular level, and to consider its possible implications for cystic fibrosis.

  14. Basolateral Cl- channels in the larval bullfrog skin epithelium

    DEFF Research Database (Denmark)

    Hillyard, Stanley D.; Rios, K.; Larsen, Erik Hviid

    2002-01-01

    The addition of 150 U/ml nystatin to the mucosal surface of isolated skin from larval bullfrogs increases apical membrane permeability and allows a voltage clamp to be applied to the basolateral membrane. With identical Ringer's solutions bathing either side of the tissue the short-circuit curren...

  15. Phosphatase inhibitors activate normal and defective CFTR chloride channels

    OpenAIRE

    Becq, F; Jensen, T J; Chang, X B; Savoia, A.; Rommens, J M; Tsui, L C; Buchwald, M; Riordan, J R; Hanrahan, J W

    1994-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is regulated by phosphorylation and dephosphorylation at multiple sites. Although activation by protein kinases has been studied in some detail, the dephosphorylation step has received little attention. This report examines the mechanisms responsible for the dephosphorylation and spontaneous deactivation ("rundown") of CFTR chloride channels excised from transfected Chinese hamster ovary (CHO) and human airway epi...

  16. 氯离子通道与肾脏病%Chloride channels and kidney diseases

    Institute of Scientific and Technical Information of China (English)

    蒲金赟(综述); 周建华(审校)

    2016-01-01

    氯离子是生物体内一类重要的阴离子,参与多种生理活动的调节。由相关基因突变引起的离子通道蛋白功能缺陷可导致离子通道功能异常,形成离子通道病。在肾脏,位于不同部位的肾小管上皮细胞的基侧质膜和顶质膜上分布有多种氯离子通道。研究发现,肾脏电压门控氯离子通道与Bartter综合征和Dent病有关;囊性纤维化跨膜转运调节体所致囊性纤维化病可累及肾脏。文章综述氯离子通道在维持正常肾脏功能中的作用及其机制,以及相关基因缺陷所致的肾脏疾病。%Chloride ion is an important anion in organisms, managing various physiological events. A particular gene mu-tation leads to involved channel deifciency and to develop channelopathy. In kidney, different chloride channels distribute along certain fractions of the renal tubule, located at apical and basolateral membranes of tubular epithelial cells. Previous studies dis-covered that voltage-sensitive chloride channels in kidney are associated with Bartter syndrome and Dent’s disease. In addition, the kidney can be involved by cystic ifbrosis resulting from dysfunction of cystic ifbrosis transmembrane conductance regulator. In this review, the function and mechanism of chloride channels in maintenance of normal renal function, and the renal diseases caused by related gene defects were discussed.

  17. Functional and molecular identification of a TASK-1 potassium channel regulating chloride secretion through CFTR channels in the shark rectal gland: implications for cystic fibrosis.

    Science.gov (United States)

    Telles, Connor J; Decker, Sarah E; Motley, William W; Peters, Alexander W; Mehr, Ali Poyan; Frizzell, Raymond A; Forrest, John N

    2016-12-01

    In the shark rectal gland (SRG), apical chloride secretion through CFTR channels is electrically coupled to a basolateral K(+) conductance whose type and molecular identity are unknown. We performed studies in the perfused SRG with 17 K(+) channel inhibitors to begin this search. Maximal chloride secretion was markedly inhibited by low-perfusate pH, bupivicaine, anandamide, zinc, quinidine, and quinine, consistent with the properties of an acid-sensitive, four-transmembrane, two-pore-domain K(+) channel (4TM-K2P). Using PCR with degenerate primers to this family, we identified a TASK-1 fragment in shark rectal gland, brain, gill, and kidney. Using 5' and 3' rapid amplification of cDNA ends PCR and genomic walking, we cloned the full-length shark gene (1,282 bp), whose open reading frame encodes a protein of 375 amino acids that was 80% identical to the human TASK-1 protein. We expressed shark and human TASK-1 cRNA in Xenopus oocytes and characterized these channels using two-electrode voltage clamping. Both channels had identical current-voltage relationships (outward rectifying) and a reversal potential of -90 mV. Both were inhibited by quinine, bupivicaine, and acidic pH. The pKa for current inhibition was 7.75 for shark TASK-1 vs. 7.37 for human TASK-1, values similar to the arterial pH for each species. We identified this protein in SRG by Western blot and confocal immunofluorescent microscopy and detected the protein in SRG and human airway cells. Shark TASK-1 is the major K(+) channel coupled to chloride secretion in the SRG, is the oldest 4TM 2P family member identified, and is the first TASK-1 channel identified to play a role in setting the driving force for chloride secretion in epithelia. The detection of this potassium channel in mammalian lung tissue has implications for human biology and disease.

  18. Differential expression of Kv3.1b and Kv3.2 potassium channel subunits in interneurons of the basolateral amygdala.

    Science.gov (United States)

    McDonald, A J; Mascagni, F

    2006-01-01

    The expression of Kv3.1 and Kv3.2 voltage-gated potassium channel subunits appears to be critical for high-frequency firing of many neuronal populations. In the cortex these subunits are mainly associated with fast-firing GABAergic interneurons containing parvalbumin or somatostatin. Since the basolateral nuclear complex of the amygdala contains similar interneurons, it is of interest to determine if these potassium channel subunits are expressed in these same interneuronal subpopulations. To investigate this issue, peroxidase and dual-labeling fluorescence immunohistochemistry combined with confocal laser scanning microscopy was used to determine which interneuronal subpopulations in the basolateral nuclear complex of the rat amygdala express Kv3.1b and Kv3.2 subunits. Antibodies to parvalbumin, somatostatin, calretinin, and cholecystokinin were used to label separate subsets of basolateral amygdalar interneurons. Examination of immunoperoxidase preparations suggested that the expression of both channels was restricted to nonpyramidal interneurons in the basolateral amygdala. Somata and proximal dendrites were intensely-stained, and axon terminals arising from presumptive basket cells and chandelier cells were lightly stained. Immunofluorescence observations revealed that parvalbumin+ neurons were the main interneuronal subpopulation expressing the Kv3.1b potassium channel subunit in the basolateral amygdala. More than 92-96% of parvalbumin+ neurons were Kv3.1b+, depending on the nucleus. These parvalbumin+/Kv3.1b+ double-labeled cells constituted 90-99% of all Kv3.1b+ neurons. Parvalbumin+ neurons were also the main interneuronal subpopulation expressing the Kv3.2 potassium channel subunit. More than 67-78% of parvalbumin+ neurons were Kv3.2+, depending on the nucleus. However, these parvalbumin+/Kv3.2+ double-labeled cells constituted only 71-81% of all Kv3.2+ neurons. Most of the remaining neurons with significant levels of the Kv3.2 subunit were somatostatin

  19. Inhibition of nitrite-induced toxicity in channel catfish by calcium chloride and sodium chloride

    Science.gov (United States)

    Tommasso J.R., Wright; Simco, B.A.; Davis, K.B.

    1980-01-01

    Environmental chloride has been shown to inhibit methemoglobin formation in fish, thereby offering a protective effect against nitrite toxicity. Channel catfish (Ictalurus punctatus) were simultaneously exposed to various environmental nitrite and chloride levels (as either CaCl2 or NaCl) in dechlorinated tap water (40 mg/L total hardness, 47 mg/L alkalinity, 4 mg/L chloride, pH = 6.9-7.1, and temperature 21-24°C). Methemoglobin levels in fish simultaneously exposed to 2.5 mg/L nitrite and up to 30 mg/L chloride as either CaCl2 or NaCl were similar but significantly lower than in unprotected fish. Exposure to 10 mg/L nitrite and 60 mg/L chloride resulted in methemoglobin levels similar to those of the controls; most unprotected fish died. Fish exposed to 10 mg/L nitrite had significantly lower methemoglobin levels when protected with 15.0 mg/L chloride as CaCl2 than with NaCl. Fish exposed to nitrite in the presence of 60 mg/L chloride (as either CaCl2 or NaCl) had similar 24-h LC50 values that were significantly elevated above those obtained in the absence of chloride. Calcium had little effect on tolerance to nitrite toxicity in channel catfish in contrast to its large effect reported in steelhead trout (Salmo gairdneri).

  20. Functional architecture of the CFTR chloride channel.

    Science.gov (United States)

    Linsdell, Paul

    2014-02-01

    Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette (ABC) family of membrane transport proteins. CFTR is unique among ABC proteins in that it functions not as an active transporter but as an ATP-gated Cl(-) channel. As an ion channel, the function of the CFTR transmembrane channel pore that mediates Cl(-) movement has been studied in great detail. On the other hand, only low resolution structural data is available on the transmembrane parts of the protein. The structure of the channel pore has, however, been modeled on the known structure of active transporter ABC proteins. Currently, significant barriers exist to building a unified view of CFTR pore structure and function. Reconciling functional data on the channel with indirect structural data based on other proteins with very different transport functions and substrates has proven problematic. This review summarizes current structural and functional models of the CFTR Cl(-) channel pore, including a comprehensive review of previous electrophysiological investigations of channel structure and function. In addition, functional data on the three-dimensional arrangement of pore-lining helices, as well as contemporary hypotheses concerning conformational changes in the pore that occur during channel opening and closing, are discussed. Important similarities and differences between different models of the pore highlight current gaps in our knowledge of CFTR structure and function. In order to fill these gaps, structural and functional models of the membrane-spanning pore need to become better integrated.

  1. Chloride channels of platelets%血小板氯通道

    Institute of Scientific and Technical Information of China (English)

    陈晓琳; 尹松梅

    2004-01-01

    Chloride channels distribute widely in the body, and participate in many physiological actions and regulatory processes. Based on their physiological roles and molecular structures, six kinds of chloride channels have been identified: (1) The chloride channels family; (2) Cystic fibrosis transmembrane conductance regulator; (3) Swelling-activated chloride channels; (4) Calcium-activated chloride channels; (5) The p64 (CLIC) gene family; (6) γ-aminobutyric acid and glycine receptors. The chloride channels do exist in platelets, and their appearances are dependent on the presence of intracellular calcium. Blocking agents of chloride channels inhibit the thrombin-activated platelet aggregation and the elevation of the intracellular calcium concentration in a dose-dependent manner. It is suggested that chloride channels play a role in the activation of platelets. In addition, chloride channels act on both the cell volume regulation and the intracellular pH regulation in platelets.

  2. Epithelial Sodium and Chloride Channels and Asthma

    Institute of Scientific and Technical Information of China (English)

    Wen Wang; Hong-Long Ji

    2015-01-01

    Objective:To focus on the asthmatic pathogenesis and clinical manifestations related to epithelial sodium channel (ENaC)/chlorine ion channel.Data Sources:The data analyzed in this review were the English articles from 1980 to 2015 from journal databases,primarily PubMed and Google Scholar.The terms used in the literature search were:(1) ENaCs;cystic fibrosis (CF) transmembrane conductance regulator (CFTR);asthma/asthmatic,(2) ENaC/sodium salt;CF;asthma/asthmatic,(3) CFTR/chlorine ion channels;asthma/asthmatic,(4) ENaC/sodium channel/scnn1a/scnn1b/scnn1g/scnn1d/amiloride-sensitive/amiloride-inhibtable sodium channels/sodium salt;asthma/asthmatic,lung/pulmonary/respiratory/tracheal/alveolar,and (5) CFTR;CF;asthma/asthmatic (ti).Study Selection:These studies included randomized controlled trials or studies covering asthma pathogenesis and clinical manifestations related to ENaC/chlorine ion channels within the last 25 years (from 1990 to 2015).The data involving chronic obstructive pulmonary disease and CF obtained from individual studies were also reviewed by the authors.Results:Airway surface liquid dehydration can cause airway inflammation and obstruction.ENaC and CFTR are closely related to the airway mucociliary clearance.Ion transporters may play a critical role in pathogenesis of asthmatic exacerbations.Conclusions:Ion channels have been the center of many studies aiming to understand asthmatic pathophysiological mechanisms or to identify therapeutic targets for better control of the disease.

  3. Lack of conventional ATPase properties in CFTR chloride channel gating.

    Science.gov (United States)

    Schultz, B D; Bridges, R J; Frizzell, R A

    1996-05-01

    CFTR shares structural homology with the ABC transporter superfamily of proteins which hydrolyze ATP to effect the transport of compounds across cell membranes. Some superfamily members are characterized as P-type ATPases because ATP-dependent transport is sensitive to the presence of vanadate. It has been widely postulated that CFTR hydrolyzes ATP to gate its chloride channel. However, direct evidence of CFTR hydrolytic activity in channel gating is lacking and existing circumstantial evidence is contradictory. Therefore, we evaluated CFTR chloride channel activity under conditions known to inhibit the activity of ATPases; i.e., in the absence of divalent cations and in the presence of a variety of ATPase inhibitors. Removal of the cytosolic cofactor, Mg2+, reduced both the opening and closing rates of CFTR suggesting that Mg2+ plays a modulatory role in channel gating. However, channels continued to both open and close showing that Mg2+ is not an absolute requirement for channel activity. The nonselective P-type ATPase inhibitor, vanadate, did not alter the gating of CFTR when used at concentrations which completely inhibit the activity of other ABC transporters (1 mM). Higher concentrations of vanadate (10 mM) blocked the closing of CFTR, but did not affect the opening of the channel. As expected, more selective P-type (Sch28080, ouabain), V-type (bafilomycin A1, SCN-) and F-type (oligomycin) ATPase inhibitors did not affect either the opening or closing of CFTR. Thus, CFTR does not share a pharmacological inhibition profile with other ATPases and channel gating occurs in the apparent absence of hydrolysis, although with altered kinetics. Vanadate inhibition of channel closure might suggest that a hydrolytic step is involved although the requirement for a high concentration raises the possibility of previously uncharacterized effects of this compound. Most conservatively, the requirement for high concentrations of vanadate demonstrates that the binding site for

  4. Non-specific activation of the epithelial sodium channel by the CFTR chloride channel

    OpenAIRE

    Nagel, Georg; Szellas, Tanjef; Riordan, John R.; Friedrich, Thomas; Hartung, Klaus

    2001-01-01

    The genetic disease cystic fibrosis is caused by mutation of the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). Controversial studies reported regulation of the epithelial sodium channel (ENaC) by CFTR. We found that uptake of 22Na+ through ENaC is modulated by activation of CFTR in oocytes, coexpressing CFTR and ENaC, depending on extracellular chloride concentration. Furthermore we found that the effect of CFTR activation could be mimicked by other chloride ...

  5. Genetically encoded optical sensors for monitoring of intracellular chloride and chloride-selective channel activity

    Directory of Open Access Journals (Sweden)

    Piotr Bregestovski

    2009-12-01

    Full Text Available This review briefly discusses the main approaches for monitoring chloride (Cl−, the most abundant physiological anion. Noninvasive monitoring of intracellular Cl− ([Cl−]i is a challenging task owing to two main difficulties: (i the low transmembrane ratio for Cl−, approximately 10:1; and (ii the small driving force for Cl−, as the Cl− reversal potential (ECl is usually close to the resting potential of the cells. Thus, for reliable monitoring of intracellular Cl−, one has to use highly sensitive probes. From several methods for intracellular Cl− analysis, genetically encoded chloride indicators represent the most promising tools. Recent achievements in the development of genetically encoded chloride probes are based on the fact that yellow fluorescent protein (YFP exhibits Cl−-sensitivity. YFP-based probes have been successfully used for quantitative analysis of Cl− transport in different cells and for high-throughput screening of modulators of Cl−-selective channels. Development of a ratiometric genetically encoded probe, Clomeleon, has provided a tool for noninvasive estimation of intracellular Cl− concentrations. While the sensitivity of this protein to Cl− is low (EC50 about 160 mM, it has been successfully used for monitoring intracellular Cl− in different cell types. Recently a CFP–YFP-based probe with a relatively high sensitivity to Cl− (EC50 about 30 mM has been developed. This construct, termed Cl-Sensor, allows ratiometric monitoring using the fluorescence excitation ratio. Of particular interest are genetically encoded probes for monitoring of ion channel distribution and activity. A new molecular probe has been constructed by introducing into the cytoplasmic domain of the Cl−-selective glycine receptor (GlyR channel the CFP–YFP-based Cl-Sensor. This construct, termed BioSensor-GlyR, has been successfully expressed in cell lines. The new genetically encoded chloride probes offer means of screening

  6. An increase in [Ca2+]i activates basolateral chloride channels and inhibits apical sodium channels in frog skin epithelium

    DEFF Research Database (Denmark)

    Brodin, Birger; Rytved, K A; Nielsen, R

    1996-01-01

    The aim of this study was to investigate the mechanisms by which increases in free cytosolic calcium ([Ca2+]i) cause a decrease in macroscopic sodium absorption across principal cells of the frog skin epithelium. [Ca2+]i was measured with fura-2 in an epifluorescence microscope set-up, sodium...

  7. Noise analysis and single-channel observations of 4 pS chloride channels in human airway epithelia.

    OpenAIRE

    Duszyk, M; French, A S; Man, S F

    1992-01-01

    Apical membranes of human airway epithelial cells have significant chloride permeability, which is reduced in cystic fibrosis (CF), causing abnormal electrochemistry and impaired mucociliary clearance. At least four types of chloride channels have been identified in these cells, but their relative roles in total permeability and CF are unclear. Noise analysis was used to measure the conductance of chloride channels in human nasal epithelial cells. The data indicate that channels with a mean c...

  8. Functional modifications of acid-sensing ion channels by ligand-gated chloride channels.

    Directory of Open Access Journals (Sweden)

    Xuanmao Chen

    Full Text Available Together, acid-sensing ion channels (ASICs and epithelial sodium channels (ENaC constitute the majority of voltage-independent sodium channels in mammals. ENaC is regulated by a chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR. Here we show that ASICs were reversibly inhibited by activation of GABA(A receptors in murine hippocampal neurons. This inhibition of ASICs required opening of the chloride channels but occurred with both outward and inward GABA(A receptor-mediated currents. Moreover, activation of the GABA(A receptors modified the pharmacological features and kinetic properties of the ASIC currents, including the time course of activation, desensitization and deactivation. Modification of ASICs by open GABA(A receptors was also observed in both nucleated patches and outside-out patches excised from hippocampal neurons. Interestingly, ASICs and GABA(A receptors interacted to regulate synaptic plasticity in CA1 hippocampal slices. The activation of glycine receptors, which are similar to GABA(A receptors, also modified ASICs in spinal neurons. We conclude that GABA(A receptors and glycine receptors modify ASICs in neurons through mechanisms that require the opening of chloride channels.

  9. The CIC-3 chloride channels in cardiovascular disease

    Institute of Scientific and Technical Information of China (English)

    Dayue Darrel DUAN

    2011-01-01

    CIC-3 is a member of the CIC voltage-gated chloride(Cl-) channel superfamily. Recent studies have demonstrated the abundant expression and pleiotropy of CIC-3 in cardiac atrial and ventricular myocytes, vascular smooth muscle cells, and endothelial cells.CIC-3 Cl- channels can be activated by increase in cell volume, direct stretch of β1-integrin through focal adhesion kinase and many active molecules or growth factors including angiotensin Ⅱ and endothelin-1-mediated signaling pathways, Ca2+/calmodulin-dependent protein kinase Ⅱ and reactive oxygen species. CIC-3 may function as a key component of the volume-regulated Cl- channels, a superoxide anion transport and/or NADPH oxidase interaction partner, and a regulator of many other transporters. CIC-3 has been implicated in the regulation of electrical activity, cell volume, proliferation, differentiation, migration, apoptosis and intracellular pH. This review will highlight the major findings and recent advances in the study of CIC-3 Cl- channels in the cardiovascular system and discuss their important roles in cardiac and vascular remodeling during hypertension, myocardial hypertrophy, ischemia/reperfusion, and heart failure.

  10. Effects of antigliomatin from the scorpion venom of Buthus martensii Karsch on chloride channels on C6 glioma cells

    Institute of Scientific and Technical Information of China (English)

    Zan Wang; Mingxian Li; Hongmei Meng; Min Huang; Weihong Lin; Li Cui; Shao Wang

    2011-01-01

    Using whole-cell patch-clamp recordings, the effects of antigliomatin were observed on chloride channels on C6 glioma cells cultured in vitro. Antigliomatin was extracted from the venom of the scorpion Buthus martensii Karsch. Chloride channels are closed under normal osmotic pressure. When osmotic pressure was reduced to 120, 110 and 100 mV, the cell volume enlarged, chloride channels opened, and the chloride channel current increased. Three minutes after antigliomatin treatment, the chloride channel current decreased in a dose-dependent manner. These results show that antigliomatin extracted from the venom of the scorpion Buthus martensii Karsch diminishes chloride channel currents on C6 glioma cells.

  11. Bile acids stimulate chloride secretion through CFTR and calcium-activated Cl- channels in Calu-3 airway epithelial cells.

    Science.gov (United States)

    Hendrick, Siobhán M; Mroz, Magdalena S; Greene, Catherine M; Keely, Stephen J; Harvey, Brian J

    2014-09-01

    Bile acids resulting from the aspiration of gastroesophageal refluxate are often present in the lower airways of people with cystic fibrosis and other respiratory distress diseases. Surprisingly, there is little or no information on the modulation of airway epithelial ion transport by bile acids. The secretory effect of a variety of conjugated and unconjugated secondary bile acids was investigated in Calu-3 airway epithelial cells grown under an air-liquid interface and mounted in Ussing chambers. Electrogenic transepithelial ion transport was measured as short-circuit current (Isc). The taurine-conjugated secondary bile acid, taurodeoxycholic acid (TDCA), was found to be the most potent modulator of basal ion transport. Acute treatment (5 min) of Calu-3 cells with TDCA (25 μM) on the basolateral side caused a stimulation of Isc, and removal of extracellular Cl(-) abolished this response. TDCA produced an increase in the cystic fibrosis transmembrane conductance regulator (CFTR)-dependent current that was abolished by pretreatment with the CFTR inhibitor CFTRinh172. TDCA treatment also increased Cl(-) secretion through calcium-activated chloride (CaCC) channels and increased the Na(+)/K(+) pump current. Acute treatment with TDCA resulted in a rapid cellular influx of Ca(2+) and increased cAMP levels in Calu-3 cells. Bile acid receptor-selective activation with INT-777 revealed TGR5 localized at the basolateral membrane as the receptor involved in TDCA-induced Cl(-) secretion. In summary, we demonstrate for the first time that low concentrations of bile acids can modulate Cl(-) secretion in airway epithelial cells, and this effect is dependent on both the duration and sidedness of exposure to the bile acid.

  12. Cystic Fibrosis Gene Encodes a cAMP-Dependent Chloride Channel in Heart

    Science.gov (United States)

    Hart, Padraig; Warth, John D.; Levesque, Paul C.; Collier, Mei Lin; Geary, Yvonne; Horowitz, Burton; Hume, Joseph R.

    1996-06-01

    cAMP-dependent chloride channels in heart contribute to autonomic regulation of action potential duration and membrane potential and have been inferred to be due to cardiac expression of the epithelial cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. In this report, a cDNA from rabbit ventricle was isolated and sequenced, which encodes an exon 5 splice variant (exon 5-) of CFTR, with >90% identity to human CFTR cDNA present in epithelial cells. Expression of this cDNA in Xenopus oocytes gave rise to robust cAMP-activated chloride currents that were absent in control water-injected oocytes. Antisense oligodeoxynucleotides directed against CFTR significnatly reduced the density of cAMP-dependent chloride currents in acutely cultured myocytes, thereby establishing a direct functional link between cardiac expression of CFTR protein and an endogenous chloride channel in native cardiac myocytes.

  13. Function of chloride intracellular channel 1 in gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Peng-Fei Ma; Jun-Qiang Chen; Zhen Wang; Jin-Lu Liu; Bo-Pei Li

    2012-01-01

    AIM:To investigate the effect of chloride intracellular channel 1 (CLIC1) on the cell proliferation,apoptosis,migration and invasion of gastric cancer cells.METHODS:CLIC1 expression was evaluated in human gastric cancer cell lines SGC-7901 and MGC-803 by real time polymerase chain reaction (RT-PCR).Four segments of small interference RNA (siRNA) targeting CLIC1 mRNA and a no-sense control segment were designed by bioinformatics technology.CLIC1 siRNA was selected using Lipofectamine 2000 and transfected transiently into human gastric cancer SGC-7901 and MGC-803 cells.The transfected efficiency was observed under fluorescence microscope.After transfection,mRNA expression of CLIC1 was detected with RT-PCR and Western blotting was used to detect the protein expression.Proliferation was examined by methyl thiazolyl tetrazolium and apoptosis was detected with flow cytometry.Polycarbonate membrane transwell chamber and Matrigel were used for the detection of the changes of invasion and migration of the two cell lines.RESULTS:In gastric cancer cell lines SGC-7901 and MGC-803,CLIC1 was obviously expressed and CLIC1 siRNA could effectively suppress the expression of CLIC1 protein and mRNA.Proliferation of cells transfected with CLIC1 siRNA3 was enhanced notably,and the highest proliferation rate was 23.3% (P =0.002) in SGC-7901 and 35.55% (P =0.001) in MGC-803 cells at 48 h.The G2/M phase proportion increased,while G0/G1 and S phase proportions decreased.The apoptotic rate of the CLIC1 siRNA3 group obviously decreased in both SGC-7901 cells (62.24%,P =0.000) and MGC-803 cells (52.67%,P =0.004).Down-regulation of CLIC1 led to the inhibition of invasion and migration by 54.31% (P =0.000) and 33.62% (P =0.001) in SGC-7901 and 40.74% (P =0.000) and 29.26% (P =0.002) in MGC-803.However,there was no significant difference between the mock group cells and the negative control group cells.CONCLUSION:High CLIC1 expression can efficiently inhibit proliferation and

  14. Identification of Herbal Compound lmperatorin with Adverse Effects on ANO1 and CFTR Chloride Channels

    Institute of Scientific and Technical Information of China (English)

    HAO Feng; YI Fei; ZHANG Di; NING Yan; SU Wei-heng; FENG Xue-chao; YANG Hong; MA Tong-hui

    2011-01-01

    Calcium-activated chloride channels(CaCCs) are the crucial regulators of transepithelial fluid secretion,smooth muscle contraction and sensory transduction. Recently, compelling evidence has indicated that TMEM 16A(ANO 1 or anoctamin-i ) is a bona fide calcium-acvtivated chloride channel. A few small molecule CaCCs regulators are available for functional and therapeutic studies. We screened 126 natural compounds from Chinese herbs. Screening was performed with an iodide influx assay in Fischer rat thyroid epithelial cells to coexpress ANOI and an iodide-sensitive fluorescent indicator(EYFP-HI48Q/I152L). lmperatorin, a coumarin compound, was identifled to inhibit ANOl-mediated chloride transport activated by multiple calcium-elevating agonists. The inhibitory effect is dose-dependent with IC50 ~14.63 μmol/L. Interestingly, imperatorin activated CFTR chloride channel with EC50 ~35.52 μmol/L. The adverse effects of imperatorin on CaCC and CFTR chloride channels will make it useful in pharmacological dissection of chloride transport in airway and intestinal epithelium. Further studies are required to evaluate the therapeutic effects of imperatorin on hypertension, asthma and certain tumors.

  15. Requirement for chloride channel function during the hepatitis C virus life cycle

    OpenAIRE

    Igloi, Z; Mohl, BP; Lippiat, JD; Harris, M.; Mankouri, J

    2015-01-01

    Hepatocytes express an array of plasma membrane and intracellular ion channels, yet their role during the hepatitis C virus (HCV) life cycle remains largely undefined. Here, we show that HCV increases intracellular hepatic chloride (Cl−) influx that can be inhibited by selective Cl− channel blockers. Through pharmacological and small interfering RNA (siRNA)-mediated silencing, we demonstrate that Cl− channel inhibition is detrimental to HCV replication. This represents the first observation o...

  16. Modulation of chloride channel functions by the plant lignan compounds kobusin and eudesmin

    Directory of Open Access Journals (Sweden)

    Yu eJiang

    2015-11-01

    Full Text Available Plant lignans are diphenolic compounds widely present in vegetables, fruits and grains. These compounds have been demonstrated to have protective effect against cancer, hypertension and diabetes. In the present study, we showed that two lignan compounds, kobusin and eudesmin, isolated from Magnoliae Flos, could modulate intestinal chloride transport mediated by cystic fibrosis transmembrane conductance regulator (CFTR and calcium-activated chloride channels (CaCCs chloride channels. The compounds potentiated CFTR channel function in both FRT cells and in HT-29 cells. The modulating effects of kobusin and eudesmin on the activity of CaCCgie (CaCC expressed in gastrointestinal epithelial cells were also investigated, and the result showed that both compounds could stimulate CaCCgie-mediated short-circuit currents and the stimulation was synergistic with ATP. In ex vivo studies, both compounds potentiated CFTR and CaCCgie chloride channel activities in mouse colonic epithelia. Remarkably, the compounds showed inhibitory effects toward ANO1/CaCC-mediated short-circuit currents in ANO1/CaCC-expressing FRT cells, with IC50 values of 75 M for kobusin and 100 M for eudesmin. In charcoal transit study, both compounds mildly reduced gastrointestinal motility in mice. Taken together, these results revealed a new kind of activity displayed by the lignan compounds, one that is concerned with the modulation of chloride channel function.

  17. Stimulation effect of wide type CFTR chloride channel by the naturally occurring flavonoid tangeretin.

    Science.gov (United States)

    Jiang, Yu; Yu, Bo; Wang, Xue; Sui, Yujie; Zhang, Yaofang; Yang, Shuang; Yang, Hong; Ma, Tonghui

    2014-12-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel expressed in the apical membrane of serous epithelial cells. Both deficiency and overactivation of CFTR may cause fluid and salt secretion related diseases. In the present study, we identified tangeretin from Pericarpium Citri Reticulatae Viride as a CFTR activator using high-throughput screening based on FRT cell-based fluorescence assay. The activation effect of tangeretin on CFTR chloride channel and the possible underlying mechanisms were investigated. Fluorescence quenching tests showed that tangeretin dose- and time-dependently activated CFTR chloride channel, the activity had rapid and reversible characteristics and the activation effect could be completely reversed by the CFTR specific blocker CFTRinh-172. Primary mechanism studies indicated that the activation effect of tangeretin on CFTR chloride channel was FSK dependent as well as had additional effect with FSK and IBMX suggesting that tangeretin activates CFTR by direct interacting with the protein. Ex-vivo tests revealed that tangeretin could accelerate the speed of the submucosal gland fluid secretion. Short-circuit current measurement demonstrated that tangeretin activated rat colonic mucosa chloride current. Thus, CFTR Cl(-) channel is a molecular target of natural compound tangeretin. Tangeretin may have potential use for the treatment of CFTR-related diseases like cystic fibrosis, bronchiectasis and habitual constipation.

  18. Effect of trimethyllead chloride on slowly activating (SV) channels in red beet (Beta vulgaris L.) taproots.

    Science.gov (United States)

    Trela, Zenon; Burdach, Zbigniew; Przestalski, Stanisław; Karcz, Waldemar

    2012-12-01

    The patch-clamp technique was used to examine the effect of trimethyllead chloride (Met(3)PbCl) on SV channel activity in red beet (Beta vulgaris L.) taproot vacuoles. It was found that in the control bath the macroscopic currents showed the typical slow activation and a strong outward rectification of the steady-state currents. An addition of Met(3)PbCl to the bath solution blocked, in a concentration-dependent manner, SV currents in red beet vacuoles. The time constant τ increased several times in the presence of 100 μM trimethyllead chloride at all voltages tested. When single channel properties were analyzed, only little channel activity could be recorded in the presence of 100 μM Met(3)PbCl. Trimethyllead chloride decreased significantly (by about one order of magnitude) the open probability of single channels. The recordings of single channel activity obtained in the presence and absence of Met(3)PbCl showed that organolead only slightly (by ca. 10%) decreased the unitary conductance of single channels. It was also found that Met(3)PbCl diminished significantly the number of SV channel openings, whereas it did not change the opening times of the channels. Taken together, these results suggest that Met(3)PbCl binding site is located outside the channel selectivity filter.

  19. Expression and distribution of Kv4 potassium channel subunits and potassium channel interacting proteins in subpopulations of interneurons in the basolateral amygdala.

    Science.gov (United States)

    Dabrowska, J; Rainnie, D G

    2010-12-15

    The Kv4 potassium channel α subunits, Kv4.1, Kv4.2, and Kv4.3, determine some of the fundamental physiological properties of neurons in the CNS. Kv4 subunits are associated with auxiliary β-subunits, such as the potassium channel interacting proteins (KChIP1 - 4), which are thought to regulate the trafficking and gating of native Kv4 potassium channels. Intriguingly, KChIP1 is thought to show cell type-selective expression in GABA-ergic inhibitory interneurons, while other β-subunits (KChIP2-4) are associated with principal glutamatergic neurons. However, nothing is known about the expression of Kv4 family α- and β-subunits in specific interneurons populations in the BLA. Here, we have used immunofluorescence, co-immunoprecipitation, and Western Blotting to determine the relative expression of KChIP1 in the different interneuron subtypes within the BLA, and its co-localization with one or more of the Kv4 α subunits. We show that all three α-subunits of Kv4 potassium channel are found in rat BLA neurons, and that the immunoreactivity of KChIP1 closely resembles that of Kv4.3. Indeed, Kv4.3 showed almost complete co-localization with KChIP1 in the soma and dendrites of a distinct subpopulation of BLA neurons. Dual-immunofluorescence studies revealed this to be in BLA interneurons immunoreactive for parvalbumin, cholecystokin-8, and somatostatin. Finally, co-immunoprecipitation studies showed that KChIP1 was associated with all three Kv4 α subunits. Together our results suggest that KChIP1 is selectively expressed in BLA interneurons where it may function to regulate the activity of A-type potassium channels. Hence, KChIP1 might be considered as a cell type-specific regulator of GABAergic inhibitory circuits in the BLA.

  20. Conformational changes opening and closing the CFTR chloride channel: insights from cysteine scanning mutagenesis.

    Science.gov (United States)

    El Hiani, Yassine; Linsdell, Paul

    2014-12-01

    Cystic fibrosis, the most common lethal genetic disease affecting young people in North America, is caused by failure of the chloride ion channel known as CFTR (cystic fibrosis transmembrane conductance regulator). CFTR belongs to the large family of ATP-binding cassette (ABC) membrane transporters. In CFTR, ATP-driven events at the nucleotide-binding domains (NBDs) open and close a gate that controls chloride permeation. However, the conformational changes concomitant with opening and closing of the CFTR gate are unknown. Diverse techniques including substituted cysteine accessibility method, disulfide cross-linking, and patch-clamp recording have been used to explore CFTR channel structure. Here, we consider the architecture of both the open and the closed CFTR channel. We review how CFTR channel structure changes between the closed and the open channel conformations and portray the relative function of both cytoplasmic and vestigial gates during the gating cycle. Understanding how the CFTR channel gates chloride permeation is central for understanding how CFTR defects lead to CF. Such knowledge opens the door for novel ways to maximize CFTR channel activity in a CF setting.

  1. Anion conductance selectivity mechanism of the CFTR chloride channel.

    Science.gov (United States)

    Linsdell, Paul

    2016-04-01

    All ion channels are able to discriminate between substrate ions to some extent, a process that involves specific interactions between permeant anions and the so-called selectivity filter within the channel pore. In the cystic fibrosis transmembrane conductance regulator (CFTR) anion-selective channel, both anion relative permeability and anion relative conductance are dependent on anion free energy of hydration--anions that are relatively easily dehydrated tend to show both high permeability and low conductance. In the present work, patch clamp recording was used to investigate the relative conductance of different anions in CFTR, and the effect of mutations within the channel pore. In constitutively-active E1371Q-CFTR channels, the anion conductance sequence was Cl(-) > NO3(-) > Br(-) > formate > SCN(-) > I(-). A mutation that disrupts anion binding in the inner vestibule of the pore (K95Q) disrupted anion conductance selectivity, such that anions with different permeabilities showed almost indistinguishable conductances. Conversely, a mutation at the putative narrowest pore region that is known to disrupt anion permeability selectivity (F337A) had minimal effects on anion relative conductance. Ion competition experiments confirmed that relatively tight binding of permeant anions resulted in relatively low conductance. These results suggest that the relative affinity of ion binding in the inner vestibule of the pore controls the relative conductance of different permeant anions in CFTR, and that the pore has two physically distinct anion selectivity filters that act in series to control anion conductance selectivity and anion permeability selectivity respectively.

  2. Regulation of CFTR chloride channel macroscopic conductance by extracellular bicarbonate.

    Science.gov (United States)

    Li, Man-Song; Holstead, Ryan G; Wang, Wuyang; Linsdell, Paul

    2011-01-01

    The CFTR contributes to Cl⁻ and HCO₃⁻ transport across epithelial cell apical membranes. The extracellular face of CFTR is exposed to varying concentrations of Cl⁻ and HCO₃⁻ in epithelial tissues, and there is evidence that CFTR is sensitive to changes in extracellular anion concentrations. Here we present functional evidence that extracellular Cl⁻ and HCO₃⁻ regulate anion conduction in open CFTR channels. Using cell-attached and inside-out patch-clamp recordings from constitutively active mutant E1371Q-CFTR channels, we show that voltage-dependent inhibition of CFTR currents in intact cells is significantly stronger when the extracellular solution contains HCO₃⁻ than when it contains Cl⁻. This difference appears to reflect differences in the ability of extracellular HCO₃⁻ and Cl⁻ to interact with and repel intracellular blocking anions from the pore. Strong block by endogenous cytosolic anions leading to reduced CFTR channel currents in intact cells occurs at physiologically relevant HCO₃⁻ concentrations and membrane potentials and can result in up to ∼50% inhibition of current amplitude. We propose that channel block by cytosolic anions is a previously unrecognized, physiologically relevant mechanism of channel regulation that confers on CFTR channels sensitivity to different anions in the extracellular fluid. We further suggest that this anion sensitivity represents a feedback mechanism by which CFTR-dependent anion secretion could be regulated by the composition of the secretions themselves. Implications for the mechanism and regulation of CFTR-dependent secretion in epithelial tissues are discussed.

  3. The ABC protein turned chloride channel whose failure causes cystic fibrosis

    OpenAIRE

    Gadsby, David C.; Vergani, Paola; Csanády, László

    2006-01-01

    CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR ch...

  4. The Validation of Nematode-Specific Acetylcholine-Gated Chloride Channels as Potential Anthelmintic Drug Targets.

    Science.gov (United States)

    Wever, Claudia M; Farrington, Danielle; Dent, Joseph A

    2015-01-01

    New compounds are needed to treat parasitic nematode infections in humans, livestock and plants. Small molecule anthelmintics are the primary means of nematode parasite control in animals; however, widespread resistance to the currently available drug classes means control will be impossible without the introduction of new compounds. Adverse environmental effects associated with nematocides used to control plant parasitic species are also motivating the search for safer, more effective compounds. Discovery of new anthelmintic drugs in particular has been a serious challenge due to the difficulty of obtaining and culturing target parasites for high-throughput screens and the lack of functional genomic techniques to validate potential drug targets in these pathogens. We present here a novel strategy for target validation that employs the free-living nematode Caenorhabditis elegans to demonstrate the value of new ligand-gated ion channels as targets for anthelmintic discovery. Many successful anthelmintics, including ivermectin, levamisole and monepantel, are agonists of pentameric ligand-gated ion channels, suggesting that the unexploited pentameric ion channels encoded in parasite genomes may be suitable drug targets. We validated five members of the nematode-specific family of acetylcholine-gated chloride channels as targets of agonists with anthelmintic properties by ectopically expressing an ivermectin-gated chloride channel, AVR-15, in tissues that endogenously express the acetylcholine-gated chloride channels and using the effects of ivermectin to predict the effects of an acetylcholine-gated chloride channel agonist. In principle, our strategy can be applied to validate any ion channel as a putative anti-parasitic drug target.

  5. The Validation of Nematode-Specific Acetylcholine-Gated Chloride Channels as Potential Anthelmintic Drug Targets.

    Directory of Open Access Journals (Sweden)

    Claudia M Wever

    Full Text Available New compounds are needed to treat parasitic nematode infections in humans, livestock and plants. Small molecule anthelmintics are the primary means of nematode parasite control in animals; however, widespread resistance to the currently available drug classes means control will be impossible without the introduction of new compounds. Adverse environmental effects associated with nematocides used to control plant parasitic species are also motivating the search for safer, more effective compounds. Discovery of new anthelmintic drugs in particular has been a serious challenge due to the difficulty of obtaining and culturing target parasites for high-throughput screens and the lack of functional genomic techniques to validate potential drug targets in these pathogens. We present here a novel strategy for target validation that employs the free-living nematode Caenorhabditis elegans to demonstrate the value of new ligand-gated ion channels as targets for anthelmintic discovery. Many successful anthelmintics, including ivermectin, levamisole and monepantel, are agonists of pentameric ligand-gated ion channels, suggesting that the unexploited pentameric ion channels encoded in parasite genomes may be suitable drug targets. We validated five members of the nematode-specific family of acetylcholine-gated chloride channels as targets of agonists with anthelmintic properties by ectopically expressing an ivermectin-gated chloride channel, AVR-15, in tissues that endogenously express the acetylcholine-gated chloride channels and using the effects of ivermectin to predict the effects of an acetylcholine-gated chloride channel agonist. In principle, our strategy can be applied to validate any ion channel as a putative anti-parasitic drug target.

  6. The Validation of Nematode-Specific Acetylcholine-Gated Chloride Channels as Potential Anthelmintic Drug Targets

    Science.gov (United States)

    Wever, Claudia M.; Farrington, Danielle; Dent, Joseph A.

    2015-01-01

    New compounds are needed to treat parasitic nematode infections in humans, livestock and plants. Small molecule anthelmintics are the primary means of nematode parasite control in animals; however, widespread resistance to the currently available drug classes means control will be impossible without the introduction of new compounds. Adverse environmental effects associated with nematocides used to control plant parasitic species are also motivating the search for safer, more effective compounds. Discovery of new anthelmintic drugs in particular has been a serious challenge due to the difficulty of obtaining and culturing target parasites for high-throughput screens and the lack of functional genomic techniques to validate potential drug targets in these pathogens. We present here a novel strategy for target validation that employs the free-living nematode Caenorhabditis elegans to demonstrate the value of new ligand-gated ion channels as targets for anthelmintic discovery. Many successful anthelmintics, including ivermectin, levamisole and monepantel, are agonists of pentameric ligand-gated ion channels, suggesting that the unexploited pentameric ion channels encoded in parasite genomes may be suitable drug targets. We validated five members of the nematode-specific family of acetylcholine-gated chloride channels as targets of agonists with anthelmintic properties by ectopically expressing an ivermectin-gated chloride channel, AVR-15, in tissues that endogenously express the acetylcholine-gated chloride channels and using the effects of ivermectin to predict the effects of an acetylcholine-gated chloride channel agonist. In principle, our strategy can be applied to validate any ion channel as a putative anti-parasitic drug target. PMID:26393923

  7. Physiology and Pathophysiology of CLC-1: Mechanisms of a Chloride Channel Disease, Myotonia

    Directory of Open Access Journals (Sweden)

    Chih-Yung Tang

    2011-01-01

    Full Text Available The CLC-1 chloride channel, a member of the CLC-channel/transporter family, plays important roles for the physiological functions of skeletal muscles. The opening of this chloride channel is voltage dependent and is also regulated by protons and chloride ions. Mutations of the gene encoding CLC-1 result in a genetic disease, myotonia congenita, which can be inherited as an autosmal dominant (Thomsen type or an autosomal recessive (Becker type pattern. These mutations are scattered throughout the entire protein sequence, and no clear relationship exists between the inheritance pattern of the mutation and the location of the mutation in the channel protein. The inheritance pattern of some but not all myotonia mutants can be explained by a working hypothesis that these mutations may exert a “dominant negative” effect on the gating function of the channel. However, other mutations may be due to different pathophysiological mechanisms, such as the defect of protein trafficking to membranes. Thus, the underlying mechanisms of myotonia are likely to be quite diverse, and elucidating the pathophysiology of myotonia mutations will require the understanding of multiple molecular/cellular mechanisms of CLC-1 channels in skeletal muscles, including molecular operation, protein synthesis, and membrane trafficking mechanisms.

  8. An improved ivermectin-activated chloride channel receptor for inhibiting electrical activity in defined neuronal populations

    DEFF Research Database (Denmark)

    Lynagh, Timothy Peter; Lynch, Joseph W

    2010-01-01

    for surgically implanted stimulus delivery methods and their use of nonhuman receptors. A third silencing method, an invertebrate glutamate-gated chloride channel receptor (GluClR) activated by ivermectin, solves the stimulus delivery problem as ivermectin is a safe, well tolerated drug that reaches the brain...

  9. The ABC protein turned chloride channel whose failure causes cystic fibrosis.

    Science.gov (United States)

    Gadsby, David C; Vergani, Paola; Csanády, László

    2006-03-23

    CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR channels has led to a unifying mechanism explaining those ATP-driven conformational changes.

  10. Slow conversions among subconductance states of cystic fibrosis transmembrane conductance regulator chloride channel.

    OpenAIRE

    Tao, T.; Xie, J; Drumm, M L; Zhao, J.; Davis, P B; Ma, J.

    1996-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel exhibits multiple subconductance states. To study the regulation of conductance states of the CFTR channel, we expressed the wild-type CFTR protein in HEK 293 cells, and isolated microsomal membrane vesicles for reconstitution studies in lipid bilayer membranes. A single CFTR channel had a dominant conductance of 7.8 pS (H), plus two sub-open states with conductances of approximately 6 pS (M) and 2.7 pS (L) in 200...

  11. The ABC protein turned chloride channel whose failure causes cystic fibrosis

    Science.gov (United States)

    Gadsby, David C.; Vergani, Paola; Csanády, László

    2006-03-01

    CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR channels has led to a unifying mechanism explaining those ATP-driven conformational changes.

  12. Two tonoplast MATE proteins function as turgor-regulating chloride channels in Arabidopsis

    Science.gov (United States)

    Zhang, Haiwen; Zhao, Fu-Geng; Tang, Ren-Jie; Yu, Yuexuan; Song, Jiali; Wang, Yuan; Li, Legong; Luan, Sheng

    2017-01-01

    The central vacuole in a plant cell occupies the majority of the cellular volume and plays a key role in turgor regulation. The vacuolar membrane (tonoplast) contains a large number of transporters that mediate fluxes of solutes and water, thereby adjusting cell turgor in response to developmental and environmental signals. We report that two tonoplast Detoxification efflux carrier (DTX)/Multidrug and Toxic Compound Extrusion (MATE) transporters, DTX33 and DTX35, function as chloride channels essential for turgor regulation in Arabidopsis. Ectopic expression of each transporter in Nicotiana benthamiana mesophyll cells elicited a large voltage-dependent inward chloride current across the tonoplast, showing that DTX33 and DTX35 each constitute a functional channel. Both channels are highly expressed in Arabidopsis tissues, including root hairs and guard cells that experience rapid turgor changes during root-hair elongation and stomatal movements. Disruption of these two genes, either in single or double mutants, resulted in shorter root hairs and smaller stomatal aperture, with double mutants showing more severe defects, suggesting that these two channels function additively to facilitate anion influx into the vacuole during cell expansion. In addition, dtx35 single mutant showed lower fertility as a result of a defect in pollen-tube growth. Indeed, patch-clamp recording of isolated vacuoles indicated that the inward chloride channel activity across the tonoplast was impaired in the double mutant. Because MATE proteins are widely known transporters of organic compounds, finding MATE members as chloride channels expands the functional definition of this large family of transporters. PMID:28202726

  13. Cystic fibrosis transmembrane conductance regulator chloride channel blockers: Pharmacological, biophysical and physiological relevance

    Institute of Scientific and Technical Information of China (English)

    Paul; Linsdell

    2014-01-01

    Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of

  14. The chloride channel inhibitor NS3736 [corrected] prevents bone resorption in ovariectomized rats without changing bone formation

    DEFF Research Database (Denmark)

    Schaller, Sophie; Henriksen, Kim; Sveigaard, Christina

    2004-01-01

    formation. This study indicates that chloride channel inhibitors are highly promising for treatment of osteoporosis. INTRODUCTION: The chloride channel inhibitor, NS3736, blocked osteoclastic acidification and resorption in vitro with an IC50 value of 30 microM. When tested in the rat ovariectomy model......: In conclusion, we show for the first time that chloride channel inhibitors can be used for prevention of ovariectomy-induced bone loss without impeding bone formation. We speculate that the coupling of bone resorption to bone formation is linked to the acidification of the resorption lacunae, thereby enabling...

  15. Inhibition of herpes simplex virus type 1 entry by chloride channel inhibitors tamoxifen and NPPB

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Kai [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of Life Science and Technology, Jinan University, Guangzhou (China); Chen, Maoyun [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of pharmacy, Jinan University, Guangzhou (China); Xiang, Yangfei; Ma, Kaiqi [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); Jin, Fujun [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of pharmacy, Jinan University, Guangzhou (China); Wang, Xiao [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Wang, Xiaoyan; Wang, Shaoxiang [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); Wang, Yifei, E-mail: twang-yf@163.com [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China)

    2014-04-18

    Highlights: • We analyze the anti-HSV potential of chloride channel inhibitors. • Tamoxifen and NPPB show anti-HSV-1 and anti-ACV-resistant HSV-1 activities. • HSV-1 infection induces intracellular chloride concentration increasing. • Tamoxifen and NPPB inhibit HSV-1 early infection. • Tamoxifen and NPPB prevent the fusion process of HSV-1. - Abstract: Herpes simplex virus type 1 (HSV-1) infection is very common worldwide and can cause significant health problems from periodic skin and corneal lesions to encephalitis. Appearance of drug-resistant viruses in clinical therapy has made exploring novel antiviral agents emergent. Here we show that chloride channel inhibitors, including tamoxifen and 5-nitro-2-(3-phenyl-propylamino) benzoic acid (NPPB), exhibited extensive antiviral activities toward HSV-1 and ACV-resistant HSV viruses. HSV-1 infection induced chloride ion influx while treatment with inhibitors reduced the increase of intracellular chloride ion concentration. Pretreatment or treatment of inhibitors at different time points during HSV-1 infection all suppressed viral RNA synthesis, protein expression and virus production. More detailed studies demonstrated that tamoxifen and NPPB acted as potent inhibitors of HSV-1 early entry step by preventing viral binding, penetration and nuclear translocation. Specifically the compounds appeared to affect viral fusion process by inhibiting virus binding to lipid rafts and interrupting calcium homeostasis. Taken together, the observation that tamoxifen and NPPB can block viral entry suggests a stronger potential for these compounds as well as other ion channel inhibitors in antiviral therapy against HSV-1, especially the compound tamoxifen is an immediately actionable drug that can be reused for treatment of HSV-1 infections.

  16. CFTR chloride channel is a molecular target of the natural cancer preventive agent resveratrol.

    Science.gov (United States)

    Yang, Shuang; Yu, B O; Sui, Yujie; Zhang, Yaofang; Wang, Xue; Hou, Shuguang; Ma, Tonghui; Yang, Hong

    2013-09-01

    The naturally occurring polyphenol compound resveratrol (RES) has been receiving wide attention because of its variety of health benefits and favourable biological activities. Previous studies have shown that RES could induce intestinal chloride secretion in mouse jejunum and stimulate cAMP-dependent Cl- secretion in T84, primary cultured murine nasal septal and human sinonasal epithelial cells, but the precise molecular target is not clear. We therefore tested the hypothesis that RES may stimulate the activity of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. Using cell-based fluorescent assays, transepithelial short-circuit current measurements and excised inside-out patch-clamp analysis; we found that RES dose-dependently potentiate CFTR Cl- channel activities, which was reversed by CFTR inhibitors CFTR(inh)-172 and GlyH101. Transepithelial Cl- secretion by CFTR-expressing FRT cells was stimulated by RES with half maximal concentration -80 microM. Intracellular cAMP content was not elevated by RES in FRT cells. Excised inside-out patch-clamp analysis indicated that RES significantly increased the chloride currents of CFTR. In ex vivo studies, RES stimulated the transmucosal chloride current of rat colon by short-circuit current assay. These data suggested that CFTR is a molecular target of RES. Our findings add a new molecular target to RES, and RES may represent a novel class of therapeutic lead compounds in treating CFTR-related diseases including CF and habitual constipation.

  17. Differential distribution of glutamate- and GABA-gated chloride channels in the housefly Musca domestica.

    Science.gov (United States)

    Kita, Tomo; Ozoe, Fumiyo; Azuma, Masaaki; Ozoe, Yoshihisa

    2013-09-01

    l-Glutamic acid (glutamate) mediates fast inhibitory neurotransmission by affecting glutamate-gated chloride channels (GluCls) in invertebrates. The molecular function and pharmacological properties of GluCls have been well studied, but not much is known about their physiological role and localization in the insect body. The distribution of GluCls in the housefly (Musca domestica L.) was thus compared with the distribution of γ-aminobutyric acid (GABA)-gated chloride channels (GABACls). Quantitative PCR and ligand-binding experiments indicate that the GluCl and GABACl transcripts and proteins are predominantly expressed in the adult head. Intense GluCl immunostaining was detected in the lamina, leg motor neurons, and legs of adult houseflies. The GABACl (Rdl) immunostaining was more widely distributed, and was found in the medulla, lobula, lobula plate, mushroom body, antennal lobe, and ellipsoid body. The present findings suggest that GluCls have physiological roles in different tissues than GABACls.

  18. Design and Synthesis of Photoaffinity Probe Candidates for the GABA-gated Chloride Channel

    Institute of Scientific and Technical Information of China (English)

    LIU Shang-Zhong; LI Qing-X.

    2006-01-01

    In order to characterize binding sites of insecticidal compounds on GABA gated chloride channel, new photoaffinity probe candidates based on 5e-t-butyl-2e-[4-(substituted-propynyl)phenyl]-1,3-dithiane for the noncompetitive blocker (NCB) site of the γ-aminobutyric acid (GABA)-gated chloride channel were designed and synthesized, and their potency as an inhibitor on NCB was measured by 4'-ethynyl-4-n-[2,3-3H2]-propylbicycloorthobenzoate (3H EBOB) assay. The synthesized compounds showed high inhibition activities with half maximum inhibition concentrations (IC50) of lower than 35 nmol/L and were very stable in binding conditions as well photoreacted quickly at 300 nm light. These new compounds are expected to be good photoaffinity labeling probes if radioisotope iodine is incorporated.

  19. Blockade of chloride channels by DIDS stimulates renin release and inhibits contraction of afferent arterioles

    DEFF Research Database (Denmark)

    Jensen, B L; Skøtt, O

    1996-01-01

    arterioles with the chloride channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). Renin secretion was equally enhanced by omission of extracellular calcium and by addition of 0.5 mM DIDS. The inhibitory effect of calcium was blocked by DIDS. The stimulatory effects of low calcium [with....... Norepinephrine (5 x 10(-7)-1 x 10(-6) M) and angiotensin II (1 x 10(-8)-10(-6) M) evoked reversible and dose-dependent contractions of microperfused rabbit afferent arterioles. DIDS (0.5 mM) did not affect the basal diameter of the arterioles but strongly inhibited the response to angiotensin II and attenuated...... the duration of the contractile response to norepinephrine. The results support the hypothesis that DIDS-sensitive calcium-activated chloride channels are involved in regulation of renin release and in the afferent arteriolar contraction after angiotensin II but do not play a pivotal role in the response...

  20. Chloride channels are involved in sperm motility and are downregulated in spermatozoa from patients with asthenozoospermia.

    Science.gov (United States)

    Liu, Shan-Wen; Li, Yuan; Zou, Li-Li; Guan, Yu-Tao; Peng, Shuang; Zheng, Li-Xin; Deng, Shun-Mei; Zhu, Lin-Yan; Wang, Li-Wei; Chen, Li-Xin

    2016-06-03

    Human spermatozoa encounter an osmotic decrease from 330 to 290 mOsm l-1 when passing through the female reproductive tract. We aimed to evaluate the role of chloride channels in volume regulation and sperm motility from patients with asthenozoospermia. Spermatozoa were purified using Percoll density gradients. Sperm volume was measured as the forward scatter signal using flow cytometry. Sperm motility was analyzed using computer-aided sperm analysis (CASA). When transferred from an isotonic solution (330 mOsm l-1 ) to a hypotonic solution (290 mOsm l-1 ), cell volume was not changed in spermatozoa from normozoospermic men; but increased in those from asthenozoospermic samples. The addition of the chloride channel blockers, 4,4'-diisothiocyanatostilbene-2,2'- isulfonic acid (DIDS) or 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) to the hypotonic solution caused the normal spermatozoa to swell but did not increase the volume of those from the asthenozoospermic semen. DIDS and NPPB decreased sperm motility in both sets of semen samples. The inhibitory effect of NPPB on normal sperm motility was much stronger than on spermatozoa from the asthenozoospermic samples. Both sperm types expressed ClC-3 chloride channels, but the expression levels in the asthenozoospermic samples were much lower, especially in the neck and mid-piece areas. Spermatozoa from men with asthenozoospermia demonstrated lower volume regulating capacity, mobility, and ClC-3 expression levels (especially in the neck) than did normal spermatozoa. Thus, chloride channels play important roles in the regulation of sperm volume and motility and are downregulated in cases of asthenozoospermia.

  1. Photoaffinity Probe Candidates for Gamma-aminobutyric Acid (GABAA)-Gated Chloride Channel

    Institute of Scientific and Technical Information of China (English)

    Shang Zhong LIU; Qing Xiao LI

    2004-01-01

    New photoaffinity ligand candidates were synthesized based on 5-t-butyl-2-(4- (substituted-ethynyl)phenyl)-1, 3-dithiane for the noncompetitive blocker site on the gamma- aminobutyric acid -gated chloride channel. Their half-maximal inhibition concentrations ranged from 4 to 32 nmol/L as measured by 4'-ethynyl-4-n-[2,3-3H2]-propylbicycloorthobenzoate (3H EBOB) assay.

  2. Effect of a chloride channel activator, lubiprostone, on colonic sensory and motor functions in healthy subjects

    OpenAIRE

    Sweetser, Seth; Busciglio, Irene A.; Camilleri, Michael; Bharucha, Adil E.; Szarka, Lawrence A.; Papathanasopoulos, Athanasios; Burton, Duane D.; Eckert, Deborah J.; Zinsmeister, Alan R.

    2008-01-01

    Lubiprostone, a bicyclic fatty acid chloride channel activator, is efficacious in treatment of chronic constipation and constipation-predominant irritable bowel syndrome. The study aim was to compare effects of lubiprostone and placebo on colonic sensory and motor functions in humans. In double-blind, randomized fashion, 60 healthy adults received three oral doses of placebo or 24 μg lubiprostone per day in a parallel-group, placebo-controlled trial. A barostat-manometry tube was placed in th...

  3. Diet-dependent hypercalciuria in transgenic mice with reduced CLC5 chloride channel expression

    OpenAIRE

    Luyckx, Valerie A.; LeClercq, Baudouin; Dowland, Lara K.; Yu, Alan S. L.

    1999-01-01

    Dent’s disease is an X-linked inherited disorder characterized by hypercalciuria, nephrocalcinosis, nephrolithiasis, low molecular weight proteinuria, Fanconi’s syndrome, and renal failure. It is caused by inactivating mutations in CLC5, a member of the CLC voltage-gated chloride channel family. CLC5 is known to be expressed in the endosomal compartment of the renal proximal tubule, where it may be required for endosomal acidification and trafficking. Although the Fanconi’s syndrome and low m...

  4. Activation Effect of Cathartic Natural Compound Rhein to CFTR Chloride Channel

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel expressed in intestinal exocrine glands, which plays a key role in intestinal fluid secretion. A natural anthraquinone activator of CFTR Cl- channel, rhein, was identified by screening 217 single compounds from Chinese herbs via a cellbased halide-sensitive fluorescent assay. Rhein activates CFTR Cl- transportation in a dose-dependent manner in the presence of cAMP with a physiological concentration. This study provides a novel molecular pharmacological mechanism for the laxative drugs in Traditional Chinese Medicine such as aloe, cascara and senna.

  5. State-dependent blocker interactions with the CFTR chloride channel: implications for gating the pore.

    Science.gov (United States)

    Linsdell, Paul

    2014-12-01

    Chloride permeation through the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel is subject to voltage-dependent open-channel block by a diverse range of cytoplasmic anions. However, in most cases the ability of these blocking substances to influence the pore opening and closing process has not been reported. In the present work, patch clamp recording was used to investigate the state-dependent block of CFTR by cytoplasmic Pt(NO2)4(2-) ions. Two major effects of Pt(NO2)4(2-) were identified. First, this anion caused fast, voltage-dependent block of open channels, leading to an apparent decrease in single-channel current amplitude. Secondly, Pt(NO2)4(2-) also decreased channel open probability due to an increase in interburst closed times. Interestingly, mutations in the pore that weakened (K95Q) or strengthened (I344K, V345K) interactions with Pt(NO2)4(2-) altered blocker effects both on Cl(-) permeation and on channel gating, suggesting that both these effects are a consequence of Pt(NO2)4(2-) interaction with a single site within the pore. Experiments at reduced extracellular Cl(-) concentration hinted that Pt(NO2)4(2-) may have a third effect, possibly increasing channel activity by interfering with channel closure. These results suggest that Pt(NO2)4(2-) can enter from the cytoplasm into the pore inner vestibule of both open and closed CFTR channels, and that Pt(NO2)4(2-) bound in the inner vestibule blocks Cl(-) permeation as well as interfering with channel opening and, perhaps, channel closure. Implications for the location of the channel gate in the pore, and the operation of this gate, are discussed.

  6. CFTR chloride channel as a molecular target of anthraquinone compounds in herbal laxatives

    Institute of Scientific and Technical Information of China (English)

    Hong YANG; Li-na XU; Cheng-yan HE; Xin LIU; Rou-yu FANG; Tong-hui MA

    2011-01-01

    Aim: To clarify whether CFTR is a molecular target of intestinal fluid secretion caused by the anthraquinone compounds from laxative herbal plants.Methods: A cell-based fluorescent assay to measure I- influx through CFTR chloride channel. A short-circuit current assay to measure transcellular Cl- current across single layer FRT cells and freshly isolated colon mucosa. A closed loop experiment to measure colon fluid secretion in vivo.Results: Anthraquinone compounds rhein, aloe-emodin and 1,8-dihydroxyanthraquinone (DHAN) stimulated l- influx through CFTR chloride channel in a dose-dependent manner in the presence of physiological concentration of cAMP. In the short-circuit current assay,the three compound enhanced Cl- currents in epithelia formed by CFTR-expressing FRT cells with EC5o values of 73±1.4, 56±1.7, and 50±0.5 μmol/L, respectively, and Rhein also enhanced Cl- current in freshly isolated rat colonic mucosa with a similar potency. These effects were completely reversed by the CFTR selective blocker CFTRinh-172. In in vivo closed loop experiments, rhein 2 mmol/L stimu-lated colonic fluid accumulation that was largely blocked by CFTRinh-172. The anthraquinone compounds did not elevate cAMP level in cultured FRT cells and rat colonic mucosa, suggesting a direct effect on CFTR activity.Conclusion: Natural anthraquinone compounds in vegetable laxative drugs are CFTR potsntiators that stimulated colonic chloride and fluid secretion. Thus CFTR chloride channel is a molecular target of vegetable laxative drugs.

  7. Channel properties of the splicing isoforms of the olfactory calcium-activated chloride channel Anoctamin 2.

    Science.gov (United States)

    Ponissery Saidu, Samsudeen; Stephan, Aaron B; Talaga, Anna K; Zhao, Haiqing; Reisert, Johannes

    2013-06-01

    Anoctamin (ANO)2 (or TMEM16B) forms a cell membrane Ca(2+)-activated Cl(-) channel that is present in cilia of olfactory receptor neurons, vomeronasal microvilli, and photoreceptor synaptic terminals. Alternative splicing of Ano2 transcripts generates multiple variants with the olfactory variants skipping exon 14 and having alternative splicing of exon 4. In the present study, 5' rapid amplification of cDNA ends analysis was conducted to characterize the 5' end of olfactory Ano2 transcripts, which showed that the most abundant Ano2 transcripts in the olfactory epithelium contain a novel starting exon that encodes a translation initiation site, whereas transcripts of the publically available sequence variant, which has an alternative and longer 5' end, were present in lower abundance. With two alternative starting exons and alternative splicing of exon 4, four olfactory ANO2 isoforms are thus possible. Patch-clamp experiments in transfected HEK293T cells expressing these isoforms showed that N-terminal sequences affect Ca(2+) sensitivity and that the exon 4-encoded sequence is required to form functional channels. Coexpression of the two predominant isoforms, one with and one without the exon 4 sequence, as well as coexpression of the two rarer isoforms showed alterations in channel properties, indicating that different isoforms interact with each other. Furthermore, channel properties observed from the coexpression of the predominant isoforms better recapitulated the native channel properties, suggesting that the native channel may be composed of two or more splicing isoforms acting as subunits that together shape the channel properties.

  8. Identification of natural coumarin compounds that rescue defective DeltaF508-CFTR chloride channel gating.

    Science.gov (United States)

    Xu, Li-Na; Na, Wan-Li; Liu, Xin; Hou, Shu-Guang; Lin, Sen; Yang, Hong; Ma, Tong-Hui

    2008-08-01

    1. Deletion of phenylalanine at position 508 (DeltaF508) of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is the most common mutation causing cystic fibrosis (CF). Effective pharmacological therapy of CF caused by the DeltaF508-CFTR mutation requires the rescue of both intracellular processing and channel gating defects. 2. We identified a class of natural coumarin compounds that can correct the defective DeltaF508-CFTR chloride channel gating by screening a collection of 386 single natural compounds from Chinese medicinal herbs. Screening was performed with an iodide influx assay in Fischer rat thyroid epithelial cells coexpressing DeltaF508-CFTR and an iodide-sensitive fluorescent indicator (YFP-H148Q/I152L). 3. Dose-dependent potentiation of defective DeltaF508-CFTR chloride channel gating by five coumarin compounds was demonstrated by the fluorescent iodide influx assay and confirmed by an Ussing chamber short-circuit current assay. Activation was fully abolished by the specific CFTR inhibitor CFTR(inh)-172. Two potent compounds, namely imperatorin and osthole, have activation K(d) values of approximately 10 micromol/L, as determined by the short-circuit current assay. The active coumarin compounds do not elevate intracellular cAMP levels. Activation of DeltaF508-CFTR by the coumarin compounds requires cAMP agonist, suggesting direct interaction with the mutant CFTR molecule. Kinetics analysis indicated rapid activation of DeltaF508-CFTR by the coumarin compounds, with half-maximal activation of CFTR activators may represent a new class of natural lead compounds for the development of pharmacological therapies for CF caused by the DeltaF508 mutation.

  9. ClC-1 chloride channels: state-of-the-art research and future challenges

    Directory of Open Access Journals (Sweden)

    Paola eImbrici

    2015-04-01

    Full Text Available The voltage-dependent ClC-1 chloride channel belongs to the CLC channel/transporter family. It is a homodimer comprising two individual pores which can operate independently or simultaneously according to two gating modes, the fast and the slow gate of the channel. ClC-1 is preferentially expressed in the skeletal muscle fibers where the presence of an efficient Cl- homeostasis is crucial for the correct membrane repolarization and propagation of action potential. As a consequence, mutations in the CLCN1 gene cause dominant and recessive forms of Myotonia Congenita, a rare skeletal muscle channelopathy caused by abnormal membrane excitation, and clinically characterized by muscle stiffness and various degrees of transitory weakness. Elucidation of the mechanistic link between the genetic defects and the disease pathogenesis is still incomplete and, at this time, there is no specific treatment for Myotonia Congenita. Still controversial is the subcellular localization pattern of ClC-1 channels in skeletal muscle as well as its modulation by some intracellular factors. The expression of ClC-1 in other tissues such as in brain and heart and the possible assembly of ClC-1/ClC-2 heterodimers further expand the physiological properties of ClC-1 and its involvement in diseases. A recent de novo CLCN1 truncation mutation in a patient with generalized epilepsy indeed postulates an unexpected role of this channel in the control of neuronal network excitability. This review summarizes the most relevant and state-of-the-art research on ClC-1 chloride channels physiology and associated diseases.

  10. Common channels for water and protons at apical and basolateral cell membranes of frog skin and urinary bladder epithelia. Effects of oxytocin, heavy metals, and inhibitors of H(+)-adenosine triphosphatase

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, B.; Lacoste, I.; Ehrenfeld, J. (Commissariat a l' Energie Atomique, Villefranche-sur-mer (France))

    1991-04-01

    We have compared the response of proton and water transport to oxytocin treatment in isolated frog skin and urinary bladder epithelia to provide further insights into the nature of water flow and H+ flux across individual apical and basolateral cell membranes. In isolated spontaneous sodium-transporting frog skin epithelia, lowering the pH of the apical solution from 7.4 to 6.4, 5.5, or 4.5 produced a fall in pHi in principal cells which was completely blocked by amiloride, indicating that apical Na+ channels are permeable to protons. When sodium transport was blocked by amiloride, the H+ permeability of the apical membranes of principal cells was negligible but increased dramatically after treatment with antidiuretic hormone (ADH). In the latter condition, lowering the pH of the apical solution caused a voltage-dependent intracellular acidification, accompanied by membrane depolarization, and an increase in membrane conductance and transepithelial current. These effects were inhibited by adding Hg2+ (100 microM) or dicyclohexylcarbodiimide (DCCD, 10(-5) M) to the apical bath. Net titratable H+ flux across frog skin was increased from 30 +/- 8 to 115 +/- 18 neq.h-1.cm-2 (n = 8) after oxytocin treatment (at apical pH 5.5 and serosal pH 7.4) and was completely inhibited by DCCD (10(-5) M). The basolateral membranes of the principal cells in frog skin epithelium were found to be spontaneously permeable to H+ and passive electrogenic H+ transport across this membrane was not affected by oxytocin. Lowering the pH of the basolateral bathing solution (pHb) produced an intracellular acidification and membrane depolarization (and an increase in conductance when the normal dominant K+ conductance of this membrane was abolished by Ba2+ 1 mM). These effects of low pHb were blocked by micromolar concentrations of heavy metals (Zn2+, Ni2+, Co2+, Cd2+, and Hg2+).

  11. [Post-translational ligation of split CFTR severed before TMD2 and its chloride channel function].

    Science.gov (United States)

    Zhu, Fuxiang; Gong, Xiandi; Liu, Zelong; Yang, Shude; Qu, Huige; Chi, Xiaoyan

    2010-12-01

    Mutations of cystic fibrosis transmembrane conductance regulator (CFTR) gene leads to cystic fibrosis, an autosomal recessive genetic disorder affecting a number of organs including the lung airways, pancreas and sweat glands. In order to investigate the post-translational ligation of CFTR with reconstructed functional chloride ion channel and the split Ssp DnaB intein-mediated protein trans-splicing was explored to co-deliver CFTR gene into eukaryotic cells with two vectors. The human CFTR cDNA was split after Glu838 codon before the second transmembrane dome (TMD2) into two halves of N- and C-parts and fused with the coding sequences of split Ssp DnaB intein. Pair of eukaryotic expression vectors pEGFP-NInt and pEYFP-IntC were constructed by inserting them into the vectors pEGFP-N1 and pEYFP-N1 respectively. The transient expression was carried out for observing the ligation of CFTR by Western blotting and recording the chloride current by patch clamps when cotransfection of the pair of vectors into baby hamster kidney (BHK) cells. The results showed that an obvious protein band proven to be ligated intact CFTR can be seen and a higher chloride current and activity of chloride channel were recorded after cotransfection. These data demonstrated that split Ssp DnaB intein could be used as a strategy in delivering CFTR gene by two vectors providing evidence for application of dual adeno-associated virus (AAV) vectors to overcome the limitation of packaging size in cystic fibrosis gene therapy.

  12. Effects of chloride channel blockers on hypotonicity-induced contractions of the rat trachea

    Science.gov (United States)

    Coelho, Roberta R; Souza, Emmanuel P; Soares, Pedro M G; Meireles, Ana Vaneska P; Santos, Geam C M; Scarparo, Henrique C; Assreuy, Ana Maria S; Criddle, David N

    2003-01-01

    We have investigated the inhibitory effects of blockers of volume-activated (Clvol) and calcium-activated (ClCa) chloride channels on hypotonic solution (HS)-induced contractions of rat trachea, comparing their effects with those of the voltage-dependent calcium channel (VDCC) blocker nifedpine. HS elicited large, stable contractions that were partially dependent on the cellular chloride gradient; a reduction to 41.45±7.71% of the control response was obtained when extracellular chloride was removed. In addition, HS-induced responses were reduced to 26.8±5.6% of the control by 1 μM nifedipine, and abolished under calcium-free conditions, indicating a substantial requirement for extracellular calcium entry, principally via VDCCs. The established Clvol blockers tamoxifen (⩽10 μM) and 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid (1–100 μM), at concentrations previously reported to inhibit Clvol in smooth muscle, did not significantly inhibit HS-induced contractions. In contrast, the recognized ClCa blocker niflumic acid (NFA; 1–100 μM) produced a reversible, concentration-dependent inhibition of HS responses, with a reduction to 36.6±6.4% of control contractions at the highest concentration. The mixed Clvol and ClCa blocker, 5-nitro 2-(3-phenylpropylamine) benzoic acid (NPPB; 10–100 μM) also elicited concentration-related inhibition of HS-induced contractions, producing a decrease to 35.9±11.3% of the control at 100 μM. Our results show that HS induces reversible, chloride-dependent contractions of rat isolated trachea that were inhibited by NFA and NPPB, while exhibiting little sensitivity to recognized blockers of Clvol. The data support the possibility that opening of calcium-activated chloride channels under hypotonic conditions in respiratory smooth muscle may ultimately lead to VDCC-mediated calcium entry and contraction. PMID:14691057

  13. Cystic fibrosis transmembrane conductance regulator: a chloride channel gated by ATP binding and hydrolysis.

    Science.gov (United States)

    Bompadre, Silvia G; Hwang, Tzyh-Chang

    2007-08-25

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that belongs to the ATP-binding cassette (ABC) transporter superfamily. Defective function of CFTR is responsible for cystic fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasian populations. The disease is manifested in defective chloride transport across the epithelial cells in various tissues. To date, more than 1400 different mutations have been identified as CF-associated. CFTR is regulated by phosphorylation in its regulatory (R) domain, and gated by ATP binding and hydrolysis at its two nucleotide-binding domains (NBD1 and NBD2). Recent studies reveal that the NBDs of CFTR may dimerize as observed in other ABC proteins. Upon dimerization of CFTR's two NBDs, in a head-to-tail configuration, the two ATP-binding pockets (ABP1 and ABP2) are formed by the canonical Walker A and B motifs from one NBD and the signature sequence from the partner NBD. Mutations of the amino acids that interact with ATP reveal that the two ABPs play distinct roles in controlling ATP-dependent gating of CFTR. It was proposed that binding of ATP to the ABP2, which is formed by the Walker A and B in NBD2 and the signature sequence in NBD1, is critical for catalyzing channel opening. While binding of ATP to the ABP1 alone may not increase the opening rate, it does contribute to the stabilization of the open channel conformation. Several disease-associated mutations of the CFTR channel are characterized by gating defects. Understanding how CFTR's two NBDs work together to gate the channel could provide considerable mechanistic information for future pharmacological studies, which could pave the way for tailored drug design for therapeutical interventions in CF.

