LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 19

Search options

  1. Article ; Online: Calmodulin Antagonist W-7 Enhances Intermediate Conductance Ca

    Bowley, Kate A / Sandle, Geoffrey I

    The Journal of membrane biology

    2021  Volume 254, Issue 4, Page(s) 423–428

    Abstract: Intermediate conductance potassium ( ... ...

    Abstract Intermediate conductance potassium (IK
    MeSH term(s) Calmodulin/metabolism ; Calmodulin/pharmacology ; Colon/metabolism ; Humans ; Potassium Channel Blockers/pharmacology ; Potassium Channels/metabolism ; Sulfonamides
    Chemical Substances Calmodulin ; Potassium Channel Blockers ; Potassium Channels ; Sulfonamides ; W 7 (65595-90-6)
    Language English
    Publishing date 2021-07-27
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 3082-x
    ISSN 1432-1424 ; 0022-2631
    ISSN (online) 1432-1424
    ISSN 0022-2631
    DOI 10.1007/s00232-021-00193-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Is intestinal transport dysfunctional in COVID-19-related diarrhea?

    Sandle, Geoffrey I / Herod, Morgan R / Fontana, Juan / Lippiat, Jonathan D / Stockley, Peter G

    American journal of physiology. Gastrointestinal and liver physiology

    2023  Volume 324, Issue 5, Page(s) G415–G418

    Abstract: Diarrhea, often severe, is a recognized and frequently early symptom during acute COVID-19 infection and may persist or develop for the first time in patients with long-COVID, with socioeconomic consequences. Diarrheal mechanisms in these cases are ... ...

    Abstract Diarrhea, often severe, is a recognized and frequently early symptom during acute COVID-19 infection and may persist or develop for the first time in patients with long-COVID, with socioeconomic consequences. Diarrheal mechanisms in these cases are poorly understood. There is evidence for disruption of intestinal epithelial barrier function and also for changes in the gut microbiome, which is critical for gut immunity and metabolism. Whether the SARS-CoV-2 virus has adverse effects on intestinal transport proteins is unclear. However, the ability of the virus to inhibit expression and activity of an aldosterone-regulated epithelial sodium (Na
    MeSH term(s) Humans ; COVID-19 ; SARS-CoV-2/metabolism ; Epithelial Sodium Channels/metabolism ; Post-Acute COVID-19 Syndrome ; Diarrhea
    Chemical Substances Epithelial Sodium Channels
    Language English
    Publishing date 2023-03-28
    Publishing country United States
    Document type Editorial
    ZDB-ID 603840-2
    ISSN 1522-1547 ; 0193-1857
    ISSN (online) 1522-1547
    ISSN 0193-1857
    DOI 10.1152/ajpgi.00021.2023
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: Colonic Potassium Absorption and Secretion in Health and Disease.

    Rajendran, Vazhaikkurichi M / Sandle, Geoffrey I

    Comprehensive Physiology

    2018  Volume 8, Issue 4, Page(s) 1513–1536

    Abstract: The colon has large capacities for ... ...

    Abstract The colon has large capacities for K
    MeSH term(s) Animals ; Colon/metabolism ; Humans ; Intestinal Absorption ; Potassium/metabolism ; Potassium Channels/metabolism
    Chemical Substances Potassium Channels ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2018-09-14
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Review
    ISSN 2040-4603
    ISSN (online) 2040-4603
    DOI 10.1002/cphy.c170030
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Infective and inflammatory diarrhoea: mechanisms and opportunities for novel therapies.

    Sandle, Geoffrey I

    Current opinion in pharmacology

    2011  Volume 11, Issue 6, Page(s) 634–639

    Abstract: There have been significant advances in unravelling the cellular mechanisms of diarrhoea in common gut infections and colonic inflammation, as well as in the identification of targets for potential antidiarrhoeal drugs. Infective diarrhoea reflects ... ...