  14. Evidence for a channel for the electrogenic transport of chloride ion in the rat hepatocyte

    Energy Technology Data Exchange (ETDEWEB)

    Bear, C.E.; Petrunka, C.N.; Strasberg, S.M.

    1985-05-01

    Chloride is the major inorganic anion in bile but its mechanism of passage from blood to bile is uncertain. Specific membrane channels account for most net inorganic anion flux in other cell types such as the proximal tubular cell and red blood cell; disulfonic stilbenes inhibit anion movement through these channels. Therefore, we have sought the presence of similar channels in the hepatocyte. Net inorganic anion flux or conductance was initiated in isolated rat hepatocytes by valinomycin in the presence of an outward potassium gradient. Potassium concentration in the extracellular medium increased from 2.75 +/- 0.02 in control cell suspensions to 3.15 +/- 0.04 in valinomycin-treated cell suspensions. Membrane potential difference (Em) (mV), determined as the distribution of (/sup 14/C)tetraphenyl phosphonium ion was -28 mV in control cells and -42 mV in valinomycin-treated cells. Intracellular chloride concentration (/sup 36/Cl-) (mEq per liter of cell water) decreased significantly from 38.6 in control cells to 32.0 in valinomycin-treated cells. The observed intracellular concentrations (/sup 36/Cl-) in both control and valinomycin-treated cell suspensions closely approximates values predicted on the basis of the Nernst equation: 41 and 29 (mEq per liter of cell water), respectively, suggesting that the chloride ion is passively distributed on the basis of the membrane potential difference. Furthermore, net rate-limited cell water loss of approximately 15% of control values was associated with the above valinomycin-stimulated changes in ion distribution, as assessed using three methods of cell water volume determination.

  15. Chloride channel-dependent copper acquisition of laccase in the basidiomycetous fungus Cryptococcus neoformans

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The CLC chloride channel gene CLC-A of the pathogen yeast Cryptococcus neoformans was previously reported to be critical for multicopper laccase activity and growth at an elevated pH.This study reports that copper homeostasis was impaired in the clc-a mutant.This was demonstrated by the substantial decrease of the intracellular quantity of copper under copper-limited growth as determined by flame atomic absorption spectrometry.CLC-A is a critical factor in copper homeostasis which is required for copper acquisition of laccase in C.neoformans.

  16. Mitochondria-Rich Cells as Experimental Model in Studies of Epithelial Chloride Channels

    DEFF Research Database (Denmark)

    Willumsen, Niels J.; Amstrup, Jan; Møbjerg, Nadja

    2002-01-01

    -actin localised in the submembrane domain in the neck region of the flask-shaped mr cell. (ii) The other identified Cl- pathway of mr cells is mediated by small-conductance apical CFTR chloride channels as concluded from its activation via ß-adrenergic receptors, ion selectivity, genistein stimulation...... and inhibition by glibenclamide. bbCFTR has been cloned, and immunostaining has shown that the gene product is selectively expressed in mr cells. There is cross-talk between the two pathways in the sense that activation of the conductance of the mr cell by voltage clamping excludes activation via receptor...

  17. The Split Personality of Glutamate Transporters: A Chloride Channel and a Transporter.

    Science.gov (United States)

    Cater, Rosemary J; Ryan, Renae M; Vandenberg, Robert J

    2016-03-01

    Transporters and ion channels are conventionally categorised into distinct classes of membrane proteins. However, some membrane proteins have a split personality and can function as both transporters and ion channels. The excitatory amino acid transporters (EAATs) in particular, function as both glutamate transporters and chloride (Cl(-)) channels. The EAATs couple the transport of glutamate to the co-transport of three Na(+) ions and one H(+) ion into the cell, and the counter-transport of one K(+) ion out of the cell. The EAAT Cl(-) channel is activated by the binding of glutamate and Na(+), but is thermodynamically uncoupled from glutamate transport and involves molecular determinants distinct from those responsible for glutamate transport. Several crystal structures of an EAAT archaeal homologue, GltPh, at different stages of the transport cycle, alongside numerous functional studies and molecular dynamics simulations, have provided extensive insights into the mechanism of substrate transport via these transporters. However, the molecular determinants involved in Cl(-) permeation, and the mechanism by which this channel is activated are not entirely understood. Here we will discuss what is currently known about the molecular determinants involved in EAAT-mediated Cl(-) permeation and the mechanisms that underlie their split personality.

  18. CFTR chloride channel in the apical compartments: spatiotemporal coupling to its interacting partners.

    Science.gov (United States)

    Li, Chunying; Naren, Anjaparavanda P

    2010-04-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel located primarily at the apical or luminal surfaces of epithelial cells in the airway, intestine, pancreas, kidney, sweat gland, as well as male reproductive tract, where it plays a crucial role in transepithelial fluid homeostasis. CFTR dysfunction can be detrimental and may result in life-threatening disorders. CFTR hypofunctioning because of genetic defects leads to cystic fibrosis, the most common lethal genetic disease in Caucasians, whereas CFTR hyperfunctioning resulting from various infections evokes secretory diarrhea, the leading cause of mortality in early childhood. Therefore, maintaining a dynamic balance between CFTR up-regulating processes and CFTR down-regulating processes is essential for maintaining fluid and body homeostasis. Accumulating evidence suggests that protein-protein interactions play a critical role in the fine-tuned regulation of CFTR function. A growing number of proteins have been reported to interact directly or indirectly with CFTR chloride channel, suggesting that CFTR might be coupled spatially and temporally to a wide variety of interacting partners including ion channels, receptors, transporters, scaffolding proteins, enzyme molecules, signaling molecules, and effectors. Most interactions occur primarily between the opposing terminal tails (amino or carboxyl) of CFTR protein and its binding partners, either directly or mediated through various PDZ scaffolding proteins. These dynamic interactions impact the channel function, as well as localization and processing of CFTR protein within cells. This article reviews the most recent progress and findings about the interactions between CFTR and its binding partners through PDZ scaffolding proteins, as well as the spatiotemporal regulation of CFTR-containing macromolecular signaling complexes in the apical compartments of polarized cells lining the secretory epithelia.

  19. Slow conversions among subconductance states of cystic fibrosis transmembrane conductance regulator chloride channel.

    Science.gov (United States)

    Tao, T; Xie, J; Drumm, M L; Zhao, J; Davis, P B; Ma, J

    1996-02-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel exhibits multiple subconductance states. To study the regulation of conductance states of the CFTR channel, we expressed the wild-type CFTR protein in HEK 293 cells, and isolated microsomal membrane vesicles for reconstitution studies in lipid bilayer membranes. A single CFTR channel had a dominant conductance of 7.8 pS (H), plus two sub-open states with conductances of approximately 6 pS (M) and 2.7 pS (L) in 200 mM KCl with 1 mM MgCl2 (intracellular) and 50 mM KCl with no MgCl2 (extracellular), with pH maintained at 7.4 by 10 mM HEPES-Tris on both sides of the channel. In 200 mM KCl, both H and L states could be measured in stable single-channel recordings, whereas M could not. Spontaneous transitions between H and L were slow; it took 4.5 min for L-->H, and 3.2 min for H-->L. These slow conversions among subconductance states of the CFTR channel were affected by extracellular Mg; in the presence of millimolar Mg, the channel remained stable in the H state. Similar phenomena were also observed with endogenous CFTR channels in T84 cells. In high-salt conditions (1.5 M KCl), all three conductance states of the expressed CFTR channel, 12.1 pS, 8.2 pS, and 3.6 pS, became stable and seemed to gate independently from each other. The existence of multiple stable conductance states associated with the CFTR channel suggests two possibilities: either a single CFTR molecule can exist in multiple configurations with different conductance values, or the CFTR channel may contain multimers of the 170-kDa CFTR protein, and different conductance states are due to different aggregation states of the CFTR protein.

  20. Cadmium regulates the expression of the CFTR chloride channel in human airway epithelial cells.

    Science.gov (United States)

    Rennolds, Jessica; Butler, Susie; Maloney, Kevin; Boyaka, Prosper N; Davis, Ian C; Knoell, Daren L; Parinandi, Narasimham L; Cormet-Boyaka, Estelle

    2010-07-01

    Cadmium is a toxic heavy metal ranked seventh on the Priority List of Hazardous Substances. As a byproduct of smelters, cadmium is a prevalent environmental contaminant. It is also a major component of cigarette smoke, and its inhalation is associated with decreased pulmonary function, lung cancer, and chronic obstructive pulmonary disease. Ion channels, including the cystic fibrosis transmembrane conductance regulator (CFTR), play a central role in maintaining fluid homeostasis and lung functions. CFTR is mostly expressed in epithelial cells, and little is known about the effect of cadmium exposure on lung epithelial cell function. We show that exposure to cadmium decreases the expression of the CFTR protein and subsequent chloride transport in human airway epithelial cells in vitro. Impairment of CFTR protein expression was also observed in vivo in the lung of mice after intranasal instillation of cadmium. We established that the inhibitory effect of cadmium was not a nonspecific effect of heavy metals, as nickel had no effect on CFTR protein levels. Finally, we show that selected antioxidants, including alpha-tocopherol (vitamin E), but not N-acetylcysteine, can prevent the cadmium-induced suppression of CFTR. In summary, we have identified cadmium as a regulator of the CFTR chloride channel present in lung epithelial cells. Future strategies to prevent the deleterious effect of cadmium on epithelial cells and lung functions may benefit from the finding that alpha-tocopherol protects CFTR expression and function.

  1. Spatiotemporal coupling of cAMP transporter to CFTR chloride channel function in the gut epithelia.

    Science.gov (United States)

    Li, Chunying; Krishnamurthy, Partha C; Penmatsa, Himabindu; Marrs, Kevin L; Wang, Xue Qing; Zaccolo, Manuela; Jalink, Kees; Li, Min; Nelson, Deborah J; Schuetz, John D; Naren, Anjaparavanda P

    2007-11-30

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel localized at apical cell membranes and exists in macromolecular complexes with a variety of signaling and transporter molecules. Here, we report that the multidrug resistance protein 4 (MRP4), a cAMP transporter, functionally and physically associates with CFTR. Adenosine-stimulated CFTR-mediated chloride currents are potentiated by MRP4 inhibition, and this potentiation is directly coupled to attenuated cAMP efflux through the apical cAMP transporter. CFTR single-channel recordings and FRET-based intracellular cAMP dynamics suggest that a compartmentalized coupling of cAMP transporter and CFTR occurs via the PDZ scaffolding protein, PDZK1, forming a macromolecular complex at apical surfaces of gut epithelia. Disrupting this complex abrogates the functional coupling of cAMP transporter activity to CFTR function. Mrp4 knockout mice are more prone to CFTR-mediated secretory diarrhea. Our findings have important implications for disorders such as inflammatory bowel disease and secretory diarrhea.

  2. Huntington disease skeletal muscle is hyperexcitable owing to chloride and potassium channel dysfunction.

    Science.gov (United States)

    Waters, Christopher W; Varuzhanyan, Grigor; Talmadge, Robert J; Voss, Andrew A

    2013-05-28

    Huntington disease is a progressive and fatal genetic disorder with debilitating motor and cognitive defects. Chorea, rigidity, dystonia, and muscle weakness are characteristic motor defects of the disease that are commonly attributed to central neurodegeneration. However, no previous study has examined the membrane properties that control contraction in Huntington disease muscle. We show primary defects in ex vivo adult skeletal muscle from the R6/2 transgenic mouse model of Huntington disease. Action potentials in diseased fibers are more easily triggered and prolonged than in fibers from WT littermates. Furthermore, some action potentials in the diseased fibers self-trigger. These defects occur because of decreases in the resting chloride and potassium conductances. Consistent with this, the expression of the muscle chloride channel, ClC-1, in Huntington disease muscle was compromised by improper splicing and a corresponding reduction in total Clcn1 (gene for ClC-1) mRNA. Additionally, the total Kcnj2 (gene for the Kir2.1 potassium channel) mRNA was reduced in disease muscle. The resulting muscle hyperexcitability causes involuntary and prolonged contractions that may contribute to the chorea, rigidity, and dystonia that characterize Huntington disease.

  3. Synthesis and Characterization of A Small Molecule CFTR Chloride Channel Inhibitor

    Institute of Scientific and Technical Information of China (English)

    HE Cheng-yan; ZHANG Heng-jun; SU Zhong-min; ZHOU Jin-song; YANG Hong; MA Tong-hui

    2004-01-01

    A thiazolidinone CFTR inhibitor(CFTRinh-172) was synthesized by a three-step procedure with trifluromethylaniline as the starting material. The synthesized CFTR inhibitor was characterized structurally by means of 1H NMR and functionally in a CFTR-expressing cell line FRT/hCFTR/EYFP-H148Q by both fluorescent and electrophysiological methods. A large amount(100 g) of high-quality small molecule thiazolidinone CFTR chloride channel inhibitor, CFTRinh-172, can be produced with this simple three-step synthetic procedure. The structure of the final product 2-thioxo-3-(3-trifluromethylphenyl)-5-[4-carboxyphenyl-methylene]-4-thiazolidinone was confirmed by 1H NMR. The overall yield was 58% with a purity over 99% as analyzed by HPLC. The synthesized CFTRinh-172 specifically inhibited CFTR chloride channel function in a cell-based fluorescence assay(Kd≈1.5 μmol/L) and in a Ussing chamber-based short-circuit current assay(Kd≈0.2 μmol/L), indicating better quality than that of the commercial combinatorial compound. The synthesized inhibitor is nontoxic to cultured cells at a high concentration and to mouse at a high dose. The synthetic procedure developed here can be used to produce a large amount of the high-quality CFTRinh-172 suitable for antidiarrheal studies and for creation of cystic fibrosis models in large animals. The procedure can be used to synthesize radiolabled CFTRinh-172 for in vivo pharmacokinetics studies.

  4. Spatiotemporal Coupling of cAMP Transporter to CFTR Chloride Channel Function in the Gut Epithelia

    Science.gov (United States)

    Li, Chunying; Krishnamurthy, Partha C.; Penmatsa, Himabindu; Marrs, Kevin L.; Wang, Xue Qing; Zaccolo, Manuela; Jalink, Kees; Li, Min; Nelson, Deborah J.; Schuetz, John D.; Naren, Anjaparavanda P.

    2007-01-01

    SUMMARY Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel localized at apical cell membranes and exists in macromolecular complexes with a variety of signaling and transporter molecules. Here we report that the multidrug resistance protein 4 (MRP4), a cAMP transporter, is functionally and physically associates with CFTR. Adenosine-stimulated CFTR-mediated chloride currents are potentiated by MRP4 inhibition, and this potentiation is directly coupled to attenuated cAMP efflux through the apical cAMP transporter. CFTR single-channel recordings and FRET-based intracellular cAMP dynamics suggest that a compartmentalized coupling of cAMP transporter and CFTR occurs via the PDZ scaffolding protein, PDZK1, forming a macromolecular complex at apical surfaces of gut epithelia. Disrupting this complex abrogates the functional coupling of cAMP transporter activity to CFTR function. MRP4 knockout mice are more prone to CFTR-mediated secretory diarrhea. Our findings have important implications for disorders such as inflammatory bowel disease and secretory diarrhea. PMID:18045536

  5. [Role and function of voltage-gated chloride channels of the CIC family and their defects leading to genetic diseases].

    Science.gov (United States)

    Dołowy, Krzysztof; Bednarczyk, Piotr; Hordejuk, Renata; Dworakowska, Beata; Nurowska, Ewa; Jarzabek, Wanda

    2002-01-01

    There are 9 channels of the ClC family in mammals and few others in fishes, plants, yeast and bacteria. The ClC channels are present in different tissues and play a role in transmembrane potential stabilization, transepithelial transport, cell volume regulation, acidification of intracellular organelles. The genetic defects of ClC-1 chloride channel lead to myotonias, the defect in ClC-5 channel to the formation of stones in kidney, while the defect in ClC-Kb channel leads to the Bartter's syndrome.

  6. Tgf-beta downregulation of distinct chloride channels in cystic fibrosis-affected epithelia.

    Directory of Open Access Journals (Sweden)

    Hongtao Sun

    Full Text Available The cystic fibrosis transmembrane conductance regulator (CFTR and Calcium-activated Chloride Conductance (CaCC each play critical roles in maintaining normal hydration of epithelial surfaces including the airways and colon. TGF-beta is a genetic modifier of cystic fibrosis (CF, but how it influences the CF phenotype is not understood.We tested the hypothesis that TGF-beta potently downregulates chloride-channel function and expression in two CF-affected epithelia (T84 colonocytes and primary human airway epithelia compared with proteins known to be regulated by TGF-beta.TGF-beta reduced CaCC and CFTR-dependent chloride currents in both epithelia accompanied by reduced levels of TMEM16A and CFTR protein and transcripts. TGF-beta treatment disrupted normal regulation of airway-surface liquid volume in polarized primary human airway epithelia, and reversed F508del CFTR correction produced by VX-809. TGF-beta effects on the expression and activity of TMEM16A, wtCFTR and corrected F508del CFTR were seen at 10-fold lower concentrations relative to TGF-beta effects on e-cadherin (epithelial marker and vimentin (mesenchymal marker expression. TGF-beta downregulation of TMEM16A and CFTR expression were partially reversed by Smad3 and p38 MAPK inhibition, respectively.TGF-beta is sufficient to downregulate two critical chloride transporters in two CF-affected tissues that precedes expression changes of two distinct TGF-beta regulated proteins. Our results provide a plausible mechanism for CF-disease modification by TGF-beta through effects on CaCC.

  7. An ivermectin-sensitive glutamate-gated chloride channel from the parasitic nematode Haemonchus contortus.

    Science.gov (United States)

    McCavera, Samantha; Rogers, Adrian T; Yates, Darran M; Woods, Debra J; Wolstenholme, Adrian J

    2009-06-01

    Nematode glutamate-gated chloride channels are targets of the macrocyclic lactones, the most important group of anthelmintics available. In Xenopus laevis oocytes, channels formed by the GluClalpha3B subunit from the parasite Haemonchus contortus were more sensitive to l-glutamate (EC(50) = 27.6 +/- 2.7 microM) than those formed by the homologous subunit from Caenorhabditis elegans (EC(50) = 2.2 +/- 0.12 mM). Ibotenate was a partial agonist (EC(50) = 87.7 +/- 3.5 microM). The H. contortus channels responded to low concentrations of ivermectin (estimated EC(50) = approximately 0.1 +/- 1.0 nM), opening slowly and irreversibly in a highly cooperative manner: the rate of channel opening was concentration-dependent. Responses to glutamate and ivermectin were inhibited by picrotoxinin and fipronil. Mutating an N-terminal domain amino acid, leucine 256, to phenylalanine increased the EC(50) for l-glutamate to 92.2 +/- 3.5 microM, and reduced the Hill number from 1.89 +/- 0.35 to 1.09 +/- 0.16. It increased the K(d) for radiolabeled ivermectin binding from 0.35 +/- 0.1 to 2.26 +/- 0.78 nM. Two other mutations (E114G and V235A) had no effect on l-glutamate activation or ivermectin binding: one (T300S) produced no detectable channel activity, but ivermectin binding was similar to wild-type. The substitution of any aromatic amino acid for Leu256 had similar effects in the radioligand binding assay. Molecular modeling studies suggested that the GluCl subunits have a fold similar to that of other Cys-loop ligand-gated ion channels and that amino acid 256 was unlikely to play a direct role in ligand binding but may be involved in mediating the allosteric properties of the receptor.

  8. Influence of salinity on the localization and expression of the CFTR chloride channel in the ionocytes of Dicentrarchus labrax during ontogeny.

    Science.gov (United States)

    Bodinier, Charlotte; Boulo, Viviane; Lorin-Nebel, Catherine; Charmantier, Guy

    2009-03-01

    The expression and localization of the cystic fibrosis transmembrane conductance regulator (CFTR) were determined in four osmoregulatory tissues during the ontogeny of the sea-bass Dicentrarchus labrax acclimated to fresh water and sea water. At hatch in sea water, immunolocalization showed an apical CFTR in the digestive tract and integumental ionocytes. During the ontogeny, although CFTR was consistently detected in the digestive tract, it shifted from the integument to the gills. In fresh water, CFTR was not present in the integument and the gills, suggesting the absence of chloride secretion. In the kidney, the CFTR expression was brief from D4 to D35, prior to the larva-juvenile transition. CFTR was apical in the renal tubules, suggesting a chloride secretion at both salinities, and it was basolateral only in sea water in the collecting ducts, suggesting chloride absorption. In the posterior intestine, CFTR was located differently from D4 depending on salinity. In sea water, the basolateral CFTR may facilitate ionic absorption, perhaps in relation to water uptake. In fresh water, CFTR was apical in the gut, suggesting chloride secretion. Increased osmoregulatory ability was acquired just before metamorphosis, which is followed by the sea-lagoon migration.

  9. A High-affinity Activator of G551D-CFTR Chloride Channel Identified By High Throughput Screening

    Institute of Scientific and Technical Information of China (English)

    ZHAO Lu; HE Cheng-yan; LIU Yan-li; ZHOU Hong-lan; ZHOU Jin-song; SHANG De-jing; YANG Hong

    2004-01-01

    A stably transfected CHO cell line coexpressing G551D-CFTR and iodide-sensitive yellow fluorescent protein mutant EYFP-H148Q-I152L was successfully established and used as assay model to identify small-molecule activators of G551D-CFTR chloride channel from 100000 diverse combinatorial compounds by high throughput screening on a customized Beckman robotic system. A bicyclooctane compound was identified to activate G551D-CFTR chloride channel with high-affinity(Kd=1.8 μmol/L). The activity of the bicyclooctane compound is G551D-CFTR-specific, reversible and non-toxic. The G551D-CFTR activator may be useful as a tool to study the mutant G551D-CFTR chloride channel structure and transport properties and as a candidate drug to cure cystic fibrosis caused by G551D-CFTR mutation.

  10. Effect of Trimethyltin Chloride on Slow Vacuolar (SV) Channels in Vacuoles from Red Beet (Beta vulgaris L.) Taproots.

    Science.gov (United States)

    Trela, Zenon; Burdach, Zbigniew; Siemieniuk, Agnieszka; Przestalski, Stanisław; Karcz, Waldemar

    2015-01-01

    In the present study, patch-clamp techniques have been used to investigate the effect of trimethyltin chloride (Met3SnCl) on the slow vacuolar (SV) channels in vacuoles from red beet (Beta vulgaris L.) taproots. Activity of SV channels has been measured in whole-vacuole and cytosolic side-out patch configurations. It was found that addition of trimethyltin chloride to the bath solution suppressed, in a concentration-dependent manner, SV currents in red beet vacuoles. The time constant, τ, increased significantly in the presence of the organotin. When single channel activity was analyzed, only little channel activity could be recorded at 100 μM Met3SnCl. Trimethyltin chloride added to the bath medium significantly decreased (by ca. threefold at 100 μM Met3SnCl and at 100 mV voltage, as compared to the control medium) the open probability of single channels. Single channel recordings obtained in the presence and absence of trimethyltin chloride showed that the organotin only slightly (by <10%) decreased the unitary conductance of single channels. It was also found that Met3SnCl significantly diminished the number of SV channel openings, whereas it did not change the opening times of the channels. Taking into account the above and the fact that under the here applied experimental conditions (pH = 7.5) Met3SnCl is a non-dissociated (more lipophilic) compound, we suggest that the suppression of SV currents observed in the presence of the organotin results probably from its hydrophobic properties allowing this compound to translocate near the selectivity filter of the channel.

  11. Electroconvulsive stimulations prevent chronic stress-induced increases in L-type calcium channel mRNAs in the hippocampus and basolateral amygdala

    DEFF Research Database (Denmark)

    Maigaard, Katrine; Pedersen, Ida Hageman; Jørgensen, Anders;

    2012-01-01

    Although affective disorders have high prevalence, morbidity and mortality, we do not fully understand disease etiopathology, nor have we determined the exact mechanisms by which treatment works. Recent research indicates that intracellular calcium ion dysfunction might be involved. Here we use...... the chronic restraint stress model of affective disorder (6 h restraint per day for 21 days) in combination with electroconvulsive stimulations to examine the effects of stress and an effective antidepressive treatment modality on L-type voltage gated calcium channel subunit mRNA expression patterns......, while stress only upregulated Ca(v)1.3 channel expression significantly in the dentate gyrus. ECS effects on Ca(v)1.2 channel expression were generally specific to stressed animals. Our findings are consistent with and extent previous studies on the involvement of intracellular calcium ion dysfunction...

  12. TRPC1 regulates calcium-activated chloride channels in salivary gland cells.

    Science.gov (United States)

    Sun, Yuyang; Birnbaumer, Lutz; Singh, Brij B

    2015-11-01

    Calcium-activated chloride channel (CaCC) plays an important role in modulating epithelial secretion. It has been suggested that in salivary tissues, sustained fluid secretion is dependent on Ca(2+) influx that activates ion channels such as CaCC to initiate Cl(-) efflux. However direct evidence as well as the molecular identity of the Ca(2+) channel responsible for activating CaCC in salivary tissues is not yet identified. Here we provide evidence that in human salivary cells, an outward rectifying Cl(-) current was activated by increasing [Ca(2+)]i, which was inhibited by the addition of pharmacological agents niflumic acid (NFA), an antagonist of CaCC, or T16Ainh-A01, a specific TMEM16a inhibitor. Addition of thapsigargin (Tg), that induces store-depletion and activates TRPC1-mediated Ca(2+) entry, potentiated the Cl(-) current, which was inhibited by the addition of a non-specific TRPC channel blocker SKF96365 or removal of external Ca(2+). Stimulation with Tg also increased plasma membrane expression of TMEM16a protein, which was also dependent on Ca(2+) entry. Importantly, in salivary cells, TRPC1 silencing, but not that of TRPC3, inhibited CaCC especially upon store depletion. Moreover, primary acinar cells isolated from submandibular gland also showed outward rectifying Cl(-) currents upon increasing [Ca(2+)]i. These Cl(-) currents were again potentiated with the addition of Tg, but inhibited in the presence of T16Ainh-A01. Finally, acinar cells isolated from the submandibular glands of TRPC1 knockout mice showed significant inhibition of the outward Cl(-) currents without decreasing TMEM16a expression. Together the data suggests that Ca(2+) entry via the TRPC1 channels is essential for the activation of CaCC.

  13. Ovine congenital myotonia associated with a mutation in the muscle chloride channel gene.

    Science.gov (United States)

    Monteagudo, Luis Vicente; Tejedor, María Teresa; Ramos, Juan José; Lacasta, Delia; Ferrer, Luis Miguel

    2015-04-01

    Congenital myotonia (CM) is characterised by a delay in muscular relaxation after sudden contractions. In a recent outbreak of ovine CM affecting 1% of new-born lambs in a Spanish flock of Rasa Aragonesa sheep, a comparative pathology approach was taken: because a mutation in the muscle chloride channel gene (CLCN1) was identified as responsible for CM in goats, the same gene was sequenced in the affected lambs. A non-synonymous single nucleotide variation (SNV) in the second exon of CLCN1 was associated with this pathology. Rams carrying this SNV heterozygously were thereafter identified and replaced by wild-type homozygous young males. No additional CM cases were detected in subsequent lambing seasons.

  14. Novel chloride channel gene mutations in two unrelated Chinese families with myotonia congenita

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    Gao Feng

    2010-12-01

    Full Text Available Myotonia congenita (MC is a genetic disease characterized by mutations in the muscle chloride channel gene (CLCN1. To date, approximately 130 different mutations on the CLCN1 gene have been identified. However, most of the studies have focused on Caucasians, and reports on CLCN1 mutations in Chinese population are rare. This study investigated the mutation of CLCN1 in two Chinese families with MC. Direct sequencing of the CLCN1 gene revealed a heterozygous mutation (892G>A, resulting in A298T in one family and a compound heterozygous mutations (782A>G, resulting in Y261C; 1679T>C, resulting in M560T in the other family, None of the 100 normal controls had these mutations. Our findings add more to the available information on the CLCN1 mutation spectrum, and provide a valuable reference for studying the mutation types and inheritance pattern of CLCN1 in the Chinese population.

  15. Emerging role of cystic fibrosis transmembrane conductance regulator- an epithelial chloride channel in gastrointestinal cancers

    Institute of Scientific and Technical Information of China (English)

    Yuning Hou; Xiaoqing Guan; Zhe Yang; Chunying Li

    2016-01-01

    Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially in gastroenterological cancers, such as pancreatic cancer and colon cancer. In this review, we summarize the emerging findings that link CFTR with various cancers, with focus on the association between CFTR defects and gastrointestinal cancers as well as the underlying mechanisms. Further study of CFTR in cancer biology may help pave a new way for the diagnosis and treatment of gastrointestinal cancers.

  16. Participation of GABAA Chloride Channels in the Anxiolytic-Like Effects of a Fatty Acid Mixture

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    Juan Francisco Rodríguez-Landa

    2013-01-01

    Full Text Available Human amniotic fluid and a mixture of eight fatty acids (FAT-M identified in this maternal fluid (C12:0, lauric acid, 0.9 μg%; C14:0, myristic acid, 6.9 μg%; C16:0, palmitic acid, 35.3 μg%; C16:1, palmitoleic acid, 16.4 μg%; C18:0, stearic acid, 8.5 μg%; C18:1cis, oleic acid, 18.4 μg%; C18:1trans, elaidic acid, 3.5 μg%; C18:2, linoleic acid, 10.1 μg% produce anxiolytic-like effects that are comparable to diazepam in Wistar rats, suggesting the involvement of γ-aminobutyric acid-A (GABAA receptors, a possibility not yet explored. Wistar rats were subjected to the defensive burying test, elevated plus maze, and open field test. In different groups, three GABAA receptor antagonists were administered 30 min before FAT-M administration, including the competitive GABA binding antagonist bicuculline (1 mg/kg, GABAA benzodiazepine antagonist flumazenil (5 mg/kg, and noncompetitive GABAA chloride channel antagonist picrotoxin (1 mg/kg. The FAT-M exerted anxiolytic-like effects in the defensive burying test and elevated plus maze, without affecting locomotor activity in the open field test. The GABAA antagonists alone did not produce significant changes in the behavioral tests. Picrotoxin but not bicuculline or flumazenil blocked the anxiolytic-like effect of the FAT-M. Based on the specific blocking action of picrotoxin on the effects of the FAT-M, we conclude that the FAT-M exerted its anxiolytic-like effects through GABAA receptor chloride channels.

  17. Conformational change opening the CFTR chloride channel pore coupled to ATP-dependent gating.

    Science.gov (United States)

    Wang, Wuyang; Linsdell, Paul

    2012-03-01

    Opening and closing of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel are controlled by ATP binding and hydrolysis by its nucleotide binding domains (NBDs). This is presumed to control opening of a single "gate" within the permeation pathway, however, the location of such a gate has not been described. We used patch clamp recording to monitor access of cytosolic cysteine reactive reagents to cysteines introduced into different transmembrane (TM) regions in a cysteine-less form of CFTR. The rate of modification of Q98C (TM1) and I344C (TM6) by both [2-sulfonatoethyl] methanethiosulfonate (MTSES) and permeant Au(CN)(2)(-) ions was reduced when ATP concentration was reduced from 1mM to 10μM, and modification by MTSES was accelerated when 2mM pyrophosphate was applied to prevent channel closure. Modification of K95C (TM1) and V345C (TM6) was not affected by these manoeuvres. We also manipulated gating by introducing the mutations K464A (in NBD1) and E1371Q (in NBD2). The rate of modification of Q98C and I344C by both MTSES and Au(CN)(2)(-) was decreased by K464A and increased by E1371Q, whereas modification of K95C and V345C was not affected. These results suggest that access from the cytoplasm to K95 and V345 is similar in open and closed channels. In contrast, modifying ATP-dependent channel gating alters access to Q98 and I344, located further into the pore. We propose that ATP-dependent gating of CFTR is associated with the opening and closing of a gate within the permeation pathway at the level of these pore-lining amino acids.

  18. Mutations at the signature sequence of CFTR create a Cd(2+)-gated chloride channel.

    Science.gov (United States)

    Wang, Xiaohui; Bompadre, Silvia G; Li, Min; Hwang, Tzyh-Chang

    2009-01-01

    The canonical sequence LSGGQ, also known as the signature sequence, defines the adenosine triphosphate (ATP)-binding cassette transporter superfamily. Crystallographic studies reveal that the signature sequence, together with the Walker A and Walker B motifs, forms the ATP-binding pocket upon dimerization of the two nucleotide-binding domains (NBDs) in a head-to-tail configuration. The importance of the signature sequence is attested by the fact that a glycine to aspartate mutation (i.e., G551D) in cystic fibrosis transmembrane conductance regulator (CFTR) results in a severe phenotype of cystic fibrosis. We previously showed that the G551D mutation completely eliminates ATP-dependent gating of the CFTR chloride channel. Here, we report that micromolar [Cd(2+)] can dramatically increase the activity of G551D-CFTR in the absence of ATP. This effect of Cd(2+) is not seen in wild-type channels or in G551A. Pretreatment of G551D-CFTR with the cysteine modification reagent 2-aminoethyl methane thiosulfonate hydrobromide protects the channel from Cd(2+) activation, suggesting an involvement of endogenous cysteine residue(s) in mediating this effect of Cd(2+). The mutants G551C, L548C, and S549C, all in the signature sequence of CFTR's NBD1, show robust response to Cd(2+). On the other hand, negligible effects of Cd(2+) were seen with T547C, Q552C, and R553C, indicating that a specific region of the signature sequence is involved in transmitting the signal of Cd(2+) binding to the gate. Collectively, these results suggest that the effect of Cd(2+) is mediated by a metal bridge formation between yet to be identified cysteine residue(s) and the engineered aspartate or cysteine in the signature sequence. We propose that the signature sequence serves as a switch that transduces the signal of ligand binding to the channel gate.

  19. Increased Expression of the Calcium-Activated Chloride Channel in Hclca1 in Airways of Patients with Obstructive Chronic Bronchitis

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    Hans-Peter Hauber

    2005-01-01

    Full Text Available BACKGROUND: Interleukin (IL-9 and its effect on enhancing the human calcium-activated chloride channel 1 (hCLCA1 expression have been shown to induce mucin production. Increased expression of hCLCA1 may, in turn, contribute to mucus overproduction in chronic obstructive pulmonary disease (COPD with a chronic bronchitis (CB phenotype.

  20. Calcium-activated chloride channel TMEM16A modulates mucin secretion and airway smooth muscle contraction

    Science.gov (United States)

    Huang, Fen; Zhang, Hongkang; Wu, Meng; Yang, Huanghe; Kudo, Makoto; Peters, Christian J.; Woodruff, Prescott G.; Solberg, Owen D.; Donne, Matthew L.; Huang, Xiaozhu; Sheppard, Dean; Fahy, John V.; Wolters, Paul J.; Hogan, Brigid L. M.; Finkbeiner, Walter E.; Li, Min; Jan, Yuh-Nung; Jan, Lily Yeh; Rock, Jason R.

    2012-01-01

    Mucous cell hyperplasia and airway smooth muscle (ASM) hyperresponsiveness are hallmark features of inflammatory airway diseases, including asthma. Here, we show that the recently identified calcium-activated chloride channel (CaCC) TMEM16A is expressed in the adult airway surface epithelium and ASM. The epithelial expression is increased in asthmatics, particularly in secretory cells. Based on this and the proposed functions of CaCC, we hypothesized that TMEM16A inhibitors would negatively regulate both epithelial mucin secretion and ASM contraction. We used a high-throughput screen to identify small-molecule blockers of TMEM16A-CaCC channels. We show that inhibition of TMEM16A-CaCC significantly impairs mucus secretion in primary human airway surface epithelial cells. Furthermore, inhibition of TMEM16A-CaCC significantly reduces mouse and human ASM contraction in response to cholinergic agonists. TMEM16A-CaCC blockers, including those identified here, may positively impact multiple causes of asthma symptoms. PMID:22988107

  1. Molecular cloning and characterization of novel glutamate-gated chloride channel subunits from Schistosoma mansoni.

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    Vanessa Dufour

    Full Text Available Cys-loop ligand-gated ion channels (LGICs mediate fast ionotropic neurotransmission. They are proven drug targets in nematodes and arthropods, but are poorly characterized in flatworms. In this study, we characterized the anion-selective, non-acetylcholine-gated Cys-loop LGICs from Schistosoma mansoni. Full-length cDNAs were obtained for SmGluCl-1 (Smp_096480, SmGluCl-2 (Smp_015630 and SmGluCl-3 (Smp_104890. A partial cDNA was retrieved for SmGluCl-4 (Smp_099500/Smp_176730. Phylogenetic analyses suggest that SmGluCl-1, SmGluCl-2, SmGluCl-3 and SmGluCl-4 belong to a novel clade of flatworm glutamate-gated chloride channels (GluCl that includes putative genes from trematodes and cestodes. The flatworm GluCl clade was distinct from the nematode-arthropod and mollusc GluCl clades, and from all GABA receptors. We found no evidence of GABA receptors in S. mansoni. SmGluCl-1, SmGluCl-2 and SmGluCl-3 subunits were characterized by two-electrode voltage clamp (TEVC in Xenopus oocytes, and shown to encode Cl⁻-permeable channels gated by glutamate. SmGluCl-2 and SmGluCl-3 produced functional homomers, while SmGluCl-1 formed heteromers with SmGluCl-2. Concentration-response relationships revealed that the sensitivity of SmGluCl receptors to L-glutamate is among the highest reported for GluCl receptors, with EC₅₀ values of 7-26 µM. Chloride selectivity was confirmed by current-voltage (I/V relationships. SmGluCl receptors are insensitive to 1 µM ivermectin (IVM, indicating that they do not belong to the highly IVM-sensitive GluClα subtype group. SmGluCl receptors are also insensitive to 10 µM meclonazepam, a schistosomicidal benzodiazepine. These results provide the first molecular evidence showing the contribution of GluCl receptors to L-glutamate signaling in S. mansoni, an unprecedented finding in parasitic flatworms. Further work is needed to elucidate the roles of GluCl receptors in schistosomes and to explore their potential as drug targets.

  2. Expression pattern and function of alternative splice variants of glutamate-gated chloride channel in the housefly Musca domestica.

    Science.gov (United States)

    Kita, Tomo; Ozoe, Fumiyo; Ozoe, Yoshihisa

    2014-02-01

    Glutamate-gated chloride channels (GluCls) mediate fast inhibitory neurotransmission in invertebrate nervous systems. cDNAs encoding two alternative splice variants (MdGluClB and C) of the GluCl subunit were cloned from the housefly Musca domestica. The expression patterns of three variants, including the previously reported MdGluClA, differed among the body parts (head, thorax, abdomen, and leg) of the adult housefly and among developmental stages (embryo, larva, pupa, and adult). The MdGluClA and B transcripts were abundant in the central nervous system of the adult, whereas the MdGluClC transcript was expressed in the central nervous system and as the predominant variant in the peripheral tissues. The sensitivities to the agonist glutamate and the allosteric activator ivermectin B1a did not differ between channels containing MdGluCl variants when they were singly or co-expressed in Xenopus oocytes. By contrast, MdGluClA and B channels were more sensitive to the channel blockers fipronil and picrotoxinin than was MdGluClC channels. Heteromeric channels containing different subunit variants were more sensitive to picrotoxinin than were homomeric channels. Heteromeric channels were more sensitive to fipronil than were homomeric MdGluClC channels but not than homomeric MdGluClA and B channels. These results suggest that functionally indistinguishable but pharmacologically distinct GluCls are expressed in a spatially and temporally distinct manner in the housefly.

  3. Role of Quercetin in Modulating Chloride Transport in the Intestine

    Science.gov (United States)

    Yu, Bo; Jiang, Yu; Jin, Lingling; Ma, Tonghui; Yang, Hong

    2016-01-01

    Epithelial chloride channels provide the pathways for fluid secretion in the intestine. Cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated chloride channels (CaCCs) are the main chloride channels in the luminal membrane of enterocytes. These transmembrane proteins play important roles in many physiological processes. In this study, we have identified a flavonoid quercetin as a modulator of CaCC chloride channel activity. Fluorescence quenching assay showed that quercetin activated Cl− transport in a dose-dependent manner, with EC50 ~37 μM. Short-circuit current analysis confirmed that quercetin activated CaCC-mediated Cl− currents in HT-29 cells that can be abolished by CaCCinh-A01. Ex vivo studies indicated that application of quercetin to mouse ileum and colon on serosal side resulted in activation of CFTR and CaCC-mediated Cl− currents. Notably, we found that quercetin exhibited inhibitory effect against ANO1 chloride channel activity in ANO1-expressing FRT cells and decreased mouse intestinal motility. Quercetin-stimulated short-circuit currents in mouse ileum was multi-component, which included elevation of Ca2+ concentration through L-type calcium channel and activation of basolateral NKCC, Na+/K+-ATPase, and K+ channels. In vivo studies further revealed that quercetin promoted fluid secretion in mouse ileum. The modulatory effect of quercetin on CaCC chloirde channels may therefore represent a potential therapeutic strategy for treating CaCC-related diseases like constipation, secretory diarrhea and hypertension. The inverse effects of quercetin on CaCCs provided evidence that ANO1 and intestinal epithelial CaCCs are different calcium-activated chloride channels. PMID:27932986

  4. Role of quercetin in modulating chloride transport in the intestine

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    Bo Yu

    2016-11-01

    Full Text Available Epithelial chloride channels provide the pathways for fluid secretion in the intestine. Cystic fibrosis transmembrane conductance regulator (CFTR and calcium-activated chloride channels (CaCCs are the main chloride channels in the luminal membrane of enterocytes. These transmembrane proteins play important roles in many physiological processes. In this study, we have identified a flavonoid quercetin as a modulator of CaCC chloride channel activity. Fluorescence quenching assay showed that quercetin activated Clˉ transport in a dose-dependent manner, with EC50 ~37 µM. Short-circuit current analysis confirmed that quercetin activated CaCC-mediated Clˉ currents in HT-29 cells that can be abolished by CaCCinh-A01. Ex-vivo studies indicated that application of quercetin to mouse ileum and colon on serosal side resulted in activation of CFTR and CaCC-mediated Clˉ currents. Notably, we found that quercetin exhibited inhibitory effect against ANO1 chloride channel activity in ANO1-expressing FRT cells and decreased mouse intestinal motility. Quercetin-stimulated short-circuit currents in mouse ileum was multi-component, which included elevation of Ca2+ concentration through L-type calcium channel and activation of basolateral NKCC, Na+/K+-ATPase and K+ channels. In vivo studies further revealed that quercetin promoted fluid secretion in mouse ileum. The modulatory effect of quercetin on CaCC chloirde channels may therefore represent a potential therapeutic strategy for treating CaCC-related diseases like constipation, secretory diarrhea and hypertension. The inverse effects of quercetin on CaCCs provided evidence that ANO1 and intestinal epithelial CaCCs are different calcium-activated chloride channels.

  5. Expression of CLC-K chloride channels in the rat cochlea.

    Science.gov (United States)

    Qu, Chunyan; Liang, Fenghe; Hu, Wei; Shen, Zhijun; Spicer, Samuel S; Schulte, Bradley A

    2006-03-01

    Current models of the lateral K+ recycling pathway in the mammalian cochlea include two multicellular transport networks separated from one another by three interstitial gaps. The first gap is between outer hair cells and Deiters cells, the second is between outer sulcus cells and type II spiral ligament fibrocytes and the third is between intermediate and marginal cells in the stria vascularis. K+ taken up by cells bordering these interstitial spaces is accompanied by Cl-. Maintaining appropriate electrolyte balance and membrane potentials in these cells requires a mechanism for exit of the resorbed Cl-. One possible candidate for regulating this Cl- efflux is ClC-K, a chloride channel previously thought to be kidney specific. Here, we demonstrate the expression of both known isoforms of ClC-K in the organ of Corti, spiral ligament and stria vascularis of the rat cochlea by immunohistochemical, Western blot and RT-PCR analysis. These results indicate a role for ClC-K in mediating Cl- recycling in the cochlea. The widespread expression of both ClC-K isoforms in the cochlea may help to explain the symptoms of Bartter's syndrome Type III, a mutation in the hClC-Kb gene (human homologue of ClC-K2), which results in renal salt wasting without deafness. These data support the hypothesis that both isoforms of ClC-K are co-expressed in some cell membranes and account for the preservation of hearing in the presence of a mutation in only one channel isoform.

  6. Effect of a chloride channel activator, lubiprostone, on colonic sensory and motor functions in healthy subjects.

    Science.gov (United States)

    Sweetser, Seth; Busciglio, Irene A; Camilleri, Michael; Bharucha, Adil E; Szarka, Lawrence A; Papathanasopoulos, Athanasios; Burton, Duane D; Eckert, Deborah J; Zinsmeister, Alan R

    2009-02-01

    Lubiprostone, a bicyclic fatty acid chloride channel activator, is efficacious in treatment of chronic constipation and constipation-predominant irritable bowel syndrome. The study aim was to compare effects of lubiprostone and placebo on colonic sensory and motor functions in humans. In double-blind, randomized fashion, 60 healthy adults received three oral doses of placebo or 24 microg lubiprostone per day in a parallel-group, placebo-controlled trial. A barostat-manometry tube was placed in the left colon by flexible sigmoidoscopy and fluoroscopy. We measured treatment effects on colonic sensation and motility with validated methods, with the following end points: colonic compliance, fasting and postprandial tone and motility indexes, pain thresholds, and sensory ratings to distensions. Among participants receiving lubiprostone or placebo, 26 of 30 and 28 of 30, respectively, completed the study. There were no overall effects of lubiprostone on compliance, fasting tone, motility indexes, or sensation. However, there was a treatment-by-sex interaction effect for compliance (P = 0.02), with lubiprostone inducing decreased fasting compliance in women (P = 0.06) and an overall decreased colonic tone contraction after a standard meal relative to fasting tone (P = 0.014), with greater effect in women (P lubiprostone 24 microg does not increase colonic motor function. The findings of decreased colonic compliance and decreased postprandial colonic tone in women suggest that motor effects are unlikely to cause accelerated colonic transit with lubiprostone, although they may facilitate laxation. Effects of lubiprostone on sensitivity deserve further study.

  7. Myotonia congenita-associated mutations in chloride channel-1 affect zebrafish body wave swimming kinematics.

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    Wei Cheng

    Full Text Available Myotonia congenita is a human muscle disorder caused by mutations in CLCN1, which encodes human chloride channel 1 (CLCN1. Zebrafish is becoming an increasingly useful model for human diseases, including muscle disorders. In this study, we generated transgenic zebrafish expressing, under the control of a muscle specific promoter, human CLCN1 carrying mutations that have been identified in human patients suffering from myotonia congenita. We developed video analytic tools that are able to provide precise quantitative measurements of movement abnormalities in order to analyse the effect of these CLCN1 mutations on adult transgenic zebrafish swimming. Two new parameters for body-wave kinematics of swimming reveal changes in body curvature and tail offset in transgenic zebrafish expressing the disease-associated CLCN1 mutants, presumably due to their effect on muscle function. The capability of the developed video analytic tool to distinguish wild-type from transgenic zebrafish could provide a useful asset to screen for compounds that reverse the disease phenotype, and may be applicable to other movement disorders besides myotonia congenita.

  8. Myotonia Congenita-Associated Mutations in Chloride Channel-1 Affect Zebrafish Body Wave Swimming Kinematics

    Science.gov (United States)

    Cheng, Wei; Tian, Jing; Burgunder, Jean-Marc; Hunziker, Walter; Eng, How-Lung

    2014-01-01

    Myotonia congenita is a human muscle disorder caused by mutations in CLCN1, which encodes human chloride channel 1 (CLCN1). Zebrafish is becoming an increasingly useful model for human diseases, including muscle disorders. In this study, we generated transgenic zebrafish expressing, under the control of a muscle specific promoter, human CLCN1 carrying mutations that have been identified in human patients suffering from myotonia congenita. We developed video analytic tools that are able to provide precise quantitative measurements of movement abnormalities in order to analyse the effect of these CLCN1 mutations on adult transgenic zebrafish swimming. Two new parameters for body-wave kinematics of swimming reveal changes in body curvature and tail offset in transgenic zebrafish expressing the disease-associated CLCN1 mutants, presumably due to their effect on muscle function. The capability of the developed video analytic tool to distinguish wild-type from transgenic zebrafish could provide a useful asset to screen for compounds that reverse the disease phenotype, and may be applicable to other movement disorders besides myotonia congenita. PMID:25083883

  9. Dual regulation of the native ClC-K2 chloride channel in the distal nephron by voltage and pH.

    Science.gov (United States)

    Pinelli, Laurent; Nissant, Antoine; Edwards, Aurélie; Lourdel, Stéphane; Teulon, Jacques; Paulais, Marc

    2016-09-01

    ClC-K2, a member of the ClC family of Cl(-) channels and transporters, forms the major basolateral Cl(-) conductance in distal nephron epithelial cells and therefore plays a central role in renal Cl(-) absorption. However, its regulation remains largely unknown because of the fact that recombinant ClC-K2 has not yet been studied at the single-channel level. In the present study, we investigate the effects of voltage, pH, Cl(-), and Ca(2+) on native ClC-K2 in the basolateral membrane of intercalated cells from the mouse connecting tubule. The ∼10-pS channel shows a steep voltage dependence such that channel activity increases with membrane depolarization. Intracellular pH (pHi) and extracellular pH (pHo) differentially modulate the voltage dependence curve: alkaline pHi flattens the curve by causing an increase in activity at negative voltages, whereas alkaline pHo shifts the curve toward negative voltages. In addition, pHi, pHo, and extracellular Ca(2+) strongly increase activity, mainly because of an increase in the number of active channels with a comparatively minor effect on channel open probability. Furthermore, voltage alters both the number of active channels and their open probability, whereas intracellular Cl(-) has little influence. We propose that changes in the number of active channels correspond to them entering or leaving an inactivated state, whereas modulation of open probability corresponds to common gating by these channels. We suggest that pH, through the combined effects of pHi and pHo on ClC-K2, might be a key regulator of NaCl absorption and Cl(-)/HCO3 (-) exchange in type B intercalated cells.

  10. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

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    Susan K Glendinning

    Full Text Available Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316 under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in

  11. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

    Science.gov (United States)

    Glendinning, Susan K; Buckingham, Steven D; Sattelle, David B; Wonnacott, Susan; Wolstenholme, Adrian J

    2011-01-01

    Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl) gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316) under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in some assays. C

  12. Comparative pharmacology of flatworm and roundworm glutamate-gated chloride channels: Implications for potential anthelmintics

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    Timothy Lynagh

    2014-12-01

    Full Text Available Pharmacological targeting of glutamate-gated chloride channels (GluCls is a potent anthelmintic strategy, evidenced by macrocyclic lactones that eliminate numerous roundworm infections by activating roundworm GluCls. Given the recent identification of flatworm GluCls and the urgent need for drugs against schistosomiasis, flatworm GluCls should be evaluated as potential anthelmintic targets. This study sought to identify agonists or modulators of one such GluCl, SmGluCl-2 from the parasitic flatworm Schistosoma mansoni. The effects of nine glutamate-like compounds and three monoterpenoid ion channel modulators were measured by electrophysiology at SmGluCl-2 recombinantly expressed in Xenopus laevis oocytes. For comparison with an established anthelmintic target, experiments were also performed on the AVR-14B GluCl from the parasitic roundworm Haemonchus contortus. l-Glutamate was the most potent agonist at both GluCls, but l-2-aminoadipate, d-glutamate and d-2-aminoadipate activated SmGluCl-2 (EC50 1.0 ± 0.1 mM, 2.4 ± 0.4 mM, 3.6 ± 0.7 mM, respectively more potently than AVR-14B. Quisqualate activated only SmGluCl-2 whereas l-aspartate activated only AVR-14B GluCls. Regarding the monoterpenoids, both GluCls were inhibited by propofol, thymol and menthol, SmGluCl-2 most potently by thymol (IC50 484 ± 85 μM and least potently by menthol (IC50 > 3 mM. Computational docking suggested that agonist and inhibitor potency is attributable to particular interactions with extracellular or membrane-spanning amino acid residues. These results reveal that flatworm GluCls are pharmacologically susceptible to numerous agonists and modulators and indicate that changes to the glutamate γ-carboxyl or to the propofol 6-isopropyl group can alter the differential pharmacology at flatworm and roundworm GluCls. This should inform the development of more potent compounds and in turn lead to novel anthelmintics.

  13. Similar expression patterns of bestrophin-4 and cGMP dependent Ca2+-activated chloride channel activity in the vasculature

    DEFF Research Database (Denmark)

    Bouzinova, Elena V.; Larsen, Per; Matchkov, Vladimir

    2008-01-01

    Bestrophin protein is involved in ion transport across the basolateral membrane of the retinal pigment epithelium. The mammalian genome encodes 4 members of the bestrophin family. Bestrophins have been proposed to comprise a new family of Ca2+-activated Cl- channels1. We have recently demonstrated......- current in SMCs of different origins. Immunohistochemistry identified bestrophin-4 both in endothelial and SMCs of the vascular tree in the brain, heart, kidney and mesentery, but not in the lungs. We suggest that bestrophin-4 is important for the cGMP dependent, Ca2+ activated Cl- conductance in many...

  14. Chloride channels in stellate cells are essential for uniquely high secretion rates in neuropeptide-stimulated Drosophila diuresis.

    Science.gov (United States)

    Cabrero, Pablo; Terhzaz, Selim; Romero, Michael F; Davies, Shireen A; Blumenthal, Edward M; Dow, Julian A T

    2014-09-30

    Epithelia frequently segregate transport processes to specific cell types, presumably for improved efficiency and control. The molecular players underlying this functional specialization are of particular interest. In Drosophila, the renal (Malpighian) tubule displays the highest per-cell transport rates known and has two main secretory cell types, principal and stellate. Electrogenic cation transport is known to reside in the principal cells, whereas stellate cells control the anion conductance, but by an as-yet-undefined route. Here, we resolve this issue by showing that a plasma membrane chloride channel, encoded by ClC-a, is exclusively expressed in the stellate cell and is required for Drosophila kinin-mediated induction of diuresis and chloride shunt conductance, evidenced by chloride ion movement through the stellate cells, leading to depolarization of the transepithelial potential. By contrast, ClC-a knockdown had no impact on resting secretion levels. Knockdown of a second CLC gene showing highly abundant expression in adult Malpighian tubules, ClC-c, did not impact depolarization of transepithelial potential after kinin stimulation. Therefore, the diuretic action of kinin in Drosophila can be explained by an increase in ClC-a-mediated chloride conductance, over and above a resting fluid transport level that relies on other (ClC-a-independent) mechanisms or routes. This key segregation of cation and anion transport could explain the extraordinary fluid transport rates displayed by some epithelia.

  15. Silent S-Type Anion Channel Subunit SLAH1 Gates SLAH3 Open for Chloride Root-to-Shoot Translocation.

    Science.gov (United States)

    Cubero-Font, Paloma; Maierhofer, Tobias; Jaslan, Justyna; Rosales, Miguel A; Espartero, Joaquín; Díaz-Rueda, Pablo; Müller, Heike M; Hürter, Anna-Lena; Al-Rasheid, Khaled A S; Marten, Irene; Hedrich, Rainer; Colmenero-Flores, José M; Geiger, Dietmar

    2016-08-22

    Higher plants take up nutrients via the roots and load them into xylem vessels for translocation to the shoot. After uptake, anions have to be channeled toward the root xylem vessels. Thereby, xylem parenchyma and pericycle cells control the anion composition of the root-shoot xylem sap [1-6]. The fact that salt-tolerant genotypes possess lower xylem-sap Cl(-) contents compared to salt-sensitive genotypes [7-10] indicates that membrane transport proteins at the sites of xylem loading contribute to plant salinity tolerance via selective chloride exclusion. However, the molecular mechanism of xylem loading that lies behind the balance between NO3(-) and Cl(-) loading remains largely unknown. Here we identify two root anion channels in Arabidopsis, SLAH1 and SLAH3, that control the shoot NO3(-)/Cl(-) ratio. The AtSLAH1 gene is expressed in the root xylem-pole pericycle, where it co-localizes with AtSLAH3. Under high soil salinity, AtSLAH1 expression markedly declined and the chloride content of the xylem sap in AtSLAH1 loss-of-function mutants was half of the wild-type level only. SLAH3 anion channels are not active per se but require extracellular nitrate and phosphorylation by calcium-dependent kinases (CPKs) [11-13]. When co-expressed in Xenopus oocytes, however, the electrically silent SLAH1 subunit gates SLAH3 open even in the absence of nitrate- and calcium-dependent kinases. Apparently, SLAH1/SLAH3 heteromerization facilitates SLAH3-mediated chloride efflux from pericycle cells into the root xylem vessels. Our results indicate that under salt stress, plants adjust the distribution of NO3(-) and Cl(-) between root and shoot via differential expression and assembly of SLAH1/SLAH3 anion channel subunits.

  16. Interaction between 2 extracellular loops influences the activity of the cystic fibrosis transmembrane conductance regulator chloride channel.

    Science.gov (United States)

    Broadbent, Steven D; Wang, Wuyang; Linsdell, Paul

    2014-10-01

    Activity of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is thought to be controlled by cytoplasmic factors. However, recent evidence has shown that overall channel activity is also influenced by extracellular anions that interact directly with the extracellular loops (ECLs) of the CFTR protein. Very little is known about the structure of the ECLs or how substances interacting with these ECLs might affect CFTR function. We used patch-clamp recording to investigate the accessibility of cysteine-reactive reagents to cysteines introduced throughout ECL1 and 2 key sites in ECL4. Furthermore, interactions between ECL1 and ECL4 were investigated by the formation of disulfide crosslinks between cysteines introduced into these 2 regions. Crosslinks could be formed between R899C (in ECL4) and a number of sites in ECL1 in a manner that was dependent on channel activity, suggesting that the relative orientation of these 2 loops changes on activation. Formation of these crosslinks inhibited channel function, suggesting that relative movement of these ECLs is important to normal channel function. Implications of these findings for the effects of mutations in the ECLs that are associated with cystic fibrosis and interactions with extracellular substances that influence channel activity are discussed.

  17. Benzopyrimido-pyrrolo-oxazine-dione (R)-BPO-27 Inhibits CFTR Chloride Channel Gating by Competition with ATP.

    Science.gov (United States)

    Kim, Yonjung; Anderson, Marc O; Park, Jinhong; Lee, Min Goo; Namkung, Wan; Verkman, A S

    2015-10-01

    We previously reported that benzopyrimido-pyrrolo-oxazinedione BPO-27 [6-(5-bromofuran-2-yl)-7,9-dimethyl-8,10-dioxo-11-phenyl-7,8,9,10-tetrahydro-6H-benzo[b]pyrimido [4',5':3,4]pyrrolo [1,2-d][1,4]oxazine-2-carboxylic acid] inhibits the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel with low nanomolar potency and reduces cystogenesis in a model of polycystic kidney disease. We used computational chemistry and patch-clamp to show that enantiomerically pure (R)-BPO-27 inhibits CFTR by competition with ATP, whereas (S)-BPO-27 is inactive. Docking computations using a homology model of CFTR structure suggested that (R)-BPO-27 binds near the canonical ATP binding site, and these findings were supported by molecular dynamics simulations showing a lower binding energy for the (R) versus (S) stereoisomers. Three additional lower-potency BPO-27 analogs were modeled in a similar fashion, with the binding energies predicted in the correct order. Whole-cell patch-clamp studies showed linear CFTR currents with a voltage-independent (R)-BPO-27 block mechanism. Single-channel recordings in inside-out patches showed reduced CFTR channel open probability and increased channel closed time by (R)-BPO-27 without altered unitary channel conductance. At a concentration of (R)-BPO-27 that inhibited CFTR chloride current by ∼50%, the EC50 for ATP activation of CFTR increased from 0.27 to 1.77 mM but was not changed by CFTRinh-172 [4-[[4-oxo-2-thioxo-3-[3-trifluoromethyl)phenyl]-5-thiazolidinylidene]methyl]benzoic acid], a thiazolidinone CFTR inhibitor that acts at a site distinct from the ATP binding site. Our results suggest that (R)-BPO-27 inhibition of CFTR involves competition with ATP.

  18. High glucose inhibits ClC-2 chloride channels and attenuates cell migration of rat keratinocytes

    Directory of Open Access Journals (Sweden)

    Pan F

    2015-08-01

    Full Text Available Fuqiang Pan, Rui Guo, Wenguang Cheng, Linlin Chai, Wenping Wang, Chuan Cao, Shirong LiDepartment of Plastic and Reconstructive Surgery, Southwestern Hospital, Third Military Medical University, Chongqing, People’s Republic of China Background: Accumulating evidence has demonstrated that migration of keratinocytes is critical to wound epithelialization, and defects of this function result in chronic delayed-healing wounds in diabetes mellitus patients, and the migration has been proved to be associated with volume-activated chloride channels. The aim of the study is to investigate the effects of high glucose (HG, 25 mM on ClC-2 chloride channels and cell migration of keratinocytes.Methods: Newborn Sprague Dawley rats were used to isolate and culture the keratinocyte in this study. Immunofluorescence assay, real-time polymerase chain reaction, and Western blot assay were used to examine the expression of ClC-2 protein or mRNA. Scratch wound assay was used to measure the migratory ability of keratinocytes. Transwell cell migration assay was used to measure the invasion and migration of keratinocytes. Recombinant lentivirus vectors were established and transducted to keratinocytes. Whole-cell patch clamp was used to perform the electrophysiological studies.Results: We found that the expression of ClC-2 was significantly inhibited when keratinocytes were exposed to a HG (25 mM medium, accompanied by the decline of volume-activated Cl- current (ICl,vol, migration potential, and phosphorylated PI3K as compared to control group. When knockdown of ClC-2 by RNAi or pretreatment with wortmannin, similar results were observed, including ICl,vol and migration keratinocytes were inhibited.Conclusion: Our study proved that HG inhibited ClC-2 chloride channels and attenuated cell migration of rat keratinocytes via inhibiting PI3K signaling.Keywords: high glucose, keratinocytes, ClC-2, cell migration, PI3K

  19. Chloride channels in the plasma membrane of a foetal Drosophila cell line, S2

    DEFF Research Database (Denmark)

    Asmild, Margit; Willumsen, Niels J.

    2000-01-01

    S2 cells, Cl- Channels, Expression system, Drosophila, Inward rectifier, Outward rectifier, Patch clamp......S2 cells, Cl- Channels, Expression system, Drosophila, Inward rectifier, Outward rectifier, Patch clamp...

  20. A solid phase honey-like channel method for synthesizing urea-ammonium chloride cocrystals on industrial scale

    Science.gov (United States)

    Xue, Bingchun; Mao, Meiling; Liu, Yanhong; Guo, Jinyu; Li, Jing; Liu, Erbao

    2016-05-01

    Unanticipated a new and simple urea-ammonium chloride cocrystal synthesis method on industrial scale was found during attempts to produce a kind of granulated compound fertilizer. The aggregation of fertilizer powder can make the interaction among particles from loose to close, which generate mechanical pressure and in turn act as the driving force to benefit cocrystal growth. Additionally, the honeycomb-like channels constructed by other coexisting compound make the water evaporates more moderate, which can help the formation of supersaturated solution at suitable rate, further promote the growth of cocrystal. This approach possibly opens a new route toward the developing methodologies for cocrystal synthesis.

  1. Regulation of the membrane insertion and conductance activity of the metamorphic chloride intracellular channel protein CLIC1 by cholesterol.

    Directory of Open Access Journals (Sweden)

    Stella M Valenzuela

    Full Text Available The Chloride Intracellular ion channel protein CLIC1 has the ability to spontaneously insert into lipid membranes from a soluble, globular state. The precise mechanism of how this occurs and what regulates this insertion is still largely unknown, although factors such as pH and redox environment are known contributors. In the current study, we demonstrate that the presence and concentration of cholesterol in the membrane regulates the spontaneous insertion of CLIC1 into the membrane as well as its ion channel activity. The study employed pressure versus area change measurements of Langmuir lipid monolayer films; and impedance spectroscopy measurements using tethered bilayer membranes to monitor membrane conductance during and following the addition of CLIC1 protein. The observed cholesterol dependent behaviour of CLIC1 is highly reminiscent of the cholesterol-dependent-cytolysin family of bacterial pore-forming proteins, suggesting common regulatory mechanisms for spontaneous protein insertion into the membrane bilayer.

  2. Regulation of the membrane insertion and conductance activity of the metamorphic chloride intracellular channel protein CLIC1 by cholesterol.

    Science.gov (United States)

    Valenzuela, Stella M; Alkhamici, Heba; Brown, Louise J; Almond, Oscar C; Goodchild, Sophia C; Carne, Sonia; Curmi, Paul M G; Holt, Stephen A; Cornell, Bruce A

    2013-01-01

    The Chloride Intracellular ion channel protein CLIC1 has the ability to spontaneously insert into lipid membranes from a soluble, globular state. The precise mechanism of how this occurs and what regulates this insertion is still largely unknown, although factors such as pH and redox environment are known contributors. In the current study, we demonstrate that the presence and concentration of cholesterol in the membrane regulates the spontaneous insertion of CLIC1 into the membrane as well as its ion channel activity. The study employed pressure versus area change measurements of Langmuir lipid monolayer films; and impedance spectroscopy measurements using tethered bilayer membranes to monitor membrane conductance during and following the addition of CLIC1 protein. The observed cholesterol dependent behaviour of CLIC1 is highly reminiscent of the cholesterol-dependent-cytolysin family of bacterial pore-forming proteins, suggesting common regulatory mechanisms for spontaneous protein insertion into the membrane bilayer.

  3. Arsenic promotes ubiquitinylation and lysosomal degradation of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels in human airway epithelial cells.

    Science.gov (United States)

    Bomberger, Jennifer M; Coutermarsh, Bonita A; Barnaby, Roxanna L; Stanton, Bruce A

    2012-05-18

    Arsenic exposure significantly increases respiratory bacterial infections and reduces the ability of the innate immune system to eliminate bacterial infections. Recently, we observed in the gill of killifish, an environmental model organism, that arsenic exposure induced the ubiquitinylation and degradation of cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel that is essential for the mucociliary clearance of respiratory pathogens in humans. Accordingly, in this study, we tested the hypothesis that low dose arsenic exposure reduces the abundance and function of CFTR in human airway epithelial cells. Arsenic induced a time- and dose-dependent increase in multiubiquitinylated CFTR, which led to its lysosomal degradation, and a decrease in CFTR-mediated chloride secretion. Although arsenic had no effect on the abundance or activity of USP10, a deubiquitinylating enzyme, siRNA-mediated knockdown of c-Cbl, an E3 ubiquitin ligase, abolished the arsenic-stimulated degradation of CFTR. Arsenic enhanced the degradation of CFTR by increasing phosphorylated c-Cbl, which increased its interaction with CFTR, and subsequent ubiquitinylation of CFTR. Because epidemiological studies have shown that arsenic increases the incidence of respiratory infections, this study suggests that one potential mechanism of this effect involves arsenic-induced ubiquitinylation and degradation of CFTR, which decreases chloride secretion and airway surface liquid volume, effects that would be proposed to reduce mucociliary clearance of respiratory pathogens.

  4. Inhibition of ANO1/TMEM16A Chloride Channel by Idebenone and Its Cytotoxicity to Cancer Cell Lines.

    Directory of Open Access Journals (Sweden)

    Yohan Seo

    Full Text Available The expression levels of anoctamin 1 (ANO1, TMEM16A, a calcium-activated chloride channel (CaCC, are significantly increased in several tumors, and inhibition of ANO1 is known to reduce cell proliferation and migration. Here, we performed cell-based screening of a collection of natural products and drug-like compounds to identify inhibitors of ANO1. As a result of the screening, idebenone, miconazole and plumbagin were identified as novel ANO1 inhibitors. Electrophysiological studies showed that idebenone, a synthetic analog of coenzyme Q10, completely blocked ANO1 activity in FRT cells expressing ANO1 without any effect on intracellular calcium signaling and CFTR, a cAMP-regulated chloride channel. The CaCC activities in PC-3 and CFPAC-1 cells expressing abundant endogenous ANO1 were strongly blocked by idebenone. Idebenone inhibited cell proliferation and induced apoptosis in PC-3 and CFPAC-1 cells, but not in A549 cells, which do not express ANO1. These data suggest that idebenone, a novel ANO1 inhibitor, has potential for use in cancer therapy.

  5. Effect of a selective chloride channel activator, lubiprostone, on gastrointestinal transit, gastric sensory, and motor functions in healthy volunteers.

    Science.gov (United States)

    Camilleri, Michael; Bharucha, Adil E; Ueno, Ryuji; Burton, Duane; Thomforde, George M; Baxter, Kari; McKinzie, Sanna; Zinsmeister, Alan R

    2006-05-01

    Chloride channels modulate gastrointestinal neuromuscular functions in vitro. Lubiprostone, a selective type 2 chloride channel (ClC-2) activator, induces intestinal secretion and has been shown to relieve constipation in clinical trials; however, the effects of lubiprostone on gastric function and whole gut transit in humans are unclear. Our aim was to compare the effects of the selective ClC-2 activator lubiprostone on maximum tolerated volume (MTV) of a meal, postprandial symptoms, gastric volumes, and gastrointestinal and colonic transit in humans. We performed a randomized, parallel-group, double-blind, placebo-controlled study evaluating the effects of lubiprostone (24 microg bid) in 30 healthy volunteers. Validated methods were used: scintigraphic gastrointestinal and colonic transit, SPECT to measure gastric volumes, and the nutrient drink ("satiation") test to measure MTV and postprandial symptoms. Lubiprostone accelerated small bowel and colonic transit, increased fasting gastric volume, and retarded gastric emptying. MTV values were reduced compared with placebo; however, the MTV was within the normal range for healthy adults in 13 of 14 participants, and there was no significant change compared with baseline measurements. Lubiprostone had no significant effect on postprandial gastric volume or aggregate symptoms but did decrease fullness 30 min after the fully satiating meal. Thus the ClC-2 activator lubiprostone accelerates small intestinal and colonic transit, which confers potential in the treatment of constipation.

  6. Neuroprotective effects of ClC-3 chloride channel in glutamate-induced retinal ganglion cell RGC-5 apoptosis

    Institute of Scientific and Technical Information of China (English)

    Li Yu; Ning Han; Ligang Jiang; Yajuan Zheng; Lifeng Liu

    2011-01-01

    Transforming growth factor β plays a role in regulation of apoptosis in ClC-3 and the Smads signaling pathway, although the underlying mechanisms remain unclear. The present study determined possible signal transduction mechanisms based on CIC-3 expression, which accordingly affected apoptosis of retinal ganglion cells in a glutamate-induced retinal ganglion cell RGC-5 apoptosis model. Results revealed significantly increased cell survival rate and significantly decreased apoptosis rate following apoptosis of ClC-3 cDNA-transfected glutamate-induced retinal ganglion cells. Following inhibition of the ClC-3 chloride channel using RNAi technology, cell survival and apoptosis rates were reversed. In addition, expression of transforming growth factor β2, Smads2, Smads3, Smads4, and Smads7 increased to varying degrees. These results suggest that ClC-3 chloride channel plays a protective role in glutamate-induced apoptosis of retinal ganglion cells, and transforming growth factor β/Smads signal transduction pathways are involved in this process.

  7. Identifying interacting proteins of a Caenorhabditis elegans voltage-gated chloride channel CLH-1 using GFP-Trap and mass spectrometry.

    Science.gov (United States)

    Zhou, Zi-Liang; Jiang, Jing; Yin, Jiang-An; Cai, Shi-Qing

    2014-06-25

    Chloride channels belong to a superfamily of ion channels that permit passive passage of anions, mainly chloride, across cell membrane. They play a variety of important physiological roles in regulation of cytosolic pH, cell volume homeostasis, organic solute transport, cell migration, cell proliferation, and differentiation. However, little is known about the functional regulation of these channels. In this study, we generated an integrated transgenic worm strain expressing green fluorescence protein (GFP) fused CLC-type chloride channel 1 (CLH-1::GFP), a voltage-gated chloride channel in Caenorhabditis elegans (C. elegans). CLH-1::GFP was expressed in some unidentified head neurons and posterior intestinal cells of C. elegans. Interacting proteins of CLH-1::GFP were purified by GFP-Trap, a novel system for efficient isolation of GFP fusion proteins and their interacting factors. Mass spectrometry (MS) analysis revealed that a total of 27 high probability interacting proteins were co-trapped with CLHp-1::GFP. Biochemical evidence showed that eukaryotic translation elongation factor 1 (EEF-1), one of these co-trapped proteins identified by MS, physically interacted with CLH-1, in consistent with GFP-Trap experiments. Further immunostaining data revealed that the protein level of CLH-1 was significantly increased upon co-expression with EEF-1. These results suggest that the combination of GFP-Trap purification with MS is an excellent tool to identify novel interacting proteins of voltage-gated chloride channels in C. elegans. Our data also show that EEF-1 is a regulator of voltage-gated chloride channel CLH-1.

  8. Contribution of a lysine residue in the first transmembrane segment to the selectivity filter region in the CFTR chloride channel.

    Science.gov (United States)

    Negoda, Alexander; El Hiani, Yassine; Cowley, Elizabeth A; Linsdell, Paul

    2017-02-21

    The anion selectivity and conductance of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel are determined predominantly by interactions between permeant anions and the narrow region of the channel pore. This narrow region has therefore been described as functioning as the "selectivity filter" of the channel. Multiple pore-lining transmembrane segments (TMs) have previously been shown to contribute to the selectivity filter region. However, little is known about the three-dimensional organization of this region, or how multiple TMs combine to determine its functional properties. In the present study we have used patch clamp recording to identify changes in channel function associated with the formation of disulfide cross-links between cysteine residues introduced into different TMs within the selectivity filter. Cysteine introduced at position L102 in TM1 was able to form disulfide bonds with F337C and T338C in TM6, two positions that are known to play key roles in determining anion permeation properties. Consistent with this proximal arrangement of L102, F337 and T338, different mutations at L102 altered anion selectivity and conductance properties in a way that suggests that this residue plays an important role in determining selectivity filter function, albeit a much lesser role than that of F337. These results suggest an asymmetric three-dimensional arrangement of the key selectivity filter region of the pore, as well as having important implications regarding the molecular mechanism of anion permeation.

  9. Control of sensory neuron excitability by serotonin involves 5HT2C receptors and Ca(2+)-activated chloride channels.

    Science.gov (United States)

    Salzer, Isabella; Gantumur, Enkhbileg; Yousuf, Arsalan; Boehm, Stefan

    2016-11-01

    Serotonin (5HT) is a constituent of the so-called "inflammatory soup" that sensitizes nociceptors during inflammation. Nevertheless, receptors and signaling mechanisms that mediate an excitation of dorsal root ganglion (DRG) neurons by 5HT remained controversial. Therefore, capsaicin-sensitive nociceptive neurons dissociated from rat DRGs were used to investigate effects of 5HT on membrane excitability and currents through ligand- as well as voltage-gated ion channels. In 58% of the neurons tested, 5HT increased action potential firing, an effect that was abolished by the 5HT2 receptor antagonist ritanserin, but not by the 5HT3 antagonist tropisetron. Unlike other algogenic mediators, such as PGE2 and bradykinin, 5HT did not affect currents through TTX-resistant Na(+) channels or Kv7 K(+) channels. In all neurons investigated, 5HT potentiated capsaicin-evoked currents through TRPV1 channels, an effect that was attenuated by antagonists at 5HT2A (4 F 4 PP), 5HT2B (SB 204741), as well as 5HT2C (RS 102221) receptors. 5HT triggered slowly arising inward Cl(-) currents in 53% of the neurons. This effect was antagonized by the 5HT2C receptor blocker only, and the current was prevented by an inhibitor of Ca(2+)-activated chloride channels (CaCC). The 5HT-induced increase in action potential firing was also abolished by this CaCC blocker and by the TRPV1 inhibitor capsazepine. Amongst the subtype selective 5HT2 antagonists, only RS 102221 (5HT2C-selectively) counteracted the rise in action potential firing elicited by 5HT. These results show that 5HT excites DRG neurons mainly via 5HT2C receptors which concomitantly mediate a sensitization of TRPV1 channels and an opening of CaCCs.

  10. Self-cleavage of Human CLCA1 Protein by a Novel Internal Metalloprotease Domain Controls Calcium-activated Chloride Channel Activation*♦

    Science.gov (United States)

    Yurtsever, Zeynep; Sala-Rabanal, Monica; Randolph, David T.; Scheaffer, Suzanne M.; Roswit, William T.; Alevy, Yael G.; Patel, Anand C.; Heier, Richard F.; Romero, Arthur G.; Nichols, Colin G.; Holtzman, Michael J.; Brett, Tom J.

    2012-01-01

    The chloride channel calcium-activated (CLCA) family are secreted proteins that regulate both chloride transport and mucin expression, thus controlling the production of mucus in respiratory and other systems. Accordingly, human CLCA1 is a critical mediator of hypersecretory lung diseases, such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis, that manifest mucus obstruction. Despite relevance to homeostasis and disease, the mechanism of CLCA1 function remains largely undefined. We address this void by showing that CLCA proteins contain a consensus proteolytic cleavage site recognized by a novel zincin metalloprotease domain located within the N terminus of CLCA itself. CLCA1 mutations that inhibit self-cleavage prevent activation of calcium-activated chloride channel (CaCC)-mediated chloride transport. CaCC activation requires cleavage to unmask the N-terminal fragment of CLCA1, which can independently gate CaCCs. Gating of CaCCs mediated by CLCA1 does not appear to involve proteolytic cleavage of the channel because a mutant N-terminal fragment deficient in proteolytic activity is able to induce currents comparable with that of the native fragment. These data provide both a mechanistic basis for CLCA1 self-cleavage and a novel mechanism for regulation of chloride channel activity specific to the mucosal interface. PMID:23112050

  11. Self-cleavage of human CLCA1 protein by a novel internal metalloprotease domain controls calcium-activated chloride channel activation.

    Science.gov (United States)

    Yurtsever, Zeynep; Sala-Rabanal, Monica; Randolph, David T; Scheaffer, Suzanne M; Roswit, William T; Alevy, Yael G; Patel, Anand C; Heier, Richard F; Romero, Arthur G; Nichols, Colin G; Holtzman, Michael J; Brett, Tom J

    2012-12-07

    The chloride channel calcium-activated (CLCA) family are secreted proteins that regulate both chloride transport and mucin expression, thus controlling the production of mucus in respiratory and other systems. Accordingly, human CLCA1 is a critical mediator of hypersecretory lung diseases, such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis, that manifest mucus obstruction. Despite relevance to homeostasis and disease, the mechanism of CLCA1 function remains largely undefined. We address this void by showing that CLCA proteins contain a consensus proteolytic cleavage site recognized by a novel zincin metalloprotease domain located within the N terminus of CLCA itself. CLCA1 mutations that inhibit self-cleavage prevent activation of calcium-activated chloride channel (CaCC)-mediated chloride transport. CaCC activation requires cleavage to unmask the N-terminal fragment of CLCA1, which can independently gate CaCCs. Gating of CaCCs mediated by CLCA1 does not appear to involve proteolytic cleavage of the channel because a mutant N-terminal fragment deficient in proteolytic activity is able to induce currents comparable with that of the native fragment. These data provide both a mechanistic basis for CLCA1 self-cleavage and a novel mechanism for regulation of chloride channel activity specific to the mucosal interface.

  12. Changes in cationic selectivity of the nicotinic channel at the rat ganglionic synapse: a role for chloride ions?

    Directory of Open Access Journals (Sweden)

    Oscar Sacchi

    Full Text Available The permeability of the nicotinic channel (nAChR at the ganglionic synapse has been examined, in the intact rat superior cervical ganglion in vitro, by fitting the Goldman current equation to the synaptic current (EPSC I-V relationship. Subsynaptic nAChRs, activated by neurally-released acetylcholine (ACh, were thus analyzed in an intact environment as natively expressed by the mature sympathetic neuron. Postsynaptic neuron hyperpolarization (from -40 to -90 mV resulted in a change of the synaptic potassium/sodium permeability ratio (P(K/P(Na from 1.40 to 0.92, corresponding to a reversible shift of the apparent acetylcholine equilibrium potential, E(ACh, by about +10 mV. The effect was accompanied by a decrease of the peak synaptic conductance (g(syn and of the EPSC decay time constant. Reduction of [Cl(-](o to 18 mM resulted in a change of P(K/P(Na from 1.57 (control to 2.26, associated with a reversible shift of E(ACh by about -10 mV. Application of 200 nM αBgTx evoked P(K/P(Na and g(syn modifications similar to those observed in reduced [Cl(-](o. The two treatments were overlapping and complementary, as if the same site/mechanism were involved. The difference current before and after chloride reduction or toxin application exhibited a strongly positive equilibrium potential, which could not be explained by the block of a calcium component of the EPSC. Observations under current-clamp conditions suggest that the driving force modification of the EPSC due to P(K/P(Na changes represent an additional powerful integrative mechanism of neuron behavior. A possible role for chloride ions is suggested: the nAChR selectivity was actually reduced by increased chloride gradient (membrane hyperpolarization, while it was increased, moving towards a channel preferentially permeable for potassium, when the chloride gradient was reduced.

  13. Dissection of the Mechanical Impedance Components of the Outer Hair Cell Using a Chloride-Channel Blocker

    Science.gov (United States)

    Harasztosi, Csaba; Gummer, Anthony W.

    2011-11-01

    The voltage-dependent chloride-channel blocker anthracene-9-carboxylic acid (9AC) has been found to reduce the imaginary but not the real part of the mechanical impedance of the organ of Corti, suggesting that the effective stiffness of outer hair cells (OHCs) is reduced by 9AC. To examine whether 9AC interacts directly with the motor protein prestin to reduce the membrane component of the impedance, the patch-clamp technique in whole-cell configuration was used to measure the nonlinear capacitance (NLC) of isolated OHCs and, as control, prestin-transfected human embryonic kidney 293 (HEK293) cells. Extracellular application of 9AC significantly reduced the NLC of both OHCs and HEK293 cells. Intracellular 9AC did not influence the blocking effect of the extracellular applied drug. These results suggest that 9AC interacts directly with prestin, reducing the effective stiffness of the motor, and that the interaction is extracellular.

  14. Propofol suppresses synaptic responsiveness of somatosensory relay neurons to excitatory input by potentiating GABAA receptor chloride channels

    Directory of Open Access Journals (Sweden)

    Goldstein Peter A

    2005-01-01

    Full Text Available Abstract Propofol is a widely used intravenous general anesthetic. Propofol-induced unconsciousness in humans is associated with inhibition of thalamic activity evoked by somatosensory stimuli. However, the cellular mechanisms underlying the effects of propofol in thalamic circuits are largely unknown. We investigated the influence of propofol on synaptic responsiveness of thalamocortical relay neurons in the ventrobasal complex (VB to excitatory input in mouse brain slices, using both current- and voltage-clamp recording techniques. Excitatory responses including EPSP temporal summation and action potential firing were evoked in VB neurons by electrical stimulation of corticothalamic fibers or pharmacological activation of glutamate receptors. Propofol (0.6 – 3 μM suppressed temporal summation and spike firing in a concentration-dependent manner. The thalamocortical suppression was accompanied by a marked decrease in both EPSP amplitude and input resistance, indicating that a shunting mechanism was involved. The propofol-mediated thalamocortical suppression could be blocked by a GABAA receptor antagonist or chloride channel blocker, suggesting that postsynaptic GABAA receptors in VB neurons were involved in the shunting inhibition. GABAA receptor-mediated inhibitory postsynaptic currents (IPSCs were evoked in VB neurons by electrical stimulation of the reticular thalamic nucleus. Propofol markedly increased amplitude, decay time, and charge transfer of GABAA IPSCs. The results demonstrated that shunting inhibition of thalamic somatosensory relay neurons by propofol at clinically relevant concentrations is primarily mediated through the potentiation of the GABAA receptor chloride channel-mediated conductance, and such inhibition may contribute to the impaired thalamic responses to sensory stimuli seen during propofol-induced anesthesia.

  15. The secret life of CFTR as a calcium-activated chloride channel.

    Science.gov (United States)

    Billet, Arnaud; Hanrahan, John W

    2013-11-01

    cAMP-stimulated anion conductance is defective in cystic fibrosis (CF). The regulatory domain of CFTR, the anion channel protein encoded by the CF gene, possesses an unusually high density of consensus sequences for phosphorylation by protein kinase A (14 in a stretch of CFTR is viewed primarily as a cAMP-stimulated anion channel, and most studies have focused on this mode of activation. However, there is growing evidence that CFTR also responds to Ca(2+)-mobilizing secretagogues and contributes substantially to cholinergic and purinergic responses in native tissues. G protein-coupled receptors that signal through Gαq can stimulate CFTR channels by activating Ca(2+)-dependent adenylyl cyclase and tyrosine kinases, and also by inhibiting protein phosphatase type 2A. Here we review evidence for these novel mechanisms of CFTR activation and discuss how they may help explain previous observations.

  16. Interactions between permeant and blocking anions inside the CFTR chloride channel pore.

    Science.gov (United States)

    Linsdell, Paul

    2015-07-01

    Binding of cytoplasmic anionic open channel blockers within the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel is antagonized by extracellular Cl(-). In the present work, patch clamp recording was used to investigate the interaction between extracellular Cl(-) (and other anions) and cytoplasmic Pt(NO2)4(2-) ions inside the CFTR channel pore. In constitutively open (E1371Q-CFTR) channels, these different anions bind to two separate sites, located in the outer and inner vestibules of the pore respectively, in a mutually antagonistic fashion. A mutation in the inner vestibule (I344K) that greatly increased Pt(NO2)4(2-) binding affinity also greatly strengthened antagonistic Cl(-):blocker interactions as well as the voltage-dependence of block. Quantitative analysis of ion binding affinity suggested that the I344K mutation strengthened interactions not only with intracellular Pt(NO2)4(2-) ions but also with extracellular Cl(-), and that altered blocker Cl(-)- and voltage-dependence were due to the introduction of a novel type of antagonistic ion:ion interaction inside the pore that was independent of Cl(-) binding in the outer vestibule. It is proposed that this mutation alters the arrangement of anion binding sites inside the pore, allowing both Cl(-) and Pt(NO2)4(2-) to bind concurrently within the inner vestibule in a strongly mutually antagonistic fashion. However, the I344K mutation does not increase single channel conductance following disruption of Cl(-) binding in the outer vestibule in R334Q channels. Implications for the arrangement of ion binding sites in the pore, and their functional consequences for blocker binding and for rapid Cl(-) permeation, are discussed.

  17. The tyrosine kinase p60c-src regulates the fast gate of the cystic fibrosis transmembrane conductance regulator chloride channel.

    OpenAIRE

    Fischer, H.; Machen, T E

    1996-01-01

    The role of the tyrosine kinase p60c-src on the gating of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel was investigated with the cell-attached and excised patch clamp technique in conjunction with current noise analysis of recordings containing multiple channels per patch. Spectra of CFTR-generated current noise contained a low-frequency and a high-frequency Lorentzian noise component. In the cell-attached mode, the high-frequency Lorentzian was significantl...

  18. Presynaptic Localization and Possible Function of Calcium-Activated Chloride Channel Anoctamin 1 in the Mammalian Retina.

    Directory of Open Access Journals (Sweden)

    Ji Hyun Jeon

    Full Text Available Calcium (Ca(2+-activated chloride (Cl(- channels (CaCCs play a role in the modulation of action potentials and synaptic responses in the somatodendritic regions of central neurons. In the vertebrate retina, large Ca(2+-activated Cl(- currents (ICl(Ca regulate synaptic transmission at photoreceptor terminals; however, the molecular identity of CaCCs that mediate ICl(Ca remains unclear. The transmembrane protein, TMEM16A, also called anoctamin 1 (ANO1, has been recently validated as a CaCC and is widely expressed in various secretory epithelia and nervous tissues. Despite the fact that tmem16a was first cloned in the retina, there is little information on its cellular localization and function in the mammalian retina. In this study, we found that ANO1 was abundantly expressed as puncta in 2 synaptic layers. More specifically, ANO1 immunoreactivity was observed in the presynaptic terminals of various retinal neurons, including photoreceptors. ICl(Ca was first detected in dissociated rod bipolar cells expressing ANO1. ICl(Ca was abolished by treatment with the Ca(2+ channel blocker Co(2+, the L-type Ca(2+ channel blocker nifedipine, and the Cl(- channel blockers 5-nitro-2-(3-phenylpropylamino benzoic acid (NPPB and niflumic acid (NFA. More specifically, a recently discovered ANO1-selective inhibitor, T16Ainh-A01, and a neutralizing antibody against ANO1 inhibited ICl(Ca in rod bipolar cells. Under a current-clamping mode, the suppression of ICl(Ca by using NPPB and T16Ainh-A01 caused a prolonged Ca(2+ spike-like depolarization evoked by current injection in dissociated rod bipolar cells. These results suggest that ANO1 confers ICl(Ca in retinal neurons and acts as an intrinsic regulator of the presynaptic membrane potential during synaptic transmission.

  19. Expression of calcium-activated chloride channels Ano1 and Ano2 in mouse taste cells.

    Science.gov (United States)

    Cherkashin, Alexander P; Kolesnikova, Alisa S; Tarasov, Michail V; Romanov, Roman A; Rogachevskaja, Olga A; Bystrova, Marina F; Kolesnikov, Stanislav S

    2016-02-01

    Specialized Ca(2+)-dependent ion channels ubiquitously couple intracellular Ca(2+) signals to a change in cell polarization. The existing physiological evidence suggests that Ca(2+)-activated Cl(-) channels (CaCCs) are functional in taste cells. Because Ano1 and Ano2 encode channel proteins that form CaCCs in a variety of cells, we analyzed their expression in mouse taste cells. Transcripts for Ano1 and Ano2 were detected in circumvallate (CV) papillae, and their expression in taste cells was confirmed using immunohistochemistry. When dialyzed with CsCl, taste cells of the type III exhibited no ion currents dependent on cytosolic Ca(2+). Large Ca(2+)-gated currents mediated by TRPM5 were elicited in type II cells by Ca(2+) uncaging. When TRPM5 was inhibited by triphenylphosphine oxide (TPPO), ionomycin stimulated a small but resolvable inward current that was eliminated by anion channel blockers, including T16Ainh-A01 (T16), a specific Ano1 antagonist. This suggests that CaCCs, including Ano1-like channels, are functional in type II cells. In type I cells, CaCCs were prominently active, blockable with the CaCC antagonist CaCCinh-A01 but insensitive to T16. By profiling Ano1 and Ano2 expressions in individual taste cells, we revealed Ano1 transcripts in type II cells only, while Ano2 transcripts were detected in both type I and type II cells. P2Y agonists stimulated Ca(2+)-gated Cl(-) currents in type I cells. Thus, CaCCs, possibly formed by Ano2, serve as effectors downstream of P2Y receptors in type I cells. While the role for TRPM5 in taste transduction is well established, the physiological significance of expression of CaCCs in type II cells remains to be elucidated.

  20. The CLC-2 Chloride Channel Modulates ECM Synthesis, Differentiation, and Migration of Human Conjunctival Fibroblasts via the PI3K/Akt Signaling Pathway.

    Science.gov (United States)

    Sun, Lixia; Dong, Yaru; Zhao, Jing; Yin, Yuan; Zheng, Yajuan

    2016-06-09

    Recent evidence suggests that chloride channels are critical for cell proliferation, migration, and differentiation. We examined the effects of transforming growth factor (TGF)-β1 on chloride channel expression and associations with human conjunctival fibroblast (HConF) biology. To investigate the potential role of chloride channel (CLC)-2 in migration, transition to myofibroblasts and extracellular matrix (ECM) synthesis of HconF, a small interfering RNA (siRNA) approach was applied. TGF-β1-induced migration and transition of fibroblasts to myofibroblasts characterized by α-smooth muscle actin (α-SMA) expression, supported by increased endogenous expression of CLC-2 protein and mRNA transcripts. ECM (collagen I and fibronectin) synthesis in HConF was enhanced by TGF-β1. CLC-2 siRNA treatment reduced TGF-β1-induced cell migration, transition of fibroblasts to myofibroblasts, and ECM synthesis of HConF. CLC-2 siRNA treatment in the presence of TGF-β1 inhibited phosphorylation of PI3K and Akt in HConF. These findings demonstrate that CLC-2 chloride channels are important for TGF-β1-induced migration, differentiation, and ECM synthesis via PI3K/Akt signaling in HConF.

  1. Influence of salinity on the localization of Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and CFTR anion channel in chloride cells of the Hawaiian goby (Stenogobius hawaiiensis)

    Science.gov (United States)

    McCormick, S.D.; Sundell, K.; Bjornsson, Bjorn Thrandur; Brown, C.L.; Hiroi, J.

    2003-01-01

    Na+/K+-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) are the three major transport proteins thought to be involved in chloride secretion in teleost fish. If this is the case, the levels of these transporters should be high in chloride cells of seawater-acclimated fish. We therefore examined the influence of salinity on immunolocalization of Na +/K+-ATPase, NKCC and CFTR in the gills of the Hawaiian goby (Stenogobius hawaiiensis). Fish were acclimated to freshwater and 20??? and 30??? seawater for 10 days. Na+/K +-ATPase and NKCC were localized specifically to chloride cells and stained throughout most of the cell except for the nucleus and the most apical region, indicating a basolateral/tubular distribution. All Na+/K +-ATPase-positive chloride cells were also positive for NKCC in all salinities. Salinity caused a slight increase in chloride cell number and size and a slight decrease in staining intensity for Na+/K +-ATPase and NKCC, but the basic pattern of localization was not altered. Gill Na+/K+-ATPase activity was also not affected by salinity. CFTR was localized to the apical surface of chloride cells, and only cells staining positive for Na+/K+-ATPase were CFTR-positive. CFTR-positive cells greatly increased in number (5-fold), area stained (53%) and intensity (29%) after seawater acclimation. In freshwater, CFTR immunoreactivity was light and occurred over a broad apical surface on chloride cells, whereas in seawater there was intense immunoreactivity around the apical pit (which was often punctate in appearance) and a light subapical staining. The results indicate that Na+/K +-ATPase, NKCC and CFTR are all present in chloride cells and support current models that all three are responsible for chloride secretion by chloride cells of teleost fish.

  2. Mechanism of interaction of niflumic acid with heterologously expressed kidney CLC-K chloride channels.

    Science.gov (United States)

    Picollo, Alessandra; Liantonio, Antonella; Babini, Elena; Camerino, Diana Conte; Pusch, Michael

    2007-04-01

    CLC-K Cl(-) channels belong to the CLC protein family. In kidney and inner ear, they are involved in transepithelial salt transport. Mutations in ClC-Kb lead to Bartter's syndrome, and mutations in the associated subunit barttin produce Bartter's syndrome and deafness. We have previously found that 3-phenyl-CPP blocks hClC-Ka and rClC-K1 from the extracellular side in the pore entrance. Recently, we have shown that niflumic acid (NFA), a nonsteroidal anti-inflammatory fenamate, produces biphasic behavior on human CLC-K channels that suggests the presence of two functionally different binding sites: an activating site and a blocking site. Here, we investigate in more detail the interaction of NFA on CLC-K channels. Mutants that altered block by 3-phenyl-2-(p-chlorophenoxy)propionic acid (CPP) had no effect on NFA block, indicating that the inhibition binding site of NFA is different from that of 3-phenyl-CPP and flufenamic acid. Moreover, NFA does not compete with extracellular Cl(-) ions, suggesting that the binding sites of NFA are not located deep in the pore. Differently from ClC-Ka, on the rat homologue ClC-K1, NFA has only an inhibitory effect. We developed a quantitative model to describe the complex action of NFA on ClC-Ka. The model predicts that ClC-Ka possesses two NFA binding sites: when only one site is occupied, NFA increases ClC-Ka currents, whereas the occupation of both binding sites leads to channel block.

  3. Physiological roles and diseases of tmem16/anoctamin proteins: are they all chloride channels?

    Institute of Scientific and Technical Information of China (English)

    Charity DURAN; H Criss HARTZELL

    2011-01-01

    The Tmem16 gene family was first identified by bioinformatic analysis in 2004. In 2008, it was shown independently by 3 laboratories that the first two members (Tmem16A and Tmem16B) of this 10-gene family are Ca2+-activated Cl- channels. Because these proteins are thought to have 8 transmembrane domains and be anion-selective channels, the alternative name, Anoctamin (anion and octa=8),has been proposed. However, it remains unclear whether all members of this family are, in fact, anion channels or have the same 8-transmembrane domain topology. Since 2008, there have been nearly 100 papers published on this gene family. The excitement about Tmem16 proteins has been enhanced by the finding that Ano1 has been linked to cancer, mutations in Ano5 are linked to several forms of muscular dystrophy (LGMDL2 and MMD-3), mutations in Ano10 are linked to autosomal recessive spinocerebellar ataxia,and mutations in Ano6 are linked to Scott syndrome, a rare bleeding disorder. Here we review some of the recent developments in understanding the physiology and structure-function of the Tmem16 gene family.

  4. The H-loop in the Second Nucleotide-binding Domain of the Cystic Fibrosis Transmembrane Conductance Regulator is Required for Efficient Chloride Channel Closing

    OpenAIRE

    Kloch, Monika; Milewski, Michał; Nurowska, Ewa; Dworakowska, Beata; Cutting, Garry R.; Dołowy, Krzysztof

    2010-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a cAMP-activated chloride channel. The recent model of CFTR gating predicts that the ATP binding to both nucleotide-binding domains (NBD1 and NBD2) of CFTR is required for the opening of the channel, while the ATP hydrolysis at NBD2 induces subsequent channel closing. In most ABC proteins, efficient hydrolysis of ATP requires the presence of the invariant histidine res...

  5. Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole-cell oscillations in smooth muscle cells

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian; Aalkjær, Christian; Nilsson, Holger;

    2007-01-01

    waves sweeping through the cytoplasm when the SR is stimulated to release calcium. A rise in cyclic guanosine monophosphate (cGMP) leads to the experimentally observed transition from waves to whole-cell calcium oscillations. At the same time membrane potential starts to oscillate and the frequency...... approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes uniform opening of L-type calcium...... onset of oscillations in membrane potential within the individual cell may underlie sudden intercellular synchronization and the appearance of vasomotion. Key words: Vasomotion, Chloride channel, cGMP, Mathematical model, Calcium waves....

  6. Cytoplasmic pathway followed by chloride ions to enter the CFTR channel pore.

    Science.gov (United States)

    El Hiani, Yassine; Negoda, Alexander; Linsdell, Paul

    2016-05-01

    Most ATP-binding cassette (ABC) proteins function as ATP-dependent membrane pumps. One exception is the cystic fibrosis transmembrane conductance regulator (CFTR), an ABC protein that functions as a Cl(-) ion channel. As such, the CFTR protein must form a continuous pathway for the movement of Cl(-) ions from the cytoplasm to the extracellular solution when in its open channel state. Extensive functional investigations have characterized most parts of this Cl(-) permeation pathway. However, one region remains unexplored-the pathway connecting the cytoplasm to the membrane-spanning pore. We used patch clamp recording and extensive substituted cysteine accessibility mutagenesis to identify amino acid side-chains in cytoplasmic regions of CFTR that lie close to the pathway taken by Cl(-) ions as they pass from the cytoplasm through this pathway. Our results suggest that Cl(-) ions enter the permeation pathway via a single lateral tunnel formed by the cytoplasmic parts of the protein, and then follow a fairly direct central pathway towards the membrane-spanning parts of the protein. However, this pathway is not lined continuously by any particular part of the protein; instead, the contributions of different cytoplasmic regions of the protein appear to change as the permeation pathway approaches the membrane, which appears to reflect the ways in which different cytoplasmic regions of the protein are oriented towards its central axis. Our results allow us to define for the first time the complete Cl(-) permeation pathway in CFTR, from the cytoplasm to the extracellular solution.

  7. CFTR mediated chloride secretion in the avian renal proximal tubule.

    Science.gov (United States)

    Laverty, Gary; Anttila, Ashley; Carty, Jenava; Reddy, Varudhini; Yum, Jamie; Arnason, Sighvatur S

    2012-01-01

    In primary cell cultures of the avian (Gallus gallus) renal proximal tubule parathyroid hormone and cAMP activation generate a Cl(-)-dependent short circuit current (I(SC)) response, consistent with net transepithelial Cl(-) secretion. In this study we investigated the expression and physiological function of the Na-K-2Cl (NKCC) transporter and CFTR chloride channel, both associated with Cl(-) secretion in a variety of tissues, in these proximal tubule cells. Using both RT-PCR and immunoblotting approaches, we showed that NKCC and CFTR are expressed, both in proximal tubule primary cultures and in a proximal tubule fraction of non-cultured (native tissue) fragments. We also used electrophysiological methods to assess the functional contribution of NKCC and CFTR to forskolin-activated I(SC) responses in filter grown cultured monolayers. Bumetanide (10 μM), a specific blocker of NKCC, inhibited forskolin activated I(SC) by about 40%, suggesting that basolateral uptake of Cl(-) is partially mediated by NKCC transport. In monolayers permeabilized on the basolateral side with nystatin, forskolin activated an apical Cl(-) conductance, manifested as bidirectional diffusion currents in the presence of oppositely directed Cl(-) gradients. Under these conditions the apical conductance appeared to show some bias towards apical-to-basolateral Cl(-) current. Two selective CFTR blockers, CFTR Inhibitor 172 and GlyH-101 (both at 20 μM) inhibited the forskolin activated diffusion currents by 38-68%, with GlyH-101 having a greater effect. These data support the conclusion that avian renal proximal tubules utilize an apical CFTR Cl(-) channel to mediate cAMP-activated Cl(-) secretion.

  8. Meroterpenoid Chrodrimanins Are Selective and Potent Blockers of Insect GABA-Gated Chloride Channels.

    Directory of Open Access Journals (Sweden)

    Yan Xu

    Full Text Available Meroterpenoid chrodrimanins, produced from Talaromyces sp. YO-2, are known to paralyze silkworm (Bombyx mori larvae, but their target is unknown. We have investigated the actions of chrodrimanin B on ligand-gated ion channels of silkworm larval neurons using patch-clamp electrophysiology. Chrodrimanin B had no effect on membrane currents when tested alone at 1 μM. However, it completely blocked the γ-aminobutyric acid (GABA-induced current and showed less pronounced actions on acetylcholine- and L-glutamate-induced currents, when delivered at 1 μM for 1 min prior to co-application with transmitter GABA. Thus, chrodrimanins were also tested on a wild-type isoform of the B. mori GABA receptor (GABAR RDL using two-electrode voltage-clamp electrophysiology. Chrodrimanin B attenuated the peak current amplitude of the GABA response of RDL with an IC50 of 1.66 nM. The order of the GABAR-blocking potency of chrodrimanins B > D > A was in accordance with their reported insecticidal potency. Chrodrimanin B had no open channel blocking action when tested at 3 nM on the GABA response of RDL. Co-application with 3 nM chrodrimanin B shifted the GABA concentration response curve to a higher concentration and further increase of chrodrimanin B concentration to 10 nM; it reduced maximum current amplitude of the GABA response, pointing to a high-affinity competitive action and a lower affinity non-competitive action. The A282S;T286V double mutation of RDL, which impairs the actions of fipronil, hardly affected the blocking action of chrodrimanin B, indicating a binding site of chrodrimanin B distinct from that of fipronil. Chrodrimanin B showed approximately 1,000-fold lower blocking action on human α1β2γ2 GABAR compared to RDL and thus is a selective blocker of insect GABARs.

  9. Meroterpenoid Chrodrimanins Are Selective and Potent Blockers of Insect GABA-Gated Chloride Channels.

    Science.gov (United States)

    Xu, Yan; Furutani, Shogo; Ihara, Makoto; Ling, Yun; Yang, Xinling; Kai, Kenji; Hayashi, Hideo; Matsuda, Kazuhiko

    2015-01-01

    Meroterpenoid chrodrimanins, produced from Talaromyces sp. YO-2, are known to paralyze silkworm (Bombyx mori) larvae, but their target is unknown. We have investigated the actions of chrodrimanin B on ligand-gated ion channels of silkworm larval neurons using patch-clamp electrophysiology. Chrodrimanin B had no effect on membrane currents when tested alone at 1 μM. However, it completely blocked the γ-aminobutyric acid (GABA)-induced current and showed less pronounced actions on acetylcholine- and L-glutamate-induced currents, when delivered at 1 μM for 1 min prior to co-application with transmitter GABA. Thus, chrodrimanins were also tested on a wild-type isoform of the B. mori GABA receptor (GABAR) RDL using two-electrode voltage-clamp electrophysiology. Chrodrimanin B attenuated the peak current amplitude of the GABA response of RDL with an IC50 of 1.66 nM. The order of the GABAR-blocking potency of chrodrimanins B > D > A was in accordance with their reported insecticidal potency. Chrodrimanin B had no open channel blocking action when tested at 3 nM on the GABA response of RDL. Co-application with 3 nM chrodrimanin B shifted the GABA concentration response curve to a higher concentration and further increase of chrodrimanin B concentration to 10 nM; it reduced maximum current amplitude of the GABA response, pointing to a high-affinity competitive action and a lower affinity non-competitive action. The A282S;T286V double mutation of RDL, which impairs the actions of fipronil, hardly affected the blocking action of chrodrimanin B, indicating a binding site of chrodrimanin B distinct from that of fipronil. Chrodrimanin B showed approximately 1,000-fold lower blocking action on human α1β2γ2 GABAR compared to RDL and thus is a selective blocker of insect GABARs.

  10. Ca(2+)-activated chloride channel activity during Ca(2+) alternans in ventricular myocytes.

    Science.gov (United States)

    Kanaporis, Giedrius; Blatter, Lothar A

    2016-11-01

    Cardiac alternans, defined beat-to-beat alternations in contraction, action potential (AP) morphology or cytosolic Ca transient (CaT) amplitude, is a high risk indicator for cardiac arrhythmias. We investigated mechanisms of cardiac alternans in single rabbit ventricular myocytes. CaTs were monitored simultaneously with membrane currents or APs recorded with the patch clamp technique. A strong correlation between beat-to-beat alternations of AP morphology and CaT alternans was observed. During CaT alternans application of voltage clamp protocols in form of pre-recorded APs revealed a prominent Ca(2+)-dependent membrane current consisting of a large outward component coinciding with AP phases 1 and 2, followed by an inward current during AP repolarization. Approximately 85% of the initial outward current was blocked by Cl(-) channel blocker DIDS or lowering external Cl(-) concentration identifying it as a Ca(2+)-activated Cl(-) current (ICaCC). The data suggest that ICaCC plays a critical role in shaping beat-to-beat alternations in AP morphology during alternans.

  11. Prevention of secretory diarrhea by ethanol extract of Bistortae rhizoma through inhibition of chloride channel

    Directory of Open Access Journals (Sweden)

    Bo Yu

    2015-08-01

    Full Text Available Inhibition of cystic fibrosis transmembrane conductance regulator (CFTR and Ca2+-activated Cl- channel (CaCC represents an attractive approach for the treatment of secretory diarrhea. The aim of the study is to investigate the molecular basis of the anti-diarrheal effect of traditional Chinese herbal anti-diarrheal medicine Bistortae rhizoma. Fluorescence quenching assay indicated that the 40% methanol /water fraction (D5 dose-dependently inhibited both CFTR and CaCC function in transfected Fischer rat thyroid (FRT cells. Ex vivo studies indicated that D5 inhibited both forskolin (FSK-activated CFTR current and CCh-induced CaCC current in rat colonic mucosa. In the mouse closed-loop model, intraluminal application of D5 (200 µg/mL significantly reduced cholera toxin-stimulated fluid secretion. In the intestinal motility model, D5 significantly delayed intestinal peristalsis in mice. Our research suggests that CFTR and CaCC-mediated intestinal epithelial Cl- secretion inhibiting and gastrointestinal motility delaying may account for the anti-diarrheal activity of B. rhizoma.

  12. Phylogenetic shadowing of a histamine-gated chloride channel involved in insect vision.

    Science.gov (United States)

    Iovchev, Mladen; Boutanaev, Alexander; Ivanov, Ivaylo; Wolstenholme, Adrian; Nurminsky, Dmitry; Semenov, Eugene

    2006-01-01

    A recently identified gene, hclA (synonym: ort), codes for an ionotrophic histamine receptor subunit in Drosophila melanogaster, and known hclA mutations lead to defects in the visual system, neurologic disorders and changed responsiveness to neurotoxins. To investigate whether this novel class of receptors is common across the Insecta, we analysed the genomes of 15 other insect species (Diptera, Hymenoptera, Coleoptera, Lepidoptera) and revealed orthologs of hclA in all of them. The predicted receptor domain of HCLA is extensively conserved (86-100% of identity) among the 16 proteins. Minor changes in the amino acid sequence that includes the putative transmembrane domains (TMs) 1-3 were found in non-drosophilid species only. Substantial amino acid variability was observed in the signal polypeptides, the intracellular loop domains and in TM4, in good accordance with known data on sequence variations in ligand-gated ion channels. Pairwise comparisons revealed three consensus sequences for N-glycosylation, conserved in HCLAs of all species studied, as well as a drosophilid-specific putative phosphorylation site. Real-time PCR analysis demonstrated that hclA-mRNA is abundant in heads of adult Drosophila. However, species- and sex-specific variations of the hclA expression levels were also observed.

  13. The chloride intracellular channel 5A stimulates podocyte Rac1, protecting against hypertension-induced glomerular injury.

    Science.gov (United States)

    Tavasoli, Mahtab; Li, Laiji; Al-Momany, Abass; Zhu, Lin-Fu; Adam, Benjamin A; Wang, Zhixiang; Ballermann, Barbara J

    2016-04-01

    Glomerular capillary hypertension elicits podocyte remodeling and is a risk factor for the progression of glomerular disease. Ezrin, which links podocalyxin to actin in podocytes, is activated through the chloride intracellular channel 5A (CLIC5A)-dependent phosphatidylinositol 4,5 bisphosphate (PI[4,5]P2) accumulation. Because Rac1 is involved in podocyte actin remodeling and can promote PI[4,5]P2 production we determined whether CLIC5A-dependent PI[4,5]P2 generation and ezrin activation are mediated by Rac1. In COS7 cells, CLIC5A expression stimulated Rac1 but not Cdc42 or Rho activity. CLIC5A also stimulated phosphorylation of the Rac1 effector Pak1 in COS7 cells and in cultured mouse podocytes. CLIC5A-induced PI[4,5]P2 accumulation and Pak1 and ezrin phosphorylation were all Rac1 dependent. In DOCA/Salt hypertension, phosphorylated Pak increased in podocytes of wild-type, but not CLIC5-deficient mice. In DOCA/salt hypertensive mice lacking CLIC5, glomerular capillary microaneurysms were more frequent and albuminuria was greater than in wild-type mice. Thus, augmented hypertension-induced glomerular capillary injury in mice lacking CLIC5 results from abrogation of Rac1-dependent Pak and ezrin activation, perhaps reducing the tensile strength of the podocyte actin cytoskeleton.

  14. Characterization of a critical role for CFTR chloride channels in cardioprotection against ischemia/reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    Sunny Yang XIANG; Linda L YE; LI-lu Marie DUAN; Li-hui LIU; Zhi-dong GE; John A AUCHAMPACH; Garrett J GROSS; Dayue Darrel DUAN

    2011-01-01

    Aim: To further characterize the functional role of cystic fibrosis transmembrane conductance regulator (CFTR) in early and late (second window) ischemic preconditioning (IPC)- and postcondtioning (POC)-mediated cardioprotection against ischemia/reperfusion (I/R) injury.Methods: CFTR knockout (CFTR-/-) mice and age- and gender-matched wild-type (CFTR+/+) and heterozygous (CFTR+/-) mice were used.In in vivo studies, the animals were subjected to a 30-min coronary occlusion followed by a 40-min reperfusion. In ex vivo (isolate heart) studies, a 45-min global ischemia was applied. To evaluate apoptosis, the level of activated caspase 3 and TdT-mediated dUTP-X nick end labeling (TUNEL) were examined.Results: In the in vivo I/R models, early IPC significantly reduced the myocardial infarct size in wild-type (CFTR+/+) (from 40.4%±5.3% to 10.4%±2.0%, n=8, P<0.001) and heterozygous (CFTR+/-) littermates (from 39.4%±2.4% to 15.4%±5.1%, n=6, P<0.001) but failed to protect CFTR knockout (CFTR-/-) mice from I/R induced myocardial infarction (46.9%±6.2% vs 55.5%±7.8%, n=6, P>0.5). Similar results were observed in the in vivo late IPC experiments. Furthermore, in both in vivo and ex vivo I/R models, POC significantly reduced myocardial infarction in wild-type mice, but not in CFTR knockout mice. In ex vivo I/R models, targeted inactivation of CFTRgene abolished the protective effects of IPC against I/R-induced apoptosis.Conclusion: These results provide compelling evidence for a critical role for CFTR Cl- channels in IPC- and POC-mediated cardioprotection against I/R-induced myocardial injury.

  15. Effects of Small Molecule Calcium-Activated Chloride Channel Inhibitors on Structure and Function of Accessory Cholera Enterotoxin (Ace of Vibrio cholerae.

    Directory of Open Access Journals (Sweden)

    Tanaya Chatterjee

    Full Text Available Cholera pathogenesis occurs due to synergistic pro-secretory effects of several toxins, such as cholera toxin (CTX and Accessory cholera enterotoxin (Ace secreted by Vibrio cholerae strains. Ace activates chloride channels stimulating chloride/bicarbonate transport that augments fluid secretion resulting in diarrhea. These channels have been targeted for drug development. However, lesser attention has been paid to the interaction of chloride channel modulators with bacterial toxins. Here we report the modulation of the structure/function of recombinant Ace by small molecule calcium-activated chloride channel (CaCC inhibitors, namely CaCCinh-A01, digallic acid (DGA and tannic acid. Biophysical studies indicate that the unfolding (induced by urea free energy increases upon binding CaCCinh-A01 and DGA, compared to native Ace, whereas binding of tannic acid destabilizes the protein. Far-UV CD experiments revealed that the α-helical content of Ace-CaCCinh-A01 and Ace-DGA complexes increased relative to Ace. In contrast, binding to tannic acid had the opposite effect, indicating the loss of protein secondary structure. The modulation of Ace structure induced by CaCC inhibitors was also analyzed using docking and molecular dynamics (MD simulation. Functional studies, performed using mouse ileal loops and Ussing chamber experiments, corroborate biophysical data, all pointing to the fact that tannic acid destabilizes Ace, inhibiting its function, whereas DGA stabilizes the toxin with enhanced fluid accumulation in mouse ileal loop. The efficacy of tannic acid in mouse model suggests that the targeted modulation of Ace structure may be of therapeutic benefit for gastrointestinal disorders.

  16. Effects of Small Molecule Calcium-Activated Chloride Channel Inhibitors on Structure and Function of Accessory Cholera Enterotoxin (Ace) of Vibrio cholerae

    Science.gov (United States)

    Chatterjee, Tanaya; Sheikh, Irshad Ali; Chakravarty, Devlina; Chakrabarti, Pinak; Sarkar, Paramita; Saha, Tultul; Chakrabarti, Manoj K.; Hoque, Kazi Mirajul

    2015-01-01

    Cholera pathogenesis occurs due to synergistic pro-secretory effects of several toxins, such as cholera toxin (CTX) and Accessory cholera enterotoxin (Ace) secreted by Vibrio cholerae strains. Ace activates chloride channels stimulating chloride/bicarbonate transport that augments fluid secretion resulting in diarrhea. These channels have been targeted for drug development. However, lesser attention has been paid to the interaction of chloride channel modulators with bacterial toxins. Here we report the modulation of the structure/function of recombinant Ace by small molecule calcium-activated chloride channel (CaCC) inhibitors, namely CaCCinh-A01, digallic acid (DGA) and tannic acid. Biophysical studies indicate that the unfolding (induced by urea) free energy increases upon binding CaCCinh-A01 and DGA, compared to native Ace, whereas binding of tannic acid destabilizes the protein. Far-UV CD experiments revealed that the α-helical content of Ace-CaCCinh-A01 and Ace-DGA complexes increased relative to Ace. In contrast, binding to tannic acid had the opposite effect, indicating the loss of protein secondary structure. The modulation of Ace structure induced by CaCC inhibitors was also analyzed using docking and molecular dynamics (MD) simulation. Functional studies, performed using mouse ileal loops and Ussing chamber experiments, corroborate biophysical data, all pointing to the fact that tannic acid destabilizes Ace, inhibiting its function, whereas DGA stabilizes the toxin with enhanced fluid accumulation in mouse ileal loop. The efficacy of tannic acid in mouse model suggests that the targeted modulation of Ace structure may be of therapeutic benefit for gastrointestinal disorders. PMID:26540279

  17. Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole cell oscillations in smooth muscle cells

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; Aalkjær, Christian; Nilsson, Holger;

    2007-01-01

    waves sweeping through the cytoplasm when the sarcoplasmic reticulum (SR) is stimulated to release calcium. A rise in cGMP leads to the experimentally observed transition from waves to whole cell calcium oscillations. At the same time, membrane potential starts to oscillate and the frequency...... approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes a uniform opening of L-type calcium...

  18. Suppression of adenosine-activated chloride transport by ethanol in airway epithelia.

    Directory of Open Access Journals (Sweden)

    Sammeta V Raju

    Full Text Available Alcohol abuse is associated with increased lung infections. Molecular understanding of the underlying mechanisms is not complete. Airway epithelial ion transport regulates the homeostasis of airway surface liquid, essential for airway mucosal immunity and lung host defense. Here, air-liquid interface cultures of Calu-3 epithelial cells were basolaterally exposed to physiologically relevant concentrations of ethanol (0, 25, 50 and 100 mM for 24 hours and adenosine-stimulated ion transport was measured by Ussing chamber. The ethanol exposure reduced the epithelial short-circuit currents (I(SC in a dose-dependent manner. The ion currents activated by adenosine were chloride conductance mediated by cystic fibrosis transmembrane conductance regulator (CFTR, a cAMP-activated chloride channel. Alloxazine, a specific inhibitor for A(2B adenosine receptor (A(2BAR, largely abolished the adenosine-stimulated chloride transport, suggesting that A(2BAR is a major receptor responsible for regulating the chloride transport of the cells. Ethanol significantly reduced intracellular cAMP production upon adenosine stimulation. Moreover, ethanol-suppression of the chloride secretion was able to be restored by cAMP analogs or by inhibitors to block cAMP degradation. These results imply that ethanol exposure dysregulates CFTR-mediated chloride transport in airways by suppression of adenosine-A(2BAR-cAMP signaling pathway, which might contribute to alcohol-associated lung infections.

  19. MiR-101 and miR-144 regulate the expression of the CFTR chloride channel in the lung.

    Science.gov (United States)

    Hassan, Fatemat; Nuovo, Gerard J; Crawford, Melissa; Boyaka, Prosper N; Kirkby, Stephen; Nana-Sinkam, Serge P; Cormet-Boyaka, Estelle

    2012-01-01

    The Cystic Fibrosis Transmembrane conductance Regulator (CFTR) is a chloride channel that plays a critical role in the lung by maintaining fluid homeostasis. Absence or malfunction of CFTR leads to Cystic Fibrosis, a disease characterized by chronic infection and inflammation. We recently reported that air pollutants such as cigarette smoke and cadmium negatively regulate the expression of CFTR by affecting several steps in the biogenesis of CFTR protein. MicroRNAs (miRNAs) have recently received a great deal of attention as both biomarkers and therapeutics due to their ability to regulate multiple genes. Here, we show that cigarette smoke and cadmium up-regulate the expression of two miRNAs (miR-101 and miR-144) that are predicted to target CFTR in human bronchial epithelial cells. When premature miR-101 and miR-144 were transfected in human airway epithelial cells, they directly targeted the CFTR 3'UTR and suppressed the expression of the CFTR protein. Since miR-101 was highly up-regulated by cigarette smoke in vitro, we investigated whether such increase also occurred in vivo. Mice exposed to cigarette smoke for 4 weeks demonstrated an up-regulation of miR-101 and suppression of CFTR protein in their lungs. Finally, we show that miR-101 is highly expressed in lung samples from patients with severe chronic obstructive pulmonary disease (COPD) when compared to control patients. Taken together, these results suggest that chronic cigarette smoking up-regulates miR-101 and that this miRNA could contribute to suppression of CFTR in the lungs of COPD patients.

  20. AB095. Increased expression of TMEM16A/Ano1 chloride channel associated with diabetic erectile dysfunction

    Science.gov (United States)

    Ruan, Yajun; Chen, Yingwei; Li, Mingchao; Wang, Tao; Yang, Jun; Rao, Ke; Wang, Shaogang; Yang, Weimin; Liu, Jihong; Ye, Zhangqun

    2016-01-01

    Objective To investigate the presence, location and functional role of TMEM16A/anotamin-1 (Ano1) calcium-activated chloride channel (CaCC) in the penile of rats with diabetic erectile dysfunction. Methods Eight-week-old male Sprague-Dawley (SD) rats were administrated streptozotocin (diabetic) or citrate buffer (control) randomly. Erectile function was measured by cavernous nerve electrostimulation at 12th week after diabetes was induced. The effect of Ano1 specific inhibitor—T16Ainh-A01 on intracavernous pressure (ICP) was evaluated. Then the penile tissues were harvested for molecular exploration. Real-time PCR and Western Blotting were used to assess the expression of Ano1 in penile tissues. Immunofluorescent labelling of penile tissue allowed localization of Ano1. Cavernous smooth muscle cell (CSMC) was cultured in high glucose medium. The change of Ano1 was measured using Western Blotting. The proliferation of CSMC was evaluated by cell counting kit-8 (CCK-8). Results Erectile function was impaired in diabetic rats. The expression of Ano1 was increased in rats with diabetic erectile dysfunction at mRNA and protein levels. Immunofluorescent labelling revealed the presence of Ano1 mainly in cavernous smooth muscle cells. The inhibition of Ano1 increased the ICP of DED rats. High glucose in vitro enhanced the proliferation of CSMC and the expression level of Ano1. Conclusions Ano1 is expressed in rat penile tissue and is increased with diabetes mellitus. The inhibition of Ano1 increased the ICP of DED rats. The alerted Ano1 may be associated with diabetic erectile dysfunction. It is a potential therapy target for ED in the future.

  1. Cloning and characterization of genes encoding alpha and beta subunits of glutamate-gated chloride channel protein in Cylicocyclus nassatus.

    Science.gov (United States)

    Tandon, Ritesh; LePage, Keith T; Kaplan, Ray M

    2006-11-01

    The invertebrate glutamate-gated chloride channels (GluCls) are receptor molecules and targets for the avermectin-milbemycin (AM) group of anthelmintics. Mutations in GluCls are associated with ivermectin resistance in the soil dwelling nematode Caenorhabditis elegans and the parasitic nematode Cooperia oncophora. In this study, full-length cDNAs encoding alpha and beta subunits of GluCl were cloned and sequenced in Cylicocyclus nassatus, a common and important cyathostomin nematode parasite of horses. Both genes possess the sequence characteristics typical of GluCls, and phylogenetic analysis confirms that these genes are evolutionarily closely related to GluCls of other nematodes and flies. Complete coding sequences of C. nassatus GluCl-alpha and GluCl-beta were subcloned into pTL1 mammalian expression vector, and proteins were expressed in COS-7 cells. Ivermectin-binding characteristics were determined by incubating COS-7 cell membranes expressing C. nassatus GluCl-alpha and GluCl-beta proteins with [(3)H]ivermectin. In competitive binding experiments, fitting the data to a one site competition model, C. nassatus GluCl-alpha was found to bind [(3)H]ivermectin with a high amount of displaceable binding (IC(50)=208 pM). Compared to the mock-transfected COS-7 cells, the means of [(3)H]ivermectin binding were significantly different for C. nassatus GluCl-alpha and the Haemonchus contortus GluCl (HcGluCla) (p=0.018 and 0.023, respectively) but not for C. nassatus GluCl-beta (p=0.370). This is the first report of orthologs of GluCl genes and in vitro expression of an ivermectin-binding protein in a cyathostomin species. These data suggest the likelihood of a similar mechanism of action of AM drugs in these parasites, and suggest that mechanisms of resistance may also be similar.

  2. Iron repletion relocalizes hephaestin to a proximal basolateral compartment in polarized MDCK and Caco2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Min [Department of Biological Sciences, University of Columbia, NY (United States); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Attieh, Zouhair K. [Department of Laboratory Science and Technology, American University of Science and Technology, Ashrafieh (Lebanon); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Son, Hee Sook [Department of Food Science and Human Nutrition, College of Human Ecology, Chonbuk National University (Korea, Republic of); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Chen, Huijun [Medical School, Nanjing University, Nanjing 210008, Jiangsu Province (China); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Bacouri-Haidar, Mhenia [Department of Biology, Faculty of Sciences (I), Lebanese University, Hadath (Lebanon); Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States); Vulpe, Chris D., E-mail: vulpe@berkeley.edu [Department of Nutritional Science and Toxicology, University of California, Berkeley, CA (United States)

    2012-05-11

    Highlights: Black-Right-Pointing-Pointer Hephaestin localizes in the perinuclear space in non-polarized cells. Black-Right-Pointing-Pointer Hephaestin localizes in the perinuclear space in iron deficient and polarized cells. Black-Right-Pointing-Pointer Hephaestin with apical iron moves near to basolateral membrane of polarized cells. Black-Right-Pointing-Pointer Peri-basolateral location of hephaestin is accessible to the extracellular space. Black-Right-Pointing-Pointer Hephaestin is involved in iron mobilization from the intestine to circulation. -- Abstract: While intestinal cellular iron entry in vertebrates employs multiple routes including heme and non-heme routes, iron egress from these cells is exclusively channeled through the only known transporter, ferroportin. Reduced intestinal iron export in sex-linked anemia mice implicates hephaestin, a ferroxidase, in this process. Polarized cells are exposed to two distinct environments. Enterocytes contact the gut lumen via the apical surface of the cell, and through the basolateral surface, to the body. Previous studies indicate both local and systemic control of iron uptake. We hypothesized that differences in iron availability at the apical and/or basolateral surface may modulate iron uptake via cellular localization of hephaestin. We therefore characterized the localization of hephaestin in two models of polarized epithelial cell lines, MDCK and Caco2, with varying iron availability at the apical and basolateral surfaces. Our results indicate that hephaestin is expressed in a supra-nuclear compartment in non-polarized cells regardless of the iron status of the cells and in iron deficient and polarized cells. In polarized cells, we found that both apical (as FeSO{sub 4}) and basolateral iron (as the ratio of apo-transferrin to holo-transferrin) affect mobilization of hephaestin from the supra-nuclear compartment. We find that the presence of apical iron is essential for relocalization of hephaestin to a

  3. The H-loop in the second nucleotide-binding domain of the cystic fibrosis transmembrane conductance regulator is required for efficient chloride channel closing.

    Science.gov (United States)

    Kloch, Monika; Milewski, Michał; Nurowska, Ewa; Dworakowska, Beata; Cutting, Garry R; Dołowy, Krzysztof

    2010-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a cAMP-activated chloride channel. The recent model of CFTR gating predicts that the ATP binding to both nucleotide-binding domains (NBD1 and NBD2) of CFTR is required for the opening of the channel, while the ATP hydrolysis at NBD2 induces subsequent channel closing. In most ABC proteins, efficient hydrolysis of ATP requires the presence of the invariant histidine residue within the H-loop located in the C-terminal part of the NBD. However, the contribution of the corresponding region (H-loop) of NBD2 to the CFTR channel gating has not been examined so far. Here we report that the alanine substitution of the conserved dipeptide HR motif (HR-->AA) in the H-loop of NBD2 leads to prolonged open states of CFTR channel, indicating that the H-loop is required for efficient channel closing. On the other hand, the HR-->AA substitution lead to the substantial decrease of CFTR-mediated current density (pA/pF) in transfected HEK 293 cells, as recorded in the whole-cell patch-clamp analysis. These results suggest that the H-loop of NBD2, apart from being required for CFTR channel closing, may be involved in regulating CFTR trafficking to the cell surface.

  4. CFTR and calcium-activated chloride channels in primary cultures of human airway gland cells of serous or mucous phenotype.

    Science.gov (United States)

    Fischer, Horst; Illek, Beate; Sachs, Lorne; Finkbeiner, Walter E; Widdicombe, Jonathan H

    2010-10-01

    Using cell culture models, we have investigated the relative importance of cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated chloride channels (CaCC) in Cl secretion by mucous and serous cells of human airway glands. In transepithelial recordings in Ussing chambers, the CFTR inhibitor CFTR(inh)-172 abolished 60% of baseline Cl secretion in serous cells and 70% in mucous. Flufenamic acid (FFA), an inhibitor of CaCC, reduced baseline Cl secretion by ∼20% in both cell types. Methacholine and ATP stimulated Cl secretion in both cell types, which was largely blocked by treatment with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) and partially by mucosal FFA or CFTR(inh)-172 with the exception of methacholine responses in mucous cells, which were not blocked by FFA and partially (∼60%) by CFTR(inh)-172. The effects of ionomycin on short-circuit current (I(sc)) were less than those of ATP or methacholine. Forskolin stimulated Cl secretion only if Cl in the mucosal medium was replaced by gluconate. In whole cell patch-clamp studies of single isolated cells, cAMP-induced Cl currents were ∼3-fold greater in serous than mucous cells. Ionomycin-induced Cl currents were 13 times (serous) or 26 times (mucous) greater than those generated by cAMP and were blocked by FFA. In serous cells, mRNA for transmembrane protein 16A (TMEM16A) was ∼10 times more abundant than mRNA for CFTR. In mucous cells it was ∼100 times more abundant. We conclude: 1) serous and mucous cells both make significant contributions to gland fluid secretion; 2) baseline Cl secretion in both cell types is mediated predominantly by CFTR, but CaCC becomes increasingly important after mediator-induced elevations of intracellular Ca; and 3) the high CaCC currents seen in patch-clamp studies and the high TMEM16A expression in intact polarized cells sheets are not reflected in transepithelial current recordings.

  5. Murine calcium-activated chloride channel family member 3 induces asthmatic airway inflammation independently of allergen exposure

    Institute of Scientific and Technical Information of China (English)

    MEI Li; HE Li; WU Si-si; ZHANG Bo; XU Yong-jian; ZHANG Zhen-xiang; ZHAO Jian-ping

    2013-01-01

    Background Expression of murine calcium-activated chloride channel family member 3 (mCLCA3) has been reported to be increased in the airway epithelium of asthmatic mice challenged with ovalbumin (OVA).However,its role in asthmatic airway inflammation under no OVA exposure has not yet been clarified.Methods mCLCA3 plasmids were transfected into the airways of normal BALB/c mice.mCLCA3 expression and airway inflammation in mouse lung tissue were evaluated.Cell differentials and cytokines in bronchoalveolar lavage fluid (BALF) were analyzed.The expression of mCLCA3 protein and mucus protein mucin-5 subtype AC (MUC5AC) were analyzed by Western blotting.The mRNA levels of mCLCA3,MUC5AC and interleukin-13 (IL-13) were determined quantitatively.Results mCLCA3 expression was not detected in the control group while strong immunoreactivity was detected in the OVA and mCLCA3 plasmid groups,and was strictly localized to the airway epithelium.The numbers of inflammatory cells in lung tissue and BALF were increased in both mCLCA3 plasmid and OVA groups.The protein and mRNA levels of mCLCA3 and MUC5AC in the lung tissue were significantly increased in the mCLCA3 plasmid and OVA groups compared to the control group.The level of IL-13,but not IL-4,IL-5,IFN-γ,CCL2,CCL5 or CCL11,was significantly increased compared with control group in BALF in the mCLCA3 plasmid and OVA groups.The level of IL-13 in the BALF in the mCLCA3 plasmid group was much higher than that in the OVA group (P <0.05).The level of mCLCA3 mRNA in lung tissue was positively correlated with the levels of MUC5AC mRNA in lung tissue,IL-13 mRNA in lung tissue,the number of eosinophils in BALF,and the content of IL-13 protein in BALF.The level of IL-13 mRNA in lung tissue was positively correlated with the number of eosinophils in BALF and the level of MUC5AC mRNA in lung tissue.Conclusion These findings suggest that increased expression of a single-gene,mCLCA3,could simulate an asthma attack,and its mechanism may

  6. Effect of antiallergic herbal agents on chloride channel-3 and immune microenvironment in nasal mucosal epithelia of allergic rhinitis rabbits

    Institute of Scientific and Technical Information of China (English)

    WANG Li-feng; XU Li-juan; GUO Feng-hua; WANG Li-na; SHEN Xiao-hong

    2010-01-01

    Background Allergic rhinitis (AR) is a Th2 dominant cytokine response. Chloride channel-3 (CIC-3) plays an important role in nasal mucosal edema and inflammatory pathologic changes in AR. Antiallergic herbal agents (AHA) are antiallergic herbal products. In the previous study, we have demonstrated that AHA clearly inhibited allergic medium and relieved allergic reaction of AR. The aim of this study was to evaluate the function of CIC-3 and discuss the possible therapeutic effects of AHA on immune microenvironment in AR.Methods AHA were produced and used to treat AR. An animal model of an AR rabbit was established by ovalbumin (OVA). The rhinitis rabbits were randomly divided into three groups: AHA treated group (AHATG), model group (MG) and healthy control group (HCG). The expressions of CIC-3 protein were examined by immunohistochemical method. The mucosal epithelial cells of all the rabbit groups were primarily cultured with tissue culture method in vitro with or without rhlL-4 or rhlL-2. Furthermore, the expressions of CIC-3 mRNA were detected by real-time PCR. The levels of monocyte chemotactic factor-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) protein in culture supernatants were measured by ELISA.Results The expressions of CIC-3 mRNA increased more in mucosal epithelial cells of MG than those in AHATG and HCG (P0.05).Conclusions AHA can inhibit the secretions of CIC-3, MCP-1 and VCAM-1 in mucosal epithelia and improve inflammatory reaction of AR. CIC-3 plays an important role in the secretion of cytokines and mucosal inflammatory response in AR. RhlL-4 can enhance the secretion of CIC-3, MCP-1 and VCAM-1 in mucosal epithelial cells, especially during the AR process. These enhanced effects of rhlL-4 were significantly suppressed by AHA. The secretions of CIC-3, MCP-1 and VCAM-1 can not be induced obviously by rhlL-2 in mucosal epithelial cells in AR.

  7. The Cullin 4A/B-DDB1-Cereblon E3 Ubiquitin Ligase Complex Mediates the Degradation of CLC-1 Chloride Channels.

    Science.gov (United States)

    Chen, Yi-An; Peng, Yi-Jheng; Hu, Meng-Chun; Huang, Jing-Jia; Chien, Yun-Chia; Wu, June-Tai; Chen, Tsung-Yu; Tang, Chih-Yung

    2015-05-29

    Voltage-gated CLC-1 chloride channels play a critical role in controlling the membrane excitability of skeletal muscles. Mutations in human CLC-1 channels have been linked to the hereditary muscle disorder myotonia congenita. We have previously demonstrated that disease-associated CLC-1 A531V mutant protein may fail to pass the endoplasmic reticulum quality control system and display enhanced protein degradation as well as defective membrane trafficking. Currently the molecular basis of protein degradation for CLC-1 channels is virtually unknown. Here we aim to identify the E3 ubiquitin ligase of CLC-1 channels. The protein abundance of CLC-1 was notably enhanced in the presence of MLN4924, a specific inhibitor of cullin-RING E3 ligases. Subsequent investigation with dominant-negative constructs against specific subtypes of cullin-RING E3 ligases suggested that CLC-1 seemed to serve as the substrate for cullin 4A (CUL4A) and 4B (CUL4B). Biochemical examinations further indicated that CUL4A/B, damage-specific DNA binding protein 1 (DDB1), and cereblon (CRBN) appeared to co-exist in the same protein complex with CLC-1. Moreover, suppression of CUL4A/B E3 ligase activity significantly enhanced the functional expression of the A531V mutant. Our data are consistent with the idea that the CUL4A/B-DDB1-CRBN complex catalyses the polyubiquitination and thus controls the degradation of CLC-1 channels.

  8. 公丁香提取物抑制CFTR氯离子通道的发现与研究%The extract of clove inhibits CFTR chloride channel

    Institute of Scientific and Technical Information of China (English)

    栾剑; 张耀方; 杨红

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is an epithelial chloride chan‐nel .In recent years ,the blockers of CFTR become the new hot spot in the treatment of secretory di‐arrhea .The aim of this research is using high‐throughput screening techniques screened blockers of CFTR chloride channel from traditional Chinese medicine .In this study ,after 40000 fractions of Chi‐nese herbal medicine have been screened ,clove extract was found .In cell‐based fluorescence assays and voltage clamp experiments ,the best active fraction‐E06 significantly blocks CFTR chloride chan‐nel .Therefore ,clove extract screened from traditional Chinese medicine blocks CFTR chloride chan‐nel and provides a theoretical basis for the in‐depth study of anti‐diarrheal drugs .%囊性纤维化跨膜电导调节因子(CFTR)是一种上皮细胞顶膜中表达的氯离子通道,是近年来治疗分泌型腹泻的新热点。利用高通量筛选技术,自中国传统中药中筛选能够抑制CFTR氯离子通道的中药组分。结果显示,自500种中草药的40000种中药组分中筛选到公丁香。经细胞荧光实验和电压膜片钳实验验证公丁香最佳活性孔———E06对CFTR具有明显的抑制作用,IC50=103 mg/L 。本研究结果为深入探讨公丁香的抗泻药物研发提供理论依据。

  9. Rattlesnake Phospholipase A2 Increases CFTR-Chloride Channel Current and Corrects ∆F508CFTR Dysfunction: Impact in Cystic Fibrosis.

    Science.gov (United States)

    Faure, Grazyna; Bakouh, Naziha; Lourdel, Stéphane; Odolczyk, Norbert; Premchandar, Aiswarya; Servel, Nathalie; Hatton, Aurélie; Ostrowski, Maciej K; Xu, Haijin; Saul, Frederick A; Moquereau, Christelle; Bitam, Sara; Pranke, Iwona; Planelles, Gabrielle; Teulon, Jacques; Herrmann, Harald; Roldan, Ariel; Zielenkiewicz, Piotr; Dadlez, Michal; Lukacs, Gergely L; Sermet-Gaudelus, Isabelle; Ollero, Mario; Corringer, Pierre-Jean; Edelman, Aleksander

    2016-07-17

    Deletion of Phe508 in the nucleotide binding domain (∆F508-NBD1) of the cystic fibrosis transmembrane regulator (CFTR; a cyclic AMP-regulated chloride channel) is the most frequent mutation associated with cystic fibrosis. This mutation affects the maturation and gating of CFTR protein. The search for new high-affinity ligands of CFTR acting as dual modulators (correctors/activators) presents a major challenge in the pharmacology of cystic fibrosis. Snake venoms are a rich source of natural multifunctional proteins, potential binders of ion channels. In this study, we identified the CB subunit of crotoxin from Crotalus durissus terrificus as a new ligand and allosteric modulator of CFTR. We showed that CB interacts with NBD1 of both wild type and ∆F508CFTR and increases their chloride channel currents. The potentiating effect of CB on CFTR activity was demonstrated using electrophysiological techniques in Xenopus laevis oocytes, in CFTR-HeLa cells, and ex vivo in mouse colon tissue. The correcting effect of CB was shown by functional rescue of CFTR activity after 24-h ΔF508CFTR treatments with CB. Moreover, the presence of fully glycosylated CFTR was observed. Molecular docking allowed us to propose a model of the complex involving of the ABCβ and F1-like ATP-binding subdomains of ΔF508-NBD1. Hydrogen-deuterium exchange analysis confirmed stabilization in these regions, also showing allosteric stabilization in two other distal regions. Surface plasmon resonance competition studies showed that CB disrupts the ∆F508CFTR-cytokeratin 8 complex, allowing for the escape of ∆F508CFTR from degradation. Therefore CB, as a dual modulator of ΔF508CFTR, constitutes a template for the development of new anti-CF agents.

  10. Metal bridges illuminate transmembrane domain movements during gating of the cystic fibrosis transmembrane conductance regulator chloride channel.

    Science.gov (United States)

    El Hiani, Yassine; Linsdell, Paul

    2014-10-10

    Opening and closing of the cystic fibrosis transmembrane conductance regulator are controlled by ATP binding and hydrolysis by the cytoplasmic nucleotide-binding domains. Different conformational changes in the channel pore have been described during channel opening and closing; however, the relative importance of these changes to the process of gating the pore is not known. We have used patch clamp recording to identify high affinity Cd(2+) bridges formed between pairs of pore-lining cysteine residues introduced into different transmembrane α-helices (TMs). Seven Cd(2+) bridges were identified forming between cysteines in TMs 6 and 12. Interestingly, each of these Cd(2+) bridges apparently formed only in closed channels, and their formation stabilized the closed state. In contrast, a single Cd(2+) bridge identified between cysteines in TMs 1 and 12 stabilized the channel open state. Analysis of the pattern of Cd(2+) bridge formation in different channel states suggests that lateral separation and convergence of different TMs, rather than relative rotation or translation of different TMs, is the key conformational change that causes the channel pore to open and close.

  11. Nanomolar-Potency Aminophenyl-1,3,5-triazine Activators of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Chloride Channel for Prosecretory Therapy of Dry Eye Diseases.

    Science.gov (United States)

    Lee, Sujin; Phuan, Puay-Wah; Felix, Christian M; Tan, Joseph-Anthony; Levin, Marc H; Verkman, Alan S

    2017-02-09

    Dry eye disorders are a significant health problem for which limited therapeutic options are available. CFTR is a major prosecretory chloride channel at the ocular surface. We previously identified, by high-throughput screening, aminophenyl-1,3,5-triazine CFTRact-K089 (1) that activated CFTR with EC50 ≈ 250 nM, which when delivered topically increased tear fluid secretion in mice and showed efficacy in an experimental dry eye model. Here, functional analysis of aminophenyl-1,3,5-triazine analogs elucidated structure-activity relationships for CFTR activation and identified substantially more potent analogs than 1. The most potent compound, 12, fully activated CFTR chloride conductance with EC50 ≈ 30 nM, without causing cAMP or calcium elevation. 12 was rapidly metabolized by hepatic microsomes, which supports its topical use. Single topical administration of 25 pmol of 12 increased tear volume in wild-type mice with sustained action for 8 h and was without effect in CFTR-deficient mice. Topically delivered 12 may be efficacious in human dry eye diseases.

  12. Altered expression of renal bumetanide-sensitive sodium-pota-ssium-2 chloride cotransporter and Cl- channel -K2 gene in angiotensin Ⅱ-infused hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    YE Tao; LIU Zhi-quan; SUN Chao-feng; ZHENG Yong; MA Ai-qun; FANG Yuan

    2005-01-01

    Background Little information is available regarding the effect of angiotensin Ⅱ (Ang Ⅱ) on the bumetanide-sensitive sodium-potassium-2 chloride cotransporter (NKCC2), the thiazide-sensitive sodium-chloride cotransporter (NCC), and the Cl- channel (CLC)-K2 at both mRNA and protein expression level in Ang Ⅱ-induced hypertensive rats. This study was conducted to investigate the influence of Ang Ⅱ with chronic subpressor infusion on nephron-specific gene expression of NKCC2, NCC and CLC-K2. Results Ang Ⅱ significantly increased blood pressure and up-regulated NKCC2 mRNA and protein expression in the kidney. Expression of CLC-K2 mRNA in the kidney increased 1.6 fold (P<0.05).There were no changes in NCC mRNA or protein expression in AngII-treated rats versus control. Conclusions Chronic subpressor Ang Ⅱ infusion can significantly alter NKCC2 and CLC-K2 mRNA expression in the kidney, and protein abundance of NKCC2 in kidney is positively regulated by Ang Ⅱ. These effects may contribute to enhanced renal Na+ and Cl- reabsorption in response to Ang Ⅱ.

  13. Sodium chloride salinity reduces Cd uptake by edible amaranth (Amaranthus mangostanus L.) via competition for Ca channels.

    Science.gov (United States)

    Mei, XiuQin; Li, SongSong; Li, QuSheng; Yang, YuFeng; Luo, Xuan; He, BaoYan; Li, Hui; Xu, ZhiMin

    2014-07-01

    Soil salinity is known to enhance cadmium (Cd) accumulation in crops. However, the mechanism by which this occurs independent of the surrounding soil remains unclear. In this study, root adsorption and uptake of salt cations and Cd by edible amaranth under NaCl salinity stress were investigated in hydroponic cultures with 0, 40, 80, 120, and 160mM of NaCl and 27nM Cd. The dominant Cd species in the nutrient solution changed from free Cd(2+) to Cd chlorocomplexes as NaCl salinity increased. High salinity significantly reduced K, Ca, and Cd root adsorption and K, Ca, Mg, and Cd uptake. High salinity decreased root adsorption of Cd by 43 and 58 percent and Cd uptake by 32 and 36 percent in salt-tolerant and salt-sensitive cultivars, respectively. Transformation of Cd from free ion to chlorocomplexes is unlikely to have significantly affected Cd uptake by the plant because of the very low Cd concentrations involved. Application of Ca ion channel blocker significantly reduced Na, K, Ca, Mg, and Cd uptake by the roots, while blocking K ion channels significantly reduced Na and K uptake but not Ca, Mg, and Cd uptake. These results suggest that Na was absorbed by the roots through both Ca and K ion channels, while Cd was absorbed by the roots mainly through Ca ion channels and not K ion channels. Salinity caused a greater degree of reduction in Cd adsorption and uptake in the salt-sensitive cultivar than in the salt-tolerant cultivar. Thus, competition between Na and Cd for Ca ion channels can reduce Cd uptake at very low Cd concentrations in the nutrient solution.

  14. Effects of glycoprotein Ⅱb/Ⅲa antagonists and chloride channel blockers on platelet cytoplasmic free calcium

    Institute of Scientific and Technical Information of China (English)

    YIN Song-mei; XIE Shuang-feng; NIE Da-nian; LI Yi-qing; LI Hai-ming; MA Li-ping; WANG Xiu-ju; WU Yu-dan; FENG Jian-hong

    2005-01-01

    @@ Platelet activation plays an important role in thrombosis. Platelet glycoprotein Ⅱb/Ⅲa (GP Ⅱb/Ⅲa) is the receptor of fibrinogen. Platelet cross-linking with fibrinogen through GPⅡb/Ⅲa is the process of thrombosis. Ca2+ is an important intracellular second messenger in platelet activation. It has been reported that GPⅡb/Ⅲa receptors were involved in the calcium influx of activated platelet, and GPⅡb/Ⅲa receptor had characteristics of calcium channel or an adjacent calcium channel.

  15. Functional differences in pore properties between wild-type and cysteine-less forms of the CFTR chloride channel.

    Science.gov (United States)

    Holstead, Ryan G; Li, Man-Song; Linsdell, Paul

    2011-10-01

    Studies of the structure and function of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel have been advanced by the development of functional channel variants in which all 18 endogenous cysteine residues have been mutated ("cys-less" CFTR). However, cys-less CFTR has a slightly higher single-channel conductance than wild-type CFTR, raising questions as to the suitability of cys-less as a model of the wild-type CFTR pore. We used site-directed mutagenesis and patch-clamp recording to investigate the origin of this conductance difference and to determine the extent of functional differences between wild-type and cys-less CFTR channel permeation properties. Our results suggest that the conductance difference is the result of a single substitution, of C343: the point mutant C343S has a conductance similar to cys-less, whereas the reverse mutation, S343C in a cys-less background, restores wild-type conductance levels. Other cysteine substitutions (C128S, C225S, C376S, C866S) were without effect. Substitution of other residues for C343 suggested that conductance is dependent on amino acid side chain volume at this position. A range of other functional pore properties, including interactions with channel blockers (Au[CN] (2) (-) , 5-nitro-2-[3-phenylpropylamino]benzoic acid, suramin) and anion permeability, were not significantly different between wild-type and cys-less CFTR. Our results suggest that functional differences between these two CFTR constructs are of limited scale and scope and result from a small change in side chain volume at position 343. These results therefore support the use of cys-less as a model of the CFTR pore region.

  16. The tyrosine kinase p60c-src regulates the fast gate of the cystic fibrosis transmembrane conductance regulator chloride channel.

    Science.gov (United States)

    Fischer, H; Machen, T E

    1996-12-01

    The role of the tyrosine kinase p60c-src on the gating of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel was investigated with the cell-attached and excised patch clamp technique in conjunction with current noise analysis of recordings containing multiple channels per patch. Spectra of CFTR-generated current noise contained a low-frequency and a high-frequency Lorentzian noise component. In the cell-attached mode, the high-frequency Lorentzian was significantly dependent on the membrane potential, while the low-frequency Lorentzian was unaffected. Excision of forskolin-stimulated patches into ATP-containing solution significantly reduced the amplitude of the voltage-dependent high-frequency Lorentzian. Addition of the tyrosine kinase p60c-src to excised, active, CFTR-containing membrane patches increased mean currents by 54%, increased the corner frequency of the low-frequency Lorentzian, and recovered the high-frequency Lorentzian and its characteristics. Treatment with lambda-phosphatase inactivated src-induced currents and changes in gating. When active patches were excised under conditions in which patch-associated tyrosine phosphatases were blocked with sodium vanadate, the high-frequency gating remained relatively unchanged. The results suggest that CFTR's open probability and its voltage-dependent fast gate are dependent on tyrosine phosphorylation, and that membrane-associated tyrosine phosphatases are responsible for inactivation of the fast gate after patch excision.

  17. Cloning and characterization of CLCN5, the human kidney chloride channel gene implicated in Dent disease (an X-linked hereditary nephrolithiasis)

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, S.E.; Van Bakel, I.; Craig, I.W. [Univ. of Oxford (United Kingdom)] [and others

    1995-10-10

    Dent disease, an X-linked familial renal tubular disorder, is a form of Fanconi syndrome associated with proteinuria, hypercalciuria, nephrocalcinosis, kidney stones, and eventual renal failure. We have previously used positional cloning to identify the 3{prime} part of a novel kidney-specific gene (initially termed hClC-K2, but now referred to as CLCN5), which is deleted in patients from one pedigree segregating Dent disease. Mutations that disrupt this gene have been identified in other patients with this disorder. Here we describe the isolation and characterization of the complete open reading frame of the human CLCN5 gene, which is predicted to encode a protein of 746 amino acids, with significant homology to all known members of the ClC family of voltage-gated chloride channels. CLCN5 belongs to a distinct branch of this family, which also includes the recently identified genes CLCN3 and CLCN4. We have shown that the coding region of CLCN5 is organized into 12 exons, spanning 25-30 kb of genomic DNA, and have determined the sequence of each exon-intron boundary. The elucidation of the coding sequence and exon-intron organization of CLCN5 will both expedite the evaluation of structure/function relationships of these ion channels and facilitate the screening of other patients with renal tubular dysfunction for mutations at this locus. 31 refs., 5 figs.

  18. Identification and functional expression of a glutamate- and avermectin-gated chloride channel from Caligus rogercresseyi, a southern Hemisphere sea louse affecting farmed fish.

    Directory of Open Access Journals (Sweden)

    Isabel Cornejo

    2014-09-01

    Full Text Available Parasitic sea lice represent a major sanitary threat to marine salmonid aquaculture, an industry accounting for 7% of world fish production. Caligus rogercresseyi is the principal sea louse species infesting farmed salmon and trout in the southern hemisphere. Most effective control of Caligus has been obtained with macrocyclic lactones (MLs ivermectin and emamectin. These drugs target glutamate-gated chloride channels (GluCl and act as irreversible non-competitive agonists causing neuronal inhibition, paralysis and death of the parasite. Here we report the cloning of a full-length CrGluClα receptor from Caligus rogercresseyi. Expression in Xenopus oocytes and electrophysiological assays show that CrGluClα is activated by glutamate and mediates chloride currents blocked by the ligand-gated anion channel inhibitor picrotoxin. Both ivermectin and emamectin activate CrGluClα in the absence of glutamate. The effects are irreversible and occur with an EC(50 value of around 200 nM, being cooperative (n(H = 2 for ivermectin but not for emamectin. Using the three-dimensional structure of a GluClα from Caenorabditis elegans, the only available for any eukaryotic ligand-gated anion channel, we have constructed a homology model for CrGluClα. Docking and molecular dynamics calculations reveal the way in which ivermectin and emamectin interact with CrGluClα. Both drugs intercalate between transmembrane domains M1 and M3 of neighbouring subunits of a pentameric structure. The structure displays three H-bonds involved in this interaction, but despite similarity in structure only of two these are conserved from the C. elegans crystal binding site. Our data strongly suggest that CrGluClα is an important target for avermectins used in the treatment of sea louse infestation in farmed salmonids and open the way for ascertaining a possible mechanism of increasing resistance to MLs in aquaculture industry. Molecular modeling could help in the design of new

  19. Extracts from plants used in Mexican traditional medicine activate Ca(2+)-dependent chloride channels in Xenopus laevis oocytes.

    Science.gov (United States)

    Rojas, A; Mendoza, S; Moreno, J; Arellano, R O

    2003-01-01

    The two-electrode voltage-clamp technique was employed to investigate the effects of chloroform-methanol (1:1) extracts derived from five medicinal plants on Xenopus laevis oocytes. When evaluated at concentrations of 1 to 500 microg/ml, the extracts prepared from the aerial parts of Baccharis heterophylla H.B.K (Asteraceae), Chenopodium murale L. (Chenopodiaceae), Desmodium grahami Gray (Leguminosae) and Solanum rostratum Dun (Solanaceae) produced concentration-dependent oscillatory inward currents in the oocytes, while the extract of Gentiana spathacea did not induce any response. The reversal potential of the currents elicited by the active extracts was -17 +/- 2 mV and was similar to the chloride equilibrium potential in oocytes. These ionic responses were independent of extracellular calcium. However, they were eliminated by overnight incubation with BAPTA-AM (10 microM), suggesting that the currents were dependent on intracellular Ca2+ increase. Thus the plant extracts activate the typical oscillatory Ca(2+)-dependent Cl- currents generated in the Xenopus oocyte membrane more probably via a mechanism that involves release of Ca2+ from intracellular reservoirs. These observations suggest that Xenopus oocyte electrophysiological recording constitutes a suitable assay for the study of the mechanisms of action of herbal medicines.

  20. Deregulation of apoptotic volume decrease and ionic movements in multidrug-resistant tumor cells: role of chloride channels

    DEFF Research Database (Denmark)

    Poulsen, Kristian Arild; Andersen, E C; Hansen, C F;

    2010-01-01

    Changes in cell volume and ion gradients across the plasma membrane play a pivotal role in the initiation of apoptosis. Here we explore the kinetics of apoptotic volume decrease (AVD) and ion content dynamics in wild-type (WT) and multidrug-resistant (MDR) Ehrlich ascites tumor cells (EATC). In WT......3728 inhibited AVD and completely abolished the differences in AVD, ionic movements, and caspase 3 activation between WT and MDR EATC. Finally, the maximal capacity of volume-regulated anion channel was found to be strongly repressed in MDR EATC. Together, these data suggest that impairment of AVD...

  1. Interactions between permeation and gating in the TMEM16B/anoctamin2 calcium-activated chloride channel

    OpenAIRE

    Betto, Giulia; Cherian, O. Lijo; Pifferi, Simone; Cenedese, Valentina; Boccaccio, Anna; Menini, Anna

    2014-01-01

    At least two members of the TMEM16/anoctamin family, TMEM16A (also known as anoctamin1) and TMEM16B (also known as anoctamin2), encode Ca2+-activated Cl− channels (CaCCs), which are found in various cell types and mediate numerous physiological functions. Here, we used whole-cell and excised inside-out patch-clamp to investigate the relationship between anion permeation and gating, two processes typically viewed as independent, in TMEM16B expressed in HEK 293T cells. The permeability ratio se...

  2. Dehydrocostuslactone, a sesquiterpene lactone activates wild-type and ΔF508 mutant CFTR chloride channel.

    Science.gov (United States)

    Wang, Xue; Zhang, Yao-Fang; Yu, Bo; Yang, Shuang; Luan, Jian; Liu, Xin; Yang, Hong

    2013-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) represents the main cAMP-activated Cl⁻ channel expressed in the apical membrane of serous epithelial cells. Both deficiency and overactivation of CFTR may cause fluid and salt secretion related diseases. The aim of this study was to identify natural compounds that are able to stimulate wild-type (wt) and ΔF508 mutant CFTR channel activities in CFTR-expressing Fischer rat thyroid (FRT) cells. We found that dehydrocostuslactone [DHC, (3aS, 6aR, 9aR, 9bS)-decahydro-3,6,9-tris (methylene) azuleno [4,5-b] furan-2(3H)-one)] dose dependently potentiates both wt and ΔF508 mutant CFTR-mediated iodide influx in cell-based fluorescent assays and CFTR-mediated Cl⁻ currents in short-circuit current studies, and the activations could be reversed by the CFTR inhibitor CFTRinh-172. Maximal CFTR-mediated apical Cl⁻ current secretion in CFTR-expressing FRT cells was stimulated by 100 μM DHC. Determination of intracellular cAMP content showed that DHC modestly but significantly increased cAMP level in FRT cells, but cAMP elevation effects contributed little to DHC-stimulated iodide influx. DHC also stimulated CFTR-mediated apical Cl⁻ current secretion in FRT cells expressing ΔF508-CFTR. Subsequent studies demonstrated that activation of CFTR by DHC is forskolin dependent. DHC represents a new class of CFTR potentiators that may have therapeutic potential in CFTR-related diseases.

  3. Protective role of acidic pH-activated chloride channel in severe acidosis-induced contraction from the aorta of spontaneously hypertensive rats.

    Directory of Open Access Journals (Sweden)

    Zhiyong Ma

    Full Text Available Severe acidic pH-activated chloride channel (ICl,acid has been found in various mammalian cells. In the present study, we investigate whether this channel participates in reactions of the thoracic aorta to severe acidosis and whether it plays a role in hypertension. We measured isometric contraction in thoracic aorta rings from spontaneously hypertensive rats (SHRs and normotensive Wistar rats. Severe acidosis induced contractions of both endothelium-intact and -denuded thoracic aorta rings. In Wistar rats, contractions did not differ at pH 6.4, 5.4 and 4.4. However, in SHRs, contractions were higher at pH 5.4 or 4.4 than pH 6.4, with no difference between contractions at pH 5.4 and 4.4. Nifedipine, ICl,acid blockers 5-nitro-2-(3-phenylpropylamino benzoic acid (NPPB and 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS inhibited severe acidosis-induced contraction of aortas at different pH levels. When blocking ICl,acid, the remnant contraction was greater at pH 4.4 than pH 5.4 and 6.4 for both SHRs and Wistar rats. With nifedipine, the remnant contraction was greatly reduced at pH 4.4 as compared with at pH 6.4 and 5.4. With NPPB or DIDS, the ratio of remnant contractions at pH 4.4 and 5.4 (R4.4/5.4 was lower for SHRs than Wistar rats (all 1. Furthermore, patch clamp recordings of ICl,acid and intracellular Ca(2+ measurements in smooth muscle cells confirmed these findings. ICl,acid may protect arteries against excess vasoconstriction under extremely acidic extracellular conditions. This protective effect may be decreased in hypertension.

  4. TMEM16A:钙激活氯通道研究进展%TMEM16A:progress in calcium activated chloride channels

    Institute of Scientific and Technical Information of China (English)

    刘雅妮; 张海林

    2011-01-01

    钙激活氯通道(calcium-activated chloride channels,CaCCs)组织分布广泛,参与了众多生理过程,如感觉传导、神经和心肌兴奋性调节、腺体和上皮分泌等,甚至可能参与细胞分裂周期与细胞增殖.钙激活氯通道生理病理意义如此重要,但直到2008年才报道了跨膜蛋白16A(transmembrane protein 16A,TMEM16A)为钙激活氯通道的分子基础,同时研究揭示TMEM16A在一些肿瘤组织中表达明显上调.该文即对钙激活氯通道的生理、病理学意义进行综述.%The Ca + activated Cl channels ( CaCCs ) play a variety of physiological roles in many organs and tissues, including transduction of sensory stimuli, regulation of neuronal and cardiac excitability, and transepithelial Cl secretion. In addition, CaCCs may be involved in the cell division cycle and cell proliferation. The molecular identity of CaCCs remained controversial until 2008 when TMEM16A, a member of the transmembraneprotein 16 family, was identified as an important subunit of CaCCs. In this review, the physiological and pathophysiological roles of CaCCs are discussed.

  5. Regulatory R region of the CFTR chloride channel is a dynamic integrator of phospho-dependent intra- and intermolecular interactions.

    Science.gov (United States)

    Bozoky, Zoltan; Krzeminski, Mickael; Muhandiram, Ranjith; Birtley, James R; Al-Zahrani, Ateeq; Thomas, Philip J; Frizzell, Raymond A; Ford, Robert C; Forman-Kay, Julie D

    2013-11-19

    Intrinsically disordered proteins play crucial roles in regulatory processes and often function as protein interaction hubs. Here, we present a detailed characterization of a full-length disordered hub protein region involved in multiple dynamic complexes. We performed NMR, CD, and fluorescence binding studies on the nonphosphorylated and highly PKA-phosphorylated human cystic fibrosis transmembrane conductance regulator (CFTR) regulatory region, a ∼200-residue disordered segment involved in phosphorylation-dependent regulation of channel trafficking and gating. Our data provide evidence for dynamic, phosphorylation-dependent, multisite interactions of various segments of the regulatory region for its intra- and intermolecular partners, including the CFTR nucleotide binding domains 1 and 2, a 42-residue peptide from the C terminus of CFTR, the SLC26A3 sulphate transporter and antisigma factor antagonist (STAS) domain, and 14-3-3β. Because of its large number of binding partners, multivalent binding of individually weak sites facilitates rapid exchange between free and bound states to allow the regulatory region to engage with different partners and generate a graded or rheostat-like response to phosphorylation. Our results enrich the understanding of how disordered binding segments interact with multiple targets. We present structural models consistent with our data that illustrate this dynamic aspect of phospho-regulation of CFTR by the disordered regulatory region.

  6. Glutamate-gated chloride channel subunit cDNA sequencing of Cochliomyia hominivorax (Diptera: Calliphoridae): cDNA variants and polymorphisms.

    Science.gov (United States)

    Lopes, Alberto Moura Mendes; de Carvalho, Renato Assis; de Azeredo-Espin, Ana Maria Lima

    2014-09-01

    The New World screwworm (NWS) Cochliomyia hominivorax (Coquerel) is one of the major myiasis-causing flies that injures livestock and leads to losses of ~US$ 2.7 billions/year in the Neotropics. Ivermectin (IVM), a macrocyclic lactone (ML), is the most used preventive insecticide for this parasite and targets the glutamate-gated chloride (GLUCLα) channels. Several authors have associated altered GluClα homologues to MLs resistance in invertebrates, although studies about resistance in NWS are limited to other genes. Here, we aimed to characterise the NWS GluClα (ChGluClα) cDNA and to search for alterations associated with IVM resistance in NWS larvae from a bioassay. The open reading frame of the ChGluClα comprised 1,359 bp and encoded a sequence of 452 amino acids. The ChGluClα cDNAs of the bioassay larvae showed different sequences that could be splice variants, which agree with the occurrence of alternative splicing in GluClα homologues. In addition, we found cDNAs with premature stop codons and the K242R SNP, which occurred more frequently in the surviving larvae and was located close to mutation (L256F) involved in ML resistance. Although these alterations were in low frequency, the ChGluClα sequencing will allow further studies to find alterations in the gene of resistant natural populations.

  7. Mapping of long-range INS promoter interactions reveals a role for calcium-activated chloride channel ANO1 in insulin secretion.

    Science.gov (United States)

    Xu, Zhixiong; Lefevre, Gaelle M; Gavrilova, Oksana; Foster St Claire, Mark B; Riddick, Gregory; Felsenfeld, Gary

    2014-11-25

    We used circular chromatin conformation capture (4C) to identify a physical contact in human pancreatic islets between the region near the insulin (INS) promoter and the ANO1 gene, lying 68 Mb away on human chromosome 11, which encodes a Ca(2+)-dependent chloride ion channel. In response to glucose, this contact was strengthened and ANO1 expression increased, whereas inhibition of INS gene transcription by INS promoter targeting siRNA decreased ANO1 expression, revealing a regulatory effect of INS promoter on ANO1 expression. Knockdown of ANO1 expression caused decreased insulin secretion in human islets, establishing a physical proximity-dependent feedback loop involving INS transcription, ANO1 expression, and insulin secretion. To explore a possible role of ANO1 in insulin metabolism, we carried out experiments in Ano1(+/-) mice. We observed reduced serum insulin levels and insulin-to-glucose ratios in high-fat diet-fed Ano1(+/-) mice relative to Ano1(+/+) mice fed the same diet. Our results show that determination of long-range contacts within the nucleus can be used to detect novel and physiologically relevant mechanisms. They also show that networks of long-range physical contacts are important to the regulation of insulin metabolism.

  8. Interactions between permeation and gating in the TMEM16B/anoctamin2 calcium-activated chloride channel.

    Science.gov (United States)

    Betto, Giulia; Cherian, O Lijo; Pifferi, Simone; Cenedese, Valentina; Boccaccio, Anna; Menini, Anna

    2014-06-01

    At least two members of the TMEM16/anoctamin family, TMEM16A (also known as anoctamin1) and TMEM16B (also known as anoctamin2), encode Ca(2+)-activated Cl(-) channels (CaCCs), which are found in various cell types and mediate numerous physiological functions. Here, we used whole-cell and excised inside-out patch-clamp to investigate the relationship between anion permeation and gating, two processes typically viewed as independent, in TMEM16B expressed in HEK 293T cells. The permeability ratio sequence determined by substituting Cl(-) with other anions (PX/PCl) was SCN(-) > I(-) > NO3 (-) > Br(-) > Cl(-) > F(-) > gluconate. When external Cl(-) was substituted with other anions, TMEM16B activation and deactivation kinetics at 0.5 µM Ca(2+) were modified according to the sequence of permeability ratios, with anions more permeant than Cl(-) slowing both activation and deactivation and anions less permeant than Cl(-) accelerating them. Moreover, replacement of external Cl(-) with gluconate, or sucrose, shifted the voltage dependence of steady-state activation (G-V relation) to more positive potentials, whereas substitution of extracellular or intracellular Cl(-) with SCN(-) shifted G-V to more negative potentials. Dose-response relationships for Ca(2+) in the presence of different extracellular anions indicated that the apparent affinity for Ca(2+) at +100 mV increased with increasing permeability ratio. The apparent affinity for Ca(2+) in the presence of intracellular SCN(-) also increased compared with that in Cl(-). Our results provide the first evidence that TMEM16B gating is modulated by permeant anions and provide the basis for future studies aimed at identifying the molecular determinants of TMEM16B ion selectivity and gating.

  9. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, J.; Kuriyama, K. (Kyoto Prefectural Univ. of Medicine (Japan))

    1990-05-01

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited (3H)flunitrazepam binding to benzodiazepine receptor, but not (3H)muscimol binding to GABAA receptor as well as t-(3H)butylbicycloorthobenzoate (( 3H) TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively (3H) flunitrazepam binding. On the other hand, the binding of beta-(3H)CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated (3H)muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-(3H)CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for (3H)flunitrazepam, (3H)muscimol and (3H)TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested.

  10. Cystic fibrosis transmembrane regulator inhibitors CFTR(inh)-172 and GlyH-101 target mitochondrial functions, independently of chloride channel inhibition.

    Science.gov (United States)

    Kelly, Mairead; Trudel, Stephanie; Brouillard, Franck; Bouillaud, Frederick; Colas, Julien; Nguyen-Khoa, Thao; Ollero, Mario; Edelman, Aleksander; Fritsch, Janine

    2010-04-01

    Two highly potent and selective cystic fibrosis (CF) transmembrane regulator (CFTR) inhibitors have been identified by high-throughput screening: the thiazolidinone CFTR(inh)-172 [3-[(3-trifluoromethyl)phenyl]-5-[(4-carboxyphenyl)methylene]- 2-thioxo-4-thiazolidinone] and the glycine hydrazide GlyH-101 [N-(2-naphthalenyl)-((3,5-dibromo-2,4-dihydroxyphenyl)methylene)glycine hydrazide]. Inhibition of the CFTR chloride channel by these compounds has been suggested to be of pharmacological interest in the treatment of secretory diarrheas and polycystic kidney disease. In addition, functional inhibition of CFTR by CFTR(inh)-172 has been proposed to be sufficient to mimic the CF inflammatory profile. In the present study, we investigated the effects of the two compounds on reactive oxygen species (ROS) production and mitochondrial membrane potential in several cell lines: the CFTR-deficient human lung epithelial IB3-1 (expressing the heterozygous F508del/W1282X mutation), the isogenic CFTR-corrected C38, and HeLa and A549 as non-CFTR-expressing controls. Both inhibitors were able to induce a rapid increase in ROS levels and depolarize mitochondria in the four cell types, suggesting that these effects are independent of CFTR inhibition. In HeLa cells, these events were associated with a decrease in the rate of oxygen consumption, with GlyH-101 demonstrating a higher potency than CFTR(inh)-172. The impact of CFTR inhibitors on inflammatory parameters was also tested in HeLa cells. CFTR(inh)-172, but not GlyH-101, induced nuclear translocation of nuclear factor-kappaB (NF-kappaB). CFTR(inh)-172 slightly decreased interleukin-8 secretion, whereas GlyH-101 induced a slight increase. These results support the conclusion that CFTR inhibitors may exert nonspecific effects regarding ROS production, mitochondrial failure, and activation of the NF-kappaB signaling pathway, independently of CFTR inhibition.

  11. Loss of chloride channel ClC-5 impairs endocytosis by defective trafficking of megalin and cubilin in kidney proximal tubules.

    Science.gov (United States)

    Christensen, Erik I; Devuyst, Olivier; Dom, Geneviève; Nielsen, Rikke; Van der Smissen, Patrick; Verroust, Pierre; Leruth, Michèle; Guggino, William B; Courtoy, Pierre J

    2003-07-08

    Loss of the renal endosome-associated chloride channel, ClC-5, in Dent's disease and knockout (KO) mice strongly inhibits endocytosis of filtered proteins by kidney proximal tubular cells (PTC). The underlying mechanism remains unknown. We therefore tested whether this endocytic failure could primarily reflect a loss of reabsorption by the multiligand receptors, megalin, and cubilin, caused by a trafficking defect. Impaired protein endocytosis in PTC of ClC-5 KO mice was demonstrated by (i) a major decreased uptake of injected 125I-beta 2-microglobulin, but not of the fluid-phase tracer, FITC-dextran, (ii) reduced labeling of endosomes by injected peroxidase and for the endogenous megalin/cubilin ligands, vitamin D- and retinol-binding proteins, and (iii) urinary appearance of low-molecular-weight proteins and the selective cubilin ligand, transferrin. Contrasting with preserved mRNA levels, megalin and cubilin abundance was significantly decreased in kidney extracts of KO mice. Percoll gradients resolving early and late endosomes (Rab5a, Rab7), brush border (villin, aminopeptidase M), and a dense peak comprising lysosomes (acid hydrolases) showed a disappearance of the brush border component for megalin and cubilin in KO mice. Quantitative ultrastructural immunogold labeling confirmed the overall decrease of megalin and cubilin in PTC and their selective loss at the brush border. In contrast, total contents of the rate-limiting endocytic catalysts, Rab5a and Rab7, were unaffected. Thus, impaired protein endocytosis caused by invalidation of ClC-5 primarily reflects a trafficking defect of megalin and cubilin in PTC.

  12. The Role of the Basolateral Amygdala in Punishment

    Science.gov (United States)

    Dit-Bressel, Philip Jean-Richard; McNally, Gavan P.

    2015-01-01

    Aversive stimuli not only support fear conditioning to their environmental antecedents, they also punish behaviors that cause their occurrence. The amygdala, especially the basolateral nucleus (BLA), has been critically implicated in Pavlovian fear learning but its role in punishment remains poorly understood. Here, we used a within-subjects…

  13. Chloride channels in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1982-01-01

    A study of the voltage and time dependence of a transepithelial Cl- current in toad skin (Bufo bufo) by the voltage-clamp method leads to the conclusion that potential has a dual role for Cl- transport. One is to control the permeability of an apical membrane Cl-pathway, the other is to drive Cl...

  14. Layer by layer growth of silver chloride nanoparticle within the pore channels of SBA-15/SO3H mesoporous silica (AgClNP/SBA-15/SO3K): Synthesis, characterization and antibacterial properties

    Science.gov (United States)

    Rostamnia, Sadegh; Doustkhah, Esmail; Estakhri, Saba; Karimi, Ziba

    2016-02-01

    The growth of silver chloride nanoparticles within the pore channels of functionalized SBA-15 mesoporous was achieved by sequential dipping steps in alternating bath of potassium chloride and silver nitrate under ultrasound irradiation at pH=9. The effects of sequential dipping steps in growth of the AgCl nanoparticles have been studied. The growth and formation of AgCl nanoparticles inside the sulfonated SBA-15 were characterized by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Antibacterial activity of the synthesized materials was investigated against Escherichia coli (E.coli) using the conventional diffusion-disc method. The materials showed high antibacterial activity.

  15. Discrete-state representation of ion permeation coupled to fast gating in a model of CLC-chloride channels: analytic estimation of the state-to-state rate constants.

    Science.gov (United States)

    Coalson, Rob D; Cheng, Mary Hongying

    2011-09-01

    Analytical estimation of state-to-state rate constants is carried out for a recently developed discrete state model of chloride ion motion in a CLC chloride channel (Coalson and Cheng, J. Phys. Chem. B 2010, 114, 1424). In the original presentation of this model, the same rate constants were evaluated via three-dimensional Brownian dynamics simulations. The underlying dynamical theory is an appropriate single- or multiparticle three-dimensional Smoluchowski equation. Taking advantage of approximate geometric symmetries (based on the details of the model channel geometry), well-known formulas for state-to-state transition rates are appealed to herein and adapted as necessary to the problem at hand. Rates of ionic influx from a bulk electrolyte reservoir to the nearest binding site within the channel pore are particularly challenging to compute analytically because they reflect multi-ion interactions (as opposed to single-ion dynamics). A simple empirical correction factor is added to the single-ion rate constant formula in this case to account for the saturation of influx rate constants with increasing bulk Cl(-) concentration. Overall, the agreement between all analytically estimated rate constants is within a factor of 2 of those computed via three-dimensional Brownian dynamics simulations, and often better than this. Current-concentration curves obtained using rate constants derived from these two different computational approaches agree to within 25%.

  16. NMDA receptors in the basolateral amygdala and gustatory neophobia.

    Science.gov (United States)

    Figueroa-Guzmán, Yazmín; Reilly, Steve

    2008-05-19

    The attenuation of gustatory neophobia occurs during repeated exposures to an initially novel taste solution that is increasingly perceived as safe and familiar. The present study examined whether NMDA receptors in the basolateral region of the amygdala (BLA) are involved in this important behavioral phenomenon. The results, which show that the attenuation, but not initial occurrence, of gustatory neophobia is dependent upon NMDA receptors in the BLA, are discussed with reference to a similar finding involving NMDA receptors in the insular cortex.

  17. Mesencephalic basolateral domain specification is dependent on Sonic Hedgehog

    Directory of Open Access Journals (Sweden)

    Jesus E. Martinez-Lopez

    2015-02-01

    Full Text Available In the study of central nervous system morphogenesis, the identification of new molecular markers allows us to identify domains along the antero-posterior and dorso-ventral axes. In the past years, the alar and basal plates of the midbrain have been divided into different domains. The precise location of the alar-basal boundary is still under discussion. We have identified Barhl1, Nhlh1 and Six3 as appropriate molecular markers to the adjacent domains of this transition. The description of their expression patterns and the contribution to the different mesencephalic populations corroborated their role in the specification of these domains. We studied the influence of Sonic Hedgehog on these markers and therefore on the specification of these territories. The lack of this morphogen produced severe alterations in the expression pattern of Barhl1 and Nhlh1 with consequent misspecification of the basolateral domain. Six3 expression was apparently unaffected, however its distribution changed leading to altered basal domains. In this study we confirmed the localization of the alar-basal boundary dorsal to the basolateral domain and demonstrated that the development of the basolateral domain highly depends on Shh.

  18. Basolateral Cl- uptake mechanisms in Xenopus laevis lung epithelium.

    Science.gov (United States)

    Berger, Jens; Hardt, Martin; Clauss, Wolfgang G; Fronius, Martin

    2010-07-01

    A thin liquid layer covers the lungs of air-breathing vertebrates. Active ion transport processes via the pulmonary epithelial cells regulate the maintenance of this layer. This study focuses on basolateral Cl(-) uptake mechanisms in native lungs of Xenopus laevis and the involvement of the Na(+)/K(+)/2 Cl(-) cotransporter (NKCC) and HCO(3)(-)/Cl(-) anion exchanger (AE), in particular. Western blot analysis and immunofluorescence staining revealed the expression of the NKCC protein in the Xenopus lung. Ussing chamber experiments demonstrated that the NKCC inhibitors (bumetanide and furosemide) were ineffective at blocking the cotransporter under basal conditions, as well as under pharmacologically stimulated Cl(-)-secreting conditions (forskolin and chlorzoxazone application). However, functional evidence for the NKCC was detected by generating a transepithelial Cl(-) gradient. Further, we were interested in the involvement of the HCO(3)(-)/Cl(-) anion exchanger to transepithelial ion transport processes. Basolateral application of DIDS, an inhibitor of the AE, resulted in a significantly decreased the short-circuit current (I(SC)). The effect of DIDS was diminished by acetazolamide and reduced by increased external HCO(3)(-) concentrations. Cl(-) secretion induced by forskolin was decreased by DIDS, but this effect was abolished in the presence of HCO(3)(-). These experiments indicate that the AE at least partially contributes to Cl(-) secretion. Taken together, our data show that in Xenopus lung epithelia, the AE, rather than the NKCC, is involved in basolateral Cl(-) uptake, which contrasts with the common model for Cl(-) secretion in pulmonary epithelia.

  19. Salt, chloride, bleach, and innate host defense.

    Science.gov (United States)

    Wang, Guoshun; Nauseef, William M

    2015-08-01

    Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense.

  20. Anoctamins support calcium-dependent chloride secretion by facilitating calcium signaling in adult mouse intestine.

    Science.gov (United States)

    Schreiber, Rainer; Faria, Diana; Skryabin, Boris V; Wanitchakool, Podchanart; Rock, Jason R; Kunzelmann, Karl

    2015-06-01

    Intestinal epithelial electrolyte secretion is activated by increase in intracellular cAMP or Ca(2+) and opening of apical Cl(-) channels. In infants and young animals, but not in adults, Ca(2+)-activated chloride channels may cause secretory diarrhea during rotavirus infection. While detailed knowledge exists concerning the contribution of cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) channels, analysis of the role of Ca(2+)-dependent Cl(-) channels became possible through identification of the anoctamin (TMEM16) family of proteins. We demonstrate expression of several anoctamin paralogues in mouse small and large intestines. Using intestinal-specific mouse knockout models for anoctamin 1 (Ano1) and anoctamin 10 (Ano10) and a conventional knockout model for anoctamin 6 (Ano6), we demonstrate the role of anoctamins for Ca(2+)-dependent Cl(-) secretion induced by the muscarinic agonist carbachol (CCH). Ano1 is preferentially expressed in the ileum and large intestine, where it supports Ca(2+)-activated Cl(-) secretion. In contrast, Ano10 is essential for Ca(2+)-dependent Cl(-) secretion in jejunum, where expression of Ano1 was not detected. Although broadly expressed, Ano6 has no role in intestinal cholinergic Cl(-) secretion. Ano1 is located in a basolateral compartment/membrane rather than in the apical membrane, where it supports CCH-induced Ca(2+) increase, while the essential and possibly only apical Cl(-) channel is CFTR. These results define a new role of Ano1 for intestinal Ca(2+)-dependent Cl(-) secretion and demonstrate for the first time a contribution of Ano10 to intestinal transport.

  1. Effects of lorazepam tolerance and withdrawal on GABA[sub A] receptor operated chloride channels in mice selected for differences in ethanol withdrawal severity

    Energy Technology Data Exchange (ETDEWEB)

    Allan, A.M.; Baier, L.D.; Zhang, Xiaoying (Washington Univ. School of Medicine, St. Louis, MO (United States))

    1992-01-01

    Withdrawal seizure prone (WSP) and withdrawal seizure resistant (WSR) mice were treated with 5 mg/kg lorazepam for 7 days via implanted osmotic mini pumps. Following chronic drug treatment, brains were assayed for GABA-mediated chloride flux (GABA-Cl[sup [minus

  2. Macula densa basolateral ATP release is regulated by luminal [NaCl] and dietary salt intake.

    Science.gov (United States)

    Komlosi, Peter; Peti-Peterdi, Janos; Fuson, Amanda L; Fintha, Attila; Rosivall, Laszlo; Bell, Phillip Darwin

    2004-06-01

    One component of the macula densa (MD) tubuloglomerular feedback (TGF) signaling pathway may involve basolateral release of ATP through a maxi-anion channel. Release of ATP has previously been studied during a maximal luminal NaCl concentration ([NaCl](L)) stimulus (20-150 mmol/l). Whether MD ATP release occurs during changes in [NaCl](L) within the physiological range (20-60 mmol/l) has not been examined. Also, because TGF is known to be enhanced by low dietary salt intake, we examined the pattern of MD ATP release from salt-restricted rabbits. Fluorescence microscopy, with fura 2-loaded cultured mouse mesangial cells as biosensors, was used to assess ATP release from the isolated, perfused thick ascending limb containing the MD segment. The mesangial biosensor cells, which contain purinergic receptors and elevate intracellular Ca(2+) concentration ([Ca(2+)](i)) on ATP binding, were placed adjacent to the MD basolateral membrane. Elevations in [NaCl](L) between 0 and 80 mmol/l, in 20-mmol/l increments, caused stepwise increases in [Ca(2+)](i), with the highest increase at [NaCl](L) of approximately 60 mmol/l. Luminal furosemide at 10(-4) mol/l blocked ATP release, which suggests that the efflux of ATP required MD Na-2Cl-K cotransport. A low-salt diet for 1 wk increased the magnitude of [NaCl](L)-dependent elevations in biosensor [Ca(2+)](i) by twofold, whereas high-salt intake had no effect. In summary, ATP release occurs over the same range of [NaCl](L) (20-60 mmol/l) previously reported for TGF responses, and, similar to TGF, ATP release was enhanced by dietary salt restriction. Thus these two findings are consistent with the role of MD ATP release as a signaling component of the TGF pathway.

  3. Distribution of Prestin on Outer Hair Cell Basolateral Surface

    Institute of Scientific and Technical Information of China (English)

    YU Ning; ZHAI Suo-qiang; YANG Shi-ming; HAN Dong-yi; ZHAO Hong-bo

    2008-01-01

    Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC eleetromotility and its associated nonlinear capacitance were mainly located at the OHC lateral wall and absent at the apical cutieular plate and the basal nucleus region. Immunofluorescent staining for prestin also failed to demonstrate prestin expression at the OHC basal ends in whole-mount preparation of the organ of Corti. However, there lacks a definitive demonstration of the pattern of prestin distribution. The OHC lateral wall has a trilaminate organization and is composed of the plasma membrane, cortical lattice, and subsurface cisternae. In this study, the location of prestin proteins in dissociated OHCs was examined using immunofluorescent staining and confocal microscopy. We found that prestin was uniformly expressed on the basolateral surface, including the basal pole. No staining was seen on the cuticular plate and stereocilia. When co-stained with a membrane marker di-8-ANEPPS, prestin-labeling was found to be in the outer layer of the OHC lateral wall. After separating the plasma membrane from the underlying subsurface eisternae using a hypotonic extracellular solution, prestin-labeling was found to be in the plasma membrane, not the subsurface cisternae. The data show that prestin is expressed in the plasma membrane on the entire OHC basolateral surface.

  4. The activation effect of nobiletin on cystic fibrosis transmembrane conductance regulator chloride channel%川陈皮素对囊性纤维化跨膜传导调节因子的激活作用

    Institute of Scientific and Technical Information of China (English)

    杨爽; 于波; 张耀方; 王雪; 杨红

    2013-01-01

    Aim of the present study is to investigate activation effect of nobiletin on cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel activity.CFTR-mediated iodide influx assay and patch-clamp tests were done on FRT cells stably co-transfected with human CFTR and EYFP/H148Q.Nobiletin potently activated CFTR chloride channel activity in a dose-and time-dependent manner.The CFTR blocker CFTRinh-172 could completely reverse the effect.Preliminary mechanism study indicated that nobiletin activated CFTR chloride channel through a direct binding way.In addition,ex vivo tests done on mice trachea showed that nobiletin time-dependently stimulated submucosal gland fluid secretion.Nobiletin may be a therapeutic lead compound in treating CFTR-related diseases including disseminated bronchiectasis.%本实验利用荧光淬灭实验和膜片钳技术在稳定表达人CFTR和荧光绿蛋白突变体EYFP/H148Q的Fischer大鼠甲状腺上皮细胞(Fischer rat thyroid,FRT)上,测定川陈皮素(nobiletin)对囊性纤维化跨膜传导因子(cystic fibrosis transmembrane conductance regulator,CFTR)氯离子通道的激活作用.结果发现,川陈皮素以剂量依赖的方式激活CFTR氯离子通道的C1-转运活性,且这种活性是快速、可逆的,并能够被CFTR特异性抑制剂CFTRinh-172完全抑制.初步的分子机制研究表明,川陈皮素是以与CFTR直接作用来激活通道活性的.进一步的研究结果显示,川陈皮素能够有效刺激小鼠气管黏膜下腺液体分泌速度.因此,川陈皮素可能发展成为治疗包括支气管扩张在内的CFTR相关疾病的先导药物.

  5. Severe stress hormone conditions cause an extended window of excitability in the mouse basolateral amygdala

    NARCIS (Netherlands)

    Karst, Henk; Joëls, Marian

    2016-01-01

    Shortly after stress, basolateral amygdala neurons are exposed to sequential yet partly overlapping waves of hormones. We examined how these hormonal waves can change activity of basolateral amygdala neurons such that emotional aspects of stress become so deeply ingrained. To this end, spontaneous g

  6. Chloride : The queen of electrolytes?

    NARCIS (Netherlands)

    Berend, Kenrick; van Hulsteijn, Leonard Hendrik; Gans, Rijk O. B.

    2012-01-01

    Background: Channelopathies, defined as diseases that are caused by mutations in genes encoding ion channels, are associated with a wide variety of symptoms and have been documented extensively over the past decade. In contrast, despite the important role of chloride in serum, textbooks in general d

  7. Isotype-specific activation of cystic fibrosis transmembrane conductance regulator-chloride channels by cGMP-dependent protein kinase II

    NARCIS (Netherlands)

    P.J. French (Pim); J. Bijman (Jan); M.J. Edixhoven (Marcel); A.B. Vaandrager (Arie); B.J. Scholte (Bob); S.M. Lohmann (Suzanne); A.C. Nairn; H.R. de Jonge (Hugo)

    1995-01-01

    textabstractType II cGMP-dependent protein kinase (cGKII) isolated from pig intestinal brush borders and type I alpha cGK (cGKI) purified from bovine lung were compared for their ability to activate the cystic fibrosis transmembrane conductance regulator (CFTR)-Cl- channel in excis

  8. Relaxation of endothelin-1-induced pulmonary arterial constriction by niflumic acid and NPPB: mechanism(s) independent of chloride channel block.

    Science.gov (United States)

    Kato, K; Evans, A M; Kozlowski, R Z

    1999-03-01

    We investigated the effects of the Cl- channel blockers niflumic acid, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) and 4, 4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) on endothelin-1 (ET-1)-induced constriction of rat small pulmonary arteries (diameter 100-400 microm) in vitro, following endothelium removal. ET-1 (30 nM) induced a sustained constriction of rat pulmonary arteries in physiological salt solution. Arteries preconstricted with ET-1 were relaxed by niflumic acid (IC50: 35.8 microM) and NPPB (IC50: 21.1 microM) in a reversible and concentration-dependent manner. However, at concentrations known to block Ca++-activated Cl- channels, DIDS (channel blockers. When L-type Ca++ channels were blocked by nifedipine (10 microM), the ET-1-induced (30 nM) constriction was inhibited by only 5.8%. However, niflumic acid (30 microM) and NPPB (30 microM) inhibited the ET-1-induced constriction by approximately 53% and approximately 60%, respectively, both in the continued presence of nifedipine and in Ca++-free physiological salt solution. The Ca++ ionophore A23187 (10 microM) also evoked a sustained constriction of pulmonary arteries. Surprisingly, the A23187-induced constriction was also inhibited in a reversible and concentration-dependent manner by niflumic acid (IC50: 18.0 microM) and NPPB (IC50: 8.8 microM), but not by DIDS (channel blockade. One possibility is that these compounds may block the Ca++-dependent contractile processes.

  9. Paradoxical facilitation of working memory after basolateral amygdala damage.

    Directory of Open Access Journals (Sweden)

    Barak Morgan

    Full Text Available Working memory is a vital cognitive capacity without which meaningful thinking and logical reasoning would be impossible. Working memory is integrally dependent upon prefrontal cortex and it has been suggested that voluntary control of working memory, enabling sustained emotion inhibition, was the crucial step in the evolution of modern humans. Consistent with this, recent fMRI studies suggest that working memory performance depends upon the capacity of prefrontal cortex to suppress bottom-up amygdala signals during emotional arousal. However fMRI is not well-suited to definitively resolve questions of causality. Moreover, the amygdala is neither structurally or functionally homogenous and fMRI studies do not resolve which amygdala sub-regions interfere with working memory. Lesion studies on the other hand can contribute unique causal evidence on aspects of brain-behaviour phenomena fMRI cannot "see". To address these questions we investigated working memory performance in three adult female subjects with bilateral basolateral amygdala calcification consequent to Urbach-Wiethe Disease and ten healthy controls. Amygdala lesion extent and functionality was determined by structural and functional MRI methods. Working memory performance was assessed using the Wechsler Adult Intelligence Scale-III digit span forward task. State and trait anxiety measures to control for possible emotional differences between patient and control groups were administered. Structural MRI showed bilateral selective basolateral amygdala damage in the three Urbach-Wiethe Disease subjects and fMRI confirmed intact functionality in the remaining amygdala sub-regions. The three Urbach-Wiethe Disease subjects showed significant working memory facilitation relative to controls. Control measures showed no group anxiety differences. Results are provisionally interpreted in terms of a 'cooperation through competition' networks model that may account for the observed paradoxical

  10. Chloride transference during electrochemical chloride extraction process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chemical titration method and lab-made chloride probes were jointly adopted to investigate the effects of water-to-cement (W/C) ratio and the impressed current density on chloride transport for cement-based materials during electrochemical chloride extraction (ECE) process.The dissolution of bound chlorides and the effect of current density on dissolution were analyzed.The variations of chloride concentration at different depths and the chloride transference process were monitored.Test results show that W/C ratios adopted have slight influence on chloride extraction,while chloride extraction efficiency is mainly determined by the impressed current density.During ECE process a portion of bound chloride ions dissolved and the amount of bound chlorides released is directly proportional to current density.

  11. Mechanism of block of single protopores of the Torpedo chloride channel ClC-0 by 2-(p-chlorophenoxy)butyric acid (CPB).

    Science.gov (United States)

    Pusch, M; Accardi, A; Liantonio, A; Ferrera, L; De Luca, A; Camerino, D C; Conti, F

    2001-07-01

    We investigated in detail the mechanism of inhibition by the S(-) enantiomer of 2-(p-chlorophenoxy)butyric acid (CPB) of the Torpedo Cl(-)channel, ClC-0. The substance has been previously shown to inhibit the homologous skeletal muscle channel, CLC-1. ClC-0 is a homodimer with probably two independently gated protopores that are conductive only if an additional common gate is open. As a simplification, we used a mutant of ClC-0 (C212S) that has the common gate "locked open" (Lin, Y.W., C.W. Lin, and T.Y. Chen. 1999. J. Gen. Physiol. 114:1-12). CPB inhibits C212S currents only when applied to the cytoplasmic side, and single-channel recordings at voltages (V) between -120 and -80 mV demonstrate that it acts independently on individual protopores by introducing a long-lived nonconductive state with no effect on the conductance and little effect on the lifetime of the open state. Steady-state macroscopic currents at -140 mV are half-inhibited by approximately 0.5 mM CPB, but the inhibition decreases with V and vanishes for V > or = 40 mV. Relaxations of CPB inhibition after voltage steps are seen in the current responses as an additional exponential component that is much slower than the gating of drug-free protopores. For V = 60 mV) with an IC50 of approximately 30-40 mM. Altogether, these findings support a model for the mechanism of CPB inhibition in which the drug competes with Cl(-) for binding to a site of the pore where it blocks permeation. CPB binds preferentially to closed channels, and thereby also strongly alters the gating of the single protopore. Since the affinity of CPB for open WT pores is extremely low, we cannot decide in this case if it acts also as an open pore blocker. However, the experiments with the mutant K519E strongly support this interpretation. CPB block may become a useful tool to study the pore of ClC channels. As a first application, our results provide additional evidence for a double-barreled structure of ClC-0 and ClC-1.

  12. Excitotoxic death induced by released glutamate in depolarized primary cultures of mouse cerebellar granule cells is dependent on GABAA receptors and niflumic acid-sensitive chloride channels.

    Science.gov (United States)

    Babot, Zoila; Cristòfol, Rosa; Suñol, Cristina

    2005-01-01

    Excitotoxic neuronal death has been linked to neurological and neurodegenerative diseases. Several studies have sought to clarify the involvement of Cl(-) channels in neuronal excitotoxicity using either N-methyl-D-aspartic acid (NMDA) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainic acid agonists. In this work we induced excitotoxic death in primary cultures of cerebellar granule cells by means of endogenously released glutamate. Excitotoxicity was provoked by exposure to high extracellular K(+) concentrations ([K(+)](o)) for 5 min. Under these conditions, a Ca(2+)-dependent release of glutamate was evoked. When extracellular glutamate concentration rose to between 2 and 4 microM, cell viability was significantly reduced by 30-40%. The NMDA receptor antagonists (MK-801 and D-2-amino-5-phosphonopentanoic acid) prevented cell death. Exposure to high [K(+)](o) produced a (36)Cl(-) influx which was significantly reduced by picrotoxinin. In addition, the GABA(A) receptor antagonists (bicuculline, picrotoxinin and SR 95531) protected cells from high [K(+)](o)-triggered excitotoxicity and reduced extracellular glutamate concentration. The Cl(-) channel blockers niflumic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid also exerted a neuroprotective effect and reduced extracellular glutamate concentration, even though they did not reduce high [K(+)](o)-induced (36)Cl(-) influx. Primary cultures of cerebellar granule cells also contain a population of GABAergic neurons that released GABA in response to high [K(+)](o). Chronic treatment of primary cultures with kainic acid abolished GABA release and rendered granule cells insensitive to high [K(+)](o) exposure, even though NMDA receptors were functional. Altogether, these results demonstrate that, under conditions of membrane depolarization, low micromolar concentrations of extracellular glutamate might induce an excitotoxic process through both NMDA and GABA(A) receptors and niflumic acid-sensitive Cl

  13. Glucocorticoids Distinctively Modulate the CFTR Channel with Possible Implications in Lung Development and Transition into Extrauterine Life.

    Directory of Open Access Journals (Sweden)

    Mandy Laube

    Full Text Available During fetal development, the lung is filled with fluid that is secreted by an active Cl- transport promoting lung growth. The basolateral Na+,K+,2Cl- cotransporter (NKCC1 participates in Cl- secretion. The apical Cl- channels responsible for secretion are unknown but studies suggest an involvement of the cystic fibrosis transmembrane conductance regulator (CFTR. CFTR is developmentally regulated with a high expression in early fetal development and a decline in late gestation. Perinatal lung transition is triggered by hormones that stimulate alveolar Na+ channels resulting in fluid absorption. Little is known on how hormones affect pulmonary Cl- channels. Since the rise of fetal cortisol levels correlates with the decrease in fetal CFTR expression, a causal relation may be assumed. The aim of this study was to analyze the influence of glucocorticoids on pulmonary Cl- channels. Alveolar cells from fetal and adult rats, A549 cells, bronchial Calu-3 and 16HBE14o- cells, and primary rat airway cells were studied with real-time quantitative PCR and Ussing chambers. In fetal and adult alveolar cells, glucocorticoids strongly reduced Cftr expression and channel activity, which was prevented by mifepristone. In bronchial and primary airway cells CFTR mRNA expression was also reduced, whereas channel activity was increased which was prevented by LY-294002 in Calu-3 cells. Therefore, glucocorticoids strongly reduce CFTR expression while their effect on CFTR activity depends on the physiological function of the cells. Another apical Cl- channel, anoctamin 1 showed a glucocorticoid-induced reduction of mRNA expression in alveolar cells and an increase in bronchial cells. Furthermore, voltage-gated chloride channel 5 and anoctamine 6 mRNA expression were increased in alveolar cells. NKCC1 expression was reduced by glucocorticoids in alveolar and bronchial cells alike. The results demonstrate that glucocorticoids differentially modulate pulmonary Cl

  14. Glucocorticoids Distinctively Modulate the CFTR Channel with Possible Implications in Lung Development and Transition into Extrauterine Life.

    Science.gov (United States)

    Laube, Mandy; Bossmann, Miriam; Thome, Ulrich H

    2015-01-01

    During fetal development, the lung is filled with fluid that is secreted by an active Cl- transport promoting lung growth. The basolateral Na+,K+,2Cl- cotransporter (NKCC1) participates in Cl- secretion. The apical Cl- channels responsible for secretion are unknown but studies suggest an involvement of the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is developmentally regulated with a high expression in early fetal development and a decline in late gestation. Perinatal lung transition is triggered by hormones that stimulate alveolar Na+ channels resulting in fluid absorption. Little is known on how hormones affect pulmonary Cl- channels. Since the rise of fetal cortisol levels correlates with the decrease in fetal CFTR expression, a causal relation may be assumed. The aim of this study was to analyze the influence of glucocorticoids on pulmonary Cl- channels. Alveolar cells from fetal and adult rats, A549 cells, bronchial Calu-3 and 16HBE14o- cells, and primary rat airway cells were studied with real-time quantitative PCR and Ussing chambers. In fetal and adult alveolar cells, glucocorticoids strongly reduced Cftr expression and channel activity, which was prevented by mifepristone. In bronchial and primary airway cells CFTR mRNA expression was also reduced, whereas channel activity was increased which was prevented by LY-294002 in Calu-3 cells. Therefore, glucocorticoids strongly reduce CFTR expression while their effect on CFTR activity depends on the physiological function of the cells. Another apical Cl- channel, anoctamin 1 showed a glucocorticoid-induced reduction of mRNA expression in alveolar cells and an increase in bronchial cells. Furthermore, voltage-gated chloride channel 5 and anoctamine 6 mRNA expression were increased in alveolar cells. NKCC1 expression was reduced by glucocorticoids in alveolar and bronchial cells alike. The results demonstrate that glucocorticoids differentially modulate pulmonary Cl- channels and are likely

  15. Tribenzylammonium chloride

    Directory of Open Access Journals (Sweden)

    Waly Diallo

    2014-05-01

    Full Text Available Single crystals of the title salt, C21H21NH+·Cl−, were isolated as a side product from the reaction involving [(C6H5CH23NH]2[HPO4] and Sn(CH33Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetrahedral environment, with angles ranging from 107.7 to 111.16 (10°. In the crystal, the tribenzylammonium cations and chloride anions are linked through N—H...Cl and C—H...Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.

  16. The basolateral amygdala in reward learning and addiction.

    Science.gov (United States)

    Wassum, Kate M; Izquierdo, Alicia

    2015-10-01

    Sophisticated behavioral paradigms partnered with the emergence of increasingly selective techniques to target the basolateral amygdala (BLA) have resulted in an enhanced understanding of the role of this nucleus in learning and using reward information. Due to the wide variety of behavioral approaches many questions remain on the circumscribed role of BLA in appetitive behavior. In this review, we integrate conclusions of BLA function in reward-related behavior using traditional interference techniques (lesion, pharmacological inactivation) with those using newer methodological approaches in experimental animals that allow in vivo manipulation of cell type-specific populations and neural recordings. Secondly, from a review of appetitive behavioral tasks in rodents and monkeys and recent computational models of reward procurement, we derive evidence for BLA as a neural integrator of reward value, history, and cost parameters. Taken together, BLA codes specific and temporally dynamic outcome representations in a distributed network to orchestrate adaptive responses. We provide evidence that experiences with opiates and psychostimulants alter these outcome representations in BLA, resulting in long-term modified action.

  17. The basolateral amygdala in reward learning and addiction

    Science.gov (United States)

    Wassum, Kate M.; Izquierdo, Alicia

    2015-01-01

    Sophisticated behavioral paradigms partnered with the emergence of increasingly selective techniques to target the basolateral amygdala (BLA) have resulted in an enhanced understanding of the role of this nucleus in learning and using reward information. Due to the wide variety of behavioral approaches many questions remain on the circumscribed role of BLA in appetitive behavior. In this review, we integrate conclusions of BLA function in reward-related behavior using traditional interference techniques (lesion, pharmacological inactivation) with those using newer methodological approaches in experimental animals that allow in vivo manipulation of cell type-specific populations and neural recordings. Secondly, from a review of appetitive behavioral tasks in rodents and monkeys and recent computational models of reward procurement, we derive evidence for BLA as a neural integrator of reward value, history, and cost parameters. Taken together, BLA codes specific and temporally dynamic outcome representations in a distributed network to orchestrate adaptive responses. We provide evidence that experiences with opiates and psychostimulants alter these outcome representations in BLA, resulting in long-term modified action. PMID:26341938

  18. Purinergic regulation of CFTR and Ca2+ -activated Cl- channels and K+ channels in human pancreatic duct epithelium

    DEFF Research Database (Denmark)

    Wang, Jing; Haanes, Kristian A; Novak, Ivana

    2013-01-01

    dependent on intracellular Ca(2+). Apically applied ATP/UTP stimulated CF transmembrane conductance regulator (CFTR) and Ca(2+)-activated Cl(-) (CaCC) channels, which were inhibited by CFTRinh-172 and niflumic acid, respectively. The basolaterally applied ATP stimulated CFTR. In CFPAC-1 cells, which have...... mutated CFTR, basolateral ATP and UTP had negligible effects. In addition to Cl(-) transport in Capan-1 cells, the effects of 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (DC-EBIO) and clotrimazole indicated functional expression of the intermediate conductance K(+) channels (IK, KCa3...... receptors both Cl(-) channels (TMEM16A/ANO1 and CFTR) and K(+) channels (IK). The K(+) channels provide the driving force for Cl(-)-channel-dependent secretion, and luminal ATP provided locally or secreted from acini may potentiate secretory processes. Future strategies in augmenting pancreatic duct...

  19. Stimulation of wild-type, F508del- and G551D-CFTR chloride channels by non toxic modified pyrrolo[2,3-b]pyrazine derivatives

    Directory of Open Access Journals (Sweden)

    Luc eDannhoffer

    2011-08-01

    Full Text Available Cystic Fibrosis is a major inherited disorder involving abnormalities of fluid and electrolyte transport in a number of different organs due to abnormal function of Cystic Fibrosis Transmembrane conductance Regulator (CFTR protein. We recently identified a family of CFTR activators, which contains the hit: RP107 [7-n-butyl-6-(4-hydroxyphenyl[5H]-pyrrolo[2,3-b]pyrazine]. Here, we further evaluated the effect of the chemical modifications of the RP107-OH radical on CFTR activation. The replacement of the OH radical by a fluorine atom at position 2 (RP193 or 4 (RP185 significantly decreased the toxicity of the compounds without altering the ability to activate CFTR, especially for RP193. The non-toxic compound RP193 has no effect on cAMP production but stimulates the channel activity of wild-type CFTR in stably transfected CHO cells, in human bronchial epithelial NuLi-1 cells and in primary culture of human bronchial epithelial cells. Whole cell and single patch clamp recordings showed that RP193 induced a linear, time and voltage-independent current, which was fully inhibited by two different and selective CFTR inhibitors (CFTRinh-172 and GPinh-5a. Moreover, RP193 stimulates CFTR in temperature-rescued CuFi-1 (F508del/F508del human bronchial epithelial cells and in CHO cells stably expressing G551D-CFTR. This study shows that it is feasible to reduce cytotoxicity of chemical compounds without affecting their potency to activate CFTR and to rescue the class 2 F508del-CFTR and class 3 G551D-CFTR CF mutant activities.

  20. 呼吸道上皮细胞钠/氯离子通道与支气管哮喘%Epithelial sodium and chloride channels and bronchial asthma

    Institute of Scientific and Technical Information of China (English)

    王雯; 吉宏龙

    2015-01-01

    支气管哮喘(简称哮喘)是一种慢性气道疾病,表现为气道高反应性和气道炎症导致的可逆性气道阻塞.研究显示,呼吸道上皮细胞钠/氯离子通道(ENaC/CFTR)调节黏液纤毛系统从而参与了慢性气道疾病的发病机制.ENaC及CFTR共同调节黏液的水质层,从而影响气道纤毛清除能力.调节上皮通道蛋白的特异性拮抗剂或激活剂将为哮喘和其他慢性气道疾病的预防和治疗开拓新的研究前景.%Bronchial asthma (asthma) is a chronic respiratory disease characterized by reversible airway obstruction with bronchial hyper-responsiveness and inflammation.Airway cilia system is implicated in the pathogenesis of chronic airway diseases.Epithelial sodium channels (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR) are closely related to the mucociliary clearance.ENaC and CFTR jointly adjust the water layer of mucus, which affects the airway cilia clearance ability.Specific antagonists or activating agents of ENaC and CFTR could be novel pharmaceutical interventions for the prevention and treatment of asthma as well as other chronic airway diseases.

  1. Recovery of mucosal barrier function in ischemic porcine ileum and colon is stimulated by a novel agonist of the ClC-2 chloride channel, lubiprostone.

    Science.gov (United States)

    Moeser, Adam J; Nighot, Prashant K; Engelke, Kory J; Ueno, Ryuji; Blikslager, Anthony T

    2007-02-01

    Previous studies utilizing an ex vivo porcine model of intestinal ischemic injury demonstrated that prostaglandin (PG)E(2) stimulates repair of mucosal barrier function via a mechanism involving Cl(-) secretion and reductions in paracellular permeability. Further experiments revealed that the signaling mechanism for PGE(2)-induced mucosal recovery was mediated via type-2 Cl(-) channels (ClC-2). Therefore, the objective of the present study was to directly investigate the role of ClC-2 in mucosal repair by evaluating mucosal recovery in ischemia-injured intestinal mucosa treated with the selective ClC-2 agonist lubiprostone. Ischemia-injured porcine ileal mucosa was mounted in Ussing chambers, and short-circuit current (I(sc)) and transepithelial electrical resistance (TER) were measured in response to lubiprostone. Application of 0.01-1 microM lubiprostone to ischemia-injured mucosa induced concentration-dependent increases in TER, with 1 microM lubiprostone stimulating a twofold increase in TER (DeltaTER = 26 Omega.cm(2); P lubiprostone (1 microM) stimulated higher elevations in TER despite lower I(sc) responses compared with the nonselective secretory agonist PGE(2) (1 microM). Furthermore, lubiprostone significantly (P lubiprostone stimulated elevations in TER and reductions in mannitol flux in ischemia-injured intestine associated with structural changes in tight junctions. Prostones such as lubiprostone may provide a selective and novel pharmacological mechanism of accelerating recovery of acutely injured intestine compared with the nonselective action of prostaglandins such as PGE(2).

  2. Modulating effect of calcium activated potassium and chloride channels on detrusor instability%钙激活钾/氯通道对大鼠逼尿肌不稳定调节作用的实验研究

    Institute of Scientific and Technical Information of China (English)

    杨航; 宋波; 金锡御; 杨昕

    2003-01-01

    目的研究钙激活钾/氯通道对逼尿肌不稳定的调节作用的变化,探讨其在逼尿肌不稳定(Detrusor instability,DI)发生中的作用.方法采用Wistar大鼠DI模型,常规制备正常及DI逼尿肌条,体外张力测定其自发收缩频率和幅度,观察通道阻断剂及开放剂的作用.结果 DI组自发收缩频率与张力较对照组显著增加.大电导钙激活钾通道(Big conductance calcium activated potassium channel,BKca)阻断后,对照组频率降低而张力增加,DI组仅频率明显提高,开放后对照组频率与张力均降低,DI组仅频率明显下降.小电导钙激活钾通道(Small conductance calcium activated potassium channel,SKca)阻断后两组的频率与张力均明显增加,而开放后则对照组均降低,DI组仅频率下降.钾通道阻断或开放后对照组频率与张力的变化幅度明显高于DI组.钙激活氯通道(Calcium activated chloride channel,Clca)阻断后,DI组频率与张力下降,而对照组无明显改变.结论钙激活钾/氯通道反馈调节逼尿肌的收缩,DI时Kca作用下调而Clca作用上调,提示钙相关的调节异常在DI的发生中具有重要作用.

  3. Impact of basal forebrain cholinergic inputs on basolateral amygdala neurons.

    Science.gov (United States)

    Unal, Cagri T; Pare, Denis; Zaborszky, Laszlo

    2015-01-14

    In addition to innervating the cerebral cortex, basal forebrain cholinergic (BFc) neurons send a dense projection to the basolateral nucleus of the amygdala (BLA). In this study, we investigated the effect of near physiological acetylcholine release on BLA neurons using optogenetic tools and in vitro patch-clamp recordings. Adult transgenic mice expressing cre-recombinase under the choline acetyltransferase promoter were used to selectively transduce BFc neurons with channelrhodopsin-2 and a reporter through the injection of an adeno-associated virus. Light-induced stimulation of BFc axons produced different effects depending on the BLA cell type. In late-firing interneurons, BFc inputs elicited fast nicotinic EPSPs. In contrast, no response could be detected in fast-spiking interneurons. In principal BLA neurons, two different effects were elicited depending on their activity level. When principal BLA neurons were quiescent or made to fire at low rates by depolarizing current injection, light-induced activation of BFc axons elicited muscarinic IPSPs. In contrast, with stronger depolarizing currents, eliciting firing above ∼ 6-8 Hz, these muscarinic IPSPs lost their efficacy because stimulation of BFc inputs prolonged current-evoked afterdepolarizations. All the effects observed in principal neurons were dependent on muscarinic receptors type 1, engaging different intracellular mechanisms in a state-dependent manner. Overall, our results suggest that acetylcholine enhances the signal-to-noise ratio in principal BLA neurons. Moreover, the cholinergic engagement of afterdepolarizations may contribute to the formation of stimulus associations during fear-conditioning tasks where the timing of conditioned and unconditioned stimuli is not optimal for the induction of synaptic plasticity.

  4. Vestibular role of KCNQ4 and KCNQ5 K+ channels revealed by mouse models

    NARCIS (Netherlands)

    G. Spitzmaul (Guillermo); L. Tolosa (Leonardo); B.H.J. Winkelman (Beerend); M. Heidenreich (Matthias); M.A. Frens (Maarten); C. Chabbert (Christian); C.I. de Zeeuw (Chris); T.J. Jentsch (Thomas)

    2013-01-01

    textabstractThe function of sensory hair cells of the cochlea and vestibular organs depends on an influx of K+ through apical mechanosensitive ion channels and its subsequent removal over their basolateral membrane. The KCNQ4 (Kv7.4) K+ channel, which is mutated in DFNA2 human hearing loss, is expre

  5. The cytosolic chloride concentration in macula densa and cortical thick ascending limb cells.

    Science.gov (United States)

    Salomonsson, M; Gonzalez, E; Kornfeld, M; Persson, A E

    1993-03-01

    It is believed that chloride transport through the macula densa (MD) cells is a factor involved in the tubuloglomerular feedback (TGF) mechanism and in MD-mediated renin release. In this study isolated and perfused rabbit kidney cortical thick ascending limb (cTAL) segments containing MD plaques and attached glomeruli were loaded with chloride (CL-sensitive) 6 methoxy-1-fluorophore (sulphanate-propyl) quinolinium (SPQ). MD and cTAL intracellular chloride concentration ([Cl-]i) was determined by using image-intensified video microscopy and digital image-processing for measuring the intensity of the emitted SPQ fluorescence. With 150 mM NaCl in lumen and bath the [Cl-]i in MD and cTAL cells was 58.8 +/- 7.2 mM (n = 20) and 68.7 +/- 9.8 mM (n = 14), respectively. When the presumed luminal Na(+)-2Cl(-)-K+ co-transporter was blocked by adding 10(-4)M furosemide, the [Cl-]i was reduced in both, MD and cTAL cells from 55.5 +/- 11.9 to 28.6 +/- 10.0 mM (n = 10) and from 43.8 +/- 2.6 to 13.1 +/- 4.5 mM (n = 5), respectively. A reduction in luminal NaCl from 150 to 30 mM also decreased both, MD and cTAL [Cl-]i from 69.4 +/- 9.1 to 36.5 +/- 5.1 mM (n = 9) and from 82.9 +/- 14.5 to 49.4 +/- 8.0 mM (n = 8), respectively. Basolateral addition of the Cl(-)-channel blocker NPPB increased MD [Cl-]i from 31.1 +/- 2.0 to 100.7 +/- 17.0 mM (n = 5) and cTAL [Cl-]i from 44.4 +/- 12.9 to 89.7 +/- 11.7 mM (n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Mutation of neuronal channels of sodium and chloride associated with generalized epilepsy with febrile seizures plus (gefs+ Mutaciones de los canales neuronales de sodio y cloro asociadas a epilepsia generalizada con convulsiones febriles plus

    Directory of Open Access Journals (Sweden)

    Gabriel Bedoya Berrío

    2004-02-01

    Full Text Available Generalized Epilepsy with Febrile Seizures Plus (GEFS+ is a frequent entity characterized by generalized seizures with a wide phenotypic variety; the age of onset is 3 months and it persists beyond 6 years. Seizures may or may not be induced by fever. The disease has shown an autosomic dominant trait, incomplete penetrance and association with mutations on the genes that encode voltage-dependent sodium channels and the chloride neuronal channels on the central nervous system. The wide spectrum GEFS+ phenotype has been related with others entities such as Severe Myoclonic Epilepsy of Infancy (SMEI and Intractable Childhood Epilepsy with Frequent Generalized Tonic-Clonic Seizures (ICEGTC; they have mutations in common with GEFS+ according to several recently published articles. This review compiles up to date information about EGCF+ with the aim of giving the reader a knowledge of this entity and of its association with mutations that participate in its pathogenesis. La Epilepsia Generalizada Con Convulsiones Febriles Plus (EGCF+, es una entidad relativamente común. Se caracteriza por convulsiones de tipo generalizado con una gran variabilidad fenotípica; se presenta desde los 3 meses de edad y persiste más allá de los 6 años; las convulsiones pueden ser precipitadas por fiebre pero se presentan también sin ella. La enfermedad se ha asociado a herencia autosómica dominante con penetrancia incompleta, en la que intervienen mutaciones de los genes que codifican los canales iónicos de sodio dependientes del voltaje y de los canales iónicos de cloro en las neuronas del Sistema Nervioso Central (SNC. El amplio fenotipo de la EGCF+ se ha encontrado en asociación con otras entidades como la Epilepsia Mioclónica Severa del Lactante (EMSL y la Epilepsia Generalizada Tónico-Clónica Intratable de la Infancia (EGTCII, las cuales han presentado mutaciones comunes con las de la EGCF+, según informes recientemente publicados. Esta revisi

  7. Cystic fibrosis transmembrane conductance regulator: a chloride channel gated by ATP binding and hydrolysis%囊性纤维化跨膜电导调节体:ATP结合和水解门控Cl-通道

    Institute of Scientific and Technical Information of China (English)

    BOMPADRE; Silvia; G; HWANG; Tzyh-Chang

    2007-01-01

    囊性纤维化跨膜电导调节体(cystic fibrosis transmembrane conductance regulator,CFTR)是一种Cl-通道,属于ATP结合(ATP-binding cassette,ABC)转运体超家族.CFTR功能缺陷是高加索人种中普遍存在的致死性常染色体隐性遗传疾病囊性纤维化(cystic fibrosis,CF)发生的主要原因.这种疾病患者各组织上皮细胞内Cl-转运失调.目前,与CF相关的不同突变超过1 400种.CFTR调节(regulatory,R)域负责调控,核苷酸结合域(nucleotide-binding domains,NBDs)NBD1和NBD2负责ATP结合和水解门控.近期研究发现CFTR的NBDs与其它ABC蛋白一样可以二聚化.二聚化过程中,NBD1和NBD2首-尾相连,一个NBD上的WalkerA和B模块与另一个NBD提供的标签序列(signature sequence)形成ATP结合袋(ATP-binding pockets,ABPs)ABP1和ABP2.ABPs中与ATP结合相关的氨基酸突变实验揭示,ABP1和ABP2在CFTR的ATP依赖门控中发挥不同作用.ABP2由NBD2上的Walk A和B模块与NBD1提供的标签序列形成,它与ATP结合催化通道开放,而ABP1单独与ATP结合不能促进通道开放,只能稳定通道构象.有一些CFTR突变相关疾病的特征就是门控失调,进一步深入研究CFTR的NBD1和NBD2如何通过相互作用而达到通道门控,将为药理学研究提供更多所需的机制信息,有利于为CF治疗的药物设计铺平道路.%The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that belongs to the ATP-binding cassette (ABC) transporter superfamily. Defective function of CFTR is responsible for cystic fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasian populations. The disease is manifested in defective chloride transport across the epithelial cells in various tissues. To date, more than 1400 different mutations have been identified as CF-associated. CFTR is regulated by phosphorylation in its regulatory (R) domain, and gated by ATP binding and hydrolysis at its two nucleotide-binding domains (NBD1

  8. Multiple anxiogenic drugs recruit a parvalbumin-containing subpopulation of GABAergic interneurons in the basolateral amygdala.

    Science.gov (United States)

    Hale, Matthew W; Johnson, Philip L; Westerman, Alex M; Abrams, Jolane K; Shekhar, Anantha; Lowry, Christopher A

    2010-10-01

    The basolateral amygdala is a nodal structure within a distributed and interconnected network that regulates anxiety states and anxiety-related behavior. Administration of multiple anxiogenic drugs increases cellular responses (i.e., increases c-Fos expression) in a subregion of the basolateral amygdala, but the neurochemical phenotypes of these cells are not known. The basolateral amygdala contains glutamatergic projection neurons and several populations of γ-aminobutyric acid-synthesizing (GABAergic) interneurons, including a population of parvalbumin (PV)-expressing GABAergic interneurons that co-express the excitatory 5-HT(2A) receptor. The role for these PV-expressing GABAergic interneurons in anxiety-states is unclear. In this experiment we examined the effects of multiple anxiogenic drugs including the 5-HT(2C/2A) receptor agonist m-chlorophenyl piperazine (mCPP), the adenosine receptor antagonist caffeine, the α(2)-adrenoreceptor antagonist yohimbine and the partial inverse agonist at the benzodiazepine allosteric site on the GABA(A) receptor, N-methyl-beta-carboline-3-carboxamide (FG-7142), on c-Fos expression in PV-immunoreactive (PV-ir) interneurons in subdivisions of the basolateral amygdala. All drugs with the exception of mCPP increased c-Fos expression in PV-ir neurons in the basolateral amygdaloid nucleus, anterior part (BLA). The numbers of c-Fos-immunoreactive (c-Fos-ir)/PV-ir GABAergic interneurons in the BLA were positively correlated with the numbers of c-Fos-ir serotonergic neurons in the mid-rostrocaudal dorsal raphe nucleus (DR) and with a measure of anxiety-related behavior. All four drugs increased c-Fos expression in non-PV-ir cells in most of the subdivisions of the basolateral amygdala that were sampled, compared with vehicle-injected controls. Together, these data suggest that the PV/5-HT(2A) receptor expressing GABAergic interneurons in the basolateral amygdala are part of a DR-basolateral amygdala neuronal circuit modulating

  9. Glutamate Receptor Antagonist Infusions into the Basolateral and Medial Amygdala Reveal Differential Contributions to Olfactory vs. Context Fear Conditioning and Expression

    Science.gov (United States)

    Walker, David L.; Paschall, Gayla Y.; Davis, Michael

    2005-01-01

    The basolateral amygdala's involvement in fear acquisition and expression to visual and auditory stimuli is well known. The involvement of the basolateral and other amygdala areas in fear acquisition and expression to stimuli of other modalities is less certain. We evaluated the contribution of the basolateral and medial amygdala to olfactory and…

  10. 硫化氢激活H9c2心肌细胞容积调节性氯通道%Hydrogen Sulfide Activated Volume-Regulated Chloride Channel in H9c2 Cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    杨春涛; 左婉红; 赵斌; 赵磊; 蔡典其; 陈丽新; 王立伟; 冯鉴强; 廖新学

    2012-01-01

    目的 观察硫化氨(H2S)对H9c2心肌细胞容积调节性氯通道(VRCC)的影响.方法 培养大鼠H9c2 心肌细胞,用H2S供体硫氢化钠(NaHS)处理H9c2心肌细胞.分别应用Western blot和全细胞膜片钳技术分析蛋白的表达和VRCC的开放和关闭.结果 等张灌流液处理的H9c2心肌细胞可记录到微弱的背景氯电流.低张灌流液处理可明显增加H9c2心肌细胞的氯电流(P<0.0l),高张灌流液处理则可减弱这种增强作用(P<0.05).Western blot检测显示H9c2心肌细胞上存在ClC-3氯通道蛋白的表达.用400 μmol/L NaHS处理0~30 min可激活H9c2心肌细胞上的氯通道,高张灌流液处理抑制NaHS处理诱导的氯通道激活.400μmol/L NaHS处理0~30min对H9c2心肌细胞ClC-3氯通道蛋白的表达无明显影响(P>0.05).结论 H9c2心肌细胞存在VRCC和ClC-3氯通道蛋白的表达,H2S处理可激活VRCC而不影响ClC-3氯通道蛋白的表达.%Aim To investigate the effect of hydrogen sulfide (H2S) on volume-regulated chloride channel (VRCC). Methods H9c2 cardiomyoeytes were cultured and treated with sodium hydrosulfide (NaHS, a H2S donor). Expression of C1C-3 protein and VRCC chloride current (/c-VRCc) were measured by Western blot assay and whole cell patch clamp, respectively. Results When H9c2 cardiomyocytes were placed in the isotonic solution, la was slightly activated. Hypotonicity obviously enhanced la(P 0. 05). Conclusions Both VRCC and C1C-3 protein were expressed in H9c2 cardiomyocytes. H2S activated VRCC in a ClC-3-independent manner.

  11. Endocannabinoids in the rat basolateral amygdala enhance memory consolidation and enable glucocorticoid modulation of memory

    NARCIS (Netherlands)

    Campolongo, Patrizia; Roozendaal, Benno; Trezza, Viviana; Hauer, Daniela; Schelling, Gustav; McGaugh, James L.; Cuomo, Vincenzo

    2009-01-01

    Extensive evidence indicates that the basolateral complex of the amygdala (BLA) modulates the consolidation of memories for emotionally arousing experiences, an effect that involves the activation of the glucocorticoid system. Because the BLA expresses high densities of cannabinoid CB1 receptors, th

  12. Cortisol-sensitive urea transport across the gill basolateral membrane of the gulf toadfish (Opsanus beta).

    Science.gov (United States)

    Rodela, Tamara M; Gilmour, Kathleen M; Walsh, Patrick J; McDonald, M Danielle

    2009-08-01

    Gulf toadfish (Opsanus beta) use a unique pulsatile urea excretion mechanism that allows urea to be voided in large pulses via the periodic insertion or activation of a branchial urea transporter. The precise cellular and subcellular location of the facilitated diffusion mechanism(s) remains unclear. An in vitro basolateral membrane vesicle (BLMV) preparation was used to test the hypothesis that urea movement across the gill basolateral membrane occurs through a cortisol-sensitive carrier-mediated mechanism. Toadfish BLMVs demonstrated two components of urea uptake: a linear element at high external urea concentrations, and a phloretin-sensitive saturable constituent (K(m) = 0.24 mmol/l; V(max) = 6.95 micromol x mg protein(-1) x h(-1)) at low urea concentrations ( 2, further suggestive of carrier-mediated processes. Our data provide evidence that a basolateral urea facilitated transporter accelerates the movement of urea between the plasma and gills to enable the pulsatile excretion of urea. Furthermore, in vivo infusion of cortisol caused a significant 4.3-fold reduction in BLMV urea transport capacity in lab-crowded fish, suggesting that cortisol inhibits the recruitment of urea transporters to the basolateral membrane, which may ultimately affect the size of the urea pulse event in gulf toadfish.

  13. Inhibition of cAMP-activated intestinal chloride secretion by diclofenac: cellular mechanism and potential application in cholera.

    Directory of Open Access Journals (Sweden)

    Pawin Pongkorpsakol

    2014-09-01

    Full Text Available Cyclic AMP-activated intestinal Cl- secretion plays an important role in pathogenesis of cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl- secretion, its underlying mechanisms, and possible application in the treatment of cholera. Diclofenac inhibited cAMP-activated Cl- secretion in human intestinal epithelial (T84 cells with IC50 of ∼ 20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic activation. Interestingly, exposures of T84 cell monolayers to diclofenac, either in apical or basolateral solutions, produced similar degree of inhibitions. Analyses of the apical Cl- current showed that diclofenac reversibly inhibited CFTR Cl- channel activity (IC50 ∼ 10 µM via mechanisms not involving either changes in intracellular cAMP levels or CFTR channel inactivation by AMP-activated protein kinase and protein phosphatase. Of interest, diclofenac had no effect on Na(+-K(+ ATPases and Na(+-K(+-Cl- cotransporters, but inhibited cAMP-activated basolateral K(+ channels with IC50 of ∼ 3 µM. In addition, diclofenac suppressed Ca(2+-activated Cl- channels, inwardly rectifying Cl- channels, and Ca(2+-activated basolateral K(+ channels. Furthermore, diclofenac (up to 200 µM; 24 h of treatment had no effect on cell viability and barrier function in T84 cells. Importantly, cholera toxin (CT-induced Cl- secretion across T84 cell monolayers was effectively suppressed by diclofenac. Intraperitoneal administration of diclofenac (30 mg/kg reduced both CT and Vibrio cholerae-induced intestinal fluid secretion by ∼ 70% without affecting intestinal fluid absorption in mice. Collectively, our results indicate that diclofenac inhibits both cAMP-activated and Ca(2+-activated Cl- secretion by inhibiting both apical Cl- channels and basolateral K+ channels in intestinal epithelial cells. Diclofenac may be useful in the treatment of cholera and other types of secretory diarrheas resulting from intestinal

  14. Involvement of the basolateral complex and central nucleus of amygdala in the omission effects of different magnitudes of reinforcement.

    Science.gov (United States)

    Judice-Daher, Danielle M; Tavares, Tatiane F; Bueno, José Lino O

    2012-07-15

    Evidence from appetitive Pavlovian and instrumental conditioning studies suggest that the amygdala is involved in modulation of responses correlated with motivational states, and therefore, to the modulation of processes probably underlying reinforcement omission effects. The present study aimed to clarify whether or not the mechanisms related to reinforcement omission effects of different magnitudes depend on basolateral complex and central nucleus of amygdala. Rats were trained on a fixed-interval 12s with limited hold 6s signaled schedule in which correct responses were always followed by one of two reinforcement magnitudes. Bilateral lesions of the basolateral complex and central nucleus were made after acquisition of stable performance. After postoperative recovery, the training was changed from 100% to 50% reinforcement schedules. The results showed that lesions of the basolateral complex and central nucleus did not eliminate or reduce, but interfere with reinforcement omission effects. The response from rats of both the basolateral complex and central nucleus lesioned group was higher relative to that of the rats of their respective sham-lesioned groups after reinforcement omission. Thus, the lesioned rats were more sensitive to the omission effect. Moreover, the basolateral complex lesions prevented the magnitude effect on reinforcement omission effects. Basolateral complex lesioned rats showed no differential performance following omission of larger and smaller reinforcement magnitude. Thus, the basolateral complex is involved in incentive processes relative to omission of different reinforcement magnitudes. Therefore, it is possible that reinforcement omission effects are modulated by brain circuitry which involves amygdala.

  15. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2012-02-01

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17beta-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17beta-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17beta-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective permeabilization of apical or basolateral membranes with amphotericin B or nystatin was used to isolate basolateral K(+) channel and apical Cl(-) channel activity, respectively. 17beta-Estradiol dose-dependently inhibited secretory responses to both toxins with IC(50) values of approximately 1nM. This effect was female-gender specific, with no inhibition observed in male tissues. 17beta-Estradiol responses were insensitive to the pure anti-estrogen ICI 182,720. 17beta-Estradiol exerted its effects downstream of enterotoxin-induced production of second messengers (cAMP and cGMP) but was dependent on PKCdelta activation. In nystatin-permeabilized tissues, apical Cl(-) currents were unaffected by 17beta-estradiol treatment while basolateral K(+) current was profoundly inhibited by the hormone. This current was sensitive to the specific KCNQ1 channel inhibitors chromanol 293B and HMR-1556. In conclusion, 17beta-estradiol inhibits enterotoxin-induced Cl(-) secretion via a PKCdelta-dependent mechanism involving inhibition of basolateral KCNQ1 channels. These data elucidate mechanisms of 17beta-estradiol inhibition of Cl(-) secretion induced by enterotoxins in intestinal epithelia, which may be relevant for the treatment of diarrheal diseases.

  16. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2011-05-08

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17β-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17β-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17β-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective permeabilization of apical or basolateral membranes with amphotericin B or nystatin was used to isolate basolateral K(+) channel and apical Cl(-) channel activity, respectively. 17β-Estradiol dose-dependently inhibited secretory responses to both toxins with IC(50) values of approximately 1nM. This effect was female-gender specific, with no inhibition observed in male tissues. 17β-Estradiol responses were insensitive to the pure anti-estrogen ICI 182,720. 17β-Estradiol exerted its effects downstream of enterotoxin-induced production of second messengers (cAMP and cGMP) but was dependent on PKCδ activation. In nystatin-permeabilized tissues, apical Cl(-) currents were unaffected by 17β-estradiol treatment while basolateral K(+) current was profoundly inhibited by the hormone. This current was sensitive to the specific KCNQ1 channel inhibitors chromanol 293B and HMR-1556. In conclusion, 17β-estradiol inhibits enterotoxin-induced Cl(-) secretion via a PKCδ-dependent mechanism involving inhibition of basolateral KCNQ1 channels. These data elucidate mechanisms of 17β-estradiol inhibition of Cl(-) secretion induced by enterotoxins in intestinal epithelia, which may be relevant for the treatment of diarrheal diseases.

  17. Chloride equilibrium potential in salamander cones

    Directory of Open Access Journals (Sweden)

    Bryson Eric J

    2004-12-01

    Full Text Available Abstract Background GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca and then determined the reversal potential for the current component that was inhibited by the Cl- channel blocker, niflumic acid. With this method, ECl was found to average -46 mV. In a complementary approach, we used a Cl-sensitive dye, MEQ, to measure the Cl- flux produced by depolarization with elevated concentrations of K+. The membrane potentials produced by the various high K+ solutions were measured in separate current clamp experiments. Consistent with electrophysiological experiments, MEQ fluorescence measurements indicated that ECl was below -36 mV. Conclusions The results of this study indicate that ECl is close to the dark resting potential. This will minimize the impact of chloride-dependent presynaptic mechanisms in cone terminals involving GABAa receptors, glutamate transporters and ICl(Ca.

  18. Long-term aldosterone treatment induces decreased apical but increased basolateral expression of AQP2 in CCD of rat kidney

    DEFF Research Database (Denmark)

    de Seigneux, Sophie; Nielsen, Jakob; Olesen, Emma T B;

    2007-01-01

    of hypokalemia in aldosterone-treated rats, we studied dietary-induced hypokalemia in rats, which also reduced apical AQP2 expression in the CCD but did not induce any increase in basolateral AQP2 expression in the CCD as observed with aldosterone treatment. The aldosterone-induced basolateral AQP2 expression...... in the CCD was thus independent of hypokalemia but was dependent on the presence of sodium and aldosterone. This redistribution was clearly blocked by mineralocorticoid receptor blockade. The increased basolateral expression of AQP2 induced by aldosterone may play a significant role in water metabolism...... in conditions with increased sodium reabsorption in the CCD....

  19. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents the state-of-the art: an analytical model which describes chloride profiles in concrete as function of depth...... makes physical sense for the design engineer, i.e. the achieved chloride diffusion coefficients at 1 year and 100 years, D1 and D100 respectively, and the corresponding achieved chloride concentrations at the exposed concrete surface, C1 and C100. Data from field exposure supports the assumption of time...... dependent surface chloride concentrations and the diffusion coefficients. Model parameters for Portland cement concretes with and without silica fume and fly ash in marine atmospheric and submerged South Scandinavian environment are suggested in a companion paper based on 10 years field exposure data....

  20. Chloride regulates afferent arteriolar contraction in response to depolarization

    DEFF Research Database (Denmark)

    Hansen, P B; Jensen, B L; Skott, O

    1998-01-01

    . The results show that K+-induced contraction of smooth muscle cells in the afferent arteriole is highly sensitive to chloride, whereas neurotransmitter release and ensuing contraction is not dependent on chloride. Thus, there are different activation pathways for depolarizing vasoconstrictors......-Renal vascular reactivity is influenced by the level of dietary salt intake. Recent in vitro data suggest that afferent arteriolar contractility is modulated by extracellular chloride. In the present study, we assessed the influence of chloride on K+-induced contraction in isolated perfused rabbit...... afferent arterioles. In 70% of vessels examined, K+-induced contraction was abolished by acute substitution of bath chloride. Consecutive addition of Cl- (30, 60, 80, 100, 110, and 117 mmol/L) restored the sensitivity to K+, and half-maximal response was observed at 82 mmol/L chloride. The calcium channel...

  1. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents experimentally based design parameters for Portland cement concretes with and without silica fume and fly ash...... in marine atmospheric and submersed South Scandinavian environment. The design parameters are based on sequential measurements of 86 chloride profiles taken over ten years from 13 different types of concrete. The design parameters provide the input for an analytical model for chloride profiles as function...

  2. Electrophysiological study of transport systems in isolated perfused pancreatic ducts: properties of the basolateral membrane

    DEFF Research Database (Denmark)

    Novak, I; Greger, R

    1988-01-01

    In order to study the mechanism of pancreatic HCO3- transport, a perfused preparation of isolated intra- and interlobular ducts (i.d. 20-40 microns) of rat pancreas was developed. Responses of the epithelium to changes in the bath ionic concentration and to addition of transport inhibitors...... was monitored by electrophysiological techniques. In this report some properties of the basolateral membrane of pancreatic duct cells are described. The transepithelial potential difference (PDte) in ducts bathed in HCO3(-)-free and HCO3(-)-containing solution was -0.8 and -2.6 mV, respectively. The equivalent...... short circuit current (Isc) under similar conditions was 26 and 50 microA . cm-2. The specific transepithelial resistance (Rte) was 88 omega cm2. In control solutions the PD across the basolateral membrane (PDbl) was -63 +/- 1 mV (n = 314). Ouabain (3 mmol/l) depolarized PDbl by 4.8 +/- 1.1 mV (n = 6...

  3. Clathrin and AP1B: Key roles in basolateral trafficking through trans-endosomal routes

    Science.gov (United States)

    Gonzalez, Alfonso; Rodriguez-Boulan, Enrique

    2013-01-01

    Research following introduction of the MDCK model system to study epithelial polarity (1978) led to an initial paradigm that posited independent roles of the trans Golgi network (TGN) and recycling endosomes (RE) in the generation of, respectively, biosynthetic and recycling routes of plasma membrane (PM) proteins to apical and basolateral PM domains. This model dominated the field for 20 years. However, studies over the past decade and the discovery of the involvement of clathrin and clathrin adaptors in protein trafficking to the basolateral PM has led to a new paradigm. TGN and RE are now believed to cooperate closely in both biosynthetic and recycling trafficking routes. Here, we critically review these recent advances and the questions that remain unanswered. PMID:19854182

  4. Post-training depletions of basolateral amygdala serotonin fail to disrupt discrimination, retention, or reversal learning

    OpenAIRE

    G. Jesus eOchoa; Alexandra eStolyarova; Amandeep eKaur; Evan eHart; Amador eBugarin; Alicia eIzquierdo

    2015-01-01

    In goal-directed pursuits, the basolateral amygdala (BLA) is critical in learning about changes in the value of rewards. BLA-lesioned rats show enhanced reversal learning, a task employed to measure the flexibility of response to changes in reward. Similarly, there is a trend for enhanced discrimination learning, suggesting that BLA may modulate formation of stimulus-reward associations. There is a parallel literature on the importance of serotonin (5HT) in new stimulus-reward and reversal le...

  5. Excitatory amino acid receptors in the basolateral amygdala regulate anxiety responses in the social interaction test.

    Science.gov (United States)

    Sajdyk, T J; Shekhar, A

    1997-08-01

    Blocking GABA(A) receptors in the basolateral amygdala (BLA) elicits increases in heart rate (HR), blood pressure (BP) and anxiety responses by enhancing a glutamate mediated excitation. The present study was conducted to determine the role of the ionotropic glutamate receptors within the BLA in regulating HR, BP and experimental anxiety. Blocking basal glutamate excitation had no significant effect on HR or BP, but did elicit a significant anxiolytic-like effect.

  6. Active and passive Na+ fluxes across the basolateral membrane of rabbit urinary bladder.

    Science.gov (United States)

    Eaton, D C; Frace, A M; Silverthorn, S U

    1982-01-01

    The apical membrane of rabbit urinary bladder can be functionally removed by application of nystatin at high concentration if the mucosal surface of the tissue is bathed in a saline which mimics intracellular ion concentrations. Under these conditions, the tissue is as far as the movement of univalent ions no more than a sheet of basolateral membrane with some tight junctional membrane in parallel. In this manner the Na+ concentration at the inner surface of the basolateral membrane can be varied by altering the concentration in the mucosal bulk solution. When this was done both mucosal-to-serosal 22Na flux and net change in basolateral current were measured. The flux and the current could be further divided into the components of each that were either blocked by ouabain or insensitive to ouabain. Ouabain-insensitive mucosal-to-serosal Na+ flux was a linear function of mucosal Na+ concentration. Ouabain-sensitive Na+ flux and ouabain-sensitive, Na+-induced current both display a saturating relationship which cannot be accounted for by the presence of unstirred layers. If the interaction of Na+ with the basolateral transport process is assumed to involve the interaction of some number of Na+ ions, n, with a maximal flux, MMAX, then the data can be fit by assuming 3.2 equivalent sites for interaction and a value for MMAX of 287.8 pM cm-2 sec-1 with an intracellular Na concentration of 2.0 mM Na+ at half-maximal saturation. By comparing these values with the ouabain-sensitive, Na+-induced current, we calculate a Na+ to K+ coupling ratio of 1.40 +/- 0.07 for the transport process.

  7. Short environmental enrichment in adulthood reverses anxiety and basolateral amygdala hypertrophy induced by maternal separation.

    Science.gov (United States)

    Koe, A S; Ashokan, A; Mitra, R

    2016-02-02

    Maternal separation during early childhood results in greater sensitivity to stressors later in adult life. This is reflected as greater propensity to develop stress-related disorders in humans and animal models, including anxiety and depression. Environmental enrichment (EE) reverses some of the damaging effects of maternal separation in rodent models when provided during peripubescent life, temporally proximal to the separation. It is presently unknown if EE provided outside this critical window can still rescue separation-induced anxiety and neural plasticity. In this report we use a rat model to demonstrate that a single short episode of EE in adulthood reduced anxiety-like behaviour in maternally separated rats. We further show that maternal separation resulted in hypertrophy of dendrites and increase in spine density of basolateral amygdala neurons in adulthood, long after initial stress treatment. This is congruent with prior observations showing centrality of basolateral amygdala hypertrophy in anxiety induced by stress during adulthood. In line with the ability of the adult enrichment to rescue stress-induced anxiety, we show that enrichment renormalized stress-induced structural expansion of the amygdala neurons. These observations argue that behavioural plasticity induced by early adversity can be rescued by environmental interventions much later in life, likely mediated by ameliorating effects of enrichment on basolateral amygdala plasticity.

  8. Role of cytoplasmic termini in sorting and shuttling of the aquaporin-2 water channel

    NARCIS (Netherlands)

    Balkom, B.W.M. van; Graat, M.P.J.; Raak, M.M.J.P. van; Hofman, E.; Sluijs, P. van der; Deen, P.M.T.

    2004-01-01

    In mammals, the regulation of water homeostasis is mediated by the aquaporin-1 (AQP1) water channel, which localizes to the basolateral and apical membranes of the early nephron segment, and AQP2, which is translocated from intracellular vesicles to the apical membrane of collecting duct cells after

  9. Acquisition of contextual Pavlovian fear conditioning is blocked by application of an NMDA receptor antagonist D,L-2-amino-5-phosphonovaleric acid to the basolateral amygdala.

    Science.gov (United States)

    Fanselow, M S; Kim, J J

    1994-02-01

    Rats, with chronic cannula placed bilaterally in the amygdala, received infusions of the N-methyl-D-aspartate (NMDA) receptor antagonist D,L-2-amino-5-phosphonovaleric acid (APV) before contextual Pavlovian fear conditioning. Administration of APV to the basolateral nucleus prevented acquisition of fear. Central nucleus infusions had no effect. It is concluded that an NMDA-mediated process near the basolateral region of the amygdala (e.g., lateral or basolateral nucleus) is essential for the learning of fear.

  10. Lithium Sulfuryl Chloride Battery.

    Science.gov (United States)

    Primary batteries , Electrochemistry, Ionic current, Electrolytes, Cathodes(Electrolytic cell), Anodes(Electrolytic cell), Thionyl chloride ...Phosphorus compounds, Electrical conductivity, Calibration, Solutions(Mixtures), Electrical resistance, Performance tests, Solvents, Lithium compounds

  11. Bioactive dietary polyphenols decrease heme iron absorption by decreasing basolateral iron release in human intestinal Caco-2 cells.

    Science.gov (United States)

    Ma, Qianyi; Kim, Eun-Young; Han, Okhee

    2010-06-01

    Because dietary polyphenolic compounds have a wide range of effects in vivo and vitro, including chelation of metals such as iron, it is prudent to test whether the regular consumption of dietary bioactive polyphenols impair the utilization of dietary iron. Because our previous study showed the inhibitory effect of (-) -epigallocatechin-3-gallate (EGCG) and grape seed extract (GSE) on nonheme iron absorption, we investigated whether EGCG and GSE also affect iron absorption from heme. The fully differentiated intestinal Caco-2 cells grown on microporous membrane inserts were incubated with heme (55)Fe in uptake buffer containing EGCG or GSE in the apical compartment for 7 h. Both EGCG and GSE decreased (P heme-derived iron. However, apical heme iron uptake was increased (P heme (55)Fe, the transfer of iron across the intestinal basolateral membrane was extremely low, indicating that basolateral export was impaired by GSE. In contrast, EGCG moderately decreased the cellular assimilation of heme (55)Fe, but the basolateral iron transfer was extremely low, suggesting that the basolateral efflux of heme iron was also inhibited by EGCG. Expression of heme oxygenase, ferroportin, and hephaestin protein was not changed by EGCG and GSE. The apical uptake of heme iron was temperature dependent and saturable in fully differentiated Caco-2 cells. Our data show that bioactive dietary polyphenols inhibit heme iron absorption mainly by reducing basolateral iron exit rather than decreasing apical heme iron uptake in intestinal cells.

  12. Basolateral Mg2+ extrusion via CNNM4 mediates transcellular Mg2+ transport across epithelia: a mouse model.

    Directory of Open Access Journals (Sweden)

    Daisuke Yamazaki

    Full Text Available Transcellular Mg(2+ transport across epithelia, involving both apical entry and basolateral extrusion, is essential for magnesium homeostasis, but molecules involved in basolateral extrusion have not yet been identified. Here, we show that CNNM4 is the basolaterally located Mg(2+ extrusion molecule. CNNM4 is strongly expressed in intestinal epithelia and localizes to their basolateral membrane. CNNM4-knockout mice showed hypomagnesemia due to the intestinal malabsorption of magnesium, suggesting its role in Mg(2+ extrusion to the inner parts of body. Imaging analyses revealed that CNNM4 can extrude Mg(2+ by exchanging intracellular Mg(2+ with extracellular Na(+. Furthermore, CNNM4 mutations cause Jalili syndrome, characterized by recessive amelogenesis imperfecta with cone-rod dystrophy. CNNM4-knockout mice showed defective amelogenesis, and CNNM4 again localizes to the basolateral membrane of ameloblasts, the enamel-forming epithelial cells. Missense point mutations associated with the disease abolish the Mg(2+ extrusion activity. These results demonstrate the crucial importance of Mg(2+ extrusion by CNNM4 in organismal and topical regulation of magnesium.

  13. Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats

    Directory of Open Access Journals (Sweden)

    Venkata Ramana Vollala

    2011-01-01

    Full Text Available OBJECTIVE: In the ancient Indian system of medicine, Ayurveda, Bacopa monniera is classified as Medhya rasayana, which includes medicinal plants that rejuvenate intellect and memory. Here, we investigated the effect of a standardized extract of Bacopa monniera on the dendritic morphology of neurons in the basolateral amygdala, a region that is concerned with learning and memory. METHODS: The present study was conducted on 2¹/2-month-old Wistar rats. The rats were divided into 2-, 4- and 6-week treatment groups. Rats in each of these groups were further divided into 20 mg/kg, 40 mg/kg and 80 mg/kg dose groups (n = 8 for each dose. After the treatment period, treated rats and age-matched control rats were subjected to spatial learning (T-maze and passive avoidance tests. Subsequently, these rats were killed by decapitation, the brains were removed, and the amygdaloid neurons were impregnated with silver nitrate (Golgi staining. Basolateral amygdaloid neurons were traced using camera lucida, and dendritic branching points (a measure of dendritic arborization and dendritic intersections (a measure of dendritic length were quantified. These data were compared with the data from the age-matched control rats. RESULTS: The results showed an improvement in spatial learning performance and enhanced memory retention in rats treated with Bacopa monniera extract. Furthermore, a significant increase in dendritic length and the number of dendritic branching points was observed along the length of the dendrites of the basolateral amygdaloid neurons of rats treated with 40 mg/kg and 80 mg/kg of Bacopa monniera (BM for longer periods of time (i.e., 4 and 6 weeks. CONCLUSION: We conclude that constituents present in Bacopa monniera extract have neuronal dendritic growth-stimulating properties.

  14. Development and physiology of GABAergic feedback excitation in parvalbumin expressing interneurons of the mouse basolateral amygdala

    OpenAIRE

    Spampanato, Jay; Sullivan, Robert K. P.; Perumal, Madhusoothanan B.; Sah, Pankaj

    2016-01-01

    Abstract We have previously shown that in the basolateral amygdala (BLA), action potentials in one type of parvalbumin (PV)‐expressing GABAergic interneuron can evoke a disynaptic feedback excitatory postsynaptic potential (fbEPSP) onto the same presynaptic interneuron. Here, using whole‐cell recordings from PV‐expressing interneurons in acute brain slices we expand on this finding to show that this response is first detectable at 2‐week postnatal, and is most prevalent in animals beyond 3 we...

  15. Intracellular calcium modulates basolateral K(+)-permeability in frog skin epithelium

    DEFF Research Database (Denmark)

    Brodin, Birger; Rytved, K A; Nielsen, R

    1994-01-01

    Cytosolic calcium ([Ca2+]i) has been suggested as a key modulator in the regulation of active sodium transport across electrically "tight" (high resistance) epithelia. In this study we investigated the effects of calcium on cellular electrophysiological parameters in a classical model tissue......, the frog skin. [Ca2+]i was measured with fura-2 in an epifluorescence microscope setup. An inhibition of basolateral potassium permeability was observed when cytosolic calcium was increased. This inhibition was reversible upon removal of calcium from the serosal solution....

  16. Morphogenesis of the epithelial cell transporting phenotype: synthesis and distribution of ion channels.

    Science.gov (United States)

    García-Villegas, M R; Valdés, J; Reyes, G; Moreno, J; Cortes, N; Contreras, R G; Cereijido, M

    1996-05-01

    The exchange of substances between higher organisms and the environment takes place across epithelia consisting of one or more cell layers. To perform this function, epithelial cells have two basic differentiated properties: 1) they form tight junctions (TJs) that seal the extracellular space, and 2) they are polarized into an apical and a basolateral domain, with entirely different structural, biochemical and physiological properties. Our understanding of the mechanisms involved in the expression of these properties has been greatly enhanced by the availability of epithelial cell lines that form TJs and polarize in vitro under conditions suitable for experimental control. In this article we summarize our studies on the synthesis and polarized expression of ion channels in epithelial cells. MDCK cells have four types of K+ channels in the apical domain, and a fifth one in the basolateral domain. The basolateral side also has a population of CI- channels. Each type of channel is absolutely polarized. Harvesting with trypsin-EDTA reduces the area of the plasma membrane by 50% and the channel population by 90%. Upon plating, these channels are recovered within a few hours. We describe here the main extracellular and intracellular mechanisms involved in these phenomena.

  17. Prefrontal cortex, hippocampus, and basolateral amygdala plasticity in a rat model of autism spectrum.

    Science.gov (United States)

    Sosa-Díaz, Nuvia; Bringas, Maria Elena; Atzori, Marco; Flores, Gonzalo

    2014-10-01

    We aimed to investigate the effect of prenatal administration of valproic acid (VPA) (500 mg/kg) at embryonic day 12.5 on the anatomical properties of the prefrontal cortex, hippocampus, and basolateral amygdala, at three different ages: immediately after weaning (postnatal day 21 [PD21]), prepubertal (PD35), and postpubertal (PD70) ages in a rat model of autistic spectrum disorder. Quantitative analysis of the thickness of the prefrontal cortex revealed a reduced size at all study ages in the cingulate 1 area of the prefrontal cortex and CA1 of the dorsal hippocampus in prenatally exposed animals compared to controls. At the level of the basolateral amygdala, a reduction in the size was observed at PD35 and PD70 in the VPA group. In addition, a reduced thickness was observed in the prelimbic region of the prefrontal cortex in VPA animals at PD35. Interestingly, no differences in cortical thickness were observed between control and VPA animals in the infralimbic region of the prefrontal at any age. Our results suggest that prenatal exposure to VPA differentially alters cortical limbic regions anatomical parameters, with implication in the autistic spectrum disorder.

  18. Cortical inputs innervate calbindin-immunoreactive interneurons of the rat basolateral amygdaloid complex.

    Science.gov (United States)

    Unal, Gunes; Paré, Jean-Francois; Smith, Yoland; Paré, Denis

    2014-06-01

    The present study was undertaken to shed light on the synaptic organization of the rat basolateral amygdala (BLA). The BLA contains multiple types of GABAergic interneurons that are differentially connected with extrinsic afferents and other BLA cells. Previously, it was reported that parvalbumin immunoreactive (PV(+) ) interneurons receive strong excitatory inputs from principal BLA cells but very few cortical inputs, implying a prevalent role in feedback inhibition. However, because prior physiological studies indicate that cortical afferents do trigger feedforward inhibition in principal cells, the present study aimed to determine whether a numerically important subtype of interneurons, expressing calbindin (CB(+) ), receives cortical inputs. Rats received injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHAL) in the perirhinal cortex or adjacent temporal neocortex. Light and electron microscopic observations of the relations between cortical inputs and BLA neurons were performed in the lateral (LA) and basolateral (BL) nuclei. Irrespective of the injection site (perirhinal or temporal neocortex) and target nucleus (LA or BL), ~90% of cortical axon terminals formed asymmetric synapses with dendritic spines of principal BLA neurons, while 10% contacted the dendritic shafts of presumed interneurons, half of which were CB(+) . Given the previously reported pattern of CB coexpression among GABAergic interneurons of the BLA, these results suggest that a subset of PV-immunonegative cells that express CB, most likely the somatostatin-positive interneurons, are important mediators of cortically evoked feedforward inhibition in the BLA.

  19. Insulin-like growth factor II stimulates production of inositol trisphosphate in proximal tubular basolateral membranes from canine kidney.

    OpenAIRE

    Rogers, S A; Hammerman, M R

    1988-01-01

    To determine whether insulin-like growth factor II (IGF-II) activates phospholipase C in the basolateral membrane of the renal proximal tubular cell, we incubated basolateral membranes isolated from canine kidney with rat IGF-II (rIGF-II) and measured levels of inositol trisphosphate (Ins-P3) in suspensions and of diacylglycerol extractable from the membranes. Incubation with rIGF-II increased levels of Ins-P3 and diacylglycerol in a concentration-dependent manner. Significant enhancement of ...

  20. Pharmacological analysis of epithelial chloride secretion mechanisms in adult murine airways.

    Science.gov (United States)

    Gianotti, Ambra; Ferrera, Loretta; Philp, Amber R; Caci, Emanuela; Zegarra-Moran, Olga; Galietta, Luis J V; Flores, Carlos A

    2016-06-15

    Defective epithelial chloride secretion occurs in humans with cystic fibrosis (CF), a genetic defect due to loss of function of CFTR, a cAMP-activated chloride channel. In the airways, absence of an active CFTR causes a severe lung disease. In mice, genetic ablation of CFTR function does not result in similar lung pathology. This may be due to the expression of an alternative chloride channel which is activated by calcium. The most probable protein performing this function is TMEM16A, a calcium-activated chloride channel (CaCC). Our aim was to assess the relative contribution of CFTR and TMEM16A to chloride secretion in adult mouse trachea. For this purpose we tested pharmacological inhibitors of chloride channels in normal and CF mice. The amplitude of the cAMP-activated current was similar in both types of animals and was not affected by a selective CFTR inhibitor. In contrast, a CaCC inhibitor (CaCCinh-A01) strongly blocked the cAMP-activated current as well as the calcium-activated chloride secretion triggered by apical UTP. Although control experiments revealed that CaCCinh-A01 also shows inhibitory activity on CFTR, our results indicate that transepithelial chloride secretion in adult mouse trachea is independent of CFTR and that another channel, possibly TMEM16A, performs both cAMP- and calcium-activated chloride transport. The prevalent function of a non-CFTR channel may explain the absence of a defect in chloride transport in CF mice.

  1. Fasting induces basolateral uptake transporters of the SLC family in the liver via HNF4alpha and PGC1alpha.

    Science.gov (United States)

    Dietrich, Christoph G; Martin, Ina V; Porn, Anne C; Voigt, Sebastian; Gartung, Carsten; Trautwein, Christian; Geier, Andreas

    2007-09-01

    Fasting induces numerous adaptive changes in metabolism by several central signaling pathways, the most important represented by the HNF4alpha/PGC-1alpha-pathway. Because HNF4alpha has been identified as central regulator of basolateral bile acid transporters and a previous study reports increased basolateral bile acid uptake into the liver during fasting, we hypothesized that HNF4alpha is involved in fasting-induced bile acid uptake via upregulation of basolateral bile acid transporters. In rats, mRNA of Ntcp, Oatp1, and Oatp2 were significantly increased after 48 h of fasting. Protein expression as determined by Western blot showed significant increases for all three transporters 72 h after the onset of fasting. Whereas binding activity of HNF1alpha in electrophoretic mobility shift assays remained unchanged, HNF4alpha binding activity to the Ntcp promoter was increased significantly. In line with this result, we found significantly increased mRNA expression of HNF4alpha and PGC-1alpha. Functional studies in HepG2 cells revealed an increased endogenous NTCP mRNA expression upon cotransfection with either HNF4alpha, PGC-1alpha, or a combination of both. We conclude that upregulation of the basolateral bile acid transporters Ntcp, Oatp1, and Oatp2 in fasted rats is mediated via the HNF4alpha/PGC-1alpha pathway.

  2. A Different Recruitment of the Lateral and Basolateral Amygdala Promotes Contextual or Elemental Conditioned Association in Pavlovian Fear Conditioning

    Science.gov (United States)

    Calandreau, Ludovic; Desmedt, Aline; Decorte, Laurence; Jaffard, Robert

    2005-01-01

    Convergent data suggest dissociated roles for the lateral (LA) and basolateral (BLA) amygdaloid nuclei in fear conditioning, depending on whether a discrete conditioned stimulus (CS)-unconditional stimulus (US) or context-US association is considered. Here, we show that pretraining inactivation of the BLA selectively impaired conditioning to…

  3. Basolateral Amygdala Projections to Ventral Hippocampus Modulate the Consolidation of Footshock, but Not Contextual, Learning in Rats

    Science.gov (United States)

    Huff, Mary L.; Emmons, Eric B.; Narayanan, Nandakumar S.; LaLumiere, Ryan T.

    2016-01-01

    The basolateral amygdala (BLA) modulates memory consolidation for a variety of types of learning, whereas other brain regions play more selective roles in specific kinds of learning suggesting a role for differential consolidation via distinct BLA pathways. The ventral hippocampus (VH), an efferent target of the BLA, has been suggested to…

  4. Distinct Contributions of the Basolateral Amygdala and the Medial Prefrontal Cortex to Learning and Relearning Extinction of Context Conditioned Fear

    Science.gov (United States)

    Laurent, Vincent; Westbrook, R. Frederick

    2008-01-01

    We studied the roles of the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC) in learning and relearning to inhibit context conditioned fear (freezing) in extinction. In Experiment 1, pre-extinction BLA infusion of the NMDA receptor (NMDAr) antagonist, ifenprodil, impaired the development and retention of inhibition but…

  5. Anti-inflammatory activity of the basolateral fraction of Caco-2 cells exposed to a rosemary supercritical extract

    NARCIS (Netherlands)

    Arranz, E.; Mes, J.J.; Wichers, H.J.; Jaime, L.; Reglero, G.; Santoyo, S.

    2015-01-01

    The anti-inflammatory activity of the basolateral fraction of Caco-2 cells exposed to a rosemary supercritical extract was examined. Uptake of rosemary extract fractions was tested on Caco-2 cell monolayers (2–12 h incubation times) and the quantification of carnosic acid and carnosol was performed

  6. 17beta-Estradiol reduces excitatory postsynaptic potential (EPSP) amplitude in rat basolateral amygdala neurons.

    Science.gov (United States)

    Womble, Mark D; Andrew, James A; Crook, Joseph J

    2002-10-11

    We examined the actions of estrogen on excitatory synaptic transmission in the basolateral amygdala (BLA), a brain region involved in learning, emotions, and the effects of stress. Intracellular recordings of monosynaptic excitatory postsynaptic potentials (EPSPs) were obtained from BLA neurons in a slice preparation. Bath application of 17beta-estradiol (2 micro M) reduced EPSP amplitude by an average of 77%. This reduction was readily reversed by washing with control saline and was not mimicked by the inactive isomer 17 alpha-estradiol. Other passive and active properties of BLA neurons were unaffected by 17beta-estradiol. The observed EPSP reduction is in sharp contrast to the potentiation of EPSPs by estrogen observed in other brain regions.

  7. Neuropeptide S interacts with the basolateral amygdala noradrenergic system in facilitating object recognition memory consolidation.

    Science.gov (United States)

    Han, Ren-Wen; Xu, Hong-Jiao; Zhang, Rui-San; Wang, Pei; Chang, Min; Peng, Ya-Li; Deng, Ke-Yu; Wang, Rui

    2014-01-01

    The noradrenergic activity in the basolateral amygdala (BLA) was reported to be involved in the regulation of object recognition memory. As the BLA expresses high density of receptors for Neuropeptide S (NPS), we investigated whether the BLA is involved in mediating NPS's effects on object recognition memory consolidation and whether such effects require noradrenergic activity. Intracerebroventricular infusion of NPS (1nmol) post training facilitated 24-h memory in a mouse novel object recognition task. The memory-enhancing effect of NPS could be blocked by the β-adrenoceptor antagonist propranolol. Furthermore, post-training intra-BLA infusions of NPS (0.5nmol/side) improved 24-h memory for objects, which was impaired by co-administration of propranolol (0.5μg/side). Taken together, these results indicate that NPS interacts with the BLA noradrenergic system in improving object recognition memory during consolidation.

  8. Low-frequency stimulation of the kindling focus delays basolateral amygdala kindling in immature rats.

    Science.gov (United States)

    Velísek, Libor; Velísková, Jana; Stanton, Patric K

    2002-06-21

    Stimulation of deep brain sites is a new approach for treatment of intractable seizures. In adult rats, low-frequency stimulation (LFS; 1-3 Hz) of the kindling site interferes with the course of kindling epileptogenesis. In this study we determined whether the LFS will be effective against the fast kindling in the basolateral amygdala in immature, 15 day old rats. LFS (15 min of 1 Hz stimulation) was applied after each of the 1 s, 60 Hz kindling stimulus. LFS suppressed afterdischarge duration and seizure stage throughout the course of kindling, which indicates a strong antiepileptogenic potential. As the kindling and LFS stimulation patterns are similar to those used for induction of long-term potentiation and long-term depression (LTD), respectively, LTD or depotentiation may play a role in the mechanism of action.

  9. Protein synthesis inhibition in the basolateral nucleus of amygdala facilitates extinction of auditory fear memory

    Institute of Scientific and Technical Information of China (English)

    JIN XinChun; QI XueLian; YANG XiaoFei; LI BaoMing

    2007-01-01

    It is known that consolidation of fear conditioning requires de novo protein synthesis in the amygdala. However, there is controversy about the role of protein synthesis in post-retrieval extinction of fear memory. The present study investigated the effect of protein synthesis inhibition (PSI) in the basolateral nucleus of amygdala (BLA) on post-retrieval extinction of auditory fear memory. Intra-BLA infusion of the protein synthesis inhibitor anisomycin '0' h post-retrieval facilitated the extinction, but was ineffective if the memory was not retrieved. Anisomycin had no effect on the extinction when it was infused 6 h post-retrieval. The present results suggest that there exists a protein-synthesis-dependent mechanism in the BLA that retards extinction of auditory fear memory.

  10. Dynamic patterns of colocalization of calbindin, parvalbumin and GABA in subpopulations of mouse basolateral amygdalar cells during development.

    Science.gov (United States)

    Dávila, José Carlos; Olmos, Luis; Legaz, Isabel; Medina, Loreta; Guirado, Salvador; Real, Maria Angeles

    2008-01-01

    Calbindin cells represent a major interneuron subtype of the cortical/pallial regions, such as the basolateral amygdala, which are often analyzed in studies of tangential migration of interneurons from the subpallial ganglionic eminences to the pallium/cortex. However, previous evidence suggests that during development the calbindin cells may include more than one of the interneuron subtypes found in the adult pallium/cortex. Furthermore, in the adult basolateral amygdala, calbindin cells include a subpopulation of non-GABAergic (non-interneuron) cells. To better characterize these cells throughout development, in the present study we investigated the colocalization of calbindin, parvalbumin and GABA in cells of the mouse basolateral amygdala during late embryonic (E16.5) and several postnatal ages from birth until 4 weeks after birth (P0, P10 and P28). Our results indicate that CB, PV and GABA show a dynamic pattern of colocalization in cells of the mouse basolateral amygdalar nucleus throughout development. From E16.5 through P28, the majority of CB+ neurons and virtually all PV+ neurons are GABAergic. However, after P10, the percentage of GABAergic CB+ cells decline from 96% to 70%. Furthermore, while only 9% of CB+ neurons are PV+ at P10, this percentage raises to 42% at P28. At all postnatal ages studied, the majority of the PV+ cells are CB+, suggesting that PV+ interneurons develop postnatally mainly as a subpopulation within the CB+ cells of the basolateral amygdalar nucleus. These results are important for interpreting data from interneuron migration.

  11. Changes of glucocorticoid receptor mRNA expression in basolateral amygdale-kindled rats

    Institute of Scientific and Technical Information of China (English)

    BAO Guan-shui; CHENG Xu-qin; HUA Yin; WANG Zhe-dong; LIU Zhen-guo

    2011-01-01

    Background Glucocorticoid receptor (GR) is believed to be a major factor in brain maturation and in modulation of a series of brain activity.Hippocampal neurons are abundant in glucocorticoid receptor,and there is significant change in GR expression under certain pathological state.Epilepsy is a special pathological state of the central nervous system.This study aimed to explore the role of GR in epilepsy by observing the change and functions of GR in hippocampus with a basolateral amygdale-electrical kindled rat epilepsy model.Methods Firstly,we established the basolateral amygdale-electrical kindled rat epilepsy model.Then GR mRNA expression in the hippocampus was assayed by semi-quantitative reverse transcription-PCR in this experiment.In addition,the processes of epileptic seizures were observed and electroencephalograms were recorded.One-way analysis of variance (ANOVA) was employed for comparing means of multiple groups,followed Fisher's least significant difference (LSD) for paired comparison.Results The rats were successfully kindled after an average of (13.50±3.99) times electrical stimulation,in which it was showed that GR mRNA expression reduced obviously as compared with the control group and the sham groups (P<0.001).The down-regulation of GR mRNA expression was abated or reversed by some anti-epilepsy drugs (P <0.001 compared with the epilepsy group),accompanied by attenuation of seizures and improvement of electroencephalograms.Conclusions Down-regulation of hippocampal GR mRNA expression may be related to the kindling.Anti-epilepsy drugs exposure can retard this change.

  12. Dynamic [Cl-]i measurement with chloride sensing quantum dots nanosensor in epithelial cells

    Science.gov (United States)

    Wang, Yuchi; Mao, Hua; Wong, Lid B.

    2010-02-01

    We have synthesized a chloride sensing quantum dots (QD) nanosensor, Cl-QD, for the dynamic measurements of chloride ion concentration in the millimolar range, a sensitivity that is applicable to most physiological intracellular chloride ion concentration ([Cl-]i) measurements in epithelial cells. The Cl-QD is synthesized by conjugating an anion receptor, 1-(2-mercapto-ethyl)-3-phenyl-thiourea (MEPTU) to a water soluble CdSe/ZnS QD at an emission wavelength of 620 nm. Upon binding of chloride ions to the Cl-QD, a photo-induced electron transfer mechanism caused the fluorescence of the QD to quench. This resulted in an inversely proportional relationship between the chloride ion concentration and the fluorescence intensity of the Cl-QD. We have utilized this Cl-QD to measure [Cl-]i in T84 and CF-PAC cultured cells, with either the C1C-2 or CFTR chloride channels being manipulated by pharmacological chloride channel activators and inhibitors. Activations of C1C-2 and CFTR chloride channels in T84 by the respective lubiprostone and genistein caused predictive increases in the fluorescence of the Cl-QD, i.e., a decrease of [Cl-]i. Conversely, glibenclamide, a chloride channel inhibitor, applied to the CF-PAC cells caused a predictable decrease in the fluorescence of Cl-QD due to the increase of [Cl-]i. These are the first data in using QD-based chloride ion sensors for dynamic measurements of intracellular chloride ion concentrations in epithelial cells.

  13. Dynamic [Cl{sup -}]{sub i} measurement with chloride sensing quantum dots nanosensor in epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yuchi; Mao Hua; Wong, Lid B, E-mail: ywang@biotechplex.com [BioTechPlex Corporation, 1205 Linda Vista Drive Suite A, San Marcos, CA 92078 (United States); Cytoptics Corporation, 1205 Linda Vista Drive Suite B, San Marcos, CA 92078 (United States)

    2010-02-05

    We have synthesized a chloride sensing quantum dots (QD) nanosensor, Cl-QD, for the dynamic measurements of chloride ion concentration in the millimolar range, a sensitivity that is applicable to most physiological intracellular chloride ion concentration ([Cl{sup -}]{sub i}) measurements in epithelial cells. The Cl-QD is synthesized by conjugating an anion receptor, 1-(2-mercapto-ethyl)-3-phenyl-thiourea (MEPTU) to a water soluble CdSe/ZnS QD at an emission wavelength of 620 nm. Upon binding of chloride ions to the Cl-QD, a photo-induced electron transfer mechanism caused the fluorescence of the QD to quench. This resulted in an inversely proportional relationship between the chloride ion concentration and the fluorescence intensity of the Cl-QD. We have utilized this Cl-QD to measure [Cl{sup -}]{sub i} in T84 and CF-PAC cultured cells, with either the C1C-2 or CFTR chloride channels being manipulated by pharmacological chloride channel activators and inhibitors. Activations of C1C-2 and CFTR chloride channels in T84 by the respective lubiprostone and genistein caused predictive increases in the fluorescence of the Cl-QD, i.e., a decrease of [Cl{sup -}]{sub i}. Conversely, glibenclamide, a chloride channel inhibitor, applied to the CF-PAC cells caused a predictable decrease in the fluorescence of Cl-QD due to the increase of [Cl{sup -}]{sub i}. These are the first data in using QD-based chloride ion sensors for dynamic measurements of intracellular chloride ion concentrations in epithelial cells.

  14. Benzalkonium Chloride and Glaucoma

    OpenAIRE

    Rasmussen, Carol A.; Kaufman, Paul L.; Kiland, Julie A.

    2014-01-01

    Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapo...

  15. Inhibition of intestinal chloride secretion by piperine as a cellular basis for the anti-secretory effect of black peppers.

    Science.gov (United States)

    Pongkorpsakol, Pawin; Wongkrasant, Preedajit; Kumpun, Saowanee; Chatsudthipong, Varanuj; Muanprasat, Chatchai

    2015-10-01

    Piperine is the principal alkaloid in black peppers (Piper nigrum L.), which is a commonly included spice in anti-diarrheal formulations. Piperine has antispasmodic activities, but its anti-secretory effect is not known. Therefore, this study investigated the anti-secretory effect of piperine and its underlying mechanism. Piperine inhibited cAMP-mediated Cl- secretion in human intestinal epithelial (T84) cells, similar to black pepper extract. Intraluminal administration of piperine (2 μg/loop) suppressed cholera toxin-induced intestinal fluid accumulation by ∼85% in mice. The anti-secretory mechanism of piperine was investigated by evaluating its effects on the activity of transport proteins involved in cAMP-mediated Cl- secretion. Notably, piperine inhibited CFTR Cl- channel activity (IC50#8'6#10 μM) without affecting intracellular cAMP levels. The mechanisms of piperine-induced CFTR inhibition did not involve MRP4-mediated cAMP efflux, AMPK or TRPV1. Piperine also inhibited cAMP-activated basolateral K+ channels, but it had no effect on Na+-K+-Cl- cotransporters or Na+-K+ ATPases. Piperine suppressed Ca2+-activated Cl- channels (CaCC) without affecting intracellular Ca2+ concentrations or Ca2+-activated basolateral K+ channels. Collectively, this study indicates that the anti-secretory effect of piperine involves the inhibition of CFTR, CaCC and cAMP-activated basolateral K+ channels. Piperine represents a novel class of drug candidates for the treatment of diarrheal diseases caused by the intestinal hypersecretion of Cl-.

  16. 高浓度胆汁改变肠上皮细胞氯通道蛋白-2和通透性%High concentration bile changes the chloride channel protein-2 and permeability of intestinal epithelium cell line

    Institute of Scientific and Technical Information of China (English)

    陈振勇; 张劲; 杨鹏; 黄文广; 冯贤松

    2011-01-01

    Objective To investigate the effects of bile on chloride channel protein-2 (CLC-2)and permeability of intestinal epithelium cell.Methods Rat intestinal epithelium cell line IEC-6 was cultured.They were exposed to 5.0%,1.0%,0.1% rat bile and chloride channel agonist Lubiprostone.After 20 h cultured,transepithelial electrical resistance (TER) of the monostratal cells was measured.The change of CLC-2 and zonula occludens-1 (ZO-1) were examined by Western blotting,and the images were analysed quantitatively.Results The TEER of 5% group was most lower.The average relative gradations of Western blotting images in 5.0% group and 1.0% were lower obviously than those in control group (0.30 ± 0.05,0.37 ± 0.08 vs.0.56 ± 0.08) ( all P < 0.05 ).The relative gradations of ZO-1 were decreaseded only in 5.0% group.After Lubiprostone added,the TER in 5.0% group was upgraded (451.3 ± 60.5 )Ω·cm2,and the average relative gradations of ZO-1 (0.32 ± 0.04).Conclusion High concentration of bile destroied enterocyte chloride channel and tight junction protein,increase epithelium permeabihty.%目的 观察胆汁对肠上皮细胞氯离子通道和通透性的影响.方法 鼠肠上皮细胞株IEC-6分别与5.0%、1.0%、0.1%胆汁及氯通道激动剂接触.20h后检测跨膜电阻,Western blot分析氯离子通道蛋白-2(CLC-2)和紧密连接闭锁小带-1(ZO-1)表达的变化及各条带的相对灰度值.结果 5.0%浓度组降低跨膜电阻作用最强.5.0%和1.0%组的CLC-2蛋白相对灰度值(0.30±0.05和0.37±0.08)低于对照组(P均<0.05).5.0%组的ZO-1相对表达量下降.添加氯通道激动剂后,5.0%浓度组的跨膜电阻(451.3±60.5)Ω.cm2及ZO-1相对表达量(0.32±0.04)较对照组上升明显(P均<0.05).结论 高浓度胆汁破坏肠上皮细胞氯离子通道和紧密连接蛋白,增加上皮细胞通透性.

  17. Fungal colonization with Pneumocystis correlates to increasing chloride channel accessory 1 (hCLCA1 suggesting a pathway for up-regulation of airway mucus responses, in infant lungs

    Directory of Open Access Journals (Sweden)

    Francisco J. Pérez

    2014-01-01

    Full Text Available Fungal colonization with Pneumocystis is associated with increased airway mucus in infants during their primary Pneumocystis infection, and to severity of COPD in adults. The pathogenic mechanisms are under investigation. Interestingly, increased levels of hCLCA1 – a member of the calcium-sensitive chloride conductance family of proteins that drives mucus hypersecretion – have been associated with increased mucus production in patients diagnosed with COPD and in immunocompetent rodents with Pneumocystis infection. Pneumocystis is highly prevalent in infants; therefore, the contribution of Pneumocystis to hCLCA1 expression was examined in autopsied infant lungs. Respiratory viruses that may potentially increase mucus, were also examined. hCLCA1 expression was measured using actin-normalized Western-blot, and the burden of Pneumocystis organisms was quantified by qPCR in 55 autopsied lungs from apparently healthy infants who died in the community. Respiratory viruses were diagnosed using RT-PCR for RSV, metapneumovirus, influenza, and parainfluenza viruses; and by PCR for adenovirus. hCLCA1 levels in virus positive samples were comparable to those in virus-negative samples. An association between Pneumocystis and increased hCLCA1 expression was documented (P=0.028. Additionally, increasing Pneumocystis burden correlated with increasing hCLCA1 protein expression levels (P=0.017. Results strengthen the evidence of Pneumocystis-associated up-regulation of mucus-related airway responses in infant lungs. Further characterization of this immunocompetent host-Pneumocystis-interaction, including assessment of potential clinical significance, is warranted.

  18. Ion channels-related diseases.

    Science.gov (United States)

    Dworakowska, B; Dołowy, K

    2000-01-01

    There are many diseases related to ion channels. Mutations in muscle voltage-gated sodium, potassium, calcium and chloride channels, and acetylcholine-gated channel may lead to such physiological disorders as hyper- and hypokalemic periodic paralysis, myotonias, long QT syndrome, Brugada syndrome, malignant hyperthermia and myasthenia. Neuronal disorders, e.g., epilepsy, episodic ataxia, familial hemiplegic migraine, Lambert-Eaton myasthenic syndrome, Alzheimer's disease, Parkinson's disease, schizophrenia, hyperekplexia may result from dysfunction of voltage-gated sodium, potassium and calcium channels, or acetylcholine- and glycine-gated channels. Some kidney disorders, e.g., Bartter's syndrome, policystic kidney disease and Dent's disease, secretion disorders, e.g., hyperinsulinemic hypoglycemia of infancy and cystic fibrosis, vision disorders, e.g., congenital stationary night blindness and total colour-blindness may also be linked to mutations in ion channels.

  19. Oxomemazine hydro-chloride.

    Science.gov (United States)

    Siddegowda, M S; Butcher, Ray J; Akkurt, Mehmet; Yathirajan, H S; Ramesh, A R

    2011-08-01

    IN THE TITLE COMPOUND [SYSTEMATIC NAME: 3-(5,5-dioxo-phen-othia-zin-10-yl)-N,N,2-trimethyl-propanaminium chloride], C(18)H(23)N(2)O(2)S(+)·Cl(-), the dihedral angle between the two outer aromatic rings of the phenothia-zine unit is 30.5 (2)°. In the crystal, the components are linked by N-H⋯Cl and C-H⋯Cl hydrogen bonds and C-H⋯π inter-actions.

  20. Basolateral P2X receptors mediate inhibition of NaCl transport in mouse medullary thick ascending limb (mTAL)

    DEFF Research Database (Denmark)

    Marques, Rita D; de Bruijn, Pauline I.A.; Sørensen, Mads Vaarby;

    2012-01-01

    Extracellular nucleotides regulate epithelial transport via luminal and basolateral P2 receptors. Renal epithelia express multiple P2 receptors, which mediate significant inhibition of solute absorption. Recently, we identified several P2 receptors in the medullary thick ascending limb (m......TAL) including luminal and basolateral P2Y(2) receptors. In addition, we found evidence for a basolateral P2X receptor. Here we investigate the effect of basolateral ATP on NaCl absorption in isolated, perfused mouse mTALs using the electrical measurement of equivalent short circuit current (I'(sc)). Non...... receptor antagonist suramin blocked the effect. P2Y receptors were found not to be involved in this effect. The P2X receptor agonist 2MeSATP mimicked the ATP effect and the P2X receptor antagonist oATP blocked it. In P2X(7)(-/-) mice the ATP effect remained unaltered. In contrast, in P2X(4)(-/-) mice...

  1. Increased basolateral sorting of carcinoembryonic antigen in a polarized colon carcinoma cell line after cholesterol depletion-Implications for treatment of inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Robert Ehehalt; Markus Krautter; Martin Zorn; Richard Sparla; Joachim Fūllekrug; Hasan Kulaksiz; Wolfgang Stremmel

    2008-01-01

    AIM:To investigate a possible increase of basolateral expression of carcinoembryonic antigen(CEA)by interfering with the apical transport machinery,we studied the effect of cholesterol depletion on CEA sorting and secretion.METHODS:Cholesterol depletion was performed in polarized Caco-2 cells using Iovastatin and methyl-βcyclodextrin.RESULTS:We show that CEA is predominantly expressed and secreted at the apical surface.Reduction of the cholesterol level of the cell by 40%-50% with Iovastatin and methyl-β-cyclodextrin led to a significant change of the apical-to-basolateral transport ratio towards the basolateral membrane.CONCLUSION:As basolateral expression of CEA has been suggested to have anti-inflamatory properties,Cholesterol depletion of enterocytes might be a potential approach to influence the course of inflammatory bowel disease.

  2. Bile Acids Trigger GLP-1 Release Predominantly by Accessing Basolaterally Located G Protein-Coupled Bile Acid Receptors

    DEFF Research Database (Denmark)

    Brighton, Cheryl A.; Rievaj, Juraj; Kuhre, Rune E.;

    2015-01-01

    Bile acids are well-recognized stimuli of glucagon-like peptide-1 (GLP-1) secretion. This action has been attributed to activation of the G protein-coupled bile acid receptor GPBAR1 (TGR5), although other potential bile acid sensors include the nuclear farnesoid receptor and the apical sodium......-coupled bile acid transporter ASBT. The aim of this study was to identify pathways important for GLP-1 release and to determine whether bile acids target their receptors on GLP-1-secreting L-cells from the apical or basolateral compartment. Using transgenic mice expressing fluorescent sensors specifically in L...... to either TLCA or TDCA. We conclude that the action of bile acids on GLP-1 secretion is predominantly mediated by GPBAR1 located on the basolateral L-cell membrane, suggesting that stimulation of gut hormone secretion may include postabsorptive mechanisms....

  3. Differential roles of the basolateral amygdala and nucleus basalis magnocellularis during post-reactivation contextual fear conditioning reconsolidation in rats.

    Science.gov (United States)

    Baldi, Elisabetta; Mariottini, Chiara; Bucherelli, Corrado

    2008-11-01

    The roles of the basolateral amygdala and nucleus basalis magnocellularis in fear conditioning reconsolidation were investigated by means of tetrodotoxin bilateral inactivation performed 96 h after conditioning, immediately after reactivation training. Footshocks of 1.2 mA intensity were employed to induce the generalization phenomenon. Basolateral amygdala inactivation disrupts the contextual fear response and its generalization but not acoustic CS trace retention, when measured 72 and 96 h after tetrodotoxin administration. Nucleus basalis magnocellularis functional inactivation does not affect memory post-reactivation phase of any of the three conditioned fear responses. The present findings show a differential role of the two structures in fear memory reconsolidation and can be a starting point for future investigation of the neural circuits subserving generalization.

  4. Chloride uptake and base secretion in freshwater fish: a transepithelial ion-transport metabolon?

    Science.gov (United States)

    Tresguerres, Martin; Katoh, Fumi; Orr, Elizabeth; Parks, Scott K; Goss, Greg G

    2006-01-01

    Despite all the efforts and technological advances during the last few decades, the cellular mechanisms for branchial chloride uptake in freshwater (FW) fish are still unclear. Although a tight 1 : 1 link with HCO-3 secretion has been established, not much is known about the identity of the ion-transporting proteins involved or the energizing steps that allow for the inward transport of Cl- against the concentration gradient. We propose a new model for Cl- uptake in FW fish whereby the combined action of an apical anion exchanger, cytoplasmic carbonic anhydrase, and basolateral V-type H+ -ATPase creates a local [HCO-3] high enough to energize Cl- uptake. Our model is based on analyses of structure-function relationships, reinterpretation of previous results, and novel observations about gill cell subtypes and immunolocalization of the V-H+ -ATPase.

  5. Stimulation of Wild-Type, F508del- and G551D-CFTR Chloride Channels by Non-Toxic Modified pyrrolo[2,3-b]pyrazine Derivatives.

    Science.gov (United States)

    Dannhoffer, Luc; Billet, Arnaud; Jollivet, Mathilde; Melin-Heschel, Patricia; Faveau, Christelle; Becq, Frédéric

    2011-01-01

    Cystic fibrosis (CF) is a major inherited disorder involving abnormalities of fluid and electrolyte transport in a number of different organs due to abnormal function of cystic fibrosis transmembrane conductance regulator (CFTR) protein. We recently identified a family of CFTR activators, which contains the hit: RP107 [7-n-butyl-6-(4-hydroxyphenyl)[5H]-pyrrolo[2,3-b]pyrazine]. Here, we further evaluated the effect of the chemical modifications of the RP107-OH radical on CFTR activation. The replacement of the OH radical by a fluorine atom at position 2 (RP193) or 4 (RP185) significantly decreased the toxicity of the compounds without altering the ability to activate CFTR, especially for RP193. The non-toxic compound RP193 has no effect on cAMP production but stimulates the channel activity of wild-type CFTR in stably transfected CHO cells, in human bronchial epithelial NuLi-1 cells, and in primary culture of human bronchial epithelial cells (HBEC). Whole-cell and single patch-clamp recordings showed that RP193 induced a linear, time- and voltage-independent current, which was fully inhibited by two different and selective CFTR inhibitors (CFTRinh-172 and GP(inh)5a). Moreover, RP193 stimulates CFTR in temperature-rescued CuFi-1 (F508del/F508del) HBEC and in CHO cells stably expressing G551D-CFTR. This study shows that it is feasible to reduce cytotoxicity of chemical compounds without affecting their potency to activate CFTR and to rescue the class 2 F508del-CFTR and class 3 G551D-CFTR CF mutant activities.

  6. Macula densa Na(+)/H(+) exchange activities mediated by apical NHE2 and basolateral NHE4 isoforms.

    Science.gov (United States)

    Peti-Peterdi, J; Chambrey, R; Bebok, Z; Biemesderfer, D; St John, P L; Abrahamson, D R; Warnock, D G; Bell, P D

    2000-03-01

    Functional and immunohistochemical studies were performed to localize and identify Na(+)/H(+) exchanger (NHE) isoforms in macula densa cells. By using the isolated perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney, intracellular pH (pH(i)) was measured with fluorescence microscopy by using 2',7'-bis-(2-carboxyethyl)-5-(and -6) carboxyfluorescein. NHE activity was assayed by measuring the initial rate of Na(+)-dependent pH(i) recovery from an acid load imposed by prior lumen and bath Na(+) removal. Removal of Na(+) from the bath resulted in a significant, DIDS-insensitive, ethylisopropyl amiloride (EIPA)-inhibitable decrease in pH(i). This basolateral transporter showed very low affinity for EIPA and Hoechst 694 (IC(50) = 9.0 and 247 microM, respectively, consistent with NHE4). The recently reported apical NHE was more sensitive to inhibition by these drugs (IC(50) = 0.86 and 7.6 microM, respectively, consistent with NHE2). Increasing osmolality, a known activator of NHE4, greatly stimulated basolateral NHE. Immunohistochemical studies using antibodies against NHE1-4 peptides demonstrated expression of NHE2 along the apical and NHE4 along the basolateral, membrane, whereas NHE1 and NHE3 were not detected. These results suggest that macula densa cells functionally and immunologically express NHE2 at the apical membrane and NHE4 at the basolateral membrane. These two isoforms likely participate in Na(+) transport, pH(i), and cell volume regulation and may be involved in tubuloglomerular feedback signaling by these cells.

  7. PAH clearance after renal ischemia and reperfusion is a function of impaired expression of basolateral Oat1 and Oat3

    OpenAIRE

    Bischoff, Ariane; Bucher, Michael; Gekle, Michael; Sauvant, Christoph

    2014-01-01

    Abstract Determination of renal plasma flow (RPF) by para‐aminohippurate (PAH) clearance leads to gross underestimation of this respective parameter due to impaired renal extraction of PAH after renal ischemia and reperfusion injury. However, no mechanistic explanation for this phenomenon is available. Based on our own previous studies we hypothesized that this may be due to impairment of expression of the basolateral rate limiting organic anion transporters Oat1 and Oat3. Thus, we investigat...

  8. Hypotonic shock mediation by p38 MAPK, JNK, PKC, FAK, OSR1 and SPAK in osmosensing chloride secreting cells of killifish opercular epithelium

    DEFF Research Database (Denmark)

    Marshall, W. S.; Ossum, Carlo Gunnar; Hoffmann, Else Kay

    2005-01-01

    at the basolateral membrane. The protein tyrosine kinase inhibitor genistein (100 µmol l-1) inhibited Cl- secretion that was high, increased Cl- secretion that was low and reduced immunocytochemical staining for phosphorylated FAK. We present a model for rapid control of CFTR and NKCC in chloride cells that includes......: (1) activation of NKCC and CFTR via cAMP/PKA, (2) activation of NKCC by PKC, myosin light chain kinase (MLCK), p38, OSR1 and SPAK, (3) deactivation of NKCC by hypotonic cell swelling, Ca2+ and an as yet unidentified protein phosphatase and (4) involvement of protein tyrosine kinase (PTK) acting...

  9. Structural lipid changes and Na(+)/K(+)-ATPase activity of gill cells' basolateral membranes during saltwater acclimation in sea lamprey (Petromyzon marinus, L.) juveniles.

    Science.gov (United States)

    Lança, Maria João; Machado, Maria; Ferreira, Ana Filipa; Quintella, Bernardo Ruivo; de Almeida, Pedro Raposo

    2015-11-01

    Seawater acclimation is a critical period for anadromous species and a process yet to be understood in lampreys. Considering that changes in lipid composition of the gill cells' basolateral membranes may disrupt the major transporter Na(+)K(+)-ATPase, the goal of this study was to detect changes at this level during juvenile sea lamprey seawater acclimation. The results showed that saltwater acclimation has a direct effect on the fatty acid composition of gill cells basolateral membrane's phospholipids. When held in full-strength seawater, the fatty acid profile of basolateral membrane's phospholipids suffered a restructure by increasing either saturation or the ratio between oleic acid and eicosapentaenoic acid. Simultaneously, the activity of Na(+)K(+)-ATPase revealed a significant and positive correlation with basolateral membrane's cholesterol content in the presence of highest salinity. Our results pointed out for lipid adjustments involving the functional transporter present on the gill cell basolateral membranes to ensure the role played by branchial Na(+)K(+)-ATPase in ion transport during saltwater acclimation process. The responses observed contributed to the strategy adopted by gill cell's basolateral membranes to compensate for osmotic and ionic stressors, to ensure the success of the process of seawater acclimation associated with the downstream trophic migration of juvenile sea lamprey.

  10. PAH clearance after renal ischemia and reperfusion is a function of impaired expression of basolateral Oat1 and Oat3.

    Science.gov (United States)

    Bischoff, Ariane; Bucher, Michael; Gekle, Michael; Sauvant, Christoph

    2014-02-01

    Determination of renal plasma flow (RPF) by para-aminohippurate (PAH) clearance leads to gross underestimation of this respective parameter due to impaired renal extraction of PAH after renal ischemia and reperfusion injury. However, no mechanistic explanation for this phenomenon is available. Based on our own previous studies we hypothesized that this may be due to impairment of expression of the basolateral rate limiting organic anion transporters Oat1 and Oat3. Thus, we investigated this phenomenon in a rat model of renal ischemia and reperfusion by determining PAH clearance, PAH extraction, PAH net secretion, and the expression of rOat1 and rOat3. PAH extraction was seriously impaired after ischemia and reperfusion which led to a threefold underestimation of RPF when PAH extraction ratio was not considered. PAH extraction directly correlated with the expression of basolateral Oat1 and Oat3. Tubular PAH secretion directly correlated with PAH extraction. Consequently, our data offer an explanation for impaired renal PAH extraction by reduced expression of the rate limiting basolateral organic anion transporters Oat1 and Oat3. Moreover, we show that determination of PAH net secretion is suitable to correct PAH clearance for impaired extraction after ischemia and reperfusion in order to get valid results for RPF.

  11. GABAA-mediated inhibition of basolateral amygdala blocks reward devaluation in macaques.

    Science.gov (United States)

    Wellman, Laurie L; Gale, Karen; Malkova, Ludise

    2005-05-04

    Amygdala ablation disrupts reinforcer "devaluation" in monkeys (Malkova et al., 1997). Here, we tested the hypothesis that transient inactivation of amygdala by the GABA(A) agonist muscimol (MUS), specifically during the period of reward satiation, would have a similar effect. Six pigtail macaques were trained on a visual object discrimination task in which 60 objects were associated with one of two specific food rewards. Subsequently, we evaluated the selective satiation-induced change (devaluation) in object preference in probe sessions. We also examined the effect of the amygdala inactivation during the probe sessions to determine whether the inactivation limited to the testing period (and not during the satiation period) is sufficient to impair the expression of reinforcer devaluation. MUS infusions were aimed at basolateral amygdala (BLA) in a pseudorandomized design; each monkey received MUS or saline either before or after selective satiation with each of the two food rewards (six infusions total). Under the control (saline) condition, the monkeys significantly shifted their preference from objects representing the sated food rewards to those representing the nonsated rewards (30% change). When BLA was inactivated during selective satiation (i.e., MUS infused before satiation), this devaluation effect was blocked. In contrast, MUS infusion after satiation, so that it was present just during the testing period, did not impair the shift in object preference (27% change). Thus, BLA is necessary for the appropriate registration of the change in the reinforcer value but not for the subsequent expression of the devaluation involving its transfer to secondary reinforcers.

  12. Transient inactivation of basolateral amygdala during selective satiation disrupts reinforcer devaluation in rats.

    Science.gov (United States)

    West, Elizabeth A; Forcelli, Patrick A; Murnen, Alice T; McCue, David L; Gale, Karen; Malkova, Ludise

    2012-08-01

    Basolateral amygdala (BLA) function is critical for flexible, goal-directed behavior, including performance on reinforcer devaluation tasks. Here we tested, in rats, the hypothesis that BLA is critical for conditioned reinforcer devaluation during the period when the primary reinforcer (food) is being devalued (by feeding it to satiety), but not thereafter for guiding behavioral choices. We used a spatially independent task that used two visual cues, each predicting one of two foods. An instrumental action (lever press) was required for reinforcer delivery. After training, rats received BLA or sham lesions, or cannulae implanted in BLA. Under control conditions (sham lesions, saline infusions), devaluation of one food significantly decreased responding to the cue associated with that food, when both cues were presented simultaneously during extinction. BLA lesions impaired this devaluation effect. Transient inactivation of BLA by microinfusion of the γ-aminobutyric acid receptor type A agonist muscimol resulted in an impairment only when BLA was inactivated during satiation. When muscimol was infused after satiation and therefore, BLA was inactivated only during the choice test, rats showed no impairment. Thus, BLA is necessary for registering or updating cues to reflect updated reinforcer values, but not for guiding choices once the value has been updated. Our results are the first to describe the contribution of rat BLA to specific components of reinforcer devaluation and are the first to show impairment in reinforcer devaluation following transient inactivation in the rat.

  13. Protein kinase A dependent phosphorylation activates Mg2+ efflux in the basolateral region of the liver.

    Science.gov (United States)

    Cefaratti, C; Ruse, Cristian

    2007-03-01

    Isolated hepatocytes in physiological [Na(+)]( 0 ) tightly maintain [Mg(2+)]( i ). Upon beta-adrenergic stimulation or in the presence of permeable cAMP, hepatocytes release 5-10% (1-3 mM Mg(2+)) of their total Mg(2+) content. However, isolated basolateral liver plasma membranes (bLPM), release Mg(2+) in the presence of [Na(+)]( o ) even in the absence of catecholamine stimulation. The data indicate that a physiological brake for Mg(2+) efflux is present in the hepatocyte and is removed upon cellular signaling. In contrast, this regulation "brake" is absent in purified bLPM thus rendering them fully active. The present study was carried out to reconstruct the missing regulatory component. Activation of Mg(2+) extrusion in intact cells is consistent with cAMP dependent phosphorylation of the transporter or a regulatory protein. Treatment of bLPM with a non-specific phosphatase such as alkaline phosphatase (AP), decreased Mg(2+) efflux by 70% compared to untreated bLPM. When AP-treated bLPM were loaded with protein kinase A (PKA), and stimulated with permeable cAMP, Mg(2+) transport fully recovered. These data suggest that phosphorylation of the Na(+)/Mg(2+) exchanger or a nearby protein activates the Mg(2+) transport mechanism in hepatocytes.

  14. Basolateral amygdala lesion inhibits the development of pain chronicity in neuropathic pain rats.

    Directory of Open Access Journals (Sweden)

    Zheng Li

    Full Text Available BACKGROUND: Chronicity of pain is one of the most interesting questions in chronic pain study. Clinical and experimental data suggest that supraspinal areas responsible for negative emotions such as depression and anxiety contribute to the chronicity of pain. The amygdala is suspected to be a potential structure for the pain chronicity due to its critical role in processing negative emotions and pain information. OBJECTIVE: This study aimed to investigate whether amygdala or its subregions, the basolateral amygdala (BLA and the central medial amygdala (CeA, contributes to the pain chronicity in the spared nerve injury (SNI-induced neuropathic pain model of rats. METHODOLOGY/PRINCIPAL FINDINGS: (1 Before the establishment of the SNI-induced neuropathic pain model of rats, lesion of the amygdaloid complex with stereotaxic injection of ibotenic acid (IBO alleviated mechanical allodynia significantly at days 7 and 14, even no mechanical allodynia at day 28 after SNI; Lesion of the BLA, but not the CeA had similar effects; (2 however, 7 days after SNI when the neuropathic pain model was established, lesion of the amygdala complex or the BLA or the CeA, mechanical allodynia was not affected. CONCLUSION: These results suggest that BLA activities in the early stage after nerve injury might be crucial to the development of pain chronicity, and amygdala-related negative emotions and pain-related memories could promote pain chronicity.

  15. Breathing is affected by dopamine D2-like receptors in the basolateral amygdala.

    Science.gov (United States)

    Sugita, Toshihisa; Kanamaru, Mitsuko; Iizuka, Makito; Sato, Kanako; Tsukada, Setsuro; Kawamura, Mitsuru; Homma, Ikuo; Izumizaki, Masahiko

    2015-04-01

    The precise mechanisms underlying how emotions change breathing patterns remain unclear, but dopamine is a candidate neurotransmitter in the process of emotion-associated breathing. We investigated whether basal dopamine release occurs in the basolateral amygdala (BLA), where sensory-related inputs are received and lead to fear or anxiety responses, and whether D1- and D2-like receptor antagonists affect breathing patterns and dopamine release in the BLA. Adult male mice (C57BL/6N) were perfused with artificial cerebrospinal fluid, a D1-like receptor antagonist (SCH 23390), or a D2-like receptor antagonist ((S)-(-)-sulpiride) through a microdialysis probe in the BLA. Respiratory variables were measured using a double-chamber plethysmograph. Dopamine release was measured by an HPLC. Perfusion of (S)-(-)-sulpiride in the BLA, not SCH 23390, specifically decreased respiratory rate without changes in local release of dopamine. These results suggest that basal dopamine release in the BLA, at least partially, increases respiratory rates only through post-synaptic D2-like receptors, not autoreceptors, which might be associated with emotional responses.

  16. Involvement of basolateral amygdala GABAA receptors in the effect of dexamethasone on memory in rats

    Institute of Scientific and Technical Information of China (English)

    Lotfollah KHAJEHPOUR; Acieh ALIZADEH-MAKVANDI; Mahnaz KESMATI; Hooman ESHAGH-HAROONI

    2011-01-01

    In this study we investigated whether GABAA receptors of the basolateral amygdala (BLA) interact with the effect of dexamethasone on the retrieval stage of memory.Adult male Wistar rats were bilaterally cannulated in the BLA by stereotaxic surgery.The animals were trained in step-through apparatus by induction of electric shock (1.5 mA,3 s) and were tested for memory retrieval after 1 d.The time of latency for entering the dark compartment of the instrument and the time spent by rats in this chamber were recorded for evaluation of the animals' retrieval in passive avoidance memory.Administration of dexamethasone (0.3 and 0.9 mg/kg,subcutaneously (s.c.)),immediately after training,enhanced memory retrieval.This effect was reduced by intra-BLA microinjection of muscimol (0.125,0.250 and 0.500 μg/rat),when administered before 0.9 mg/kg of dexamethasone.Microinjection of bicuculline (0.75 μg/rat,intra-BLA) with an ineffective dose of dexamethasone (0.1 mg/kg,s.c.) increased memory retrieval.However,the same doses of muscimol and bicuculline without dexamethasone did not affect memory processes.Our data support reports that dexamethasone enhances memory retrieval.It seems that GABAA receptors of the BLA mediate the effect of dexamethasone on memory retrieval in rats.

  17. Leptin receptor expression in the basolateral nucleus of amygdala of conditioned taste aversion rats

    Institute of Scientific and Technical Information of China (English)

    Zhen Han; Jian-Qun Yan; Guo-Gang Luo; Yong Liu; Yi-Li Wang

    2003-01-01

    AIM: To determine whether serum leptin level and the leptin receptor (OB-R) expression in the basolateral amygdala (BLA)change following conditioned taste aversion (CTA) formation.METHODS: The serum leptin concentration was measured by rat leptin RIA kit, long and short forms of leptin receptor (OB-Rb and OB-Ra) mRNA in the brain sections were examined by in situ hybridization (ISH) and the expression of OB-R was assessed by immunohistochemistry ABC method with a highly specific goat anti-OB-R antibody.RESULTS: The level of serum leptin didn't show significant difference between CTA and control group. Comparing with the control group, the CTA group had an increase on count of OB-R immunohistochemistry positive-stained cells in the BLA (127±12 vs 48±9 per 1 mm2). The OB-Rb mRNA expression level enhanced by 11.9 % in the BLA, while OBRa mRNA level increased by 7.4 % on the choroid plexus in CTA group. So BLA was supposed to be a region where interactions between gustatory and vagal signals take place.CONCLUSION: BLA is one of the sites, which are responsible for CTA formation in the brain. Leptin and OB-R maybe involved in neuronal communication for CTA. So leptin and its receptors probably take part in CTA and integration of autonomic and extroceptive information.

  18. Endocannabinoid Signaling within the Basolateral Amygdala Integrates Multiple Stress Hormone Effects on Memory Consolidation

    Science.gov (United States)

    Atsak, Piray; Hauer, Daniela; Campolongo, Patrizia; Schelling, Gustav; Fornari, Raquel V; Roozendaal, Benno

    2015-01-01

    Glucocorticoid hormones are known to act synergistically with other stress-activated neuromodulatory systems, such as norepinephrine and corticotropin-releasing factor (CRF), within the basolateral complex of the amygdala (BLA) to induce optimal strengthening of the consolidation of long-term memory of emotionally arousing experiences. However, as the onset of these glucocorticoid actions appear often too rapid to be explained by genomic regulation, the neurobiological mechanism of how glucocorticoids could modify the memory-enhancing properties of norepinephrine and CRF remained elusive. Here, we show that the endocannabinoid system, a rapidly activated retrograde messenger system, is a primary route mediating the actions of glucocorticoids, via a glucocorticoid receptor on the cell surface, on BLA neural plasticity and memory consolidation. Furthermore, glucocorticoids recruit downstream endocannabinoid activity within the BLA to interact with both the norepinephrine and CRF systems in enhancing memory consolidation. These findings have important implications for understanding the fine-tuned crosstalk between multiple stress hormone systems in the coordination of (mal)adaptive stress and emotional arousal effects on neural plasticity and memory consolidation. PMID:25547713

  19. Histamine in the basolateral amygdala promotes inhibitory avoidance learning independently of hippocampus.

    Science.gov (United States)

    Benetti, Fernando; Furini, Cristiane Regina Guerino; de Carvalho Myskiw, Jociane; Provensi, Gustavo; Passani, Maria Beatrice; Baldi, Elisabetta; Bucherelli, Corrado; Munari, Leonardo; Izquierdo, Ivan; Blandina, Patrizio

    2015-05-12

    Recent discoveries demonstrated that recruitment of alternative brain circuits permits compensation of memory impairments following damage to brain regions specialized in integrating and/or storing specific memories, including both dorsal hippocampus and basolateral amygdala (BLA). Here, we first report that the integrity of the brain histaminergic system is necessary for long-term, but not for short-term memory of step-down inhibitory avoidance (IA). Second, we found that phosphorylation of cyclic adenosine monophosphate (cAMP) responsive-element-binding protein, a crucial mediator in long-term memory formation, correlated anatomically and temporally with histamine-induced memory retrieval, showing the active involvement of histamine function in CA1 and BLA in different phases of memory consolidation. Third, we found that exogenous application of histamine in either hippocampal CA1 or BLA of brain histamine-depleted rats, hence amnesic, restored long-term memory; however, the time frame of memory rescue was different for the two brain structures, short lived (immediately posttraining) for BLA, long lasting (up to 6 h) for the CA1. Moreover, long-term memory was formed immediately after training restoring of histamine transmission only in the BLA. These findings reveal the essential role of histaminergic neurotransmission to provide the brain with the plasticity necessary to ensure memorization of emotionally salient events, through recruitment of alternative circuits. Hence, our findings indicate that the histaminergic system comprises parallel, coordinated pathways that provide compensatory plasticity when one brain structure is compromised.

  20. Histamine in the basolateral amygdala promotes inhibitory avoidance learning independently of hippocampus

    Science.gov (United States)

    Benetti, Fernando; Furini, Cristiane Regina Guerino; de Carvalho Myskiw, Jociane; Provensi, Gustavo; Passani, Maria Beatrice; Baldi, Elisabetta; Bucherelli, Corrado; Munari, Leonardo; Izquierdo, Ivan; Blandina, Patrizio

    2015-01-01

    Recent discoveries demonstrated that recruitment of alternative brain circuits permits compensation of memory impairments following damage to brain regions specialized in integrating and/or storing specific memories, including both dorsal hippocampus and basolateral amygdala (BLA). Here, we first report that the integrity of the brain histaminergic system is necessary for long-term, but not for short-term memory of step-down inhibitory avoidance (IA). Second, we found that phosphorylation of cyclic adenosine monophosphate (cAMP) responsive-element-binding protein, a crucial mediator in long-term memory formation, correlated anatomically and temporally with histamine-induced memory retrieval, showing the active involvement of histamine function in CA1 and BLA in different phases of memory consolidation. Third, we found that exogenous application of histamine in either hippocampal CA1 or BLA of brain histamine-depleted rats, hence amnesic, restored long-term memory; however, the time frame of memory rescue was different for the two brain structures, short lived (immediately posttraining) for BLA, long lasting (up to 6 h) for the CA1. Moreover, long-term memory was formed immediately after training restoring of histamine transmission only in the BLA. These findings reveal the essential role of histaminergic neurotransmission to provide the brain with the plasticity necessary to ensure memorization of emotionally salient events, through recruitment of alternative circuits. Hence, our findings indicate that the histaminergic system comprises parallel, coordinated pathways that provide compensatory plasticity when one brain structure is compromised. PMID:25918368

  1. Development and physiology of GABAergic feedback excitation in parvalbumin expressing interneurons of the mouse basolateral amygdala.

    Science.gov (United States)

    Spampanato, Jay; Sullivan, Robert K P; Perumal, Madhusoothanan B; Sah, Pankaj

    2016-01-01

    We have previously shown that in the basolateral amygdala (BLA), action potentials in one type of parvalbumin (PV)-expressing GABAergic interneuron can evoke a disynaptic feedback excitatory postsynaptic potential (fbEPSP) onto the same presynaptic interneuron. Here, using whole-cell recordings from PV-expressing interneurons in acute brain slices we expand on this finding to show that this response is first detectable at 2-week postnatal, and is most prevalent in animals beyond 3 weeks of age (>P21). This circuit has a very high fidelity, and single action potential evoked fbEPSPs display few failures. Reconstruction of filled neurons, and electron microscopy show that interneurons that receive feedback excitation make symmetrical synapses on both the axon initial segments (AIS), as well as the soma and proximal dendrites of local pyramidal neurons, suggesting fbEPSP interneurons are morphologically distinct from the highly specialized chandelier neurons that selectively target the axon initial segment of pyramidal neurons. Single PV interneurons could trigger very large (~ 1 nA) feedback excitatory postsynaptic currents (fbEPSCs) suggesting that these neurons are heavily reciprocally connected to local glutamatergic principal cells. We conclude that in the BLA, a subpopulation of PV interneurons forms a distinct neural circuit in which a single action potential can recruit multiple pyramidal neurons to discharge near simultaneously and feed back onto the presynaptic interneuron.

  2. Target-specific suppression of GABA release from parvalbumin interneurons in the basolateral amygdala by dopamine.

    Science.gov (United States)

    Chu, Hong-Yuan; Ito, Wataru; Li, Jiayang; Morozov, Alexei

    2012-10-17

    Dopamine (DA) in the basolateral amygdala (BLA) promotes fear learning by disinhibiting principal neurons (PNs) and enabling synaptic plasticity in their sensory inputs. While BLA interneurons (INs) are heterogeneous, it is unclear which interneuron subtypes decrease GABAergic input to PNs in the presence of DA. Here, using cell type-selective photostimulation by channelrhodopsin 2 in BLA slices from mouse brain, we examined the role of parvalbumin-positive INs (PV-INs), the major interneuronal subpopulation in BLA, in the disinhibitory effect of DA. We found that DA selectively suppressed GABAergic transmission from PV-INs to PNs by acting on presynaptic D(2) receptors, and this effect was mimicked by Rp-cAMP, an inhibitor of cAMP-dependent signaling. In contrast, DA did not alter GABA release from PV-INs to INs. Furthermore, neither suppressing cAMP-dependent signaling by Rp-cAMP nor enhancing it by forskolin altered GABA release from PV-INs to BLA INs. Overall, DA disinhibits BLA, at least in part, by suppressing GABA release from PV-INs in the target cell-specific manner that results from differential control of this release by cAMP-dependent signaling.

  3. Stimulus Intensity-dependent Modulations of Hippocampal Long-term Potentiation by Basolateral Amygdala Priming

    Directory of Open Access Journals (Sweden)

    Zexuan eLi

    2012-05-01

    Full Text Available There is growing realization that the relationship between memory and stress/emotionality is complicated, and may include both memory enhancing and memory impairing aspects. It has been suggested that the underlying mechanisms involve amygdalar modulation of hippocampal synaptic plasticity, such as long-term potentiation (LTP. We recently reported that while in CA1 basolateral amygdala (BLA priming impaired theta stimulation induced LTP, it enhanced LTP in the dentate gyrus (DG. However, emotional and stressfull experiences were found to activate synaptic plasticity within the BLA, rasing the possibility that BLA modulation of other brain regions may be altered as well, as it may depend on the way the BLA is activated or is responding. In previous studies BLA priming stimulation was relatively weak (1V, 50 µs pulse duration. In the present study we assessed the effects of two stronger levels of BLA priming stimulation (1V or 2V, 100 µs pulse duration on LTP induction in hippocampal DG and CA1, in anesthetized rats. Results show that 1V-BLA priming stimulation enhanced but 2V-BLA priming stimulation impaired DG LTP; however, both levels of BLA priming stimulation impaired CA1 LTP, suggesting that modulation of hippocampal synaptic plasticity by amygdala is dependent on the degree of amygdala activation. These findings suggest that plasticity induced within the amygdala, by stressful experiences induces a form of metaplasticity that would alter the way the amygdala may modulate memory-related processes in other brain areas, such as the hippocampus.

  4. Effect of genistein on basal jejunal chloride secretion in R117H CF mice is sex and route specific

    Directory of Open Access Journals (Sweden)

    Rayyan E

    2015-01-01

    Full Text Available Esa Rayyan,1 Sarah Polito,1 Lana Leung,1 Ashesh Bhakta,1 Jonathan Kang,1 Justin Willey,1 Wasim Mansour,1 Mitchell L Drumm,2 Layla Al-Nakkash11Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA; 2Pediatric Pulmonology Division, Case Western Reserve University, Cleveland, OH, USAAbstract: Cystic fibrosis (CF results from the loss or reduction in function of the CFTR (cystic fibrosis transmembrane conductance regulatory protein chloride channel. The third most common CFTR mutation seen clinically is R117H. Genistein, a naturally occurring phytoestrogen, is known to stimulate CFTR function in vitro. We aimed to determine whether route of administration of genistein could mediate differential effects in R117H male and female CF mice. Mice were fed (4 weeks or injected subcutaneously (1 week with the following: genistein 600 mg/kg diet (600Gd; genistein-free diet (0Gd; genistein injection 600 mg/kg body weight (600Gi; dimethyl sulfoxide control (0Gi. In male R117H mice fed 600Gd, basal short circuit current (Isc was unchanged. In 600Gd-fed female mice, there was a subgroup that demonstrated a significant increase in basal Isc (53.14±7.92 µA/cm2, n=6, P<0.05 and a subgroup of nonresponders (12.05±6.59 µA/cm2, n=4, compared to 0Gd controls (29.3±6.5 µA/cm2, n=7. In R117H mice injected with 600Gi, basal Isc was unchanged in both male and female mice compared to 0Gi controls. Isc was measured in response to the following: the adenylate cyclase activator forskolin (10 µM, bilateral, bumetanide (100 µM, basolateral to indicate the Cl- secretory component, and acetazolamide (100 µM, bilateral to indicate the HCO3- secretory component; however, there was no effect of genistein (diet or injection on any of these parameters. Jejunal morphology (ie, villi length, number of goblet cells per villus, crypt depth, and number of goblet cells per crypt in R117H mice suggested no genistein

  5. Chloride is essential for contraction of afferent arterioles after agonists and potassium

    DEFF Research Database (Denmark)

    Jensen, B L; Ellekvist, Peter; Skøtt, O

    1997-01-01

    A depolarizing chloride efflux has been suggested to activate voltage-dependent calcium channels in renal afferent arteriolar smooth muscle cells in response to vasoconstrictors. To test this proposal, rabbit afferent arterioles were microperfused, and the contractile dose responses to norepineph......A depolarizing chloride efflux has been suggested to activate voltage-dependent calcium channels in renal afferent arteriolar smooth muscle cells in response to vasoconstrictors. To test this proposal, rabbit afferent arterioles were microperfused, and the contractile dose responses......). Reintroduction of chloride fully restored the sensitivity to norepinephrine. Contractions after ANG II and potassium were totally abolished in the absence of chloride (n = 6). In additional experiments (n = 7), the arteriolar contraction to 100 mM potassium was abolished only 1 min after removal of extracellular...... chloride. We conclude that norepinephrine and ANG II use different mechanisms for contraction and that extracellular chloride is essential for contraction in afferent arterioles after activation of voltage-dependent calcium channels. We suggest that a chloride influx pathway is activated concomitantly...

  6. Benzalkonium chloride and glaucoma.

    Science.gov (United States)

    Rasmussen, Carol A; Kaufman, Paul L; Kiland, Julie A

    2014-01-01

    Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapoptosis, cytoskeleton changes, and immunoinflammatory reactions. These same effects have been reported in cultured human TM cells exposed to concentrations of BAK found in common glaucoma drugs and in the TM of primary open-angle glaucoma donor eyes. It is possible that a relationship exists between chronic exposure to BAK and glaucoma. The hypothesis that BAK causes/worsens glaucoma is being tested experimentally in an animal model that closely reflects human physiology.

  7. Chloride on the Move

    KAUST Repository

    Li, Bo

    2017-01-09

    Chloride (Cl−) is an essential plant nutrient but under saline conditions it can accumulate to toxic levels in leaves; limiting this accumulation improves the salt tolerance of some crops. The rate-limiting step for this process – the transfer of Cl− from root symplast to xylem apoplast, which can antagonize delivery of the macronutrient nitrate (NO3−) to shoots – is regulated by abscisic acid (ABA) and is multigenic. Until recently the molecular mechanisms underpinning this salt-tolerance trait were poorly defined. We discuss here how recent advances highlight the role of newly identified transport proteins, some that directly transfer Cl− into the xylem, and others that act on endomembranes in ‘gatekeeper’ cell types in the root stele to control root-to-shoot delivery of Cl−.

  8. Effect of Chloride Channels on Apoptotic Volume Decrease and Apoptosis in Nasopharyngeal Carcinoma Cells%氯通道在鼻咽癌细胞凋亡性细胞容积减小和细胞凋亡中的作用

    Institute of Scientific and Technical Information of China (English)

    潘廷才; 杨林杰; 刘善文; 李华荣; 朱林燕; 叶文才; 王立伟; 陈丽新

    2011-01-01

    目的:探讨氯通道在5-氟尿嘧啶(5-Fu)诱导的低分化鼻咽癌细胞CNE-2Z凋亡性细胞容积减小(AVD)和细胞凋亡中的作用.方法:培养CNE-2Z细胞后,分别用100μmol/L 5-Fu(5-Fu组)、100μmol/L 5-Fu+100μmol/L 5-硝基-2-(3-苯丙胺)苯甲酸(5-Fu+NPPB组)处理细胞,采用活细胞影像系统实时拍摄细胞图像,检测细胞容积变化,Hochest 33258荧光染色技术检测细胞凋亡并计算细胞凋亡率.结果:5-Fu处理使细胞皱缩,体积变小;5-Fu+NPPB处理后细胞体积变化不明显.在5个不同时间点,细胞受到5-Fu刺激后,标准化细胞容积(Vst)均小于对照组,5-Fu+NPPB组对细胞Vst的影响均小于5-Fu组,差异均有统计学意义.对照组细胞凋亡率(1.8+0.5)%,5-Fu处理使细胞凋亡率增加至(49.2±2.6)%,5-Fu+NPPB处理使细胞凋亡率降至(12.5±2.9)%.结论:抑制氯通道可显著拮抗5-Fu诱导的凋亡性细胞容积减小和细胞凋亡.%Objective: To investigate the roles of chloride channels in apoptotic volume decrease (AVD) and apoptosis in nasopharyngeal carcinoma cells (CNE-2Z). Methods: The CNE-2Z was cultured and treated with 100 μmol/L 5-Fu (5-Fu group), 100 μmol/L 5-Fu+l00 μmol/L 5-nitro-2-(3-phenylpropylamino) henzoic acid (5-Fu+NPPB group). Changes of the cell volume were monitored and analyzed by the time-lapse imaging technique. Cell apoptotic rates were measured and analysed by Hoechst 33258 staining. Results : The results showed that 5-Fu induced the early cell volume decrease in a few minutes. The cell shrinkage and volume decrease were found after 5-Fu treatment. No significant change was found in cell volume after treatment with 5-Fu+NPPB. The cell volumes were significantly decreased in 5 time points in 5-Fu group than those of control. The effect of 5-Fu+NPPB on the cell volume was significantly smaller than that of 5-Fu. The apoptotic rate induced by 5-Fu was (49.2±2.6)% compared with (1.8±0.5)% in control group. The apoptotic rate was

  9. Post-training depletions of basolateral amygdala serotonin fail to disrupt discrimination, retention, or reversal learning.

    Science.gov (United States)

    Ochoa, Jesus G; Stolyarova, Alexandra; Kaur, Amandeep; Hart, Evan E; Bugarin, Amador; Izquierdo, Alicia

    2015-01-01

    In goal-directed pursuits, the basolateral amygdala (BLA) is critical in learning about changes in the value of rewards. BLA-lesioned rats show enhanced reversal learning, a task employed to measure the flexibility of response to changes in reward. Similarly, there is a trend for enhanced discrimination learning, suggesting that BLA may modulate formation of stimulus-reward associations. There is a parallel literature on the importance of serotonin (5HT) in new stimulus-reward and reversal learning. Recent postulations implicate 5HT in learning from punishment. Whereas, dopaminergic involvement is critical in behavioral activation and reinforcement, 5HT may be most critical for aversive processing and behavioral inhibition, complementary cognitive processes. Given these findings, a 5HT-mediated mechanism in BLA may mediate the facilitated learning observed previously. The present study investigated the effects of selective 5HT lesions in BLA using 5,7-dihydroxytryptamine (5,7-DHT) vs. infusions of saline (Sham) on discrimination, retention, and deterministic reversal learning. Rats were required to reach an 85% correct pairwise discrimination and single reversal criterion prior to surgery. Postoperatively, rats were then tested on the (1) retention of the pretreatment discrimination pair, (2) discrimination of a novel pair, and (3) reversal learning performance. We found statistically comparable preoperative learning rates between groups, intact postoperative retention, and unaltered novel discrimination and reversal learning in 5,7-DHT rats. These findings suggest that 5HT in BLA is not required for formation and flexible adjustment of new stimulus-reward associations when the strategy to efficiently solve the task has already been learned. Given the complementary role of orbitofrontal cortex in reward learning and its interconnectivity with BLA, these findings add to the list of dissociable mechanisms for BLA and orbitofrontal cortex in reward learning.

  10. Pharmacological depletion of serotonin in the basolateral amygdala complex reduces anxiety and disrupts fear conditioning.

    Science.gov (United States)

    Johnson, Philip L; Molosh, Andrei; Fitz, Stephanie D; Arendt, Dave; Deehan, Gerald A; Federici, Lauren M; Bernabe, Cristian; Engleman, Eric A; Rodd, Zachary A; Lowry, Christopher A; Shekhar, Anantha

    2015-11-01

    The basolateral and lateral amygdala nuclei complex (BLC) is implicated in a number of emotional responses including conditioned fear and social anxiety. Based on previous studies demonstrating that enhanced serotonin release in the BLC leads to increased anxiety and fear responses, we hypothesized that pharmacologically depleting serotonin in the BLC using 5,7-dihydroxytryptamine (5,7-DHT) injections would lead to diminished anxiety and disrupted fear conditioning. To test this hypothesis, 5,7-DHT(a serotonin-depleting agent) was bilaterally injected into the BLC. Desipramine (a norepinephrine reuptake inhibitor) was systemically administered to prevent non-selective effects on norepinephrine. After 5days, 5-7-DHT-treated rats showed increases in the duration of social interaction (SI) time, suggestive of reduced anxiety-like behavior. We then used a cue-induced fear conditioning protocol with shock as the unconditioned stimulus and tone as the conditioned stimulus for rats pretreated with bilateral 5,7-DHT, or vehicle, injections into the BLC. Compared to vehicle-treated rats, 5,7-DHT rats had reduced acquisition of fear during conditioning (measured by freezing time during tone), also had reduced fear retrieval/recall on subsequent testing days. Ex vivo analyses revealed that 5,7-DHT reduced local 5-HT concentrations in the BLC by ~40% without altering local norepinephrine or dopamine concentrations. These data provide additional support for 5-HT playing a critical role in modulating anxiety-like behavior and fear-associated memories through its actions within the BLC.

  11. Basolateral amygdala CB1 cannabinoid receptors mediate nicotine-induced place preference.

    Science.gov (United States)

    Hashemizadeh, Shiva; Sardari, Maryam; Rezayof, Ameneh

    2014-06-03

    In the present study, the effects of bilateral microinjections of cannabinoid CB1 receptor agonist and antagonist into the basolateral amygdala (intra-BLA) on nicotine-induced place preference were examined in rats. A conditioned place preference (CPP) apparatus was used for the assessment of rewarding effects of the drugs in adult male Wistar rats. Subcutaneous (s.c.) administration of nicotine (0.2mg/kg) induced a significant CPP, without any effect on the locomotor activity during the testing phase. Intra-BLA microinjection of a non-selective cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (0.1-0.5 μg/rat) with an ineffective dose of nicotine (0.1mg/kg, s.c.) induced a significant place preference. On the other hand, intra-BLA administration of AM251 (20-60 ng/rat), a selective cannabinoid CB1 receptor antagonist inhibited the acquisition of nicotine-induced place preference. It should be considered that the microinjection of the same doses of WIN 55,212-2 or AM251 into the BLA, by itself had no effect on the CPP score. The administration of a higher dose of AM251 (60 ng/rat) during the acquisition decreased the locomotor activity of animals on the testing phase. Interestingly, the microinjection of AM251 (20 and 40 ng/rat), but not WIN55,212-2 (0.1-0.5 μg/rat), into the BLA inhibited the expression of nicotine-induced place preference without any effect on the locomotor activity. Taken together, these findings support the possible role of endogenous cannabinoid system of the BLA in the acquisition and the expression of nicotine-induced place preference. Furthermore, it seems that there is a functional interaction between the BLA cannabinoid receptors and nicotine in producing the rewarding effects.

  12. Sulfate transport by chick renal tubule brush-border and basolateral membranes

    Energy Technology Data Exchange (ETDEWEB)

    Renfro, J.L.; Clark, N.B.; Metts, R.E.; Lynch, M.A.

    1987-01-01

    Brush-border and basolateral membrane vesicles (BBMV and BLMV, respectively) were prepared from chick kidney by a calcium precipitation method and by centrifugation on an 8% Percoll self-generating gradient, respectively. In BBMV a 100-mM Na gluconate gradient, out>in, caused concentrative (/sup 35/S) sulfate uptake approximately fivefold greater at 1 min than at 60 min (equilibrium) whether or not the membranes were short-circuited with 100 mM K gluconate, in=out, plus 20 ..mu..g valinomycin/mg protein. A 48-mM HCO/sub 3//sup -/ gradient, in>out, stimulated a 2.5-fold higher uptake at 1 min than at 60 min, and short circuiting as above had no effect on the magnitude of this response. Imposition of a H/sup +/ gradient caused concentrative uptake fourfold higher at 1 min than at equilibrium. Short circuiting as above or addition of 0.1 mM carbonyl cyanide m-chlorophenylhydrazone (CCCP) significantly inhibited the pH gradient effect. Creation of an inside positive electrical potential with 100 mM K gluconate, out>in, plus valinomycin, also caused concentrative sulfate uptake. Based on inhibitor/competitor effects, these are distinct sulfate transport processes. In chick BLMV, imposition of an HCO/sub 3//sup -/ gradient, in>out, produced concentrative sulfate uptake. 4-Acetamido-4'-isothiocyanostilbene 2,2'-disulfonic acid disodium at 0.1 mM was an effective inhibitor of BLMV bicarbonate-sulfate exchange.

  13. Variation in mouse basolateral amygdala volume is associated with differences in stress reactivity and fear learning.

    Science.gov (United States)

    Yang, Rebecca J; Mozhui, Khyobeni; Karlsson, Rose-Marie; Cameron, Heather A; Williams, Robert W; Holmes, Andrew

    2008-10-01

    A wealth of research identifies the amygdala as a key brain region mediating negative affect, and implicates amygdala dysfunction in the pathophysiology of anxiety disorders. Although there is a strong genetic component to anxiety disorders such as posttraumatic stress disorder (PTSD) there remains debate about whether abnormalities in amygdala function predispose to these disorders. In the present study, groups of C57BL/6 x DBA/2 (B x D) recombinant inbred strains of mice were selected for differences in volume of the basolateral amygdala complex (BLA). Strains with relatively small, medium, or large BLA volumes were compared for Pavlovian fear learning and memory, anxiety-related behaviors, depression-related behavior, and glucocorticoid responses to stress. Strains with relatively small BLA exhibited stronger conditioned fear responses to both auditory tone and contextual stimuli, as compared to groups with larger BLA. The small BLA group also showed significantly greater corticosterone responses to stress than the larger BLA groups. BLA volume did not predict clear differences in measures of anxiety-like behavior or depression-related behavior, other than greater locomotor inhibition to novelty in strains with smaller BLA. Neither striatal, hippocampal nor cerebellar volumes correlated significantly with any behavioral measure. The present data demonstrate a phenotype of enhanced fear conditioning and exaggerated glucocorticoid responses to stress associated with small BLA volume. This profile is reminiscent of the increased fear processing and stress reactivity that is associated with amygdala excitability and reduced amygdala volume in humans carrying loss of function polymorphisms in the serotonin transporter and monoamine oxidase A genes. Our study provides a unique example of how natural variation in amygdala volume associates with specific fear- and stress-related phenotypes in rodents, and further supports the role of amygdala dysfunction in anxiety

  14. Inactivation of basolateral amygdala specifically eliminates palatability-related information in cortical sensory responses

    Science.gov (United States)

    Piette, Caitlin E.; Baez-Santiago, Madelyn A.; Reid, Emily E.; Katz, Donald B.; Moran, Anan

    2012-01-01

    Evidence indirectly implicates the amygdala as the primary processor of emotional information used by cortex to drive appropriate behavioral responses to stimuli. Taste provides an ideal system with which to test this hypothesis directly, as neurons in both basolateral amygdala (BLA) and gustatory cortex (GC)—anatomically interconnected nodes of the gustatory system—code the emotional valence of taste stimuli (i.e., palatability), in firing rate responses that progress similarly through “epochs.” The fact that palatability-related firing appears one epoch earlier in BLA than GC is broadly consistent with the hypothesis that such information may propagate from the former to the latter. Here, we provide evidence supporting this hypothesis, assaying taste responses in small GC single-neuron ensembles before, during and after temporarily inactivating BLA (BLAx) in awake rats. BLAx changed responses in 98% of taste-responsive GC neurons, altering the entirety of every taste response in many neurons. Most changes involved reductions in firing rate, but regardless of the direction of change, the effect of BLAx was epoch-specific: while firing rates were changed, the taste-specificity of responses remained stable; information about taste palatability, however, which normally resides in the “Late” epoch, was reduced in magnitude across the entire GC sample and outright eliminated in most neurons. Only in the specific minority of neurons for which BLAx enhanced responses did palatability-specificity survive undiminished. Our data therefore provide direct evidence that BLA is a necessary component of GC gustatory processing, and that cortical palatability processing in particular is, in part, a function of BLA activity. PMID:22815512

  15. Progressively Disrupted Intrinsic Functional Connectivity of Basolateral Amygdala in Very Early Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Marion Ortner

    2016-09-01

    Full Text Available Abstract:Very early Alzheimer’s disease (AD - i.e., AD at stages of mild cognitive impairment (MCI and mild dementia - is characterized by progressive structural and neuropathologic changes such as atrophy or tangle deposition in medial temporal lobes, including hippocampus and entorhinal cortex but also adjacent amygdala. While progressively disrupted intrinsic connectivity of hippocampus with other brain areas has been demonstrated by many studies, amygdala connectivity was rarely investigated in AD, notwithstanding its known relevance for emotion processing and mood disturbances, which are both important in early AD. Intrinsic functional connectivity (iFC patterns of hippocampus and amygdala overlap in healthy persons. Thus, we hypothesized that increased alteration of iFC patterns along AD is not limited to the hippocampus but also concerns the amygdala, independent from atrophy. To address this hypothesis, we applied structural and functional resting-state MRI in healthy controls (CON, n=33 and patients with AD in the stages of MCI (AD-MCI, n=38 and mild dementia (AD-D, n=36. Outcome measures were voxel-based morphometry (VBM values and region of interest-based intrinsic functional connectivity maps (iFC of basolateral amygdala, which has extended cortical connectivity. Amygdala VBM values were progressively reduced in patients (CON > AD-MCI and AD-D. Amygdala iFC was progressively reduced along impairment severity (CON > AD-MCI > AD-D, particularly for hippocampus, temporal lobes, and fronto-parietal areas. Notably, decreased iFC was independent of amygdala atrophy. Results demonstrate progressively impaired amygdala intrinsic connectivity in temporal and fronto-parietal lobes independent from increasing amygdala atrophy in very early AD. Data suggest that early AD disrupts intrinsic connectivity of medial temporal lobe key regions including that of amygdala.

  16. Luminal NaCl delivery regulates basolateral PGE2 release from macula densa cells.

    Science.gov (United States)

    Peti-Peterdi, Janos; Komlosi, Peter; Fuson, Amanda L; Guan, Youfei; Schneider, Andre; Qi, Zhonghua; Redha, Reyadh; Rosivall, Laszlo; Breyer, Matthew D; Bell, P Darwin

    2003-07-01

    Macula densa (MD) cells express COX-2 and COX-2-derived PGs appear to signal the release of renin from the renal juxtaglomerular apparatus, especially during volume depletion. However, the synthetic machinery and identity of the specific prostanoid released from intact MD cells remains uncertain. In the present studies, a novel biosensor tool was engineered to directly determine whether MD cells release PGE2 in response to low luminal NaCl concentration ([NaCl]L). HEK293 cells were transfected with the Ca2+-coupled E-prostanoid receptor EP1 (HEK/EP1) and loaded with fura-2. HEK/EP1 cells produced a significant elevation in intracellular [Ca2+] ([Ca2+]i) by 29.6 +/- 12.8 nM (n = 6) when positioned at the basolateral surface of isolated perfused MD cells and [NaCl]L was reduced from 150 mM to zero. HEK/EP1 [Ca2+]i responses were observed mainly in preparations from rabbits on a low-salt diet and were completely inhibited by either a selective COX-2 inhibitor or an EP1 antagonist, and also by 100 microM luminal furosemide. Also, 20-mM graduated reductions in [NaCl]L between 80 and 0 mM caused step-by-step increases in HEK/EP1 [Ca2+]i. Low-salt diet greatly increased the expression of both COX-2 and microsome-associated PGE synthase (mPGES) in the MD. These studies provide the first direct evidence that intact MD cells synthesize and release PGE2 during reduced luminal salt content and suggest that this response is important in the control of renin release and renal vascular resistance during salt deprivation.

  17. Blockade of glutamatergic transmission in the primate basolateral amygdala suppresses active behavior without altering social interaction.

    Science.gov (United States)

    Forcelli, Patrick A; Wellman, Laurie L; Malkova, Ludise

    2017-04-01

    The amygdala is an integrator of affective processing, and a key component of a network regulating social behavior. While decades of lesion studies in nonhuman primates have shown alterations in social interactions after amygdala damage, acute manipulations of the amygdala in primates have been underexplored. We recently reported (Wellman, Forcelli, Aguilar, & Malkova, 2016) that acute pharmacological inhibition of the basolateral complex of the amygdala (BLA) or the central nucleus of the amygdala increased affiliative social interactions in experimental dyads of macaques; this was achieved through microinjection of a GABA-A receptor agonist. Prior studies in rodents have shown similar effects achieved by blocking NMDA receptors or AMPA receptors within the BLA. Here, we sought to determine the role of these receptor systems in the primate BLA in the context of social behavior. In familiar dyads, we microinjected the NMDA receptor antagonist 2-amino-7-phosphonoheptanoic acid (AP7) or the AMPA receptor antagonist 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX) and observed behaviors and social interactions in the immediate postinjection period. In striking contrast with our prior report using GABA agonists, and in contrast with prior reports in rodents using glutamate antagonists, we found that neither NMDA nor AMPA blockade increase social interaction. Both treatments, however, were associated with decreases in locomotion and manipulation and increases in passive behavior. These data suggest that local blockade of glutamatergic neurotransmission in BLA is not the functional equivalent of local activation of GABAergic signaling, and raise interesting questions regarding the functional microcircuitry of the nonhuman primate amygdala in the context of social behavior. (PsycINFO Database Record

  18. The role of basolateral amygdala adrenergic receptors in hippocampus dependent spatial memory in rat

    Directory of Open Access Journals (Sweden)

    Vafaei A.L.

    2008-03-01

    Full Text Available Background and the purpose of the study: There are extensive evidences indicating that the noradrenergic system of the basolateral nucleus of the amygdala (BLA is involved in memory processes. The present study investigated the role of the BLA adrenergic receptors (ARs in hippocampus dependent spatial memory in place avoidance task in male rat. Material and Methods: Long Evans rats (n=150 were trained to avoid footshock in a 60° segment while foraging for scattered food on a circular (80-cm diameter arena. The rats were injected bilaterally in the BLA specific ARS (Adrenergic receptors agonist norepinephrine (NE, 0.5 and 1 µg/µl and specific β-ARs antagonist propranolol (PRO, 0.5 and 1 µg/µl before acquisition, after training or before retrieval of the place avoidance task. Control rats received vehicle at the same volume. The learning in a single 30-min session was assessed 24h later by a 30-min extinction trial in which the time to first entrance and the number of entrances to the shocked area measured the avoidance memory. Results: Acquisition and consolidation were enhanced and impaired significantly by NE and PRO when the drugs were injected 10 min before or immediately after training, respectively. In contrast, neither NE nor PRO influenced animal performances when injected before retention testing. Conclusion: Findings of this study indicates that adrenergic system of the BLA plays an important role in regulation of memory storage and show further evidences for the opinion that the BLA plays an important role in integrating hormonal and neurotransmitter influences on memory storage.

  19. Enhancing second-order conditioning with lesions of the basolateral amygdala.

    Science.gov (United States)

    Holland, Peter C

    2016-04-01

    Because the occurrence of primary reinforcers in natural environments is relatively rare, conditioned reinforcement plays an important role in many accounts of behavior, including pathological behaviors such as the abuse of alcohol or drugs. As a result of pairing with natural or drug reinforcers, initially neutral cues acquire the ability to serve as reinforcers for subsequent learning. Accepting a major role for conditioned reinforcement in everyday learning is complicated by the often-evanescent nature of this phenomenon in the laboratory, especially when primary reinforcers are entirely absent from the test situation. Here, I found that under certain conditions, the impact of conditioned reinforcement could be extended by lesions of the basolateral amygdala (BLA). Rats received first-order Pavlovian conditioning pairings of 1 visual conditioned stimulus (CS) with food prior to receiving excitotoxic or sham lesions of the BLA, and first-order pairings of another visual CS with food after that surgery. Finally, each rat received second-order pairings of a different auditory cue with each visual first-order CS. As in prior studies, relative to sham-lesioned control rats, lesioned rats were impaired in their acquisition of second-order conditioning to the auditory cue paired with the first-order CS that was trained after surgery. However, lesioned rats showed enhanced and prolonged second-order conditioning to the auditory cue paired with the first-order CS that was trained before amygdala damage was made. Implications for an enhanced role for conditioned reinforcement by drug-related cues after drug-induced alterations in neural plasticity are discussed. (PsycINFO Database Record

  20. Post-training depletions of basolateral amygdala serotonin fail to disrupt discrimination, retention, or reversal learning

    Directory of Open Access Journals (Sweden)

    G. Jesus eOchoa

    2015-05-01

    Full Text Available In goal-directed pursuits, the basolateral amygdala (BLA is critical in learning about changes in the value of rewards. BLA-lesioned rats show enhanced reversal learning, a task employed to measure the flexibility of response to changes in reward. Similarly, there is a trend for enhanced discrimination learning, suggesting that BLA may modulate formation of stimulus-reward associations. There is a parallel literature on the importance of serotonin (5HT in new stimulus-reward and reversal learning. Recent postulations implicate 5HT in learning from punishment. Whereas dopaminergic involvement is critical in behavioral activation and reinforcement, 5HT may be most critical for aversive processing and behavioral inhibition, complementary cognitive processes. Given these findings, a 5HT-mediated mechanism in BLA may mediate the facilitated learning observed previously. The present study investigated the effects of selective 5HT lesions in BLA using 5,7-dihydroxytryptamine (5,7-DHT versus infusions of saline (Sham on discrimination, retention, and deterministic reversal learning. Rats were required to reach an 85% correct pairwise discrimination and single reversal criterion prior to surgery. Postoperatively, rats were then tested on the 1 retention of the pretreatment discrimination pair 2 discrimination of a novel pair and 3 reversal learning performance. We found statistically comparable preoperative learning rates between groups, intact postoperative retention, and unaltered novel discrimination and reversal learning in 5,7-DHT rats. These findings suggest that 5HT in BLA is not required for formation and flexible adjustment of new stimulus-reward associations when the strategy to efficiently solve the task has already been learned. Given the complementary role of orbitofrontal cortex in reward learning and its interconnectivity with BLA, these findings add to the list of dissociable mechanisms for BLA and orbitofrontal cortex in reward learning.

  1. Basolateral membrane Na+/H+ exchange enhances HCO3- absorption in rat medullary thick ascending limb: evidence for functional coupling between basolateral and apical membrane Na+/H+ exchangers.

    Science.gov (United States)

    Good, D W; George, T; Watts, B A

    1995-01-01

    The role of basolateral membrane Na+/H+ exchange in transepithelial HCO3- absorption (JHCO3) was examined in the isolated, perfused medullary thick ascending limb (MTAL) of the rat. In Na(+)-free solutions, addition of Na+ to the bath resulted in a rapid, amiloride-sensitive increase in intracellular pH. In MTALs perfused and bathed with solutions containing 146 mM Na+ and 25 mM HCO3-, bath addition of amiloride (1 mM) or 5-(N-ethyl-N-isopropyl) amiloride (EIPA, 50 microM) reversibly inhibited JHCO3 by 50%. Evidence that the inhibition of JHCO3 by bath amiloride was the result of inhibition of Na+/H+ exchange included the following: (i) the IC50 for amiloride was 5-10 microM, (ii) EIPA was a 50-fold more potent inhibitor than amiloride, (iii) the inhibition by bath amiloride was Na+ dependent, and (iv) significant inhibition was observed with EIPA as low as 0.1 microM. Fifty micromolar amiloride or 1 microM EIPA inhibited JHCO3 by 35% when added to the bath but had no effect when added to the tubule lumen, indicating that addition of amiloride to the bath did not directly inhibit apical membrane Na+/H+ exchange. In experiments in which apical Na+/H+ exchange was assessed from the initial rate of cell acidification following luminal EIPA addition, bath EIPA secondarily inhibited apical Na+/H+ exchange activity by 46%. These results demonstrate basolateral membrane Na+/H+ exchange enhances transepithelial HCO3- absorption in the MTAL. This effect appears to be the result of cross-talk in which an increase in basolateral membrane Na+/H+ exchange activity secondarily increases apical membrane Na+/H+ exchange activity. PMID:8618934

  2. Studies Update Vinyl Chloride Hazards.

    Science.gov (United States)

    Rawls, Rebecca

    1980-01-01

    Extensive study affirms that vinyl chloride is a potent animal carcinogen. Epidemiological studies show elevated rates of human cancers in association with extended contact with the compound. (Author/RE)

  3. LXR/RXR ligand activation enhances basolateral efflux of beta-sitosterol in CaCo-2 cells.

    Science.gov (United States)

    Field, F Jeffrey; Born, Ella; Mathur, Satya N

    2004-05-01

    To examine whether intestinal ABCA1 was responsible for the differences observed between cholesterol and beta-sitosterol absorption, ABCA1-facilitated beta-sitosterol efflux was investigated in CaCo-2 cells following liver X receptor/retinoid X receptor (LXR/RXR) activation. Both the LXR agonist T0901317 and the natural RXR/LXR agonists 22-hydroxycholesterol and 9-cis retinoic acid enhanced the basolateral efflux of beta-sitosterol without altering apical efflux. LXR-mediated enhanced beta-sitosterol efflux occurred between 6 h and 12 h after activation, suggesting that transcription, protein synthesis, and trafficking was likely necessary prior to facilitating efflux. The transcription inhibitor actinomycin D prevented the increase in beta-sitosterol efflux by T0901317. Glybenclamide, an inhibitor of ABCA1 activity, and arachidonic acid, a fatty acid that interferes with LXR activation, also prevented beta-sitosterol efflux in response to the LXR ligand activation. Influx of beta-sitosterol mass did not alter the basolateral or apical efflux of the plant sterol, nor did it alter ABCA1, ABCG1, ABCG5, or ABCG8 gene expression or ABCA1 mass. Similar to results observed with intestinal ABCA1-facilitated cholesterol efflux, LXR/RXR ligand activation enhanced the basolateral efflux of beta-sitosterol without affecting apical efflux. The results suggest that ABCA1 does not differentiate between cholesterol and beta-sitosterol and thus is not responsible for the selectivity of sterol absorption by the intestine. ABCA1, however, may play a role in beta-sitosterol absorption.

  4. Serotonergic innervation and serotonin receptor expression of NPY-producing neurons in the rat lateral and basolateral amygdaloid nuclei.

    Science.gov (United States)

    Bonn, M; Schmitt, A; Lesch, K-P; Van Bockstaele, E J; Asan, E

    2013-03-01

    Pharmacobehavioral studies in experimental animals, and imaging studies in humans, indicate that serotonergic transmission in the amygdala plays a key role in emotional processing, especially for anxiety-related stimuli. The lateral and basolateral amygdaloid nuclei receive a dense serotonergic innervation in all species studied to date. We investigated interrelations between serotonergic afferents and neuropeptide Y (NPY)-producing neurons, which are a subpopulation of inhibitory interneurons in the rat lateral and basolateral nuclei with particularly strong anxiolytic properties. Dual light microscopic immunolabeling showed numerous appositions of serotonergic afferents on NPY-immunoreactive somata. Using electron microscopy, direct membrane appositions and synaptic contacts between serotonin-containing axon terminals and NPY-immunoreactive cellular profiles were unequivocally established. Double in situ hybridization documented that more than 50 %, and about 30-40 % of NPY mRNA-producing neurons, co-expressed inhibitory 5-HT1A and excitatory 5-HT2C mRNA receptor subtype mRNA, respectively, in both nuclei with no gender differences. Triple in situ hybridization showed that individual NPY mRNA-producing interneurons co-express both 5-HT1A and 5-HT2C mRNAs. Co-expression of NPY and 5-HT3 mRNA was not observed. The results demonstrate that serotonergic afferents provide substantial innervation of NPY-producing neurons in the rat lateral and basolateral amygdaloid nuclei. Studies of serotonin receptor subtype co-expression indicate a differential impact of the serotonergic innervation on this small, but important, population of anxiolytic interneurons, and provide the basis for future studies of the circuitry underlying serotonergic modulation of emotional stimulus processing in the amygdala.

  5. Parameters Affecting Hydrogen Chloride Measurements

    Science.gov (United States)

    1993-06-01

    contain sea salt, which is hygroscopic because of the magnesium chloride present, or ammonium bisulfate , which mostly comes from sulfur pollution and is...boosters release hydrogen chloride as a combustion product, and hydrazines or nitric acid can be spilled from liquid fuel motors. Monitoring the...solubility constant, and the second is the acid ionization constant. From experimental work, the product of the two constants is well established (Reference

  6. Ion channels in inflammation.

    Science.gov (United States)

    Eisenhut, Michael; Wallace, Helen

    2011-04-01

    Most physical illness in vertebrates involves inflammation. Inflammation causes disease by fluid shifts across cell membranes and cell layers, changes in muscle function and generation of pain. These disease processes can be explained by changes in numbers or function of ion channels. Changes in ion channels have been detected in diarrhoeal illnesses, pyelonephritis, allergy, acute lung injury and systemic inflammatory response syndromes involving septic shock. The key role played by changes in ion transport is directly evident in inflammation-induced pain. Expression or function of all major categories of ion channels like sodium, chloride, calcium, potassium, transient receptor potential, purinergic receptor and acid-sensing ion channels can be influenced by cyto- and chemokines, prostaglandins, leukotrienes, histamine, ATP, reactive oxygen species and protons released in inflammation. Key pathways in this interaction are cyclic nucleotide, phosphoinositide and mitogen-activated protein kinase-mediated signalling, direct modification by reactive oxygen species like nitric oxide, ATP or protons and disruption of the cytoskeleton. Therapeutic interventions to modulate the adverse and overlapping effects of the numerous different inflammatory mediators on each ion transport system need to target adversely affected ion transport systems directly and locally.

  7. 21 CFR 184.1138 - Ammonium chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138 Food... Specific Substances Affirmed as GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution....

  8. Adrenomedullin increases the short-circuit current in the mouse seminal vesicle: actions on chloride secretion.

    Science.gov (United States)

    Liao, S B; Cheung, K H; O, W S; Tang, Fai

    2014-08-01

    Adrenomedullin (ADM) may regulate seminal vesicle fluid secretion, and this may affect sperm quality. In this study, we investigated the effect of ADM on chloride secretion in the mouse seminal vesicle. The presence of ADM in mouse seminal vesicle was confirmed using immunostaining, and the molecular species was determined using gel filtration chromatography coupled with enzyme-linked assay for ADM. The effects of ADM on chloride secretion were studied by short-circuit current technique in a whole-mount preparation of mouse seminal vesicle in an Ussing chamber. The effects of specific ADM and calcitonin gene-related peptide (CGRP) receptor antagonists were investigated. Whether the ADM effect depended on the cAMP- and/or calcium-activated chloride channel was also studied using specific chloride channel blockers. The results showed that ADM was present in seminal vesicle epithelial cells. The major molecular species was precursor in the mouse seminal vesicle. ADM increased short-circuit current through the calcium-activated chloride channel in mouse seminal vesicle, and CGRP receptor was involved. We conclude that ADM may regulate chloride and fluid secretion from the seminal vesicle, which may affect the composition of the seminal plasma bathing the sperm and, hence, fertility.

  9. 46 CFR 151.50-34 - Vinyl chloride (vinyl chloride monomer).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vinyl chloride (vinyl chloride monomer). 151.50-34... chloride (vinyl chloride monomer). (a) Copper, aluminum, magnesium, mercury, silver, and their alloys shall... equipment that may come in contact with vinyl chloride liquid or vapor. (b) Valves, flanges, and...

  10. 40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.

    Science.gov (United States)

    2010-07-01

    ... dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection of Environment... AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. An owner or operator of an ethylene...

  11. Purinergic receptor signaling at the basolateral membrane of macula densa cells.

    Science.gov (United States)

    Liu, Ruisheng; Bell, P Darwin; Peti-Peterdi, Janos; Kovacs, Gergly; Johansson, Alf; Persson, A Erik G

    2002-05-01

    Purinergic receptors are important in the regulation of renal hemodynamics; therefore, this study sought to determine if such receptors influence macula densa cell function. Isolated glomeruli containing macula densa cells, with and without the cortical thick ascending limb, were loaded with the Ca(2+) sensitive indicators, Fura Red (confocal microscopy) or fura 2 (conventional video image analysis). Studies were performed on an inverted microscope in a chamber with a flow-through perfusion system. Changes in cytosolic calcium concentration ([Ca(2+)](i)) from exposed macula densa plaques were assessed upon addition of adenosine, ATP, UTP, ADP, or 2-methylthio-ATP (2- MeS-ATP) for 2 min added to the bathing solution. There was no change in [Ca(2+)](i) with addition of adenosine (10(-7) to 10(-3) M). UTP and ATP (10(-4) M) caused [Ca(2+)](i) to increase by 268 +/- 40 nM (n = 21) and 295 +/- 53 nM (n = 21), respectively, whereas in response to 2MesATP and ADP, [Ca(2+)](i) increased by only 67 +/- 13 nM (n = 8) and 93 +/- 36 nM (n = 14), respectively. Dose response curve for ATP (10(-7) to 10(-3) M) added in bath showed an EC(50) of 15 microM. No effect on macula densa [Ca(2+)](i) was seen when ATP was added from the lumen. ATP caused similar increases in macula densa [Ca(2+)](i) in the presence or absence of bath Ca(2+) and addition of 5 mM ethyleneglycotetraacetic acid (EGTA). Suramin (an antagonist of P2X and P2Y receptors) completely inhibited ATP-induced [Ca(2+)](i) dynamics. Also, ATP-Ca(2+) responsiveness was prevented by the phospholipase C inhibitor, U-73122, but not by its inactive analog, U-73343. These results suggest that macula densa cells possess P2Y(2) purinergic receptors on basolateral but not apical membranes and that activation of these receptors results in the mobilization of Ca(2+).

  12. Third trimester-equivalent ethanol exposure increases anxiety-like behavior and glutamatergic transmission in the basolateral amygdala.

    Science.gov (United States)

    Baculis, Brian C; Diaz, Marvin R; Valenzuela, C Fernando

    2015-10-01

    Ethanol consumption during pregnancy produces a wide range of morphological and behavioral alterations known as fetal alcohol spectrum disorder (FASD). Among the behavioral deficits associated with FASD is an increased probability of developing anxiety disorders. Studies with animal models of FASD have demonstrated that ethanol exposure during the equivalent to the 1(st) and 2(nd) trimesters of human pregnancy increases anxiety-like behavior. Here, we examined the impact on this type of behavior of exposure to high doses of ethanol in vapor inhalation chambers during the rat equivalent to the human 3rd trimester of pregnancy (i.e., neonatal period in these animals). We evaluated anxiety-like behavior with the elevated plus maze. Using whole-cell patch-clamp electrophysiological techniques in brain slices, we also characterized glutamatergic and GABAergic synaptic transmission in the basolateral amygdala, a brain region that has been implicated to play a role in emotional behavior. We found that ethanol-exposed adolescent offspring preferred the closed arms over the open arms in the elevated plus maze and displayed lower head dipping activity than controls. Electrophysiological measurements showed an increase in the frequency of spontaneous and miniature excitatory postsynaptic currents in pyramidal neurons from the ethanol group. These findings suggest that high-dose ethanol exposure during the equivalent to the last trimester of human pregnancy can persistently increase excitatory synaptic inputs to principal neurons in the basolateral amygdala, leading to an increase in anxiety-like behaviors.

  13. Fatty acids affect micellar properties and modulate vitamin D uptake and basolateral efflux in Caco-2 cells.

    Science.gov (United States)

    Goncalves, Aurélie; Gleize, Béatrice; Roi, Stéphanie; Nowicki, Marion; Dhaussy, Amélie; Huertas, Alain; Amiot, Marie-Josèphe; Reboul, Emmanuelle

    2013-10-01

    We have recently shown that vitamin D3 (cholecalciferol) absorption is not a simple passive diffusion but involves cholesterol transporters. As free fatty acids (FAs) modulate cholesterol intestinal absorption and metabolism, we hypothesized that FAs may also interact with vitamin D absorption. Effects of FAs were evaluated at different levels of cholecalciferol intestinal absorption. First, the physicochemical properties of micelles formed with different FAs were analyzed. The micelles were then administered to human Caco-2 cells in culture to evaluate FA effects on (i) cholecalciferol uptake and basolateral efflux and (ii) the regulation of genes coding proteins involved in lipid absorption process. Micellar electric charge was correlated with both FA chain length and degree of unsaturation. Long-chain FAs at 500 μM in mixed micelles decreased cholecalciferol uptake in Caco-2 cells. This decrease was annihilated as soon as the long-chain FAs were mixed with other FAs. Oleic acid significantly improved cholecalciferol basolateral efflux compared to other FAs. These results were partly explained by a modulation of genes coding for lipid transport proteins such as Niemann-pick C1-like 1 and scavenger receptor class B type I. The data reported here show for the first time that FAs can interact with cholecalciferol intestinal absorption at different key steps of the absorption process. Cholecalciferol intestinal absorption may thus be optimized according to oil FA composition.

  14. Electrochemical Chloride extraction using external electrodes?

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Pedersen, Anne Juul

    2006-01-01

    Electrochemical methods for the removal of chloride from concrete have been developed and the methods are primarily designed for situations where corrosion has started due to an increased chloride concentration in the vicinity of the reinforcement. In these methods the reinforcement is used...... as the cathode. However, some unwanted side effects can occur, including alkali-silica reaction and in some cases hydrogen embrittlement. It is also suggested also to use electrochemical chloride extraction in a preventive way in constructions where chloride induced corrosion is likely to be a problem after...... a period of time, i.e. remove the chlorides before the chloride front reaches the reinforcement. If the chlorides are removed from outer few centimetres from the surface, the chloride will not reach the reinforcement and cause damage. By using the electrochemical chloride removal in this preventive way...

  15. The Effect of Silver Chloride Formation on the Kinetics of Silver Dissolution in Chloride Solution

    Science.gov (United States)

    Ha, Hung; Payer, Joe

    2011-01-01

    The precipitation and growth of AgCl on silver in physiological NaCl solution were investigated. AgCl was found to form at bottom of scratches on the surface which may be the less effective sites for diffusion or the favorable sites for heterogeneous nucleation. Patches of silver chloride expanded laterally on the substrate until a continuous film formed. The ionic transport path through this newly formed continuous film was via spaces between AgCl patches. As the film grew, the spaces between AgCl patches closed and ion transport was primarily via micro-channels running through AgCl patches. The decrease of AgCl layer conductivity during film growth were attributed to the clogging of micro-channels or decrease in charge carrier concentration inside the micro-channels. Under thin AgCl layer, i.e. on the order of a micrometer, the dissolution of silver substrate was under mixed activation-Ohmic control. Under thick AgCl layer, i.e. on the order of tens of micrometers, the dissolution of silver substrate was mediated by the Ohmic resistance of AgCl layer. PMID:21516171

  16. The Effect of Silver Chloride Formation on the Kinetics of Silver Dissolution in Chloride Solution.

    Science.gov (United States)

    Ha, Hung; Payer, Joe

    2011-02-28

    The precipitation and growth of AgCl on silver in physiological NaCl solution were investigated. AgCl was found to form at bottom of scratches on the surface which may be the less effective sites for diffusion or the favorable sites for heterogeneous nucleation. Patches of silver chloride expanded laterally on the substrate until a continuous film formed. The ionic transport path through this newly formed continuous film was via spaces between AgCl patches. As the film grew, the spaces between AgCl patches closed and ion transport was primarily via micro-channels running through AgCl patches. The decrease of AgCl layer conductivity during film growth were attributed to the clogging of micro-channels or decrease in charge carrier concentration inside the micro-channels. Under thin AgCl layer, i.e. on the order of a micrometer, the dissolution of silver substrate was under mixed activation-Ohmic control. Under thick AgCl layer, i.e. on the order of tens of micrometers, the dissolution of silver substrate was mediated by the Ohmic resistance of AgCl layer.

  17. Ion channel expression in the developing enteric nervous system.

    Directory of Open Access Journals (Sweden)

    Caroline S Hirst

    Full Text Available The enteric nervous system arises from neural crest-derived cells (ENCCs that migrate caudally along the embryonic gut. The expression of ion channels by ENCCs in embryonic mice was investigated using a PCR-based array, RT-PCR and immunohistochemistry. Many ion channels, including chloride, calcium, potassium and sodium channels were already expressed by ENCCs at E11.5. There was an increase in the expression of numerous ion channel genes between E11.5 and E14.5, which coincides with ENCC migration and the first extension of neurites by enteric neurons. Previous studies have shown that a variety of ion channels regulates neurite extension and migration of many cell types. Pharmacological inhibition of a range of chloride or calcium channels had no effect on ENCC migration in cultured explants or neuritogenesis in vitro. The non-selective potassium channel inhibitors, TEA and 4-AP, retarded ENCC migration and neuritogenesis, but only at concentrations that also resulted in cell death. In summary, a large range of ion channels is expressed while ENCCs are colonizing the gut, but we found no evidence that ENCC migration or neuritogenesis requires chloride, calcium or potassium channel activity. Many of the ion channels are likely to be involved in the development of electrical excitability of enteric neurons.

  18. Ion Channel Expression in the Developing Enteric Nervous System

    Science.gov (United States)

    Stamp, Lincon A.; Fegan, Emily; Dent, Stephan; Cooper, Edward C.; Lomax, Alan E.; Anderson, Colin R.; Bornstein, Joel C.; Young, Heather M.; McKeown, Sonja J.

    2015-01-01

    The enteric nervous system arises from neural crest-derived cells (ENCCs) that migrate caudally along the embryonic gut. The expression of ion channels by ENCCs in embryonic mice was investigated using a PCR-based array, RT-PCR and immunohistochemistry. Many ion channels, including chloride, calcium, potassium and sodium channels were already expressed by ENCCs at E11.5. There was an increase in the expression of numerous ion channel genes between E11.5 and E14.5, which coincides with ENCC migration and the first extension of neurites by enteric neurons. Previous studies have shown that a variety of ion channels regulates neurite extension and migration of many cell types. Pharmacological inhibition of a range of chloride or calcium channels had no effect on ENCC migration in cultured explants or neuritogenesis in vitro. The non-selective potassium channel inhibitors, TEA and 4-AP, retarded ENCC migration and neuritogenesis, but only at concentrations that also resulted in cell death. In summary, a large range of ion channels is expressed while ENCCs are colonizing the gut, but we found no evidence that ENCC migration or neuritogenesis requires chloride, calcium or potassium channel activity. Many of the ion channels are likely to be involved in the development of electrical excitability of enteric neurons. PMID:25798587

  19. Intracellular mechanisms of cocaine-memory reconsolidation in the basolateral amygdala and dorsal hippocampus

    Science.gov (United States)

    Wells, Audrey Marie

    The ability of cocaine-associated environmental contexts to promote relapse in abstinent humans and reinstatement of cocaine-seeking behavior in laboratory animals depends on the formation and maintenance of maladaptive context-response-cocaine associative memories, the latter of which can be disrupted by manipulations that interfere with memory reconsolidation. Memory reconsolidation refers to a protein synthesis-dependent phenomenon whereby memory traces are reincorporated back into long-term memory storage following their retrieval and subsequent destabilization. To elucidate the distinctive roles of the basolateral amygdala (BLA) and dorsal hippocampus (DH) in the reconsolidation of context-response-cocaine memories, Experiments 1-3 evaluated novel molecular mechanisms within each structure that control this phenomenon. Experiment 1 tested the hypothesis that activation of the extracellular signal-regulated kinase (ERK) in the BLA and nucleus accumbens core (NACc - a substrate for Pavlovian cocaine-memory reconsolidation) would critically control instrumental cocaine-memory reconsolidation. To determine this, rats were re-exposed to a context that had previously been used for cocaine self-administration (i.e., cocaine memory-reactivation) and immediately thereafter received bilateral intra-BLA or intra-NACc microinfusions of the ERK inhibitor U0126 or vehicle (VEH) and were subsequently tested for drug context-induced cocaine-seeking behavior (non-reinforced lever responding) ~72 h later. Re-exposure to the cocaine-paired context at test fully reinstated cocaine-seeking behavior, relative to responding in an alternate, extinction context, and post-reactivation U0126 treatment in the BLA, but not the NACc, impaired cocaine-seeking behavior, relative to VEH. This effect was associated with a temporary increase in ERK2, but not ERK1, phosphorylation in the BLA and required explicit reactivation of the target memory trace (i.e., did not similarly manifest when U

  20. Dengue virus M protein C-terminal peptide (DVM-C) forms ion channels.

    Science.gov (United States)

    Premkumar, A; Horan, C R; Gage, P W

    2005-03-01

    A chemically synthesized peptide consisting of the C-terminus of the M protein of the Dengue virus type 1 strain Singapore S275/90 (DVM-C) produced ion channel activity in artificial lipid bilayers. The channels had a variable conductance and were more permeable to sodium and potassium ions than to chloride ions and more permeable to chloride ions than to calcium ions. Hexamethylene amiloride (100 microM) and amantadine (10 microM), blocked channels formed by DVM-C. Ion channels may play an important role in the life cycle of many viruses and drugs that block these channels may prove to be useful antiviral agents.

  1. Basolateral Na+/HCO3– cotransport activity is regulated by the dissociable Na+/H+ exchanger regulatory factor

    Science.gov (United States)

    Bernardo, Angelito A.; Kear, Felicidad T.; Santos, Anna V.P.; Ma, Jianfei; Steplock, Debra; Robey, R. Brooks; Weinman, Edward J.

    1999-01-01

    In the renal proximal tubule, the activities of the basolateral Na+/HCO3– cotransporter (NBC) and the apical Na+/H+ exchanger (NHE3) uniformly vary in parallel, suggesting that they are coordinately regulated. PKA-mediated inhibition of NHE3 is mediated by a PDZ motif–containing protein, the Na+/H+ exchanger regulatory factor (NHE-RF). Given the common inhibition of these transporters after protein kinase A (PKA) activation, we sought to determine whether NHE-RF also plays a role in PKA-regulated NBC activity. Renal cortex immunoblot analysis using anti-peptide antibodies directed against rabbit NHE-RF demonstrated the presence of this regulatory factor in both brush-border membranes (BBMs) and basolateral membranes (BLMs). Using a reconstitution assay, we found that limited trypsin digestion of detergent solubilized rabbit renal BLM preparations resulted in NBC activity that was unaffected by PKA activation. Co-reconstitution of these trypsinized preparations with a recombinant protein corresponding to wild-type rabbit NHE-RF restored the inhibitory effect of PKA on NBC activity in a concentration-dependent manner. NBC activity was inhibited 60% by 10–8M NHE-RF; this effect was not observed in the absence of PKA. Reconstitution with heat-denatured NHE-RF also failed to attenuate NBC activity. To establish further a physiologic role for NHE-RF in NBC regulation, the renal epithelial cell line B-SC-1, which lacks detectable endogenous NHE-RF expression, was engineered to express stably an NHE-RF transgene. NHE-RF–expressing B-SC-1 cells (B-SC-RF) exhibited markedly lower basal levels of NBC activity than did wild-type controls. Inhibition of NBC activity in B-SC-RF cells was enhanced after 10 μM of forskolin treatment, consistent with a postulated role for NHE-RF in mediating the inhibition of NBC activity by PKA. These findings not only suggest NHE-RF involvement in PKA-regulated NBC activity, but also provide a unique molecular mechanism whereby

  2. Molecular and functional expression of high conductance Ca 2+ activated K+ channels in the eel intestinal epithelium

    DEFF Research Database (Denmark)

    Lionetto, Maria G; Rizzello, Antonia; Giordano, Maria E;

    2008-01-01

    Several types of K(+) channels have been identified in epithelial cells. Among them high conductance Ca(2+)-activated K(+) channels (BK channels) are of relevant importance for their involvement in regulatory volume decrease (RVD) response following hypotonic stress. The aim of the present work...... and morphometric analysis on the intact tissue. BK(Ca) channels appeared to be localized along all the plasma membrane of the enterocytes; the apical part of the villi showed the most intense immunostaining. These channels were silent in basal condition, but were activated on both membranes (apical and basolateral......) by increasing intracellular Ca(2+) concentration with the Ca(2+) ionophore ionomycin (1 microM). BK(Ca) channels were also activated on both membranes by hypotonic swelling of the epithelium and their inhibition by 100 nM iberiotoxin (specific BK(Ca) inhibitor) abolished the Regulatory Volume Decrease (RVD...

  3. Solvolyses of Benzoyl Chlorides in Weakly Nucleophilic Media

    Directory of Open Access Journals (Sweden)

    Haldon Carl Harris

    2011-07-01

    Full Text Available Rate constants and activations parameters are reported for solvolyses of p-Z-substituted benzoyl chlorides (1, Z = OMe, Me, H, and Cl in 97% w/w hexafluoroisopropanol-water (97H. Additional kinetic data are reported for solvolyses in acetic and formic acids. Plots of log k vs. σp in 97H are consistent with previous research showing that a cationic reaction channel is dominant, even for solvolyses of 1, Z = NO2. A benzoyl cation intermediate was trapped by Friedel-Crafts reaction with 1,3,5-trimethoxybenzene in hexafluoroisopropanol. The results are explained by an SN2-SN1 spectrum of mechanisms with variations in nucleophilic solvent assistance. Ab initio calculations of heterolytic bond dissociation energies of various chloro- and fluoro-substituted and other benzoyl chlorides are correlated with log k for solvolyses.

  4. Proteolytic Cleavage of ProBDNF into Mature BDNF in the Basolateral Amygdala Is Necessary for Defeat-Induced Social Avoidance

    Science.gov (United States)

    Dulka, Brooke N.; Ford, Ellen C.; Lee, Melissa A.; Donnell, Nathaniel J.; Goode, Travis D.; Prosser, Rebecca; Cooper, Matthew A.

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) is essential for memory processes. The present study tested whether proteolytic cleavage of proBDNF into mature BDNF (mBDNF) within the basolateral amygdala (BLA) regulates the consolidation of defeat-related memories. We found that acute social defeat increases the expression of mBDNF, but not proBDNF, in…

  5. Oxytocin Signaling in Basolateral and Central Amygdala Nuclei Differentially Regulates the Acquisition, Expression, and Extinction of Context-Conditioned Fear in Rats

    Science.gov (United States)

    Campbell-Smith, Emma J.; Holmes, Nathan M.; Lingawi, Nura W.; Panayi, Marios C.; Westbrook, R. Frederick

    2015-01-01

    The present study investigated how oxytocin (OT) signaling in the central (CeA) and basolateral (BLA) amygdala affects acquisition, expression, and extinction of context-conditioned fear (freezing) in rats. In the first set of experiments, acquisition of fear to a shocked context was impaired by a preconditioning infusion of synthetic OT into the…

  6. Interaction between the Basolateral Amygdala and Dorsal Hippocampus Is Critical for Cocaine Memory Reconsolidation and Subsequent Drug Context-Induced Cocaine-Seeking Behaviorin Rats

    Science.gov (United States)

    Wells, Audrey M.; Lasseter, Heather C.; Xie, Xiaohu; Cowhey, Kate E.; Reittinger, Andrew M.; Fuchs, Rita A.

    2011-01-01

    Contextual stimulus control over instrumental drug-seeking behavior relies on the reconsolidation of context-response-drug associative memories into long-term memory storage following retrieval-induced destabilization. According to previous studies, the basolateral amygdala (BLA) and dorsal hippocampus (DH) regulate cocaine-related memory…

  7. [Headspace GC/MS analysis of residual vinyl chloride and vinylidene chloride in polyvinyl chloride and polyvinylidene chloride products].

    Science.gov (United States)

    Ohno, Hiroyuki; Mutsuga, Motoh; Kawamura, Yoko; Suzuki, Masako; Aoyama, Taiki

    2005-02-01

    A headspace GC/MS analysis method for the simultaneous determination of residual vinyl chloride (VC) and vinylidene chloride (VDC) in polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) products was developed. A test sample was swelled overnight with N,N-dimethylacetamide in a sealed vial. The vial was incubated for 1 hour at 90 degrees C, then the headspace gas was analyzed by GC/MS using a PLOT capillary column. The recoveries from spiked PVC and PVDC samples were 90.0-112.3% for VC and 85.2-108.3% for VDC. The determination limits were 0.01 microg/g for VC and 0.06/microg/g for VDC, respectively. By this method, VC was detected in two PVC water supply pipes at the levels of 0.61 and 0.01 microg/g. On the other hand, VC and VDC were not detected in any of the food container-packages or toys tested.

  8. 1,5-Diaminotetrazolium chloride

    Directory of Open Access Journals (Sweden)

    Ling-Qiao Meng

    2010-04-01

    Full Text Available The title compound, CH5N6+·Cl−, crystallized with two indepedent 1,5-diaminotetrazolium cations and two independent chloride anions in the asymmetric unit. In the crystal, there are a number of N—H...Cl hydrogen-bonding interactions, which generate a three-dimensional network.

  9. NIFLUMIC ACID BLOCKS NATIVE AND RECOMBINANT T-TYPE CHANNELS

    OpenAIRE

    Balderas, E; Arteaga-Tlecuitl, R; Rivera, M; Gomora, JC; Darszon, A.

    2012-01-01

    Voltage-dependent calcium channels are widely distributed in animal cells, including spermatozoa. Calcium is fundamental in many sperm functions such as: motility, capacitation and the acrosome reaction, all essential for fertilization. Pharmacological evidence has suggested T-type calcium channels participate in the acrosome reaction. Niflumic acid (NA), a non-steroidal anti-inflammatory drug commonly used as chloride channel blocker, blocks T-currents in mouse spermatogenic cells and Cl− ch...

  10. 21 CFR 173.375 - Cetylpyridinium chloride.

    Science.gov (United States)

    2010-04-01

    ... CONSUMPTION Specific Usage Additives § 173.375 Cetylpyridinium chloride. Cetylpyridinium chloride (CAS Reg. No... Nutrition's Library, Food and Drug Administration, 5100 Paint Branch Pkwy., College Park, MD 20740, or...

  11. The role of chloride anion and CFTR in killing of Pseudomonas aeruginosa by normal and CF neutrophils.

    Science.gov (United States)

    Painter, Richard G; Bonvillain, Ryan W; Valentine, Vincent G; Lombard, Gisele A; LaPlace, Stephanie G; Nauseef, William M; Wang, Guoshun

    2008-06-01

    Chloride anion is essential for myeloperoxidase (MPO) to produce hypochlorous acid (HOCl) in polymorphonuclear neutrophils (PMNs). To define whether chloride availability to PMNs affects their HOCl production and microbicidal capacity, we examined how extracellular chloride concentration affects killing of Pseudomonas aeruginosa (PsA) by normal neutrophils. PMN-mediated bacterial killing was strongly dependent on extracellular chloride concentration. Neutrophils in a chloride-deficient medium killed PsA poorly. However, as the chloride level was raised, the killing efficiency increased in a dose-dependent manner. By using specific inhibitors to selectively block NADPH oxidase, MPO, and cystic fibrosis transmembrane conductance regulator (CFTR) functions, neutrophil-mediated killing of PsA could be attributed to three distinct mechanisms: CFTR-dependent and oxidant-dependent; chloride-dependent but not CFTR- and oxidant-dependent; and independent of any of the tested factors. Therefore, chloride anion is involved in oxidant- and nonoxidant-mediated bacterial killing. We previously reported that neutrophils from CF patients are defective in chlorination of ingested bacteria, suggesting that the chloride channel defect might impair the MPO-hydrogen peroxide-chloride microbicidal function. Here, we compared the competence of killing PsA by neutrophils from normal donors and CF patients. The data demonstrate that the killing rate by CF neutrophils was significantly lower than that by normal neutrophils. CF neutrophils in a chloride-deficient environment had only one-third of the bactericidal capacity of normal neutrophils in a physiological chloride environment. These results suggest that CFTR-dependent chloride anion transport contributes significantly to killing PsA by normal neutrophils and when defective as in CF, may compromise the ability to clear PsA.

  12. Progress of Carbonation in Chloride Contaminated Concretes

    OpenAIRE

    Wang, Yaocheng; Basheer, P. A.M.; Nanukuttan, S; Bai, Y.

    2016-01-01

    Concretes used in marine environment are generally under the cyclic effect of CO2 and chloride ions (Cl-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate ...

  13. Microbial reductive dehalogenation of vinyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Spormann, Alfred M [Stanford, CA; Muller, Jochen A [Baltimore, MD; Rosner, Bettina M [Berlin, DE; Von Abendroth, Gregory [Mannheim, DE; Meshulam-Simon, Galit [Los Angeles, CA; McCarty, Perry L [Stanford, CA

    2014-02-11

    Compositions and methods are provided that relate to the bioremediation of chlorinated ethenes, particularly the bioremediation of vinyl chloride by Dehalococcoides-like organisms. An isolated strain of bacteria, Dehalococcoides sp. strain VS, that metabolizes vinyl chloride is provided; the genetic sequence of the enzyme responsible for vinyl chloride dehalogenation; methods of assessing the capability of endogenous organisms at an environmental site to metabolize vinyl chloride; and a method of using the strains of the invention for bioremediation.

  14. Long-term memory for pavlovian fear conditioning requires dopamine in the nucleus accumbens and basolateral amygdala.

    Directory of Open Access Journals (Sweden)

    Jonathan P Fadok

    Full Text Available The neurotransmitter dopamine (DA is essential for learning in a pavlovian fear conditioning paradigm known as fear-potentiated startle (FPS. Mice lacking the ability to synthesize DA fail to learn the association between the conditioned stimulus and the fear-inducing footshock. Previously, we demonstrated that restoration of DA synthesis to neurons of the ventral tegmental area (VTA was sufficient to restore FPS. Here, we used a target-selective viral restoration approach to determine which mesocorticolimbic brain regions receiving DA signaling from the VTA require DA for FPS. We demonstrate that restoration of DA synthesis to both the basolateral amygdala (BLA and nucleus accumbens (NAc is required for long-term memory of FPS. These data provide crucial insight into the dopamine-dependent circuitry involved in the formation of fear-related memory.

  15. Injections of urocortin 1 into the basolateral amygdala induce anxiety-like behavior and c-Fos expression in brainstem serotonergic neurons.

    Science.gov (United States)

    Spiga, F; Lightman, S L; Shekhar, A; Lowry, C A

    2006-01-01

    The amygdala plays a key role in emotional processing and anxiety-related physiological and behavioral responses. Previous studies have shown that injections of the anxiety-related neuropeptide corticotropin-releasing factor or the related neuropeptide urocortin 1 into the region of the basolateral amygdaloid nucleus induce anxiety-like behavior in several behavioral paradigms. Brainstem serotonergic systems in the dorsal raphe nucleus and median raphe nucleus may be part of a distributed neural system that, together with the basolateral amygdala, regulates acute and chronic anxiety states. We therefore investigated the effect of an acute bilateral injection of urocortin 1 into the basolateral amygdala on behavior in the social interaction test and on c-Fos expression within serotonergic neurons in the dorsal raphe nucleus and median raphe nucleus. Male rats were implanted with bilateral cannulae directed at the region of the basolateral amygdala; 72 h after surgery, rats were injected with urocortin 1 (50 fmol/100 nl) or vehicle (100 nl of 1% bovine serum albumin in distilled water). Thirty minutes after injection, a subgroup of rats from each experimental group was exposed to the social interaction test; remaining animals were left in the home cage. Two hours after injection rats were perfused with paraformaldehyde and brains were removed and processed for immunohistochemistry. Acute injection of urocortin 1 had anxiogenic effects in the social interaction test, reducing total interaction time without affecting locomotor activity or exploratory behavior. These behavioral effects were associated with increases in c-Fos expression within brainstem serotonergic neurons. In home cage rats and rats exposed to the social interaction test, urocortin 1 treatment increased the number of c-Fos-immunoreactive serotonergic neurons within subdivisions of both the dorsal raphe nucleus and median raphe nucleus. These results are consistent with the hypothesis that the

  16. Development of neurons and fibers containing calcium binding proteins in the pallial amygdala of mouse, with special emphasis on those of the basolateral amygdalar complex.

    Science.gov (United States)

    Legaz, Isabel; Olmos, Luis; Real, M Angeles; Guirado, Salvador; Dávila, José Carlos; Medina, Loreta

    2005-08-08

    We studied the development of neurons and fibers containing calbindin, calretinin, and parvalbumin in the mouse pallial amygdala, with special emphasis on those of the basolateral amygdalar complex. Numerous calbindin-immunoreactive (CB+) cells were observed in the incipient basolateral amygdalar complex and cortical amygdalar area from E13.5. At E16.5, CB+ cells became more abundant in the lateral and basolateral nuclei than in the basomedial nucleus, showing a pattern very similar to that of gamma-aminobutyric acid (GABA)ergic neurons. Many CB+ cells observed in the pallial amygdala appeared to originate in the anterior entopeduncular area/ganglionic eminences of the subpallium. The density of CB+ cells gradually increased in the pallial amygdala until the first postnatal week and appeared to decrease later, coinciding with the postnatal appearance of parvalbumin cells and raising the possibility of a partial phenotypic shift. Calretinin (CR) immunoreactivity could be observed in a few cells and fibers in the pallial amygdala at E14.5, and by E16.5 it became a good marker of the different nuclei of the basolateral amygdalar complex. Numerous CB+ and CR+ varicosities, part of which have an intrinsic origin, were observed in the basolateral amygdalar complex from E16.5, and some surrounded unstained perikarya and/or processes before birth, indicating an early formation of inhibitory networks. Each calcium binding protein showed a distinct spatiotemporal expression pattern of development in the mouse pallial amygdala. Any alteration in the development of neurons and fibers containing calcium binding proteins of the pallial amygdala may result in important disorders of emotional and social behavior.

  17. Endomorphins exit the brain by a saturable efflux system at the basolateral surface of cerebral endothelial cells.

    Science.gov (United States)

    Somogyvari-Vigh, Aniko; Kastin, Abba J; Liao, Jie; Zadina, James E; Pan, Weihong

    2004-05-01

    Endomorphin-1 (EM-1) and endomorphin-2 (EM-2) are two highly selective mu-opiate receptor agonists. We recently demonstrated that EM-1 and EM-2 have a saturable transport system from brain-to-blood in vivo. Since the endothelial cells are the main component of the non-fenestrated microvessels of the blood-brain barrier (BBB), we examined whether these endogenous tetrapeptides have a saturable transport system in cultured cerebral endothelial cells. EM-1 and EM-2 binding and transport were studied in a transwell system in which primary mouse endothelial cells were co-cultured with rat glioma cells. We found that binding of both endomorphins was greater on the basolateral than the apical cell surface. Flux of EM-1 and EM-2 occurred predominantly in the basolateral to apical direction, each showing self-inhibition with an excess of the respective endomorphin. Transport was not influenced by the addition of the P-glycoprotein inhibitor, cyclosporin A. Neither the mu-opiate receptor agonist DAMGO nor the delta-opiate receptor agonist DPDPE had any effect on the transport. Thus, the results show that a saturable transport system for EM-1 and EM-2 occurs at the level of endothelial cells of the BBB, and unlike beta-endorphin and morphine, P-glycoprotein is not needed for the brain-to-blood transport. Cross-inhibition of the transport of each endomorphin by the other suggests a shared transport system that is different from mu- or delta-opiate receptors. As endormorphins are mainly produced in the CNS, the presence of the efflux system at the BBB could play an important role in pain modulation and neuroendocrine control.

  18. Dorsal Periaqueductal gray simultaneously modulates ventral Subiculum induced-plasticity in the Basolateral Amygdala and the Nucleus Accumbens

    Directory of Open Access Journals (Sweden)

    Omer eHorovitz

    2015-03-01

    Full Text Available The ventral subiculum of the hippocampus projects both to the basolateral amygdala, which is typically, associated with a response to aversive stimuli, as well as to the nucleus accumbens, which is typically associated with a response to appetitive stimuli. Traditionally, studies of the responses to emotional events focus on either negative or positive affect-related processes, however, emotional experiences often affect both. The ability of high-level processing brain regions (e.g. medial prefrontal cortex to modulate the balance between negative and positive affect-related regions was examined extensively. In contrast, the ability of low-level processing areas (e.g. periaqueductal grey - PAG to do so, has not been sufficiently studied. To address whether midbrain structures have the ability to modulate limbic regions, we first examined the ventral subiculum stimulation’s (vSub ability to induce plasticity in the basolateral amygdala (BLA and nucleus accumbens (NAcc simultaneously in rats. Further, dorsal PAG (dPAG priming ability to differentially modulate vSub stimulation induced plasticity in the BLA and the NAcc was subsequently examined. vSub stimulation resulted in plasticity in both the BLA and the NAcc simultaneously. Moreover, depending on stimulus intensity, differential dPAG priming effects on LTP in these two regions were observed. The results demonstrate that negative and positive affect-related processes may be simultaneously modulated. Furthermore, under some conditions lower-level processing areas, such as the dPAG, may differentially modulate plasticity in these regions and thus affect the long-term emotional outcome of the experience.

  19. 21 CFR 184.1426 - Magnesium chloride.

    Science.gov (United States)

    2010-04-01

    ... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O,...

  20. Cystic Fibrosis (CF): Chloride Sweat Test

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Cystic Fibrosis (CF) Chloride Sweat Test KidsHealth > For Parents > Cystic Fibrosis (CF) Chloride Sweat Test Print A A A ... It Is A chloride sweat test helps diagnose cystic fibrosis (CF) , an inherited disorder that makes kids sick ...

  1. 75 FR 33824 - Barium Chloride From China

    Science.gov (United States)

    2010-06-15

    ... COMMISSION Barium Chloride From China Determination On the basis of the record\\1\\ developed in the subject... order on barium chloride from China would be likely to lead to continuation or recurrence of material... Barium Chloride from China: Investigation No. 731-TA-149 (Third Review). By order of the...

  2. 75 FR 19657 - Barium Chloride From China

    Science.gov (United States)

    2010-04-15

    ... COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Notice of... chloride from China. SUMMARY: The Commission hereby gives notice that it will proceed with a full review... revocation of the antidumping duty order on barium chloride from China would be likely to lead...

  3. 21 CFR 172.180 - Stannous chloride.

    Science.gov (United States)

    2010-04-01

    ... Preservatives § 172.180 Stannous chloride. The food additive stannous chloride may be safely used for color... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Stannous chloride. 172.180 Section 172.180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  4. Activation of AMPK inhibits cholera toxin stimulated chloride secretion in human and murine intestine.

    Directory of Open Access Journals (Sweden)

    Ailín C Rogers

    Full Text Available Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR, is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK, can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK. In order to substantiate our findings on the whole tissue level, short-circuit current (SCC was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness.

  5. Neuronal chloride accumulation and excitatory GABA underlie aggravation of neonatal epileptiform activities by phenobarbital.

    Science.gov (United States)

    Nardou, Romain; Yamamoto, Sumii; Chazal, Geneviève; Bhar, Asma; Ferrand, Nadine; Dulac, Olivier; Ben-Ari, Yehezkel; Khalilov, Ilgam

    2011-04-01

    Phenobarbital produces its anti-epileptic actions by increasing the inhibitory drive of γ-aminobutyric acid. However, following recurrent seizures, γ-aminobutyric acid excites neurons because of a persistent increase of chloride raising the important issue of whether phenobarbital could aggravate persistent seizures. Here we compared the actions of phenobarbital on initial and established ictal-like events in an in vitro model of mirror focus. Using the in vitro three-compartment chamber preparation with the two hippocampi and their commissural fibres placed in three different chambers, kainate was applied to one hippocampus and phenobarbital contralaterally, either after one ictal-like event or after many recurrent ictal-like events that produce an epileptogenic mirror focus. Field, perforated patch and single-channel recordings were used to determine the effects of γ-aminobutyric acid and their modulation by phenobarbital, and alterations of the chloride cotransporters were investigated using sodium-potassium-chloride cotransporter 1 and potassium chloride cotransporter 2 antagonists, potassium chloride cotransporter 2 immunocytochemistry and sodium-potassium-chloride cotransporter 1 knockouts. Phenobarbital reduced initial ictal-like events and prevented the formation of a mirror focus when applied from the start. In contrast, phenobarbital aggravated epileptiform activities when applied after many ictal-like events by enhancing the excitatory actions of γ-aminobutyric acid due to increased chloride. The accumulation of chloride and the excitatory actions of γ-aminobutyric acid in mirror foci neurons are mediated by the sodium-potassium-chloride cotransporter 1 chloride importer and by downregulation and internalization of the chloride-exporter potassium-chloride cotransporter 2. Finally, concomitant applications of the sodium-potassium-chloride cotransporter 1 antagonist bumetanide and phenobarbital decreased excitatory actions of γ-aminobutyric acid and

  6. Two cystic fibrosis transmembrane conductance regulator mutations have different effects on both pulmonary phenotype and regulation of outwardly rectified chloride currents.

    OpenAIRE

    Fulmer, S B; Schwiebert, E M; M.M. Morales; Guggino, W B; Cutting, G R

    1995-01-01

    Cystic fibrosis (CF), a disorder of electrolyte transport manifest in the lungs, pancreas, sweat duct, and vas deferens, is caused by mutations in the CF transmembrane conductance regulator (CFTR). The CFTR protein has been shown to function as a cAMP-activated chloride channel and also regulates a separate protein, the outwardly rectifying chloride channel (ORCC). To determine the consequence of disease-producing mutations upon these functions, mutant CFTR was transiently expressed in Xenopu...

  7. 人类胞内氯离子通道蛋白3在原核细胞及真核细胞内的表达%The expression of human intracellular chloride channel protein 3 in eukaryotic and prokaryotic cells

    Institute of Scientific and Technical Information of China (English)

    李春雨; 潘林鑫; 刘晓颖; 范礼斌

    2014-01-01

    目的研究人类胞内氯离子通道蛋白3(CLIC3)在真核细胞中的定位和表达,及其GST融合蛋白在原核细胞中的表达。方法以含人CLIC3的全长cDNA序列的质粒为模板,PCR扩增CLIC3片段,构建真核表达载体pcDNA3.1-CLIC3-FLAG,检测其定位及表达;构建原核表达载体pGEX-5X-3-CLIC3,转化到大肠杆菌 BL21菌株,IPTG诱导融合蛋白GST-CLIC3表达。结果细胞免疫荧光结果表明 CLIC3在COS7细胞质和细胞核中均有分布;Western blot结果显示CLIC3在HEK-293T细胞中能有效表达;考马斯亮蓝染色结果表明融合蛋白GST-CLIC3在BL21菌株中能有效表达。结论人类的CLIC3蛋白COS7、HEK-293T及大肠杆菌BL21菌株均能有效表达,为进一步了解CLIC3的功能奠定了一定的基础。%Objective To investigate the expression and localization of the human chloride channel protein 3 (CLIC3) in eukaryotic cells, and the expression of GST fusion protein in prokaryotic cells. Methods Plasmids containing full length of human CLIC3 cDNA was used as PCR template to construct the prokaryotic and eukaryotic expression vectors. The pcDNA3. 1-CLIC3-FLAG was transfected into COS7 and HEK-293T cells respectively to detect the localization and expression of CLIC3. The pGEX-5X-3-CLIC3 was transformed into E. coli BL21 to inves-tigate the expression of fusion protein GST-CLIC3 . Results The immunofluorescence results indicated that CLIC3 was distributed in both cytoplasm and nucleus of COS7 cells;Western blot showed CLIC3 could be effectively ex-pressed in HEK-293T cells;Coomassie blue staining proved GST-CLIC3 could be expressed in E. coli BL21. Con-clusion Human CLIC3 protein can be expressed effectively both in eukaryotic and prokaryotic cells, which is im-portant for further research on the function of human CLIC3 .

  8. Oxomemazine hydro­chloride

    OpenAIRE

    Siddegowda, M. S.; Butcher, Ray J.; Mehmet Akkurt; Yathirajan, H.S.; Ramesh, A. R.

    2011-01-01

    In the title compound [systematic name: 3-(5,5-dioxophenothiazin-10-yl)-N,N,2-trimethylpropanaminium chloride], C18H23N2O2S+·Cl−, the dihedral angle between the two outer aromatic rings of the phenothiazine unit is 30.5 (2)°. In the crystal, the components are linked by N—H...Cl and C—H...Cl hydrogen bonds and C—H...π interactions.

  9. Shock compression of polyvinyl chloride

    Science.gov (United States)

    Neogi, Anupam; Mitra, Nilanjan

    2016-04-01

    This study presents shock compression simulation of atactic polyvinyl chloride (PVC) using ab-initio and classical molecular dynamics. The manuscript also identifies the limits of applicability of classical molecular dynamics based shock compression simulation for PVC. The mechanism of bond dissociation under shock loading and its progression is demonstrated in this manuscript using the density functional theory based molecular dynamics simulations. The rate of dissociation of different bonds at different shock velocities is also presented in this manuscript.

  10. Developing chloride resisting concrete using PFA

    Energy Technology Data Exchange (ETDEWEB)

    Dhir, R.K.; El-Mohr, M.A.K.; Dyer, T.D. [Univ. of Dundee (United Kingdom). Dept. of Civil Engineering

    1997-11-01

    PFA concrete mixes were designed to optimize resistance to chloride ingress. Chloride binding capacity, intrinsic permeability and their concomitant influence on the coefficient of chloride diffusion have been investigated. PFA replacements up to 67% and exposure concentrations of 0.1, 0.5, 1.0 and 5.0 mole/liter were used. Chloride binding capacity was found to increase with increasing PFA replacement up to 50% and to then decline. It increased with chloride exposure concentration as well as water/binder ratio. The coefficient of chloride diffusion of concrete samples was found to be dependent on both the intrinsic permeability of the concrete and the ability of its cement matrix to bind chlorides.

  11. Ultrastructural Observation of the Skin Chloride Cells of Japanese Flounder Paralichthys olivaceus and Turbot Scophthamus maximus Larvae

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The ultrastructures of skin chloride cells in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These developed skin chloride cells were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride cells of euryhaline fish gill. They locate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels. The cytoplasm of cell is full of numerous mitochondria and a ramifying network of tubules. The degeneration of skin chloride cells is observed with development of Japanese flounder larvae. Skin chloride cells of turbot are less developmental than those of Japanese flounder in the same developmental stage.

  12. Mechanosensitive Channels

    Science.gov (United States)

    Martinac, Boris

    Living cells are exposed to a variety of mechanical stimuli acting throughout the biosphere. The range of the stimuli extends from thermal molecular agitation to potentially destructive cell swelling caused by osmotic pressure gradients. Cellular membranes present a major target for these stimuli. To detect mechanical forces acting upon them cell membranes are equipped with mechanosensitive (MS) ion channels. Functioning as molecular mechanoelectrical transducers of mechanical forces into electrical and/or chemical intracellular signals these channels play a critical role in the physiology of mechanotransduction. Studies of prokaryotic MS channels and recent work on MS channels of eukaryotes have significantly increased our understanding of their gating mechanism, physiological functions, and evolutionary origins as well as their role in the pathology of disease.

  13. The effect of verapamil and diltiazem on cardiac stimulant effect of adrenaline and calcium chloride on isolated frog heart

    Directory of Open Access Journals (Sweden)

    Lakhavat Sudhakar, Naveen Kumar T, Tadvi NA, Venkata Rao Y

    2013-04-01

    Full Text Available Background: Calcium channel blockers block voltage dependent L-type of calcium channel and thus reduce the frequency of opening of these channels in response to depolarization. The result is a marked decrease in transmembrane calcium current associated with long lasting relaxation of vascular smooth muscle, reduction in contractility in cardiac muscle, decrease in pacemaker activity in the SA node and decrease in conduction velocity in the AV node. Among Calcium channel blockers verapamil, is cardio selective, nifedipine is vascular smooth muscle selective, while diltiazem exhibits intermediate selectivity. Methods: In the present study, the effect of two Ca++ channel blocker, Verapamil and Diltiazem were compared on the isolated frog heart by using adrenaline & calcium chloride as standard on frog heart contractility. Results and conclusion: Adrenaline and calcium chloride increased the amplitude of contraction of isolated perfused frog heart. The L- type of Ca2+ channel blockers verapamil and diltiazem produced dose dependent (2mg, 4mg, 8mg, and 16mg reduction in the amplitude of contraction produced by calcium chloride in isolated perfused frog heart. There was no statistical significant difference (p > 0.05 between the inhibitory effect of diltiazem and verapamil on calcium chloride induced contraction of isolated frog heart.

  14. Research on Regulating and Controlling Roles of Chloride and Zinc Ions to Swine Sperm Calcium Channel and Some Enzyme Activities%氯、锌离子对猪精子钙通道和若干酶活调控作用的研究

    Institute of Scientific and Technical Information of China (English)

    周明; 刘芳芳; 李晓东; 邢立东; 吴金节; 解正会; 郭森

    2012-01-01

    The regulating and controlling roles of chloride and zinc ions to swine sperm calcium channel and their mechanism were studied.Semen from healthy boar were filtered with gauze and divided into three groups,each group having 6 repeats.The group 1 semen was not added anything;the group 2 and 3 semen were added NaCl and ZnSO 4 solution respectively.Being mixed and placed 2.5 h,various parameters of 3 experimental semen were measured.Experimental results showed that:(1) supplementation of optimum chlorine ions or zinc ions in semen could stimulate migration of calcium ions from Seminal plasm to sperm,thus calcium ion concentration in sperm raised significantly(P 〈 0.05),calcium ion concentration in Seminal plasm decreasesd slightly;(2) supplementation of chlorine or zinc ions in semen could strengthen sperm motility highly significantly(P 〈 0.01);(3) after supplementation of zinc ions in semen,the activities of AKP,CA and AC and the concentration of cAMP in sperm increased highly significantly(P 〈 0.01),the activities of AKP and AC in seminal plasm raised highly significantly(P 〈 0.01),the concentration of cAMP in seminal plasm increased significantly(P 〈 0.05);(4) after supplementation of chlorine ions in semen,the activities of AKP and AC in seminal plasm raised highly significantly(P 〈 0.01),the concentration of cAMP in Seminal l plasm increased significantly(P 〉 0.05).These results suggested that supplementation of optimum zinc or chlorine ions in boar semen may up-regulate the function of sperm calcium channel,and can improve the activities of AKP,CA and AC and the concentration of cAMP in semen,strengthen sperm motility.%研究了氯离子、锌离子等对猪精子钙通道的调控作用及其机理。将由健康公猪采得的精液经纱布过滤后分为3组,每组6个重复。第1组精液不加任何物质,第2、3组精液分别加氯化钠液和硫酸锌液,混匀并静置2.5h后,观测精子

  15. Hydrolysis of cupric chloride in aqueous ammoniacal ammonium chloride solutions

    Directory of Open Access Journals (Sweden)

    Limpo, J. L.

    1995-06-01

    Full Text Available Cupric solubility in the CuCl2-NH4Cl-NH3-H2O system for chloride concentrations lower than 4 molal in the temperature range 25-60 °C was studied. The experimental results show that for chloride concentration between 3.0 and 1.0 molal the cupric solubility is determined by the solubility of the cupric hydroxychloride Cu(OH1.5Cl0.5. For a chloride concentration value of 4.0 molal, there are two cupric compounds, the hydroxychloride Cu(OH1.5Cl0.5 or the diammine chloride Cu(NH32Cl2, on which the solubility of Cu(II depends, according to the temperature and the value of the ratio [NH3]Total/[Cu]Total.

    Se estudia la solubilidad del Cu(II en el sistema CuCl2-NH4Cl-NH3-H2O para concentraciones de cloruro inferiores a 4 molal en el intervalo de temperaturas 25-60 °C. Los resultados experimentales muestran que, para concentraciones de cloruros comprendidas entre 3,0 y 1,0 molal, la solubilidad cúprica viene determinada por la solubilidad del hidroxicloruro cúprico, Cu(OH1.5Cl0.5. Para concentraciones de cloruro 4,0 molal, existen dos compuestos cúpricos, el hidroxicloruro, Cu(OH1.5Cl0.5 o el cloruro de diamina, Cu(NH32Cl2, de los que, de acuerdo con la temperatura y con el valor de la relación [NH3]Total/[Cu]Total depende la solubilidad del Cu(II.

  16. Lubiprostone activates non-CFTR-dependent respiratory epithelial chloride secretion in cystic fibrosis mice.

    Science.gov (United States)

    MacDonald, Kelvin D; McKenzie, Karen R; Henderson, Mark J; Hawkins, Charles E; Vij, Neeraj; Zeitlin, Pamela L

    2008-11-01

    Periciliary fluid balance is maintained by the coordination of sodium and chloride channels in the apical membranes of the airways. In the absence of the cystic fibrosis transmembrane regulator (CFTR), chloride secretion is diminished and sodium reabsorption exaggerated. ClC-2, a pH- and voltage-dependent chloride channel, is present on the apical membranes of airway epithelial cells. We hypothesized that ClC-2 agonists would provide a parallel pathway for chloride secretion. Using nasal potential difference (NPD) measurements, we quantified lubiprostone-mediated Cl(-) transport in sedated cystic fibrosis null (gut-corrected), C57Bl/6, and A/J mice during nasal perfusion of lubiprostone (a putative ClC-2 agonist). Baseline, amiloride-inhibited, chloride-free gluconate-substituted Ringer with amiloride and low-chloride Ringer plus lubiprostone (at increasing concentrations of lubiprostone) were perfused, and the NPD was continuously recorded. A clear dose-response relationship was detected in all murine strains. The magnitude of the NPD response to 20 muM lubiprostone was -5.8 +/- 2.1 mV (CF, n = 12), -8.1 +/- 2.6 mV (C57Bl/6 wild-type, n = 12), and -5.3 +/- 1.2 mV (AJ wild-type, n = 8). A cohort of ClC-2 knockout mice did not respond to 20 muM lubiprostone (n = 6, P = 0.27). In C57Bl/6 mice, inhibition of CFTR with topical application of CFTR inhibitor-172 did not abolish the lubiprostone response, thus confirming the response seen is independent of CFTR regulation. RT-PCR confirmed expression of ClC-2 mRNA in murine lung homogenate. The direct application of lubiprostone in the CF murine nasal airway restores nearly normal levels of chloride secretion in nasal epithelia.

  17. Exposure to an open-field arena increases c-Fos expression in a distributed anxiety-related system projecting to the basolateral amygdaloid complex

    DEFF Research Database (Denmark)

    Hale, M.W.; Hay-Schmidt, A.; Mikkelsen, J.D.;

    2008-01-01

    Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of brain structures including the basolateral amygdala. Our previous studies demonstrate that exposure of rats to an open-field in high- and low-light conditions results in a marked...... of specific afferent input to this region of the amygdala. In order to identify candidate brain regions mediating anxiety-induced activation of the basolateral amygdaloid complex in rats, we used cholera toxin B subunit (CTb) as a retrograde tracer to identify neurons with direct afferent projections...... amygdaloid complex. Rats were housed individually for 11 days after CTb injections and handled (HA) for 2 min each day. On the test day rats were either, 1) exposed to an open-field in low-light conditions (8-13 lux) for 15 min (OF); 2) briefly HA or 3) left undisturbed (control). We report that dual...

  18. Oxomemazine hydro­chloride

    Science.gov (United States)

    Siddegowda, M. S.; Butcher, Ray J.; Akkurt, Mehmet; Yathirajan, H. S.; Ramesh, A. R.

    2011-01-01

    In the title compound [systematic name: 3-(5,5-dioxo­phen­othia­zin-10-yl)-N,N,2-trimethyl­propanaminium chloride], C18H23N2O2S+·Cl−, the dihedral angle between the two outer aromatic rings of the phenothia­zine unit is 30.5 (2)°. In the crystal, the components are linked by N—H⋯Cl and C—H⋯Cl hydrogen bonds and C—H⋯π inter­actions. PMID:22090928

  19. Simple chloride sensors for continuous groundwater monitoring

    DEFF Research Database (Denmark)

    Thorn, Paul; Mortensen, John

    2012-01-01

    The development of chloride sensors which can be used for continuous, on-line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used...... in continuous application. This study looks at the development of a simple, inexpensive chloride electrode, and evaluates its performance under continuous use, both in the laboratory and in a field test in a monitoring well. The results from the study showed a consistent response to changing chloride...... sensor remained responsive even at low chloride concentrations, where the conductivity electrode was no longer responding to changing chloride levels. With the results, it is believed that the simple chloride sensor could be used for continuous monitoring of groundwater quality....

  20. Angiotensin II’s role in sodium lactate-induced panic-like responses in rats with repeated urocortin 1 injections into the basolateral amygdala

    OpenAIRE

    Johnson, Philip L.; Sajdyk, Tammy J.; Fitz, Stephanie D; Hale, Mathew W.; Lowry, Christopher A.; Hay-Schmidt, Anders; Shekhar, Anantha

    2013-01-01

    Rats treated with three daily urocortin 1 (UCN) injections into the basolateral amygdala (BLA; i.e., UCN/BLA-primed rats) develop prolonged anxiety-associated behavior and vulnerability to panic-like physiological responses (i.e., tachycardia, hypertension and tachypnea) following intravenous infusions of 0.5 M sodium lactate (NaLac, an ordinarily mild interoceptive stressor). In these UCN-primed rats, the osmosensitive subfornical organ (SFO) may be a potential site that detects increases in...

  1. Sodium chloride precipitation reaction coefficient from crystallization experiment in a microfluidic device

    Science.gov (United States)

    Naillon, A.; Joseph, P.; Prat, M.

    2017-04-01

    The crystal growth of sodium chloride from an aqueous solution is studied from evaporation experiments in microfluidic channels in conjunction with analytical and numerical computations. The crystal growth kinetics is recorded using a high speed camera in order to determine the intrinsic precipitation reaction coefficient. The study reveals that the crystal growth rates determined in previous studies are all affected by the ions transport phenomena in the solution and thus not representative of the precipitation reaction. It is suggested that accurate estimate of sodium chloride precipitation reaction coefficient presented here offers new opportunities for a better understanding of important issues involved in the damages of porous materials induced by the salt crystallization.

  2. Time-resolved energy transfer from single chloride terminated nanocrystals to graphene

    CERN Document Server

    Ajayi, O A; Cotlet, M; Petrone, N; Gu, T; Wolcott, A; Gesuele, F; Hone, J; Owen, J S; Wong, C W

    2014-01-01

    We examine the time-resolved resonance energy transfer of excitons from single n-butyl amine-bound, chloride-terminated nanocrystals to two-dimensional graphene through time-correlated single photon counting. The radiative biexponential lifetime kinetics and blinking statistics of the individual surface-modified nanocrystal elucidate the non-radiative decay channels. Blinking modification as well as a 4 times reduction in spontaneous emission were observed with the short chloride and n-butylamine ligands, probing the energy transfer pathways for the development of graphene-nanocrystal nanophotonic devices.

  3. Chloride Ion Critical Content in Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chloride ion critical content was studied under soaking and cycle of dry and wet conditions,with three electrochemical nondestructive measuring techniques, i e, half-cell potential, A C impedance, and time potential. The experimental results show that chloride ion critical content is primarily determined by the water cement ratio, while for the same concrete mixture the chloride ion critical content in soaking conditions is larger than that in a cycle of dry and wet conditions.

  4. Microtubule-dependent relocation of branchial V-H+-ATPase to the basolateral membrane in the Pacific spiny dogfish (Squalus acanthias): a role in base secretion.

    Science.gov (United States)

    Tresguerres, Martin; Parks, Scott K; Katoh, Fumi; Goss, Greg G

    2006-02-01

    We have previously shown that continuous intravenous infusion of NaHCO3 for 24 h ( approximately 1000 micromol kg(-1) h(-1)) results in the relocation of V-H+-ATPase from the cytoplasm to the basolateral membrane in the gills of the Pacific dogfish. To further investigate this putative base-secretive process we performed similar experiments with the addition of colchicine, an inhibitor of cytoskeleton-dependent cellular trafficking processes. Blood pH and plasma total CO2 were significantly higher in the colchicines-treated, HCO3- -infused fish compared with fish infused with HCO3- alone. The effect of colchicine was highest after 24 h of infusion (8.33+/-0.06 vs 8.02+/-0.03 pH units, 15.72+/-3.29 vs 6.74+/-1.34 mmol CO2 l(-1), N=5). Immunohistochemistry and western blotting confirmed that colchicine blocked the transit of V-H+-ATPase to the basolateral membrane. Furthermore, western blotting analyses from whole gill and cell membrane samples suggest that the short-term (6 h) response to alkaline stress consists of relocation of V-H+-ATPases already present in the cell to the basolateral membrane, while in the longer term (24 h) there is both relocation of preexistent enzyme and upregulation in the synthesis of new units. Our results strongly suggest that cellular relocation of V-H+-ATPase is necessary for enhanced HCO3- secretion across the gills of the Pacific dogfish.

  5. Chloride binding site of neurotransmitter sodium symporters

    DEFF Research Database (Denmark)

    Kantcheva, Adriana Krassimirova; Quick, Matthias; Shi, Lei

    2013-01-01

    Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs...... have a serine. The LeuT-E290S mutant displays chloride-dependent activity. We show that, in LeuT-E290S cocrystallized with bromide or chloride, the anion is coordinated by side chain hydroxyls from Tyr47, Ser290, and Thr254 and the side chain amide of Gln250. The bound anion and the nearby sodium ion...

  6. Chloride ingress in cement paste and mortar

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, O.M.; Hansen, P.F.; Coats, A.M.; Glasser, F.P.

    1999-09-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature). The measurements are modelled on Fick's law modified by a term for chloride binding. Inclusion of chloride binding significantly improves the profile shape of the modelled ingress profiles. The presence of fine aggregate and formation of interfacial transition zones at paste-aggregate boundaries does not significantly affect diffusion rates.

  7. Green process to recover magnesium chloride from residue solution of potassium chloride production plant

    Institute of Scientific and Technical Information of China (English)

    Lin WANG; Yunliang HE; Yanfei WANG; Ying BAO; Jingkang WANG

    2008-01-01

    The green process to recover magnesium chlor-ide from the residue solution of a potassium chloride pro-duction plant, which comes from the leach solution of a potash mine in Laos, is designed and optimized. The res-idue solution contains magnesium chloride above 25 wt-%, potassium chloride and sodium chloride together below 5 wt-% and a few other ions such as Br-, SO2-4and Ca2+. The recovery process contains two steps: the previous impurity removal operation and the two-stage evapora-tion-cooling crystallization procedure to produce magnes-ium chloride. The crystallized impurity carnallite obtained from the first step is recycled to the potassium chloride plant to recover the potassium salt. The developed process is a zero discharge one and thus fulfills the requirements for green chemical industrial production. The produced magnesium chloride is up to industrial criteria.

  8. ENVIRONMENTAL EXPOSURE TO VINYL CHLORIDE

    Directory of Open Access Journals (Sweden)

    Henryka Langauer-Lewowicka

    2010-09-01

    Full Text Available Vinyl chloride (VC monomer is a wellknown carcinogenic and mutagenic substance causes liver damages, angiosarcoma of the liver, acro – osteolysis, sclerodermalike changes in workers chronically exposed to this gas. There are following VC emitors to the environment: VC production plants, polymerization facilities and planes where polyvinyl products are fabricated. Because of that, the general population is coming into VC contact through polluted air, food and water. VC concentration in all mentioned sites is very low, often not detectable. There was found any health risk for the general population. The VC air concentration in the vicinity to antropogenic emitors is always higher. Such a situation may causes undesirable health effect for residents living in the neighbourhood. Epidemiological studies are performed to detect the adverse VC effect in selected cohorts. Non of the study did not confirmed cases of angiosarcoma among residents living near a vinyl chloride sites. VC production is growing permanently, so VC emission will be higher. Because of that health monitoring of general population and especially of selected groups seems to be necessary in the future.

  9. Basolateral sorting and transcytosis define the Cu+-regulated translocation of ATP7B to the bile canaliculus.

    Science.gov (United States)

    Lalioti, Vasiliki; Peiró, Ramón; Pérez-Berlanga, Manuela; Tsuchiya, Yo; Muñoz, Angeles; Villalba, Teresa; Sanchez, Carlos; Sandoval, Ignacio V

    2016-06-01

    The Cu(+) pump ATP7B plays an irreplaceable role in the elimination of excess Cu(+) by the hepatocyte into the bile. The trafficking and site of action of ATP7B are subjects of controversy. One current proposal is that an increase in intracellular Cu(+) results in the translocation of ATP7B to the lysosomes and excretion of excess Cu(+) through lysosomal-mediated exocytosis at the bile canaliculus. Here, we show that ATP7B is transported from the trans-Golgi network (TGN) to the bile canaliculus by basolateral sorting and endocytosis, and microtubule-mediated transcytosis through the subapical compartment. Trafficking ATP7B is not incorporated into lysosomes, and addition of Cu(+) does not cause relocalization of lysosomes and the appearance of lysosome markers in the bile canaliculus. Our data reveal the pathway of the Cu(+)-mediated transport of ATP7B from the TGN to the bile canaliculus and indicates that the bile canaliculus is the primary site of ATP7B action in the elimination of excess Cu(.)

  10. Infusion of methylphenidate into the basolateral nucleus of amygdala or anterior cingulate cortex enhances fear memory consolidation in rats

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The psychostimulant methylphenidate (MPD; also called Ritalin) is a blocker of dopamine and norepi-nephrine transporter. It has been clinically used for treatment of Attention Deficit and Hyperactivity Disorder (ADHD). There have been inconsistent reports regarding the effects of systemically adminis-tered MPD on learning and memory, either in animals or humans. In the present study, we investigated the effect of direct infusion of MPD into the basolateral nucleus of amygdala (BLA) or the anterior cin-gulate cortex (ACC) on conditioned fear memory. Rats were trained on a one-trial step-through inhibi-tory avoidance task. MPD was infused bilaterally into the BLA or the ACC, either at ‘0’ or 6 h post-training. Saline was administered as control. Memory retention was tested 48 h post-training. In-tra-BLA or intra-ACC infusion of MPD ‘0’ h but not 6 h post-training significantly improved 48-h memory retention: the MPD-treated rats had significant longer step-through latency than controls. The present results indicate that action of MPD in the BLA or the ACC produces a beneficial effect on the consoli-dation of inhibitory avoidance memory.

  11. β-Adrenergic activation enhances NMDA-induced current in pyramidal cells of the basolateral nucleus of amygdala

    Institute of Scientific and Technical Information of China (English)

    LIU Xinqiu; CAO Xiaohua; LI Bao-ming

    2005-01-01

    NMDA receptor (NMDA-R) in the amygdala complex is critical for both long-term potentiation (LTP) and formation of conditioned fear memory. It is reported that activation of β-adrenoceptors (β-AR) in the amygdala facilitates LTP and enhances memory consolidation. The present study examined the regulatory effect of β-AR activation on NMDA-R mediated current in pyramidal cells of the basolateral nucleus of amygdala (BLA), using whole-cell recording technique. Bath application of the β-AR agonist isoproterenol enhanced NMDA-induced current, and this facilitatory effect was blocked by co-administered propranolol, a β-AR antagonist. The facilitatory effect of isoproterenol on NMDA-induced current could not be induced when the protein kinase A (PKA) inhibitor Rp-cAMPs was added in electrode internal solution.The present results suggest that β-AR activation in the BLA could modulate NMDA-R activity directly and positively, probably via PKA.

  12. Chronic cerebrolysin administration attenuates neuronal abnormalities in the basolateral amygdala induced by neonatal ventral hippocampus lesion in the rat.

    Science.gov (United States)

    Vázquez-Roque, Rubén Antonio; Ubhi, Kiren; Masliah, Eliezer; Flores, Gonzalo

    2014-01-01

    The neonatal ventral hippocampal lesion (nVHL) has emerged as a model of schizophrenia-related behavior in the rat. Our previous report demonstrated that cerebrolysin (Cbl), a neuropeptide preparation which mimics the action of endogenous neurotrophic factors on brain protection and repair, promoted recovery of dendritic and neuronal damage of the prefrontal cortex and nucleus accumbens and behavioral improvements in postpubertal nVHL rats. We recently demonstrated that nVHL animals exhibit dendritic atrophy and spine loss in the basolateral amygdala (BLA). This study aimed to determine whether Cbl treatment was capable of reducing BLA neuronal alterations observed in nVHL rats. The morphological evaluation included examination of dendrites using the Golgi-Cox procedure and stereology to quantify the total cell number in BLA. Golgi-Cox staining revealed that nVHL induced dendritic retraction and spine loss in BLA pyramidal neurons. Stereological analysis demonstrated nVHL also produced a reduction in cells in BLA. Interestingly, repeated Cbl treatment ameliorated dendritic pathology and neuronal loss in the BLA of the nVHL rats. Our data show that Cbl may foster recovery of BLA damage in postpubertal nVHL rats and suggests that the use of neurotrophic agents for the management of some schizophrenia-related symptoms may present an alternative therapeutic pathway in these disorders.

  13. Basolateral amygdala lesions attenuate safe taste memory-related c-fos expression in the rat perirhinal cortex.

    Science.gov (United States)

    Gómez-Chacón, Beatriz; Gámiz, Fernando; Gallo, Milagros

    2012-05-01

    Previous results indicated that damage and pharmacological inactivation of the basolateral amygdala (BLA) interfere with the attenuation of taste neophobia. A similar disruption of safe taste memories formation induced by the inhibition of protein synthesis in the perirhinal cortex (PRh) has been reported. Thus, we have assessed the effect of bilateral BLA neurotoxic lesions on PRh activity after novel and familiar taste exposure. Wistar male rats with NMDA lesions of the BLA and SHAM-operated received two consecutive exposures to a 3% cider vinegar solution. Fos-like immunoreactivity (FLI) was examined as a marker of neuronal activity in PRh. As expected the BLA lesioned group showed no evidence of neophobia attenuation. A similar number of PRh Fos-positive cells were found in SHAM and BLA groups exposed to the novel taste solution. However, the BLA-lesioned group exhibited a lower number of Fos stained cells than the SHAM-lesioned group after being exposed to the familiar taste solution. This supports the notion of BLA and PRh as components of a neural circuit involved in safe taste recognition memory and suggests a role of PRh in various forms of recognition memory.

  14. IGF-II receptors in luminal and basolateral membranes isolated from pars convoluta and pars recta of rabbit proximal tubule

    DEFF Research Database (Denmark)

    Jacobsen, Christian; Jessen, H; Flyvbjerg, A

    1995-01-01

    The binding of 125I-labeled insulin-like growth factor-II (125I-IGF-II) to luminal and basolateral membrane vesicles isolated from pars convoluta and the straight part (pars recta) of rabbit proximal tubule was investigated. Analyses of the binding data by use of the general stoichiometric binding...... equation revealed, that in all preparations IGF-II was bound to one high-affinity binding site and other sites with lower affinities. The specificity of the high-affinity 125I-IGF-II binding to the membrane vesicles assessed by displacement by unlabeled IGF-II, IGF-I and insulin showed that IGF-I displaced...... 125I-IGF-II in the range 22.5-47.9 nM (IC50) whereas insulin did not effect 125I-IGF-II binding at all. beta-Galactosidase inhibited the 125I-IGF-II binding with half-maximal inhibition of 20-30 nM beta-galactosidase. D-Mannose 6-phosphate increased the binding of 125I-IGF-II and reversed...

  15. Basolateral amygdala response to food cues in the absence of hunger is associated with weight gain susceptibility.

    Science.gov (United States)

    Sun, Xue; Kroemer, Nils B; Veldhuizen, Maria G; Babbs, Amanda E; de Araujo, Ivan E; Gitelman, Darren R; Sherwin, Robert S; Sinha, Rajita; Small, Dana M

    2015-05-20

    In rodents, food-predictive cues elicit eating in the absence of hunger (Weingarten, 1983). This behavior is disrupted by the disconnection of amygdala pathways to the lateral hypothalamus (Petrovich et al., 2002). Whether this circuit contributes to long-term weight gain is unknown. Using fMRI in 32 healthy individuals, we demonstrate here that the amygdala response to the taste of a milkshake when sated but not hungry positively predicts weight change. This effect is independent of sex, initial BMI, and total circulating ghrelin levels, but it is only present in individuals who do not carry a copy of the A1 allele of the Taq1A polymorphism. In contrast, A1 allele carriers, who have decreased D2 receptor density (Blum et al., 1996), show a positive association between caudate response and weight change. Regardless of genotype, however, dynamic causal modeling supports unidirectional gustatory input from basolateral amygdala (BLA) to hypothalamus in sated subjects. This finding suggests that, as in rodents, external cues gain access to the homeostatic control circuits of the human hypothalamus via the amygdala. In contrast, during hunger, gustatory inputs enter the hypothalamus and drive bidirectional connectivity with the amygdala. These findings implicate the BLA-hypothalamic circuit in long-term weight change related to nonhomeostatic eating and provide compelling evidence that distinct brain mechanisms confer susceptibility to weight gain depending upon individual differences in dopamine signaling.

  16. CRF1 receptor activation increases the response of neurons in the basolateral nucleus of the amygdala to afferent stimulation

    Directory of Open Access Journals (Sweden)

    2008-07-01

    Full Text Available The basolateral nucleus (BLA of the amygdala contributes to the consolidation of memories for emotional or stressful events. The nucleus contains a high density of CRF1 receptors that are activated by corticotropin-releasing factor (CRF. Modulation of the excitability of neurons in the BLA by CRF may regulate the immediate response to stressful events and the formation of associated memories. In the present study, CRF was found to increase the amplitude of field potentials recorded in the BLA following excitatory afferent stimulation, in vitro. The increase was mediated by CRF1 receptors, since it could be blocked by the selective, non-peptide antagonists, NBI30775 and NBI35583, but not by the CRF2-selective antagonist, astressin 2B. Furthermore, the CRF2-selective agonist, urocortin II had no effect on field potential amplitude. The increase induced by CRF was long-lasting, could not be reversed by subsequent administration of NBI35583, and required the activation of protein kinase C. This effect of CRF in the BLA may be important for increasing the salience of aversive stimuli under stressful conditions, and for enhancing the consolidation of associated memories. The results provide further justification for studying the efficacy of selective antagonists of the CRF1 receptor to reduce memory formation linked to emotional or traumatic events, and suggest that these compounds might be useful as prophylactic treatment for stress-related illness such as post-traumatic stress disorder.

  17. Inhibition of projections from the basolateral amygdala to the entorhinal cortex disrupts the acquisition of contextual fear

    Directory of Open Access Journals (Sweden)

    Dennis R. Sparta

    2014-05-01

    Full Text Available The development of excessive fear and/or stress responses to environmental cues such as contexts associated with a traumatic event is a hallmark of post-traumatic stress disorder (PTSD. The basolateral amygdala (BLA has been implicated as a key structure mediating contextual fear conditioning. In addition, the hippocampus has an integral role in the encoding and processing of contexts associated with strong, salient stimuli such as fear. Given that both the BLA and hippocampus play an important role in the regulation of contextual fear conditioning, examining the functional connectivity between these two structures may elucidate a role for this pathway in the development of PTSD. Here, we used optogenetic strategies to demonstrate that the BLA sends a strong glutamatergic projection to the hippocampal formation through the entorhinal cortex (EC. Next, we photoinhibited glutamatergic fibers from the BLA terminating in the EC during the acquisition or expression of contextual fear conditioning. In mice that received optical inhibition of the BLA-to-EC pathway during the acquisition session, we observed a significant decrease in freezing behavior in a context re-exposure session. In contrast, we observed no differences in freezing behavior in mice that were only photoinhibited during the context re-exposure session. These data demonstrate an important role for the BLA-to-EC glutamatergic pathway in the acquisition of contextual fear conditioning.

  18. Mineralocorticoids decrease the activity of the apical small-conductance K channel in the cortical collecting duct.

    Science.gov (United States)

    Wei, Yuan; Babilonia, Elisa; Sterling, Hyacinth; Jin, Yan; Wang, Wen-Hui

    2005-11-01

    We used the patch-clamp technique to examine the effect of DOCA treatment (2 mg/kg) on the apical small-conductance K (SK) channels, epithelial Na channels (ENaC), and the basolateral 18-pS K channels in the cortical collecting duct (CCD). Treatment of rats with DOCA for 6 days significantly decreased the plasma K from 3.8 to 3.1 meq and reduced the activity of the SK channel, defined as NP(o), from 1.3 in the CCD of control rats to 0.6. In contrast, DOCA treatment significantly increased ENaC activity from 0.01 to 0.53 and the basolateral 18-pS K channel activity from 0.67 to 1.63. Moreover, Western blot analysis revealed that DOCA treatment significantly increased the expression of the nonreceptor type of protein tyrosine kinase (PTK), cSrc, and the tyrosine phosphorylation of ROMK in the renal cortex and outer medulla. The possibility that decreases in apical SK channel activity induced by DOCA treatment were the result of stimulation of PTK activity was further supported by experiments in which inhibition of PTK with herbimycin A significantly increased NP(o) from 0.6 to 2.1 in the CCD from rats receiving DOCA. Also, when rats were fed a high-K (10%) diet, DOCA treatment did not increase the expression of c-Src and decrease the activity of the SK channel in the CCD. We conclude that DOCA treatment decreased the apical SK channel activity in rats on a normal-K diet and that an increase in PTK expression may be responsible for decreased channel activity in the CCD from DOCA-treated rats.

  19. Brands & Channels

    Institute of Scientific and Technical Information of China (English)

    Alice Yang

    2009-01-01

    @@ "Brands" and "Channels" are the two most important things in Ku-Hai Chen's eyes when doing business with Main-land China. Ku-Hai Chen, Executive Director of the International Trade Institute of Taiwan External Trade Development Council (TAITRA), flies frequently between Chinese Taipei and Mainland China, and was in Beijing earlier this month for his seminar.

  20. Positron Channeling

    CERN Document Server

    Badikyan, Karen

    2016-01-01

    The possibility of channeling the low-energy relativistic positrons around separate crystallographic axes with coaxial symmetry of negative ions in some types of crystals is shown. The process of annihilation of positrons with electrons of medium was studied in detail.

  1. Glucose stimulates calcium-activated chloride secretion in small intestinal cells.

    Science.gov (United States)

    Yin, Liangjie; Vijaygopal, Pooja; MacGregor, Gordon G; Menon, Rejeesh; Ranganathan, Perungavur; Prabhakaran, Sreekala; Zhang, Lurong; Zhang, Mei; Binder, Henry J; Okunieff, Paul; Vidyasagar, Sadasivan

    2014-04-01

    The sodium-coupled glucose transporter-1 (SGLT1)-based oral rehydration solution (ORS) used in the management of acute diarrhea does not substantially reduce stool output, despite the fact that glucose stimulates the absorption of sodium and water. To explain this phenomenon, we investigated the possibility that glucose might also stimulate anion secretion. Transepithelial electrical measurements and isotope flux measurements in Ussing chambers were used to study the effect of glucose on active chloride and fluid secretion in mouse small intestinal cells and human Caco-2 cells. Confocal fluorescence laser microscopy and immunohistochemistry measured intracellular changes in calcium, sodium-glucose linked transporter, and calcium-activated chloride channel (anoctamin 1) expression. In addition to enhancing active sodium absorption, glucose increased intracellular calcium and stimulated electrogenic chloride secretion. Calcium imaging studies showed increased intracellular calcium when intestinal cells were exposed to glucose. Niflumic acid, but not glibenclamide, inhibited glucose-stimulated chloride secretion in mouse small intestines and in Caco-2 cells. Glucose-stimulated chloride secretion was not seen in ileal tissues incubated with the intracellular calcium chelater BAPTA-AM and the sodium-potassium-2 chloride cotransporter 1 (NKCC1) blocker bumetanide. These observations establish that glucose not only stimulates active Na absorption, a well-established phenomenon, but also induces a Ca-activated chloride secretion. This may explain the failure of glucose-based ORS to markedly reduce stool output in acute diarrhea. These results have immediate potential to improve the treatment outcomes for acute and/or chronic diarrheal diseases by replacing glucose with compounds that do not stimulate chloride secretion.

  2. Comparing polyaluminum chloride and ferric chloride for antimony removal.

    Science.gov (United States)

    Kang, Meea; Kamei, Tasuku; Magara, Yasumoto

    2003-10-01

    Antimony has been one of the contaminants required to be regulated, however, only limited information has been collected to date regarding antimony removal by polyaluminium chloride (PACl) and ferric chloride (FC). Accordingly, the possible use of coagulation by PACl or FC for antimony removal was investigated. Jar tests were used to determine the effects of solution pH, coagulant dosage, and pre-chlorination on the removal of various antimony species. Although high-efficiency antimony removal by aluminum coagulation has been expected because antimony is similar to arsenic in that both antimony and arsenic are a kind of metalloid in group V of the periodic chart, this study indicated: (1) removal density (arsenic or antimony removed per mg coagulant) for antimony by PACl was about one forty-fifth as low as observed for As(V); (2) although the removal of both Sb(III) and Sb(V) by coagulation with FC was much higher than that of PACl, a high coagulant dose of 10.5mg of FeL(-1) at optimal pH of 5.0 was still not sufficient to meet the standard antimony level of 2 microg as SbL(-1) for drinking water when around 6 microg as SbL(-1) were initially present. Consequently, investigation of a more appropriate treatment process is necessary to develop economical Sb reduction; (3) although previous studies concluded that As(V) is more effectively removed than As(III), this study showed that the removal of Sb(III) by coagulation with FC was much more pronounced than that of Sb(V); (4) oxidation of Sb(III) with chlorine decreased the ability of FC to remove antimony. Accordingly, natural water containing Sb(III) under anoxic condition should be coagulated without pre-oxidation.

  3. Electrochemical Behavior of Copper in Thionyl Chloride Solutions.

    Science.gov (United States)

    1980-12-01

    lithium - thionyl chloride batteries . Thionyl chloride is known *3 to react...electrolyte for lithium - thionyl chloride batteries . 8R. K. McAlpine and B. A. Soule, Prescott and Johnson’s Qualitative Chemical Analysis, D. Van...black carbon electrodes, cupric chloride appears to be a useful cathode additive for lithium - thionyl chloride batteries . Preliminary results2l

  4. Macula densa cell signaling involves ATP release through a maxi anion channel.

    Science.gov (United States)

    Bell, Phillip Darwin; Lapointe, Jean-Yves; Sabirov, Ravshan; Hayashi, Seiji; Peti-Peterdi, Janos; Manabe, Ken-Ichi; Kovacs, Gergely; Okada, Yasunobu

    2003-04-01

    Macula densa cells are unique renal biosensor cells that detect changes in luminal NaCl concentration ([NaCl](L)) and transmit signals to the mesangial cellafferent arteriolar complex. They are the critical link between renal salt and water excretion and glomerular hemodynamics, thus playing a key role in regulation of body fluid volume. Since identification of these cells in the early 1900s, the nature of the signaling process from macula densa cells to the glomerular contractile elements has remained unknown. In patch-clamp studies of macula densa cells, we identified an [NaCl](L)-sensitive ATP-permeable large-conductance (380 pS) anion channel. Also, we directly demonstrated the release of ATP (up to 10 microM) at the basolateral membrane of macula densa cells, in a manner dependent on [NaCl](L), by using an ATP bioassay technique. Furthermore, we found that glomerular mesangial cells respond with elevations in cytosolic Ca(2+) concentration to extracellular application of ATP (EC(50) 0.8 microM). Importantly, we also found increases in cytosolic Ca(2+) concentration with elevations in [NaCl](L), when fura-2-loaded mesangial cells were placed close to the basolateral membrane of macula densa cells. Thus, cell-to-cell communication between macula densa cells and mesangial cells, which express P2Y(2) receptors, involves the release of ATP from macula densa cells via maxi anion channels at the basolateral membrane. This mechanism may represent a new paradigm in cell-to-cell signal transduction mediated by ATP.

  5. Voltage-gated sodium channels in taste bud cells

    Directory of Open Access Journals (Sweden)

    Williams Mark E

    2009-03-01

    Full Text Available Abstract Background Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown. Results We describe the molecular and histological expression profiles of cation channels involved in electrical signal transmission from apical to basolateral membrane domains. TRPM5 was positioned immediately beneath tight junctions to receive calcium signals originating from sweet, bitter, and umami receptor activation, while PKD2L1 was positioned at the taste pore. Using mouse taste bud and lingual epithelial cells collected by laser capture microdissection, SCN2A, SCN3A, and SCN9A voltage-gated sodium channel transcripts were expressed in taste tissue. SCN2A, SCN3A, and SCN9A were expressed beneath tight junctions in subsets of taste cells. SCN3A and SCN9A were expressed in TRPM5 cells, while SCN2A was expressed in TRPM5 and PKD2L1 cells. HCN4, a gene previously implicated in sour taste, was expressed in PKD2L1 cells and localized to cell processes beneath the taste pore. Conclusion SCN2A, SCN3A and SCN9A voltage-gated sodium channels are positioned to sense initial depolarizing signals stemming from taste receptor activation and initiate taste cell action potentials. SCN2A, SCN3A and SCN9A gene products likely account for the tetrodotoxin-sensitive sodium currents in taste receptor cells.

  6. Channel Power in Multi-Channel Environments

    NARCIS (Netherlands)

    M.G. Dekimpe (Marnik); B. Skiera (Bernd)

    2004-01-01

    textabstractIn the literature, little attention has been paid to instances where companies add an Internet channel to their direct channel portfolio. However, actively managing multiple sales channels requires knowing the customers’ channel preferences and the resulting channel power. Two key compon

  7. Chronopotentiometric chloride sensing using transition time measurement

    NARCIS (Netherlands)

    Abbas, Y.; Graaf, de D.B.; Olthuis, W.; Berg, van den A.

    2013-01-01

    Detection of chloride ions is crucial to accurately access the concrete structure durability[1]. The existing electrochemical method of chloride ions detection in concrete, potentiometry[1], is not suitable for in-situ measurement due to the long term stability issue of conventional reference electr

  8. 29 CFR 1915.1017 - Vinyl chloride.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Vinyl chloride. 1915.1017 Section 1915.1017 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1017 Vinyl chloride. Note: The requirements applicable to shipyard employment under this...

  9. 29 CFR 1926.1117 - Vinyl chloride.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Vinyl chloride. 1926.1117 Section 1926.1117 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1117 Vinyl chloride. Note: The requirements applicable to construction work under this section are identical to...

  10. Chemische contaminanten in diervoeder additief Choline Chloride

    NARCIS (Netherlands)

    Traag, W.A.; Hoogenboom, L.A.P.; Jong, de J.; Egmond, van H.J.; Dam, ten G.

    2010-01-01

    Dit briefrapport beschrijft de resultaten van een onderzoek naar chemische contaminanten in Choline Chloride. De doelstellingen waren: 1) Inzicht te verkrijgen in het voorkomen van (gebromeerde) vlamvertragers en broomdioxines in het diervoederadditief Choline Chloride en het, op basis van de result

  11. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements...

  12. Nonlinear channelizer

    Science.gov (United States)

    In, Visarath; Longhini, Patrick; Kho, Andy; Neff, Joseph D.; Leung, Daniel; Liu, Norman; Meadows, Brian K.; Gordon, Frank; Bulsara, Adi R.; Palacios, Antonio

    2012-12-01

    The nonlinear channelizer is an integrated circuit made up of large parallel arrays of analog nonlinear oscillators, which, collectively, serve as a broad-spectrum analyzer with the ability to receive complex signals containing multiple frequencies and instantaneously lock-on or respond to a received signal in a few oscillation cycles. The concept is based on the generation of internal oscillations in coupled nonlinear systems that do not normally oscillate in the absence of coupling. In particular, the system consists of unidirectionally coupled bistable nonlinear elements, where the frequency and other dynamical characteristics of the emergent oscillations depend on the system's internal parameters and the received signal. These properties and characteristics are being employed to develop a system capable of locking onto any arbitrary input radio frequency signal. The system is efficient by eliminating the need for high-speed, high-accuracy analog-to-digital converters, and compact by making use of nonlinear coupled systems to act as a channelizer (frequency binning and channeling), a low noise amplifier, and a frequency down-converter in a single step which, in turn, will reduce the size, weight, power, and cost of the entire communication system. This paper covers the theory, numerical simulations, and some engineering details that validate the concept at the frequency band of 1-4 GHz.

  13. Swelling-Activated Anion Channels Are Essential for Volume Regulation of Mouse Thymocytes

    Directory of Open Access Journals (Sweden)

    Ravshan Z. Sabirov

    2011-12-01

    Full Text Available Channel-mediated trans-membrane chloride movement is a key process in the active cell volume regulation under osmotic stress in most cells. However, thymocytes were hypothesized to regulate their volume by activating a coupled K-Cl cotransport mechanism. Under the patch-clamp, we found that osmotic swelling activates two types of macroscopic anion conductance with different voltage-dependence and pharmacology. At the single-channel level, we identified two types of events: one corresponded to the maxi-anion channel, and the other one had characteristics of the volume-sensitive outwardly rectifying (VSOR chloride channel of intermediate conductance. A VSOR inhibitor, phloretin, significantly suppressed both macroscopic VSOR-type conductance and single-channel activity of intermediate amplitude. The maxi-anion channel activity was largely suppressed by Gd3+ ions but not by phloretin. Surprisingly, [(dihydroindenyloxy] alkanoic acid (DIOA, a known antagonist of K-Cl cotransporter, was found to significantly suppress the activity of the VSOR-type single-channel events with no effect on the maxi-anion channels at 10 μM. The regulatory volume decrease (RVD phase of cellular response to hypotonicity was mildly suppressed by Gd3+ ions and was completely abolished by phloretin suggesting a major impact of the VSOR chloride channel and modulatory role of the maxi-anion channel. The inhibitory effect of DIOA was also strong, and, most likely, it occurred via blocking the VSOR Cl− channels.

  14. The basolateral amygdala is critical to the expression of pavlovian and instrumental outcome-specific reinforcer devaluation effects.

    Science.gov (United States)

    Johnson, Alexander W; Gallagher, Michela; Holland, Peter C

    2009-01-21

    Considerable evidence implicates the basolateral amygdala (BLA) in the formation of outcome representations that link cues to the incentive properties of reinforcers. Animals with BLA damage show impaired performance in reinforcer devaluation tasks, in which the value of the food reinforcer is reduced by satiation or food-toxin pairings after the completion of cue or response training. Although intact animals spontaneously reduce their conditioned responding after such reinforcer devaluation procedures, animals with BLA lesions made before training typically do not, as evidenced across a range of species, training contingencies, and devaluation procedures. In contrast, the role of the BLA in devaluation task performance once such outcome representations are established is unclear. Whereas Pickens et al. (2003) found normal devaluation performance in rats when BLA lesions were made after pavlovian light-food pairings but before devaluation by food-toxin pairings, Ostlund and Balleine (2008) found impaired devaluation performance when BLA lesions were made after instrumental training with multiple instrumental responses and food reinforcers but before devaluation of one reinforcer by selective satiation. Those studies differed in their use of pavlovian or operant training contingencies, single or multiple reinforcers, and associative or motivational devaluation procedures. Here we found that, when multiple reinforcers were used, posttraining BLA lesions disrupted the expression of devaluation performance in rats, using either pavlovian or instrumental training procedures and either conditioned taste aversion or satiation devaluation procedures. Thus, BLA apparently plays a critical role in maintaining or using sensory associations of reinforcer value when multiple outcomes must be coded but not under single-outcome conditions.

  15. Dissociable roles for the basolateral amygdala and orbitofrontal cortex in decision-making under risk of punishment.

    Science.gov (United States)

    Orsini, Caitlin A; Trotta, Rose T; Bizon, Jennifer L; Setlow, Barry

    2015-01-28

    Several neuropsychiatric disorders are associated with abnormal decision-making involving risk of punishment, but the neural basis of this association remains poorly understood. Altered activity in brain systems including the basolateral amygdala (BLA) and orbitofrontal cortex (OFC) can accompany these same disorders, and these structures are implicated in some forms of decision-making. The current study investigated the role of the BLA and OFC in decision-making under risk of explicit punishment. Rats were trained in the risky decision-making task (RDT), in which they chose between two levers, one that delivered a small safe reward, and the other that delivered a large reward accompanied by varying risks of footshock punishment. Following training, they received sham or neurotoxic lesions of BLA or OFC, followed by RDT retesting. BLA lesions increased choice of the large risky reward (greater risk-taking) compared to both prelesion performance and sham controls. When reward magnitudes were equated, both BLA lesion and control groups shifted their choice to the safe (no shock) reward lever, indicating that the lesions did not impair punishment sensitivity. In contrast to BLA lesions, OFC lesions significantly decreased risk-taking compared with sham controls, but did not impair discrimination between different reward magnitudes or alter baseline levels of anxiety. Finally, neither lesion significantly affected food-motivated lever pressing under various fixed ratio schedules, indicating that lesion-induced alterations in risk-taking were not secondary to changes in appetitive motivation. Together, these findings indicate distinct roles for the BLA and OFC in decision-making under risk of explicit punishment.

  16. Unilateral inactivation of the basolateral amygdala attenuates context-induced renewal of Pavlovian-conditioned alcohol-seeking.

    Science.gov (United States)

    Chaudhri, N; Woods, C A; Sahuque, L L; Gill, T M; Janak, P H

    2013-09-01

    Environmental contexts associated with drug use promote craving in humans and drug-seeking in animals. We hypothesized that the basolateral amygdala (BLA) itself as well as serial connectivity between the BLA and nucleus accumbens core (NAC core) were required for context-induced renewal of Pavlovian-conditioned alcohol-seeking. Male Long-Evans rats were trained to discriminate between two conditioned stimuli (CS): a CS+ that was paired with ethanol (EtOH, 20%, v/v) delivery into a fluid port (0.2 mL/CS+, 3.2 mL per session) and a CS- that was not. Entries into the port during each CS were measured. Next, rats received extinction in a different context where both cues were presented without EtOH. At test, responding to the CS+ and CS- without EtOH was evaluated in the prior training context. Control subjects showed a selective increase in CS+ responding relative to extinction, indicative of renewal. This effect was blocked by pre-test, bilateral inactivation of the BLA using a solution of GABA receptor agonists (0.1 mm muscimol and 1.0 mm baclofen; M/B; 0.3 μL per side). Renewal was also attenuated following unilateral injections of M/B into the BLA, combined with either M/B, the dopamine D1 receptor antagonist SCH 23390 (0.6 μg per side) or saline infusion in the contralateral NAC core. Hence, unilateral BLA inactivation was sufficient to disrupt renewal, highlighting a critical role for functional activity in the BLA in enabling the reinstatement of alcohol-seeking driven by an alcohol context.

  17. Noradrenergic Activation of the Basolateral Amygdala Enhances Object Recognition Memory and Induces Chromatin Remodeling in the Insular Cortex

    Directory of Open Access Journals (Sweden)

    Hassiba eBeldjoud

    2015-04-01

    Full Text Available It is well established that arousal-induced memory enhancement requires noradrenergic activation of the basolateral complex of the amygdala (BLA and modulatory influences on information storage processes in its many target regions. While this concept is well accepted, the molecular basis of such BLA effects on neural plasticity changes within other brain regions remains to be elucidated. The present study investigated whether noradrenergic activation of the BLA after object recognition training induces chromatin remodeling through histone post-translational modifications in the insular cortex (IC, a brain region that is importantly involved in object recognition memory. Male Sprague–Dawley rats were trained on an object recognition task, followed immediately by bilateral microinfusions of norepinephrine (1.0 µg or saline administered into the BLA. Saline-treated control rats exhibited poor 24-h retention, whereas norepinephrine treatment induced robust 24-h object recognition memory. Most importantly, this memory-enhancing dose of norepinephrine induced a global reduction in the acetylation levels of histone H3 at lysine 14, H2B and H4 in the IC 1 h later, whereas it had no effect on the phosphorylation of histone H3 at serine 10 or tri-methylation of histone H3 at lysine 27. Norepinephrine administered into the BLA of non-trained control rats did not induce any changes in the histone marks investigated in this study. These findings indicate that noradrenergic activation of the BLA induces training-specific effects on chromatin remodeling mechanisms, and presumably gene transcription, in its target regions, which may contribute to the understanding of the molecular mechanisms of stress and emotional arousal effects on memory consolidation.

  18. β1-adrenoceptor activation is required for ethanol enhancement of lateral paracapsular GABAergic synapses in the rat basolateral amygdala.

    Science.gov (United States)

    Silberman, Yuval; Ariwodola, Olusegun J; Weiner, Jeff L

    2012-11-01

    Ethanol (EtOH) potentiation of GABAergic neurotransmission in the basolateral amygdala (BLA) may contribute to the acute anxiolytic effects of this drug. Previous studies have shown that BLA pyramidal neurons receive GABAergic input from two distinct sources: local interneurons and a cluster of GABAergic cells termed lateral paracapsular (LPCS) interneurons. It is noteworthy that whereas EtOH enhances local GABAergic synapses via a presynaptic increase in GABA release, EtOH potentiation of LPCS inhibition is mediated via a distinct mechanism that requires adrenoceptor (AR) activation. Here, we sought to further characterize the interaction between the AR system and EtOH enhancement of LPCS GABAergic synapses by using in vitro electrophysiology techniques in male Sprague-Dawley rats. Exogenous norepinephrine (NE) enhanced LPCS-evoked inhibitory postsynaptic currents (eIPSCs) via the activation of β-ARs, because this effect was blocked by propranolol. EtOH potentiation of LPCS eIPSCs was also blocked by propranolol and significantly reduced by NE pretreatment, suggesting that NE and EtOH may enhance LPCS inhibition via a common mechanism. EtOH enhancement of LPCS eIPSCs was significantly reduced by a selective β1-, but not β2- or β3-, AR antagonist, and both EtOH and NE potentiation of LPCS IPSCs was blocked by postsynaptic disruption of cAMP signaling. These data suggest that EtOH enhances LPCS synapses via a postsynaptic β1-AR, cAMP-dependent cascade. Because enhancement of LPCS inhibition can reduce anxiety-like behaviors, these findings shed light on a novel mechanism that may play a role in some of the anxiolytic effects of EtOH that are thought to contribute to the development and progression of alcoholism.

  19. Histamine acting on the basolateral amygdala reverts the impairment of aversive memory of rats submitted to neonatal maternal deprivation.

    Science.gov (United States)

    Benetti, Fernando; da Silveira, Clarice Kras Borges; Rosa, Jessica; Izquierdo, Ivan

    2015-02-01

    Recent findings suggest a role of brain histamine in the regulation of memory consolidation, particularly in one-trial inhibitory avoidance (IA) learning and that disruption in the mother infant relationship i.e. maternal deprivation induces cognitive deficits. We investigate whether histamine itself, and histaminergic compounds given into the basolateral amygdala (BLA) immediately post-training can affect retention (24 h after training) of one-trial (IA) in rats submitted to early postnatal maternal deprivation. In all cases, deprived (Dep) animals had lower retention scores than non-deprived controls (N-dep). Histamine induced memory enhancement on its own in N-dep animals and was able to overcome the deleterious effect of Dep. The effects by SKF-91488 is similar to histamine. The H3 agonist, imetit mimetized the enhancing effects of histamine; neither agonist H1 pyridylethylamine nor the H2 dimaprit had any effect. Ranitidine and thioperamide (50 nmol) co-infused with histamine (10 nmol) fully blocked the restorative effect of histamine on retention in Dep animals. Thioperamide, in addition, blocked the enhancing effect of histamine on memory of the N-dep animals as well. None of the drugs used given into BLA had any effect on open-field or elevated plus-maze behavior in N-dep or Dep rats. Our results are limited to experimental design in rats. Extrapolation i.e. in humans requires further experimentations. The present results suggest that the memory deficit induced by early postnatal maternal deprivation in rats may at least in part be due to an impairment of histamine H3 receptor-mediated mediated mechanisms in the BLA.

  20. Interactions between ethanol and the endocannabinoid system at GABAergic synapses on basolateral amygdala principal neurons.

    Science.gov (United States)

    Talani, Giuseppe; Lovinger, David M

    2015-12-01

    The basolateral amygdala (BLA) plays crucial roles in stimulus value coding, as well as drug and alcohol dependence. Ethanol alters synaptic transmission in the BLA, while endocannabinoids (eCBs) produce presynaptic depression at BLA synapses. Recent studies suggest interactions between ethanol and eCBs that have important consequences for alcohol drinking behavior. To determine how ethanol and eCBs interact in the BLA, we examined the physiology and pharmacology of GABAergic synapses onto BLA pyramidal neurons in neurons from young rats. Application of ethanol at concentrations relevant to intoxication increased, in both young and adult animals, the frequency of spontaneous and miniature GABAergic inhibitory postsynaptic currents, indicating a presynaptic site of ethanol action. Ethanol did not potentiate sIPSCs during inhibition of adenylyl cyclase while still exerting its effect during inhibition of protein kinase A. Activation of type 1 cannabinoid receptors (CB1) in the BLA inhibited GABAergic transmission via an apparent presynaptic mechanism, and prevented ethanol potentiation. Surprisingly, ethanol potentiation was also prevented by CB1 antagonists/inverse agonists. Brief depolarization of BLA pyramidal neurons suppressed GABAergic transmission (depolarization-induced suppression of inhibition [DSI]), an effect previously shown to be mediated by postsynaptic eCB release and presynaptic CB1 activation. A CB1-mediated suppression of GABAergic transmission was also produced by combined afferent stimulation at 0.1 Hz (LFS), and postsynaptic loading with the eCB arachidonoyl ethanolamide (AEA). Both DSI and LFS-induced synaptic depression were prevented by ethanol. Our findings indicate antagonistic interactions between ethanol and eCB/CB1 modulation at GABAergic BLA synapses that may contribute to eCB roles in ethanol seeking and drinking.

  1. Differential role of muscarinic transmission within the entorhinal cortex and basolateral amygdala in the processing of irrelevant stimuli.

    Science.gov (United States)

    Barak, Segev; Weiner, Ina

    2010-04-01

    Cholinergic projections to the entorhinal cortex (EC) and basolateral amygdala (BLA) mediate distinct cognitive processes through muscarinic acetylcholine receptors (mAChRs). In this study, we sought to further differentiate the role of muscarinic transmission in these regions in cognition, using the latent inhibition (LI) phenomenon. LI is a cross-species phenomenon manifested as poorer conditioning to a stimulus experienced as irrelevant during an earlier stage of repeated non-reinforced pre-exposure to that stimulus, and is considered to index the ability to ignore, or to in-attend to, irrelevant stimuli. Given our recent findings that systemic administration of the mAChR antagonist scopolamine can produce two contrasting LI abnormalities in rats, ie, abolish LI under conditions yielding LI in non-treated controls, or produce abnormally persistent LI under conditions preventing its expression in non-treated controls, we tested whether mAChR blockade in the EC and BLA would induce LI abolition and persistence, respectively. We found that intra-EC scopolamine infusion (1, 10 mug per hemisphere) abolished LI when infused in pre-exposure or both pre-exposure and conditioning, but not in conditioning alone, whereas intra-BLA scopolamine infusion led to persistent LI when infused in conditioning or both stages, but not in pre-exposure alone. Although cholinergic innervation of the EC and BLA has long been implicated in attention to novel stimuli and in processing of motivationally significant stimuli, respectively, our results provide evidence that EC mAChRs also have a role in the development of inattention to stimuli, whereas BLA mAChRs have a role in re-attending to previously irrelevant stimuli that became motivationally relevant.

  2. Involvement of BDNF signaling transmission from basolateral amygdala to infralimbic prefrontal cortex in conditioned taste aversion extinction.

    Science.gov (United States)

    Xin, Jian; Ma, Ling; Zhang, Tian-Yi; Yu, Hui; Wang, Yue; Kong, Liang; Chen, Zhe-Yu

    2014-05-21

    Brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase receptor B (TrkB), play a critical role in memory extinction. However, the detailed role of BDNF in memory extinction on the basis of neural circuit has not been fully understood. Here, we aim to investigate the role of BDNF signaling circuit in mediating conditioned taste aversion (CTA) memory extinction of the rats. We found region-specific changes in BDNF gene expression during CTA extinction. CTA extinction led to increased BDNF gene expression in the basolateral amygdala (BLA) and infralimbic prefrontal cortex (IL) but not in the central amygdaloid nucleus (CeA) and hippocampus (HIP). Moreover, blocking BDNF signaling or exogenous microinjection of BDNF into the BLA or IL could disrupt or enhance CTA extinction, which suggested that BDNF signaling in the BLA and IL is necessary and sufficient for CTA extinction. Interestingly, we found that microinjection of BDNF-neutralizing antibody into the BLA could abolish the extinction training-induced BDNF mRNA level increase in the IL, but not vice versa, demonstrating that BDNF signaling is transmitted from the BLA to IL during extinction. Finally, the accelerated extinction learning by infusion of exogenous BDNF in the BLA could also be blocked by IL infusion of BDNF-neutralizing antibody rather than vice versa, indicating that the IL, but not BLA, is the primary action site of BDNF in CTA extinction. Together, these data suggest that BLA-IL circuit regulates CTA memory extinction by identifying BDNF as a key regulator.

  3. TRH and TRH receptor system in the basolateral amygdala mediate stress-induced depression-like behaviors.

    Science.gov (United States)

    Choi, Juli; Kim, Ji-eun; Kim, Tae-Kyung; Park, Jin-Young; Lee, Jung-Eun; Kim, Hannah; Lee, Eun-Hwa; Han, Pyung-Lim

    2015-10-01

    Chronic stress is a potent risk factor for depression, but the mechanism by which stress causes depression is not fully understood. To investigate the molecular mechanism underlying stress-induced depression, C57BL/6 inbred mice were treated with repeated restraint to induce lasting depressive behavioral changes. Behavioral states of individual animals were evaluated using the forced swim test, which measures psychomotor withdrawals, and the U-field test, which measures sociability. From these behavioral analyses, individual mice that showed depression-like behaviors in both psychomotor withdrawal and sociability tests, and individuals that showed a resiliency to stress-induced depression in both tests were selected. Among the neuropeptides expressed in the amygdala, thyrotropin-releasing hormone (TRH) was identified as being persistently up-regulated in the basolateral amygdala (BLA) in individuals exhibiting severe depressive behaviors in the two behavior tests, but not in individuals displaying a stress resiliency. Activation of TRH receptors by local injection of TRH in the BLA in normal mice produced depressive behaviors, mimicking chronic stress effects, whereas siRNA-mediated suppression of either TRH or TRHR1 in the BLA completely blocked stress-induced depressive symptoms. The TRHR1 agonist, taltirelin, injection in the BLA increased the level of p-ERK, which mimicked the increased p-ERK level in the BLA that was induced by treatment with repeated stress. Stereotaxic injection of U0126, a potent inhibitor of the ERK pathway, within the BLA blocked stress-induced behavioral depression. These results suggest that repeated stress produces lasting depression-like behaviors via the up-regulation of TRH and TRH receptors in the BLA.

  4. Glutamate transporters combine transporter- and channel-like features

    NARCIS (Netherlands)

    Slotboom, DJ; Konings, WN; Lolkema, JS

    2001-01-01

    Glutamate transporters in the mammalian central nervous system have a unique position among secondary transport proteins as they exhibit glutamate-gated chloride-channel activity in addition to glutamate-transport activity. In this article, the available data on the structure of the glutamate transp

  5. Chloride Transport in Undersea Concrete Tunnel

    Directory of Open Access Journals (Sweden)

    Yuanzhu Zhang

    2016-01-01

    Full Text Available Based on water penetration in unsaturated concrete of underwater tunnel, a diffusion-advection theoretical model of chloride in undersea concrete tunnel was proposed. The basic parameters including porosity, saturated hydraulic conductivity, chloride diffusion coefficient, initial water saturation, and moisture retention function of concrete specimens with two water-binder ratios were determined through lab-scale experiments. The variation of chloride concentration with pressuring time, location, solution concentration, initial saturation, hydraulic pressure, and water-binder ratio was investigated through chloride transport tests under external water pressure. In addition, the change and distribution of chloride concentration of isothermal horizontal flow were numerically analyzed using TOUGH2 software. The results show that chloride transport in unsaturated concrete under external water pressure is a combined effect of diffusion and advection instead of diffusion. Chloride concentration increased with increasing solution concentration for diffusion and increased with an increase in water pressure and a decrease in initial saturation for advection. The dominant driving force converted with time and saturation. When predicting the service life of undersea concrete tunnel, it is suggested that advection is taken into consideration; otherwise the durability tends to be unsafe.

  6. Hydrogeologic Processes Impacting Storage, Fate, and Transport of Chloride from Road Salt in Urban Riparian Aquifers.

    Science.gov (United States)

    Ledford, Sarah H; Lautz, Laura K; Stella, John C

    2016-05-17

    Detrimental effects of road salt runoff on urban streams are compounded by its facilitated routing via storm drains, ditches, and flood channels. Elevated in-stream salinity may also result from seasonal storage and discharge of chloride in groundwater, and previous work has hypothesized that groundwater discharge to streams may have the effect of diluting stream chloride concentrations in winter and enriching them in summer. However, the hydrogeological processes controlling these patterns have not been thoroughly investigated. Our research focuses on an urban stream and floodplain system in Syracuse, NY, to understand how groundwater and surface water exchange impacts chloride storage, fate, and transport. We created a 3D groundwater flow and solute transport model of the floodplain, calibrated to the distributions of floodplain hydraulic heads and groundwater fluxes to the stream throughout the reach. We used a sensitivity analysis to calibrate and evaluate the influence of model parameters, and compared model outputs to field observations. The main source mechanism of chloride to the floodplain aquifer was high-concentration, overbank flood events in winter that directly recharged groundwater. The modeled residence time and storage capacity of the aquifer indicate that restoration projects designed to promote floodplain reconnection and the frequency of overbank flooding in winter have the potential to temporarily store chloride in groundwater, buffer surface water concentrations, and reduce stream concentrations following periods of road salting.

  7. Effects of lithium chloride on outward potassium currents in acutely isolated hippocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chaofeng; DU Huizhi; YANG Pin

    2006-01-01

    Although lithium possesses neuroprotective functions, the molecular mechanism underlying its actions has not been fully elucidated. In the present paper, the effects of lithium chloride on voltage-dependent potassium currents in the CA1 pyramidal neurons acutely isolated from rat hippocampus were studied using the whole-cell patch-clamp technique. Depolarizing test pulses activated two components of outward potassium currents: a rapidly activating and inactivating component, IA and a delayed component, IK. Results showed that lithium chloride increased the amplitude of IA in a concentration-dependent manner. Half enhancement concentration (EC50) was 22.80±5.45 μmol·L-1. Lithium chloride of 25 μmol·L-1 shifted the steady-state activation curve and inactivation curve of IA to more negative potentials, but mainly affected the activation kinetics. The amplitude and the activation processes of IK were not affected by lithium chloride. The effects of lithium chloride on potassium channel appear to possess neuroprotective properties by Ca2+-lowing effects modulate neuronal excitability by activating IA in rat hippocampal neurons.

  8. Chloride Ingress into Concrete under Water Pressure

    OpenAIRE

    Lund, Mia Schou; Sander, Lotte Braad; Grelk, Bent; Hansen, Kurt Kielsgaard

    2011-01-01

    The chloride ingress into concrete under water pressures of 100 kPa and 800 kPa have been investigated by experiments. The specimens were exposed to a 10% NaCl solution and water mixture. For the concrete having w/c = 0.35 the experimental results show the chloride diffusion coefficient at 800 kPa (~8 atm.) is 12 times greater than at 100 kPa (~1 atm.). For w/c = 0.45 and w/c = 0.55 the chloride diffusion coefficients are 7 and 3 times greater. This means that a change in pressure highly infl...

  9. Reliability-Based Planning of Chloride Measurements

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Engelund, S.

    1996-01-01

    on measurements of the chloride content obtained from the given structure. In the present paper optimal planning of measurements of the chloride content in reinforced concrete structures is considered. It is shown how optimal experimental plans can be obtained using FORM-analysis. Bayesian statistics are used......In reinforced concrete structures corrosion is initiated when the chloride concentration around the reinforcement exceeds a threshold value. If corrosion starts then expensive repairs can be necessary. The estimation of the probability that corrosion has been initiated in a given structure is based...

  10. Mechanisms underlying KCNQ1channel cell volume sensitivity

    DEFF Research Database (Denmark)

    Hammami, Sofia

    Cells are constantly exposed to changes in cell volume during cell metabolism, nutrient uptake, cell proliferation, cell migration and salt and water transport. In order to cope with these perturbations, potassium channels in line with chloride channels have been shown to be likely contributors...... to the process of cell volume adjustments. A great diversity of potassium channels being members of either the 6TM, 4 TM or 2 TM K+ channel gene family have been shown to be strictly regulated by small, fast changes in cell volume. However, the precise mechanism underlying the K+ channel sensitivity to cell...... mechanism of regulation. Besides being regulated by cell volume, KCNQ1 is also modulated by the interaction of the ß subunit KCNE1 giving rise to the cardiac IKs delayed rectifier potassium current. Apart from altering the kinetic characteristics of the KCNQ1 channel current, KCNE1 also augments the KCNQ1...

  11. Absorption Mechanism of Palmatine Chloride Across Caco-2 Cell Monolayer Mode%盐酸巴马汀在Caco-2细胞中的吸收机制

    Institute of Scientific and Technical Information of China (English)

    谢社平; 谭晓婧; 毕开顺; 张蕾; 廖琼峰

    2011-01-01

    Objective: To investigate the absorption mechanism of palmatine chloride by using Caco-2 monolayer model. Method: A Caco-2 cell monolayer model was used to investigate the bi-directional transport of palmatine chloride. The effect of time, drug concentration, temperature, pH and inhibitors on the absorption of palmatine chloride was studied. Apparent permeability coefficient (Papp) of palmatine was calculated based on quantitation by HPLC. Result: Directional flux studies with palmatine chloride suggested transport with the permeability in the apical to basolateral direction higher than that in the basolateral to apical direction. Transport of palmatine chloride could be of saturation with time and concentration, and it was also effected by P-glycoprotein inhibitor, pH and temperature. Conclusion: The absorption of palmatine chloride in Caco-2 cell model was an active transportation mediated by transporter, which mainly located in the apical side of Caco-2 cell monolayer.%目的:研究盐酸巴马汀在Caco-2细胞模型中的吸收机制.方法:用Caco-2细胞单层模型研究盐酸巴马汀的双向转运,并考察时间、药物浓度、抑制剂、pH及温度对盐酸巴马汀吸收的影响.用高效液相色谱法检测药物浓度,计算其表观渗透系数.结果:盐酸巴马汀在Caco-2细胞模型中,从单层细胞层顶端到基底端的转运大于基底端到顶端的转运,随时间和浓度的增加,药物吸收呈饱和趋势,且P-糖蛋白(P-glycoprotein,P-gp)抑制剂维拉帕米、pH和温度对它的转运有影响.结论:盐酸巴马汀在Caco-2细胞模型中的吸收主要是由载体介导的主动转运,且该主动转运的载体位于Caco-2细胞单层的顶端.

  12. Localization of the CB1 type cannabinoid receptor in the rat basolateral amygdala: high concentrations in a subpopulation of cholecystokinin-containing interneurons.

    Science.gov (United States)

    McDonald, A J; Mascagni, F

    2001-01-01

    The neuronal localization of the CB1 cannabinoid receptor in the rat basolateral amygdala was studied using peroxidase and fluorescence immunohistochemical techniques. All nuclei of the basolateral amygdala contained a large number of lightly stained pyramidal neurons and a small number of more intensely stained non-pyramidal neurons. Most of the latter cells had medium-sized to large multipolar somata and three to four aspiny dendrites, but some exhibited smaller oval somata. The axon initial segments of some of these non-pyramidal neurons exhibited large swollen varicosities in colchicine-injected animals, suggesting that much of the CB1 receptor protein is transported down the axons of these cells. Double-labeling studies using immunofluorescence histochemistry combined with confocal laser scanning microscopy revealed that the great majority of non-pyramidal neurons with CB1 receptor immunoreactivity belonged to a cholecystokinin-containing subpopulation. Whereas none of the other subpopulations of non-pyramidal neurons (exhibiting immunoreactivity for calretinin, parvalbumin, or somatostatin) expressed high levels of CB1 receptor immunoreactivity, a small percentage of these cells exhibited low levels of immunoreactivity. The results indicate that cannabinoids may modulate the activity of pyramidal projection neurons as well as a subpopulation of cholecystokinin-containing non-pyramidal neurons in the basolateral amygdala. Previous studies indicate that most of the latter are inhibitory interneurons that utilize GABA as a neurotransmitter. The intense staining of the cholecystokinin-containing interneurons and the evidence that large amounts of CB1 receptor protein are transported down the axons of these cells suggests that, as in the hippocampus, cannabinoids may inhibit the release of GABA from the axon terminals of these neurons.

  13. Ketamine prevents lidocaine-caused neurotoxicity in the CA3 hippocampal and basolateral amygdala regions of the brain in adult rats.

    Science.gov (United States)

    Lopez-Galindo, Gabriel Eduardo; Cano-Europa, Edgar; Ortiz-Butron, Rocio

    2008-01-01

    Our objective was to prove whether blocking the action of glutamate on N-methyl-D: -aspartate (NMDA) receptors could prevent the neuronal damage caused by the acute administration of lidocaine. Twenty male 2-month-old Wistar rats were randomly assigned to the following groups (n = 5 in each group): groups I and II received 0.9% saline i.p., and groups III and IV received 100 mg x kg(-1) of ketamine i.p. Thirty minutes later, groups I and III were again dosed with 0.9% saline i.p., and groups II and IV received 60 mg x kg(-1) of lidocaine i.p. During treatment, the rectal temperature of the animals was monitored and maintained at 37.5 +/- 0.5 degrees C. Ten days after administration of the agents, all rats were transcardially perfused, under pentobarbital anesthesia, with 10% formaldehyde. Their brains were removed and were embedded in paraffin. Coronal cuts of 7 microm were obtained from -2.3 to -3.8 mm from the bregma. Each brain section was stained with cresyl violet-eosin. The number of normal and abnormal pyramidal neurons in the CA3 hippocampal region and the number of large and medium neurons in the basolateral amygdala within an area of 10 000 microm2 were evaluated. We found that lidocaine significantly reduced the number of normal neurons in both the CA3 hippocampal region (F (3,16) = 225.8; P lidocaine-induced damage in the CA3 hippocampal region and the basolateral amygdala. These results demonstrate the participation of NMDA-receptor activation by lidocaine in the CA3 hippocampal and basolateral amygdala regions as a neurotoxic mechanism.

  14. Low dose prenatal ethanol exposure induces anxiety-like behaviour and alters dendritic morphology in the basolateral amygdala of rat offspring.

    Directory of Open Access Journals (Sweden)

    Carlie L Cullen

    Full Text Available Prenatal exposure to high levels of alcohol is strongly associated with poor cognitive outcomes particularly in relation to learning and memory. It is also becoming more evident that anxiety disorders and anxiety-like behaviour can be associated with prenatal alcohol exposure. This study used a rat model to determine if prenatal exposure to a relatively small amount of alcohol would result in anxiety-like behaviour and to determine if this was associated with morphological changes in the basolateral amygdala. Pregnant Sprague Dawley rats were fed a liquid diet containing either no alcohol (Control or 6% (vol/vol ethanol (EtOH throughout gestation. Male and Female offspring underwent behavioural testing at 8 months (Adult or 15 months (Aged of age. Rats were perfusion fixed and brains were collected at the end of behavioural testing for morphological analysis of pyramidal neuron number and dendritic morphology within the basolateral amygdala. EtOH exposed offspring displayed anxiety-like behaviour in the elevated plus maze, holeboard and emergence tests. Although sexually dimorphic behaviour was apparent, sex did not impact anxiety-like behaviour induced by prenatal alcohol exposure. This increase in anxiety - like behaviour could not be attributed to a change in pyramidal cell number within the BLA but rather was associated with an increase in dendritic spines along the apical dendrite which is indicative of an increase in synaptic connectivity and activity within these neurons. This study is the first to link increases in anxiety like behaviour to structural changes within the basolateral amygdala in a model of prenatal ethanol exposure. In addition, this study has shown that exposure to even a relatively small amount of alcohol during development leads to long term alterations in anxiety-like behaviour.

  15. Effects of calcium channel on 3-morpholinosydnonimine-induced rat hippocampal neuronal apoptosis

    Institute of Scientific and Technical Information of China (English)

    Quanzhong Chang; Shuling Zhang; Yuanyin Zheng; Lijuan Xu; Jinbao Yin; Shining Cai

    2011-01-01

    Previous studies have demonstrated that increased chloride channel activity plays a role in nitric oxide-induced neuronal apoptosis in the rat hippocampus.The present study investigated the effects of the broad-spectrum calcium channel blocker CdC12 on survival rate, percentage of apoptosis, and morphological changes in hippocampal neurons cultured in vitro, as well as the effects of calcium channels on neuronal apoptosis.The chloride channel blockers 4-acetamido-4'-isothiocyanatostilbene-2, 2'-disulfonic acid (SITS) or 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) increased the survival rate of 3-morpholinosydnonimine (SIN-1)-treated neurons and suppressed SIN-1-induced neuronal apoptosis.The calcium channel blocker CdC12 did not increase the survival rate of neurons and did not affect SIN-1-induced apoptosis or SITS- or DIDS-suppressed neuronal apoptosis.Results demonstrated that calcium channels did not significantly affect neuronal apoptosis.

  16. Catastrophic event modeling. [lithium thionyl chloride batteries

    Science.gov (United States)

    Frank, H. A.

    1981-01-01

    A mathematical model for the catastrophic failures (venting or explosion of the cell) in lithium thionyl chloride batteries is presented. The phenomenology of the various processes leading to cell failure is reviewed.

  17. Surface adsorption in strontium chloride ammines

    DEFF Research Database (Denmark)

    Ammitzbøll, Andreas L.; Lysgaard, Steen; Klukowska, Agata

    2013-01-01

    An adsorbed state and its implications on the ab- and desorption kinetics of ammonia in strontium chloride ammine is identified using a combination of ammonia absorption measurements, thermogravimetric analysis, and density functional theory calculations. During thermogravimetric analysis, ammoni...

  18. Qualitative Determination of Nitrate with Triphenylbenzylphosphonium Chloride.

    Science.gov (United States)

    Berry, Donna A.; Cole, Jerry J.

    1984-01-01

    Discusses two procedures for the identification of nitrate, the standard test ("Brown Ring" test) and a new procedure using triphenylbenzylphosphonium chloride (TPBPC). Effectiveness of both procedures is compared, with the TPBPC test proving to be more sensitive and accurate. (JM)

  19. Corneal Neurotoxicity Due to Topical Benzalkonium Chloride

    OpenAIRE

    Sarkar, Joy; Chaudhary, Shweta; Namavari, Abed; Ozturk, Okan; Chang, Jin-Hong; Yco, Lisette; Sonawane, Snehal; Khanolkar, Vishakha; Hallak, Joelle; Jain, Sandeep

    2012-01-01

    Topical application of benzalkonium chloride (BAK) to the eye causes dose-related corneal neurotoxicity. Corneal inflammation and reduction in aqueous tear production accompany neurotoxicity. Cessation of BAK treatment leads to recovery of corneal nerve density.

  20. Chloride Ingress into Concrete under Water Pressure

    DEFF Research Database (Denmark)

    Lund, Mia Schou; Sander, Lotte Braad; Grelk, Bent;

    2011-01-01

    The chloride ingress into concrete under water pressures of 100 kPa and 800 kPa have been investigated by experiments. The specimens were exposed to a 10% NaCl solution and water mixture. For the concrete having w/c = 0.35 the experimental results show the chloride diffusion coefficient at 800 k......Pa (~8 atm.) is 12 times greater than at 100 kPa (~1 atm.). For w/c = 0.45 and w/c = 0.55 the chloride diffusion coefficients are 7 and 3 times greater. This means that a change in pressure highly influences the chloride ingress into the concrete and thereby the life length models for concrete structures....

  1. 75 FR 20625 - Barium Chloride From China

    Science.gov (United States)

    2010-04-20

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject review. DATES: Effective Date: April 9, 2010. FOR FURTHER INFORMATION CONTACT:...

  2. Telomerization of Vinyl Chloride with Chloroform Initiated by Ferrous Chloride-Dimethylacetamide under Ultrasonic Conditions

    Directory of Open Access Journals (Sweden)

    Hua Qian

    2015-01-01

    Full Text Available Telomerization of vinyl chloride with chloroform was investigated using ferrous chloride-dimethylacetamide system, and 42.1% yield, more than four times the one reported before, was achieved. The addition of ultrasound further improved the reaction and yield was raised to 51.9% with trace byproducts at highly reduced reaction time and temperature. Ferrous chloride-dimethylacetamide under ultrasonic irradiation acts as a very efficient catalyst system for the 1 : 1 telomerization.

  3. Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating

    OpenAIRE

    Csanády, László; Töröcsik, Beáta

    2014-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is the chloride ion channel mutated in cystic fibrosis (CF) patients. It is an ATP-binding cassette protein, and its resulting cyclic nonequilibrium gating mechanism sets it apart from most other ion channels. The most common CF mutation (ΔF508) impairs folding of CFTR but also channel gating, reducing open probability (Po). This gating defect must be addressed to effectively treat CF. Combining single-channel and macroscopic current ...

  4. Cesium chloride-induced torsades de pointes

    OpenAIRE

    Wiens, Matthew; Gordon, Wendy; Baulcomb, Daisy; Mattman, Andre; Mock, Tom; Brown, Robert

    2009-01-01

    The chloride salt of cesium, a group 1A element, is gaining popularity as an alternative treatment of advanced cancers. Cesium chloride has primarily been used in cardiovascular research for arrhythmogenesis in animals because of its potassium-blocking effects. The present report describes a 45-year-old woman with metastatic breast cancer who experienced repeated episodes of torsades de pointes polymorphic ventricular tachycardia after several months of oral cesium therapy. There was a clear ...

  5. The kinetics of the hydrogen chloride oxidation

    Directory of Open Access Journals (Sweden)

    Gonzalez Martinez Isai

    2013-01-01

    Full Text Available Hydrogen chloride (HCl oxidation has been investigated on technical membrane electrode assemblies in a cyclone flow cell. Influence of Nafion loading, temperature and hydrogen chloride mole fraction in the gas phase has been studied. The apparent kinetic parameters like reaction order with respect to HCl, Tafel slope and activation energy have been determined from polarization data. The apparent kinetic parameters suggest that the recombination of adsorbed Cl intermediate is the rate determining step.

  6. Effect of Chloride Type on Penetration of Chloride Ions in Concrete

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The influence of chloride type on the diffusivity of chloride ions in concrete was studied by experiment. The result shows that the glectric resistance of concrete and the chloride diffusion coefficient are influenced by chloride type. For the same water/cement ratio (W/C), the diffusion coefficient D in KCl solution is larger than that in NaCl solution; however, the concrete resistance in KCl solution is smaller than that in NaCl solution. The experimental result is analyzed with theory of diffusion.

  7. Influence of Chloride-Ion Adsorption Agent on Chloride Ions in Concrete and Mortar

    Directory of Open Access Journals (Sweden)

    Gai-Fei Peng

    2014-04-01

    Full Text Available The influence of a chloride-ion adsorption agent (Cl agent in short, composed of zeolite, calcium aluminate hydrate and calcium nitrite, on the ingress of chloride ions into concrete and mortar has been experimentally studied. The permeability of concrete was measured, and the chloride ion content in mortar was tested. The experimental results reveal that the Cl agent could adsorb chloride ions effectively, which had penetrated into concrete and mortar. When the Cl agent was used at a dosage of 6% by mass of cementitious materials in mortar, the resistance to the penetration of chloride ions could be improved greatly, which was more pronounced when a combination of the Cl agent and fly ash or slag was employed. Such an effect is not the result of the low permeability of the mortar, but might be a result of the interaction between the Cl agent and the chloride ions penetrated into the mortar. There are two possible mechanisms for the interaction between the Cl agent and chloride ion ingress. One is the reaction between calcium aluminate hydrate in the Cl agent and chloride ions to form Friedel’s salt, and the other one is that calcium aluminate hydrate reacts with calcium nitrite to form AFm during the early-age hydration of mortar and later the NO2− in AFm is replaced by chloride ions, which then penetrate into the mortar, also forming Friedel’s salt. More research is needed to confirm the mechanisms.

  8. Cooperative interaction between the basolateral amygdala and ventral tegmental area modulates the consolidation of inhibitory avoidance memory.

    Science.gov (United States)

    Nazari-Serenjeh, Farzaneh; Rezayof, Ameneh

    2013-01-10

    The aim of the current study was to examine the existence of a cooperative interaction between the basolateral nucleus of amygdala (BLA) and the ventral tegmental area (VTA) in inhibitory avoidance task. The BLA and the VTA regions of adult male Wistar rats were simultaneously cannulated and memory consolidation was measured in a step-through type inhibitory avoidance apparatus. Post-training microinjection of muscimol, a potent GABA-A receptor agonist (0.01-0.02 μg/rat), into the VTA impaired memory in a dose-dependent manner. Post-training intra-BLA microinjection of NMDA (0.02-0.04 μg/rat), 5 min before the intra-VTA injection of muscimol (0.02 μg/rat), attenuated muscimol-induced memory impairment. Microinjection of a NMDA receptor antagonist, D-AP5 (0.02-0.06 μg/rat) into the BLA inhibited NMDA effect on the memory impairment induced by intra-VTA microinjection of muscimol. On the other hand, post-training intra-BLA microinjection of muscimol (0.02-0.04 μg/rat) dose-dependently decreased step-through latency, indicating an impairing effect on memory. This impairing effect was however significantly attenuated by intra-VTA microinjection of NMDA (0.01-0.03 μg/rat). Intra-VTA microinjection of D-AP5 (0.02-0.08 μg/rat), 5 min prior to NMDA injection, inhibited NMDA response on the impairing effect induced by intra-BLA microinjection of muscimol. It should be considered that post-training microinjection of the same doses of NMDA or D-AP5 into the BLA or the VTA alone had no effect on memory consolidation. The data suggest that the relationship between the BLA and the VTA in mediating memory consolidation in inhibitory avoidance learning may be dependent on a cooperative interaction between the glutamatergic and GABAergic systems via NMDA and GABA-A receptors.

  9. Activation of the basolateral amygdala induces long-term enhancement of specific memory representations in the cerebral cortex.

    Science.gov (United States)

    Chavez, Candice M; McGaugh, James L; Weinberger, Norman M

    2013-03-01

    The basolateral amygdala (BLA) modulates memory, particularly for arousing or emotional events, during post-training periods of consolidation. It strengthens memories whose substrates in part or whole are stored remotely, in structures such as the hippocampus, striatum and cerebral cortex. However, the mechanisms by which the BLA influences distant memory traces are unknown, largely because of the need for identifiable target mnemonic representations. Associative tuning plasticity in the primary auditory cortex (A1) constitutes a well-characterized candidate specific memory substrate that is ubiquitous across species, tasks and motivational states. When tone predicts reinforcement, the tuning of cells in A1 shifts toward or to the signal frequency within its tonotopic map, producing an over-representation of behaviorally important sounds. Tuning shifts have the cardinal attributes of forms of memory, including associativity, specificity, rapid induction, consolidation and long-term retention and are therefore likely memory representations. We hypothesized that the BLA strengthens memories by increasing their cortical representations. We recorded multiple unit activity from A1 of rats that received a single discrimination training session in which two tones (2.0 s) separated by 1.25 octaves were either paired with brief electrical stimulation (400 ms) of the BLA (CS+) or not (CS-). Frequency response areas generated by presenting a matrix of test tones (0.5-53.82 kHz, 0-70 dB) were obtained before training and daily for 3 weeks post-training. Tuning both at threshold and above threshold shifted predominantly toward the CS+ beginning on day 1. Tuning shifts were maintained for the entire 3 weeks. Absolute threshold and bandwidth decreased, producing less enduring increases in sensitivity and selectivity. BLA-induced tuning shifts were associative, highly specific and long-lasting. We propose that the BLA strengthens memory for important experiences by increasing the

  10. Proteins involved in uptake, intracellular transport and basolateral secretion of fat-soluble vitamins and carotenoids by mammalian enterocytes.

    Science.gov (United States)

    Reboul, Emmanuelle; Borel, Patrick

    2011-10-01

    Our understanding of the molecular mechanisms responsible for fat-soluble vitamin uptake and transport at the intestinal level has advanced considerably over the past decade. On one hand, it has long been considered that vitamin D and E as well as β-carotene (the main provitamin A carotenoid in human diet) were absorbed by a passive diffusion process, although this could not explain the broad inter-individual variability in the absorption efficiency of these molecules. On the other hand, it was assumed that preformed vitamin A (retinol) and vitamin K1 (phylloquinone) absorption occurred via energy-dependent processes, but the transporters involved have not yet been identified. The recent discovery of intestinal proteins able to facilitate vitamin E and carotenoid uptake and secretion by the enterocyte has spurred renewed interest in studying the fundamental mechanisms involved in the absorption of these micronutrients. The proteins identified so far are cholesterol transporters such as SR-BI (scavenger receptor class B type I), CD36 (cluster determinant 36), NPC1L1 (Niemann-Pick C1-like 1) or ABCA1 (ATP-Binding Cassette A1) displaying a broad substrate specificity, but it is likely that other membrane proteins are also involved. After overviewing the metabolism of fat-soluble vitamins and carotenoids in the human upper gastrointestinal lumen, we will focus on the putative or identified proteins participating in the intestinal uptake, intracellular transport and basolateral secretion of these fat-soluble vitamins and carotenoids, and outline the uncertainties that need to be explored in the future. Identifying the proteins involved in intestinal uptake and transport of fat-soluble vitamins and carotenoids across the enterocyte is of great importance, especially as some of them are already targets for the development of drugs able to slow cholesterol absorption. Indeed, these drugs may also interfere with lipid vitamin uptake. A better understanding of the molecular

  11. Functional lateralization of the baso-lateral amygdala neural circuits modulating the motivated exploratory behaviour in rats: role of histamine.

    Science.gov (United States)

    Alvarez, Edgardo O; Banzan, Arturo M

    2011-03-17

    Functional laterality appears to be present in many brain functions in man and animals. The existence of paired neural circuits which act differentially to modulate a specific behavioural function seems to be an evolutionary successful strategy in animal evolution. In spite of many examples described in mammals, birds and other vertebrates and invertebrates, still its intrinsic mechanism is not completely understood. In this work the participation of the baso-lateral amygdala (BLA) on lateralized motivated exploratory behaviour and the possible influence of histamine neurons in these mechanisms were studied in rats. Different groups of animals under xylacine-ketamine anesthesia were implanted with microinjection guide cannulae into the right or left BLA. 72 h after implantation, animals were tested in hole-board cage (OVM) with a novelty object positioned in the center of the arena, as a model of exploration of a non-conflictive environment, and 24h later they were tested in the Elevated Asymmetric Plus Maze (APM) as a model of conflictive exploration. In the day of the experiment, lidocaine was applied into the left, or right BLA in order to block the electrical activity of BLA neurons. Saline in the contralateral BLA was considered control. Results showed that exploratory activity in the OVM was significantly inhibited when lidocaine was microinjected into the left BLA, and no changes were observed when lidocaine was applied into the right BLA. When histamine was microinjected into the right BLA and lidocaine into the contralateral BLA, head-dipping, rearing, and focalized exploration behaviour were significantly inhibited. In the APM, lidocaine treatment increased equally the exploration of the "single wall" and "high and low walls" arms of the labyrinth, independently if blocking of electrical activity of the BLA neurons was performed in the left or right amygdala. Histamine treatment inhibited significantly exploration of the lesser fear-inducing arms of the

  12. DBS in the baso-lateral amygdala improves symptoms of autism and related self-injurious behaviourA case report and hypothesis on the pathogenesis of the disorder

    Directory of Open Access Journals (Sweden)

    Volker eSturm

    2013-01-01

    Full Text Available We treated a thirteen year old boy for life-threatening self-injurious behavior (SIB and severe Kanner’s autism with Deep Brain Stimulation (DBS in the amygdaloid complex as well as in the supra-amygdaloid projection system. Two DBS-electrodes were placed in both structures of each hemisphere. The stimulation contacts targeted the paralaminar, the basolateral, the central amygdala as well as the supra-amygdaloid projection system. DBS was applied to each of these structures, but only stimulation of the baso-lateral part proved effective in improving SIB and core symptoms of the autism spectrum in the emotional, social and even cognitive domains over a follow up of now 24 months. These results, which have been gained for the first time in a patient, support hypotheses, according to which the amygdala may be pivotal in the pathogeneses of autism and point to the special relevance of the baso-lateral part.

  13. 42 CFR 84.250 - Vinyl chloride respirators; description.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Vinyl chloride respirators; description. 84.250... Respirators § 84.250 Vinyl chloride respirators; description. Vinyl chloride respirators, including all... escape from vinyl chloride atmospheres containing adequate oxygen to support life, are...

  14. Factors influencing chloride deposition in a coastal hilly area and application to chloride deposition mapping

    Directory of Open Access Journals (Sweden)

    H. Guan

    2009-09-01

    Full Text Available Chloride is commonly used as an environmental tracer for studying water flow and solute transport in the environment. It is especially useful for estimating groundwater recharge based on the commonly used chloride mass balance (CMB method. Strong spatial variability in chloride deposition in coastal areas is one difficulty encountered in appropriately applying the CMB approach. Furthermore, intensive vegetation clearance for agriculture, for example during the European settlement in many coastal areas of Australia, may have perturbed catchment chloride balance conditions for appropriate use in CMB applications. In order to deal with these issues, a high resolution chloride deposition map in the coastal region is needed. In this study, we examined geographic, orographic, and atmospheric factors influencing chloride deposition in the Mount Lofty Ranges (MLR, a coastal hilly area of approximately 9000 km2 spatial extent in South Australia, using partial correlation and regression analyses. The results indicate that coastal distance, and terrain aspect and slope are two most significant factors controlling chloride deposition. Coastal distance accounts for 65% spatial variability in chloride deposition, with terrain aspect and slope for 8%. The deposition gradient is about 0.08 gm-2 year-1 km-1 as one progresses inland. The results are incorporated into a published de-trended residual kriging approach (ASOADeK to produce a 1 km×1 km resolution annual chloride deposition map and a bulk precipitation chloride concentration map. The average uncertainty of the deposition map is about 30% in the western MLR, and over 50% in the eastern MLR. The maps will form a very useful basis for examining catchment chloride balances for use in the CMB application in the study area.

  15. Discerning apical and basolateral properties of HT-29/B6 and IPEC-J2 cell layers by impedance spectroscopy, mathematical modeling and machine learning.

    Directory of Open Access Journals (Sweden)

    Thomas Schmid

    Full Text Available Quantifying changes in partial resistances of epithelial barriers in vitro is a challenging and time-consuming task in physiology and pathophysiology. Here, we demonstrate that electrical properties of epithelial barriers can be estimated reliably by combining impedance spectroscopy measurements, mathematical modeling and machine learning algorithms. Conventional impedance spectroscopy is often used to estimate epithelial capacitance as well as epithelial and subepithelial resistance. Based on this, the more refined two-path impedance spectroscopy makes it possible to further distinguish transcellular and paracellular resistances. In a next step, transcellular properties may be further divided into their apical and basolateral components. The accuracy of these derived values, however, strongly depends on the accuracy of the initial estimates. To obtain adequate accuracy in estimating subepithelial and epithelial resistance, artificial neural networks were trained to estimate these parameters from model impedance spectra. Spectra that reflect behavior of either HT-29/B6 or IPEC-J2 cells as well as the data scatter intrinsic to the used experimental setup were created computationally. To prove the proposed approach, reliability of the estimations was assessed with both modeled and measured impedance spectra. Transcellular and paracellular resistances obtained by such neural network-enhanced two-path impedance spectroscopy are shown to be sufficiently reliable to derive the underlying apical and basolateral resistances and capacitances. As an exemplary perturbation of pathophysiological importance, the effect of forskolin on the apical resistance of HT-29/B6 cells was quantified.

  16. A comprehensive probabilistic model of chloride ingress in unsaturated concrete

    OpenAIRE

    Bastidas-Arteaga, Emilio; Chateauneuf, Alaa; Sánchez-Silva, Mauricio; Bressolette, Philippe; Schoefs, Franck

    2011-01-01

    International audience; Corrosion induced by chloride ions has become a critical issue for many reinforced concrete structures. The chloride ingress into concrete has been usually simplified as a diffusion problem where the chloride concentration throughout concrete is estimated analytically. However, this simplified approach has several limitations. For instance, it does not consider chloride ingress by convection which is essential to model chloride penetration in unsaturated conditions as ...

  17. Congenital Chloride Diarrhea: Diagnosis by Easy-Accessible Chloride Measurement in Feces

    Directory of Open Access Journals (Sweden)

    C. Gils

    2016-01-01

    Full Text Available Background. Congenital chloride diarrhea (CCD is an autosomal recessive disorder caused by mutations in the genes encoding the intestinal Cl−/HCO3- exchanger and is clinically characterized by watery, profound diarrhea, electrolyte disturbances, and metabolic alkalosis. The CCD diagnosis is based on the clinical symptoms and measurement of high chloride concentration in feces (>90 mmol/L and is confirmed by DNA testing. Untreated CCD is lethal, while long-term clinical outcome improves when treated correctly. Case Presentation. A 27-year-old woman had an emergency caesarian due to pain and discomfort in gestational week 36 + 4. The newborn boy had abdominal distension and yellow fluid per rectum. Therapy with intravenous glucose and sodium chloride decreased his stool frequency and improved his clinical condition. A suspicion of congenital chloride diarrhea was strongly supported using blood gas analyzer to measure an increased chloride concentration in the feces; the diagnosis was confirmed by DNA testing. Discussion. Measurement of chloride in feces using an ordinary blood gas analyzer can serve as a preliminary analysis when congenital chloride diarrhea is suspected. This measurement can be easily performed with a watery feces composition. An easy-accessible chloride measurement available will facilitate the diagnostics and support the initial treatment if CCD is suspected.

  18. Amine and Titanium (IV Chloride, Boron (III Chloride or Zirconium (IV Chloride-Promoted Baylis-Hillman Reactions

    Directory of Open Access Journals (Sweden)

    Shi-Cong Cui

    2001-10-01

    Full Text Available The Baylis-Hillman reactions of various aryl aldehydes with methyl vinyl ketone at temperatures below -20oC using Lewis acids such as titanium (IV chloride, boron (III chloride or zirconium (IV chloride in the presence of a catalytic amount of selected amines used as a Lewis bases afford the chlorinated compounds 1 as the major product in very high yields. Acrylonitrile can also undergo the same reaction to give the corresponding chlorinated product in moderate yield. A plausible reaction mechanism is proposed. However, if the reaction was carried out at room temperature (ca. 20oC, then the Z-configuration of the elimination product 3, derived from 1, was formed as the major product.

  19. Mutational consequences of aberrant ion channels in neurological disorders.

    Science.gov (United States)

    Kumar, Dhiraj; Ambasta, Rashmi K; Kumar, Pravir

    2014-11-01

    Neurological channelopathies are attributed to aberrant ion channels affecting CNS, PNS, cardiac, and skeletal muscles. To maintain the homeostasis of excitable tissues, functional ion channels are necessary to rely electrical signals, whereas any malfunctioning serves as an intrinsic factor to develop neurological channelopathies. Molecular basis of these disease is studied based on genetic and biophysical approaches, e.g., loci positional cloning, whereas pathogenesis and bio-behavioral analysis revealed the dependency on genetic mutations and inter-current triggering factors. Although electrophysiological studies revealed the possible mechanisms of diseases, analytical study of ion channels remained unsettled and therefore underlying mechanism in channelopathies is necessary for better clinical application. Herein, we demonstrated (i) structural and functional role of various ion channels (Na(+), K(+), Ca(2+),Cl(-)), (ii) pathophysiology involved in the onset of their associated channelopathies, and (iii) comparative sequence and phylogenetic analysis of diversified sodium, potassium, calcium, and chloride ion channel subtypes.

  20. Dynamic Electrochemical Measurement of Chloride Ions.

    Science.gov (United States)

    Abbas, Yawar; de Graaf, Derk B; Olthuis, Wouter; van den Berg, Albert

    2016-02-05

    This protocol describes the dynamic measurement of chloride ions using the transition time of a silver silver chloride (Ag/AgCl) electrode. Silver silver chloride electrode is used extensively for potentiometric measurement of chloride ions concentration in electrolyte. In this measurement, long-term and continuous monitoring is limited due to the inherent drift and the requirement of a stable reference electrode. We utilized the chronopotentiometric approach to minimize drift and avoid the use of a conventional reference electrode. A galvanostatic pulse is applied to an Ag/AgCl electrode which initiates a faradic reaction depleting the Cl- ions near the electrode surface. The transition time, which is the time to completely deplete the ions near the electrode surface, is a function of the ion concentration, given by the Nernst equation. The square root of the transition time is in linear relation to the chloride ion concentration. Drift of the response over two weeks is negligible (59 µM/day) when measuring 1 mM [Cl-]using a current pulse of 10 Am(-2). This is a dynamic measurement where the moment of transition time determines the response and thus is independent of the absolute potential. Any metal wire can be used as a pseudo-reference electrode, making this approach feasible for long-term measurement inside concrete structures.

  1. Chloride binding site of neurotransmitter sodium symporters.

    Science.gov (United States)

    Kantcheva, Adriana K; Quick, Matthias; Shi, Lei; Winther, Anne-Marie Lund; Stolzenberg, Sebastian; Weinstein, Harel; Javitch, Jonathan A; Nissen, Poul

    2013-05-21

    Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs have a serine. The LeuT-E290S mutant displays chloride-dependent activity. We show that, in LeuT-E290S cocrystallized with bromide or chloride, the anion is coordinated by side chain hydroxyls from Tyr47, Ser290, and Thr254 and the side chain amide of Gln250. The bound anion and the nearby sodium ion in the Na1 site organize a connection between their coordinating residues and the extracellular gate of LeuT through a continuous H-bond network. The specific insights from the structures, combined with results from substrate binding studies and molecular dynamics simulations, reveal an anion-dependent occlusion mechanism for NSS and shed light on the functional role of chloride binding.

  2. CLC channel function and dysfunction in health and disease

    Directory of Open Access Journals (Sweden)

    Gabriel eStölting

    2014-10-01

    Full Text Available CLC channels and transporters are expressed in most tissues and fulfill diverse functions. There are four human CLC channels, ClC-1, ClC-2, ClC-Ka and ClC-Kb, and five CLC transporters, ClC-3 through -7. Some of the CLC channels additionally associate with accessory subunits. Whereas barttin is mandatory for the functional expression of CLC-K, GlialCam is a facultative subunit of ClC-2 which modifies gating and thus increases the functional variability within the CLC family. Isoform-specific ion conduction and gating properties optimize distinct CLC channels for their cellular tasks. ClC-1 preferentially conducts at negative voltages, and the resulting inward rectification provides a large resting chloride conductance without interference with the muscle action potential. Exclusive opening at voltages negative to the chloride reversal potential allows for ClC-2 to regulate intracellular chloride concentrations. ClC-Ka and ClC-Kb are equally suited for inward and outward currents to support transcellular chloride fluxes. Every human CLC channel gene has been linked to a genetic disease, and studying these mutations has provided much information about the physiological roles and the molecular basis of CLC channel function. Mutations in the gene encoding ClC-1 cause myotonia congenita, a disease characterized by sarcolemmal hyperexcitability and muscle stiffness. Loss-of-function of ClC-Kb/barttin channels in patients suffering from Bartter syndrome identified the determinants of chloride conductances in the limb of Henle. Mutations in CLCN2 were found in patients with CNS disorders but the functional role of this isoform is still not understood. Recent links between ClC-1 and epilepsy and ClC-Ka and heart failure suggested novel cellular functions of these proteins. This review aims to survey the knowledge about physiological and pathophysiological functions of human CLC channels in the light of recent discoveries from biophysical, physiological

  3. Voltage-Gated Channels as Causative Agents for Epilepsies

    Directory of Open Access Journals (Sweden)

    Mutasem Abuhamed

    2008-01-01

    Full Text Available Problem statement: Epilepsy is a common neurological disorder that afflicts 1-2% of the general population worldwide. It encompasses a variety of disorders with seizures. Approach: Idiopathic epilepsies were defined as a heterogeneous group of seizure disorders that show no underlying cause .Voltage-gated ion channels defect were recognized etiology of epilepsy in the central nervous system. The aim of this article was to provide an update on voltage-gated channels and their mutation as causative agents for epilepsies. We described the structures of the voltage-gated channels, discuss their current genetic studies, and then review the effects of voltage-gated channels as causative agents for epilepsies. Results: Channels control the flow of ions in and out of the cell causing depolarization and hyper polarization of the cell. Voltage-gated channels were classified into four types: Sodium, potassium calcium ands chloride. Voltage-gated channels were macromolecular protein complexes within the lipid membrane. They were divided into subunits. Each subunit had a specific function and was encoded by more than one gen. Conclusion: Current genetic studies of idiopathic epilepsies show the importance of genetic influence on Voltage-gated channels. Different genes may regulate a function in a channel; the channel defect was directly responsible for neuronal hyper excitability and seizures.

  4. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  5. SN2 and SN2' reaction dynamics of cyclopropenyl chloride with halide ion : A direct ab initio molecular dynamics (MD) study

    OpenAIRE

    Tachikawa, Hiroto

    2005-01-01

    Direct ab initio molecular dynamics (MD) calculations have been carried out for the reaction of cyclopropenyl chloride with halide ion (F–) (F– + (CH)3Cl → F(CH)3 + Cl–) in gas phase. Both SN2 and SN2′ channels were found as product channels. These channels are strongly dependent on the collision angle of F– to the target (CH)3Cl molecule. The collision at one of the carbon atoms of the C=C double bond leads to the SN2′ reaction channel; whereas the collision at the methylene carbon atom lead...

  6. Alkali metal and ammonium chlorides in water and heavy water (binary systems)

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

    This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

  7. Synthetic ion transporters can induce apoptosis by facilitating chloride anion transport into cells.

    Science.gov (United States)

    Ko, Sung-Kyun; Kim, Sung Kuk; Share, Andrew; Lynch, Vincent M; Park, Jinhong; Namkung, Wan; Van Rossom, Wim; Busschaert, Nathalie; Gale, Philip A; Sessler, Jonathan L; Shin, Injae

    2014-10-01

    Anion transporters based on small molecules have received attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis. However, a direct correlation between a change in cellular chloride anion concentration and cytotoxicity has not been established for synthetic ion carriers. Here we show that two pyridine diamide-strapped calix[4]pyrroles induce coupled chloride anion and sodium cation transport in both liposomal models and cells, and promote cell death by increasing intracellular chloride and sodium ion concentrations. Removing either ion from the extracellular media or blocking natural sodium channels with amiloride prevents this effect. Cell experiments show that the ion transporters induce the sodium chloride influx, which leads to an increased concentration of reactive oxygen species, release of cytochrome c from the mitochondria and apoptosis via caspase activation. However, they do not activate the caspase-independent apoptotic pathway associated with the apoptosis-inducing factor. Ion transporters, therefore, represent an attractive approach for regulating cellular processes that are normally controlled tightly by homeostasis.

  8. 5-HT1A and benzodiazepine receptors in the basolateral amygdala modulate anxiety in the social interaction test, but not in the elevated plus-maze.

    Science.gov (United States)

    Gonzalez, L E; Andrews, N; File, S E

    1996-09-01

    In order to investigate the role of the 5-HT1A receptors of the amygdala in modulating anxiety, rats were implanted with bilateral cannulae aimed at the basolateral nucleus of the amygdala complex and infused with either artificial cerebrospinal fluid (aCSF) or the selective 5-HT1A receptor agonist 8-OH-DPAT (50-200 ng) and tested in two animal models of anxiety. In the elevated plus-maze test, no significant effects were detected in this dose range. In contrast, 8-OH-DPAT caused an overall reduction in levels of social investigation, thus indicating anxiogenic actions in the social interaction test. At 50 ng, 8-OH-DPAT had a selective action on anxiety, while at 200 ng there was a concomitant reduction in locomotor activity and, in some animals, signs of the 5-HT1A syndrome. Evidence that the anxiogenic effect of 8-OH-DPAT (50 ng) was due to activation of 5-HT1A receptors came from the finding that (-)-tertatolol, a 5-HT1A receptor antagonist, reversed this effect at a dose (1.5 micrograms) which was silent when given alone. The benzodiazepine receptor agonist, midazolam (1 and 2 micrograms) was bilaterally administered into the basolateral nucleus of the amygdala and evoked clear-cut anxiolytic effects in the social interaction test. These data indicate that the agonist activation of post-synaptic 5-HT1A receptors in the basolateral nucleus of the amygdala may produce anxiogenic effects, while agonist activation of BDZ receptors in the same areas evokes anxiolytic effects. Our results from the social interaction test are similar to those previously reported from tests of anxiety using punished paradigms, but contrast with those found in the elevated plus-maze. Thus, it is concluded that either the two tests have different sensitivities to midazolam and 8-OH-DPAT or more intriguingly, the tests are evoking fundamentally different states of anxiety, with that evoked by the plus-maze being mediated via brain areas or receptors different from those studied here.

  9. Hazards of lithium thionyl chloride batteries

    Science.gov (United States)

    Parry, J. M.

    1978-01-01

    Two different topics which only relate in that they are pertinent to lithium thionyl chloride battery safety are discussed. The first topic is a hazards analysis of a system (risk assessment), a formal approach that is used in nuclear engineering, predicting oil spills, etc. It is a formalized approach for obtaining assessment of the degree of risk associated with the use of any particular system. The second topic is a small piece of chemistry related to the explosions that can occur with lithium thionyl chloride systems. After the two topics are presented, a discussion is generated among the Workshop participants.

  10. EVALUATION OF BACTERICIDAL EFFECTIVENESS OF BENZALKONIUM CHLORIDE

    Directory of Open Access Journals (Sweden)

    K. Imandel

    1996-06-01

    Full Text Available Benzalkonium chloride is a quaternary ammounium Compounds derivative under different names such as Afxhang, Hamoon, Mahan etc, which have great and expanded use in sanitation and medical affairs. Bactericidal activity of these disinfectants was fulfilled according to National Standard Method No.2842 on Staph. Aureus, Sal. Typhimouium and E. coli. This laboratory test showed that, except Mahan that has not bactericidal efficacy on E.coli at concentration 0.4 percent, other disinfectants under the study in concentrations of 0.4, 0.8, 1, 1.2 percent have reliable antibacterial properties, and bacterial resistance to benzalkonium chloride has not occurred yet.

  11. Cesium chloride-induced torsades de pointes.

    Science.gov (United States)

    Wiens, Matthew; Gordon, Wendy; Baulcomb, Daisy; Mattman, Andre; Mock, Tom; Brown, Robert

    2009-09-01

    The chloride salt of cesium, a group 1A element, is gaining popularity as an alternative treatment of advanced cancers. Cesium chloride has primarily been used in cardiovascular research for arrhythmogenesis in animals because of its potassium-blocking effects. The present report describes a 45-year-old woman with metastatic breast cancer who experienced repeated episodes of torsades de pointes polymorphic ventricular tachycardia after several months of oral cesium therapy. There was a clear temporal relationship between cesium ingestion and the arrhythmia, which later resolved following discontinuation of cesium therapy. Serial cesium plasma and whole blood levels were measured over the ensuing six months and pharmacokinetic analysis was performed.

  12. The K+ channel opener 1-EBIO potentiates residual function of mutant CFTR in rectal biopsies from cystic fibrosis patients.

    Directory of Open Access Journals (Sweden)

    Eva K Roth

    Full Text Available BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF. Previous studies demonstrated that the K⁺ channel opener 1-ethyl-2-benzimidazolone (1-EBIO potentiates CFTR-mediated Cl⁻ secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Cl⁻ secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Cl⁻ secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Cl⁻ secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Cl⁻ secretion by 39.2±6.7% (P<0.001 via activation of basolateral Ca²⁺-activated and clotrimazole-sensitive KCNN4 K⁺ channels. In CF specimens, 1-EBIO potentiated cAMP-induced Cl⁻ secretion in tissues with residual CFTR function by 44.4±11.5% (P<0.001, but had no effect on tissues lacking CFTR-mediated Cl⁻ conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Cl⁻secretion in native CF tissues expressing CFTR mutants with residual Cl⁻ channel function by activation of basolateral KCNN4 K⁺ channels that increase the driving force for luminal Cl⁻ exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF.

  13. Proton pump-driven cutaneous chloride uptake in anuran amphibia

    DEFF Research Database (Denmark)

    Jensen, Lars Jørn; Willumsen, Niels J.; Amstrup, Jan

    2003-01-01

    is saturating, voltage independent, and sensitive to DIDS and carbonic-anhydrase inhibitors. Depending on anuran species and probably on acid/base balance of the animal, apical exit of protons is coupled to an exchange of Cl(-) with base (HCO(3)(-)) either in the apical membrane (gamma-type of MR cell......) or in the basolateral membrane (alpha-type MR cell). The gamma-cell model accounts for the rheogenic active uptake of Cl(-) observed in several anuran species. There is indirect evidence also for non-rheogenic active uptake accomplished by a beta-type MR cell with apical base secretion and basolateral proton pumping...... with serosa-negative V(t). In diluted freshwater, exchange of cellular HCO(3)(-) with external Cl(-) seems to be possible only if the proton pump has the additional function of keeping the external concentration of HCO(3)(-) low. Quantitative considerations also lead to the conclusion that with the above...

  14. Apical Ca2+-activated potassium channels in mouse parotid acinar cells.

    Science.gov (United States)

    Almassy, Janos; Won, Jong Hak; Begenisich, Ted B; Yule, David I

    2012-02-01

    Ca(2+) activation of Cl and K channels is a key event underlying stimulated fluid secretion from parotid salivary glands. Cl channels are exclusively present on the apical plasma membrane (PM), whereas the localization of K channels has not been established. Mathematical models have suggested that localization of some K channels to the apical PM is optimum for fluid secretion. A combination of whole cell electrophysiology and temporally resolved digital imaging with local manipulation of intracellular [Ca(2+)] was used to investigate if Ca(2+)-activated K channels are present in the apical PM of parotid acinar cells. Initial experiments established Ca(2+)-buffering conditions that produced brief, localized increases in [Ca(2+)] after focal laser photolysis of caged Ca(2+). Conditions were used to isolate K(+) and Cl(-) conductances. Photolysis at the apical PM resulted in a robust increase in K(+) and Cl(-) currents. A localized reduction in [Ca(2+)] at the apical PM after photolysis of Diazo-2, a caged Ca(2+) chelator, resulted in a decrease in both K(+) and Cl(-) currents. The K(+) currents evoked by apical photolysis were partially blocked by both paxilline and TRAM-34, specific blockers of large-conductance "maxi-K" (BK) and intermediate K (IK), respectively, and almost abolished by incubation with both antagonists. Apical TRAM-34-sensitive K(+) currents were also observed in BK-null parotid acini. In contrast, when the [Ca(2+)] was increased at the basal or lateral PM, no increase in either K(+) or Cl(-) currents was evoked. These data provide strong evidence that K and Cl channels are similarly distributed in the apical PM. Furthermore, both IK and BK channels are present in this domain, and the density of these channels appears higher in the apical versus basolateral PM. Collectively, this study provides support for a model in which fluid secretion is optimized after expression of K channels specifically in the apical PM.

  15. Mobile radio channels

    CERN Document Server

    Pätzold, Matthias

    2011-01-01

    Providing a comprehensive overview of the modelling, analysis and simulation of mobile radio channels, this book gives a detailed understanding of fundamental issues and examines state-of-the-art techniques in mobile radio channel modelling. It analyses several mobile fading channels, including terrestrial and satellite flat-fading channels, various types of wideband channels and advanced MIMO channels, providing a fundamental understanding of the issues currently being investigated in the field. Important classes of narrowband, wideband, and space-time wireless channels are explored in deta

  16. Ion Channels in Obesity: Pathophysiology and Potential Therapeutic Targets.

    Science.gov (United States)

    Vasconcelos, Luiz H C; Souza, Iara L L; Pinheiro, Lílian S; Silva, Bagnólia A

    2016-01-01

    Obesity is a multifactorial disease related to metabolic disorders and associated with genetic determinants. Currently, ion channels activity has been linked to many of these disorders, in addition to the central regulation of food intake, energetic balance, hormone release and response, as well as the adipocyte cell proliferation. Therefore, the objective of this work is to review the current knowledge about the influence of ion channels in obesity development. This review used different sources of literature (Google Scholar, PubMed, Scopus, and Web of Science) to assess the role of ion channels in the pathophysiology of obesity. Ion channels present diverse key functions, such as the maintenance of physiological homeostasis and cell proliferation. Cell biology and pharmacological experimental evidences demonstrate that proliferating cells exhibit ion channel expression, conductance, and electrical properties different from the resting cells. Thereby, a large variety of ion channels has been identified in the pathogenesis of obesity such as potassium, sodium, calcium and chloride channels, nicotinic acetylcholine receptor and transient receptor potential channels. The fundamental involvement of these channels on the generation of obesity leads to the progress in the knowledge about the mechanisms responsible for the obesity pathophysiology, consequently emerging as new targets for pharmacological modulation.

  17. Ion Channels in Obesity: Pathophysiology and Potential Therapeutic Targets

    Directory of Open Access Journals (Sweden)

    LUIZ HENRIQUE CÉSAR VASCONCELOS

    2016-03-01

    Full Text Available Obesity is a multifactorial disease related to metabolic disorders and associated with genetic determinants. Currently, ion channels activity has been linked to many of these disorders, in addition to the central regulation of food intake, energetic balance, hormone release and response, as well as the adipocyte cell proliferation. Therefore, the objective of this work is to review the current knowledge about the influence of ion channels in obesity development. This review used different sources of literature (Google Scholar, PubMed, Scopus and Web of Science to assess the role of ion channels in the pathophysiology of obesity. Ion channels present diverse key functions, such as the maintenance of physiological homeostasis and cell proliferation. Cell biology and pharmacological experimental evidences demonstrate that proliferating cells exhibit ion channel expression, conductance and electrical properties different from the resting cells. Thereby, a large variety of ion channels has been identified in the pathogenesis of obesity such as potassium, sodium, calcium and chloride channels, nicotinic acetylcholine receptor and transient receptor potential channels. The fundamental involvement of these channels on the generation of obesity leads to the progress in the knowledge about the mechanisms responsible for the obesity pathophysiology, consequently emerging as new targets for pharmacological modulation.

  18. Solvothermal synthesis of strontium phosphate chloride nanowire

    Science.gov (United States)

    Lam, W. M.; Wong, C. T.; Li, Z. Y.; Luk, K. D. K.; Chan, W. K.; Yang, C.; Chiu, K. Y.; Xu, B.; Lu, W. W.

    2007-08-01

    Strontium phosphate chloride nanowire was synthesized via a solvothermal treatment of strontium tri-polyphosphate and Collin salt in 1,4-dioxane at 150 °C. The effects of 1,4-dioxane concentration on particle morphology, crystallinity and phase purity were investigated in this study. The specimen morphology was analyzed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). When the concentration of 1,4-dioxane was below 10%, micron-sized whisker was the dominant form. At 20-25% concentration of 1,4-dioxane, strontium phosphate chloride single-crystalline nanowire was 31±12 nm in diameter and 1.43±0.6 μm in length with an aspect ratio of 52.28±29.41. X-ray diffraction (XRD) pattern of this nanowire matched with that of strontium phosphate chloride (JCPDS #083-0973). When 1,4-dioxane concentration exceeded 25%, nanorod aggregate was the dominant form instead of nanowire. At 20-25% 1,4-dioxane concentration suitable strontium concentration combine with high chemical potential environment favors the formation of nanowires. By adding 1,4-dioxane impure phase such as β-strontium hydrogen phosphate, nanorod formation was suppressed. This method provides an efficient way to synthesize high aspect ratio strontium phosphate chloride nanowire. It has potential bioactive nanocomposite, high mechanical performance bioactive bone cement filler and fluorescent material applications.

  19. Controlling chloride ions diffusion in concrete.

    Science.gov (United States)

    Zeng, Lunwu; Song, Runxia

    2013-11-28

    The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle.

  20. Influence of compaction on chloride ingress

    NARCIS (Netherlands)

    Zlopasa, J.

    2012-01-01

    Experiences from practice show the need for more of an understanding and optimization of the compaction process in order to design a more durable concrete structure. Local variations in compaction are very often the reason for initiation of local damage and initiation of chloride induced corrosion.

  1. Liquid crystalline critical dynamics in decylammonium chloride

    CERN Document Server

    Lee, K W; Lee, C E; Kang, K H; Rhee, C; Kang, J K

    1999-01-01

    Collective chain dynamics and phase transitions in a model biomembrane, decylammonium chloride (C sub 1 sub 0 H sub 2 sub 1 NH sub 3 Cl), were studied by means of proton nuclear magnetic resonance. Our measurements sensitively reflect the critical dynamics associated with the smectic C to smectic A transition of the lipid bilayer.

  2. Chloride migration in concrete with superabsorbent polymers

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    2015-01-01

    Superabsorbent polymers (SAP) can be used as a means for internal curing of concrete. In the present study, the development of transport properties of concrete with SAP is investigated. The chloride migration coefficient according to NT BUILD 492 is used as a measure of this. Twenty concrete mixt...

  3. Gebromeerde vlamvertragers en broomdioxines in Choline Chloride

    NARCIS (Netherlands)

    Egmond, van H.J.; Traag, W.A.; Hoogenboom, L.A.P.

    2008-01-01

    Sinds begin 2008 worden in het Nationaal Plan Diervoeder Choline Chloride monsters (= diervoeder additief) gevonden waarbij de DR CALUX screenings-assay een sterk verdacht signaal geeft, maar bij de GC-HRMS geen dioxines en dl-PCB's worden gevonden. Dit rapport beschrijft de resultaten van nader ond

  4. Amperometric Sensor for Detection of Chloride Ions

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2008-09-01

    Full Text Available Chloride ion sensing is important in many fields such as clinical diagnosis, environmental monitoring and industrial applications. We have measured chloride ions at a carbon paste electrode (CPE and at a CPE modified with solid AgNO3, a solution of AgNO3 and/or solid silver particles. Detection limits (3 S/N for chloride ions were 100 μM, 100 μM and 10 μM for solid AgNO3, solution of AgNO3 and/or solid silver particles, respectively. The CPE modified with silver particles is the most sensitive to the presence chloride ions. After that we approached to the miniaturization of the whole electrochemical instrument. Measurements were carried out on miniaturized instrument consisting of a potentiostat with dimensions 35 × 166 × 125 mm, screen printed electrodes, a peristaltic pump and a PC with control software. Under the most suitable experimental conditions (Britton-Robinson buffer, pH 1.8 and working electrode potential 550 mV we estimated the limit of detection (3 S/N as 500 nM.

  5. 21 CFR 582.3845 - Stannous chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Stannous chloride. 582.3845 Section 582.3845 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  6. 29 CFR 1910.1017 - Vinyl chloride.

    Science.gov (United States)

    2010-07-01

    ... possible exposure conditions. (2) Protective garments shall be provided clean and dry for each use. (i... Required Authorized Personnel Only (3) Containers of polyvinyl chloride resin waste from reactors or other... which may be useful: A. For kidney dysfunction: urine examination for albumin, red blood cells,...

  7. Channel nut tool

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Marvin

    2016-01-12

    A method, system, and apparatus for installing channel nuts includes a shank, a handle formed on a first end of a shank, and an end piece with a threaded shaft configured to receive a channel nut formed on the second end of the shaft. The tool can be used to insert or remove a channel nut in a channel framing system and then removed from the channel nut.

  8. Spatial variability of chloride in concrete within homogeneously exposed areas

    NARCIS (Netherlands)

    Angst, U.M.; Polder, R.B.

    2014-01-01

    The concept of variability is increasingly considered in service life predictions. This paper reports experimental data on the spatial distribution of chloride in uncracked concrete subjected to homogeneous exposure. Chloride concentrations were measured with potentiometric sensors embedded in concr

  9. Viscosity and density tables of sodium chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fair, J.A.; Ozbek, H. (comps.)

    1977-04-01

    A file is presented containing tabulated data extracted from the scientific literature on the density and viscosity of aqueous sodium chloride solutions. Also included is a bibliography of the properties of aqueous sodium chloride solutions. (MHR)

  10. Hydrolysis of ferric chloride in solution

    Energy Technology Data Exchange (ETDEWEB)

    Lussiez, G.; Beckstead, L.

    1996-11-01

    The Detox{trademark} process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200{degrees}C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl{sub 3 liquid} + H{sub 2}O {r_arrow} FeOCl{sub solid} + 2 HCl{sub gas} During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOCl{sub solid} + H{sub 2}O {r_arrow} Fe{sub 2}O{sub 3 solid} + 2 HCl{sub gas}. The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way.

  11. Investigation of factors influencing chloride extraction efficiency during electrochemical chloride extraction from reinforcing concrete

    Science.gov (United States)

    Sharp, Stephen R.

    2005-11-01

    Electrochemical chloride extraction (ECE) is an accelerated bridge restoration method similar to cathodic protection, but operates at higher current densities and utilizes a temporary installation. Both techniques prolong the life of a bridge by reducing the corrosion rate of the reinforcing bar when properly applied. ECE achieves this by moving chlorides away from the reinforcement and out of the concrete while simultaneously increasing the alkalinity of the electrolyte near the reinforcing steel. Despite the proven success, significant use of ECE has not resulted in part due to an incomplete understanding in the following areas: (1) An estimation of the additional service life that can be expected following treatment when the treated member is again subjected to chlorides; (2) The cause of the decrease in current flow and, therefore, chloride removal rate during treatment; (3) Influence of water-to-cement (w/c) ratio and cover depth on the time required for treatment. This dissertation covers the research that is connected to the last two areas listed above. To begin examining these issues, plain carbon steel reinforcing bars (rebar) were embedded in portland cement concrete slabs of varying water-to-cement (w/c) ratios and cover depths, and then exposed to chlorides. A fraction of these slabs had sodium chloride added as an admixture, with all of the slabs subjected to cyclical ponding with a saturated solution of sodium chloride. ECE was then used to remove the chlorides from these slabs while making electrical measurements in the different layers between the rebar (cathode) and the titanium mat (anode) to follow the progress of the ECE process. During this study, it was revealed that the resistance of the outer concrete surface layer increases during ECE, inevitably restricting current flow, while the resistance of the underlying concrete decreases or remains constant. During ECE treatment, a white residue formed on the surface of the concrete. Analyses of the

  12. Aspergilli Response to Benzalkonium Chloride and Novel-Synthesized Fullerenol/Benzalkonium Chloride Nanocomposite

    OpenAIRE

    Nikola Unković; Milica Ljaljević Grbić; Miloš Stupar; Jelena Vukojević; Vesna Janković; Danica Jović; Aleksandar Djordjević

    2015-01-01

    A comprehensive comparative analysis of antifungal potential of benzalkonium chloride and newly synthesized fullerenol/benzalkonium chloride nanocomposite was conducted to assess the possible impact of carbon-based nanocarrier on antimicrobial properties of the commonly used biocide. Physical characterization of synthesized nanocomposite showed zeta potential of +37.4 mV and inhomogeneous particles size distribution, with nanocomposite particles’ dimensions within 30–143 nm and maximum number...

  13. Prenatal susceptibility to car