    Abstract There have been significant advances in unravelling the cellular mechanisms of diarrhoea in common gut infections and colonic inflammation, as well as in the identification of targets for potential antidiarrhoeal drugs. Infective diarrhoea reflects activation of electrogenic Cl⁻ secretion, inhibition of electroneutral NaCl absorption and in some cases, downregulation of tight junctional proteins and increased apoptosis. In colonic inflammation, diarrhoea mainly reflects impairment of colonic Na⁺ and Cl⁻ absorption by inflammatory cytokines, leading to decreased water absorption. Stimulation of endogenous opiate-dependent pathways, manipulation of epithelial ion (Na⁺, K⁺ and Cl⁻) channels and suppression of proinflammatory cytokine production by a variety of drugs and novel molecules, offer opportunities to move evaluation of these potential antisecretory and anti-inflammatory agents from the laboratory into clinical trials.
    MeSH term(s) Animals ; Anti-Inflammatory Agents/pharmacology ; Anti-Inflammatory Agents/therapeutic use ; Antidiarrheals/pharmacology ; Antidiarrheals/therapeutic use ; Cytokines/metabolism ; Diarrhea/etiology ; Diarrhea/prevention & control ; Dysentery/drug therapy ; Dysentery/metabolism ; Dysentery/physiopathology ; Humans ; Inflammatory Bowel Diseases/drug therapy ; Inflammatory Bowel Diseases/metabolism ; Inflammatory Bowel Diseases/physiopathology ; Intestinal Mucosa/drug effects ; Intestinal Mucosa/metabolism ; Ion Channels/agonists ; Ion Channels/antagonists & inhibitors ; Molecular Targeted Therapy ; Signal Transduction/drug effects
    Chemical Substances Anti-Inflammatory Agents ; Antidiarrheals ; Cytokines ; Ion Channels
    Language English
    Publishing date 2011-12
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2037057-X
    ISSN 1471-4973 ; 1471-4892
    ISSN (online) 1471-4973
    ISSN 1471-4892
    DOI 10.1016/j.coph.2011.09.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Liddle-Mutation of the β-Subunit, but not the γ-Subunit, Attenuates Protein Kinase C-Mediated Inhibition of Human Epithelial Sodium Channels (hENaC).

    Robins, Gerard G / Sandle, Geoffrey I

    The Journal of membrane biology

    2016  Volume 249, Issue 3, Page(s) 271–279

    Abstract: Mammalian distal nephron and distal colon, prime sites for Na(+) homeostasis, contain amiloride-sensitive epithelial sodium channels (ENaC). Protein kinase C (PKC) inhibits ENaC by phosphorylating serine and threonine residues within COOH termini of the ... ...

    Abstract Mammalian distal nephron and distal colon, prime sites for Na(+) homeostasis, contain amiloride-sensitive epithelial sodium channels (ENaC). Protein kinase C (PKC) inhibits ENaC by phosphorylating serine and threonine residues within COOH termini of the β- and/or γ-subunits. Although some of these phosphorylation sites are close to the PY motifs, it is unclear whether they remain susceptible to PKC in Liddle-mutated ENaC β- and/or γ-subunits, where PY motifs are truncated, resulting in increased apical ENaC expression. We therefore studied the effects of PKC in wild-type and Liddle-mutated human epithelial Na(+) channels (hENaC) expressed in Xenopus oocytes, using the dual-electrode voltage clamp technique. PKC activation using 500 nmol/l phorbol 12-myristate 13-acetate (PMA) decreased amiloride-sensitive Na(+) currents by 80 % in oocytes expressing wild-type hENaC, an effect largely prevented by co-exposure to 50 µmol/l calphostin C (a specific inhibitor of PKC), whereas 500 nmol/l phorbol didecanoate (PDD), an inactive phorbol ester which does not stimulate PKC, had no effect. In oocytes expressing hENaC containing the Liddle-mutated β-subunit, PMA elicited a 54 % decrease in amiloride-sensitive Na(+) currents, significantly (P < 0.0025) less than that in oocytes expressing wild-type hENaC. By contrast, in oocytes expressing hENaC containing the Liddle-mutated γ-subunit, PMA elicited a 68 % decrease in amiloride-sensitive Na(+) current, similar (P = 0.10) to that in oocytes expressing wild-type hENaC. We conclude that hENaC incorporating the Liddle-mutated β-subunit lacks one or more PKC phosphorylation sites, thereby significantly reducing the inhibitory effect of PKC on Na(+) channel activity, whereas hENaC incorporating Liddle-mutated γ-subunits remains as susceptible to PKC as wild-type hENaC.
    MeSH term(s) Animals ; Epithelial Sodium Channels/metabolism ; Humans ; Kidney/metabolism ; Mutation ; Naphthalenes/pharmacology ; Oocytes/metabolism ; Patch-Clamp Techniques ; Phorbol Esters/pharmacology ; Protein Interaction Domains and Motifs/genetics ; Protein Kinase C/chemistry ; Protein Kinase C/genetics ; Protein Kinase C/metabolism ; Protein Subunits/genetics ; Protein Subunits/metabolism ; Xenopus laevis
    Chemical Substances Epithelial Sodium Channels ; Naphthalenes ; Phorbol Esters ; Protein Subunits ; phorbol-12-myristate (20839-06-9) ; Protein Kinase C (EC 2.7.11.13) ; calphostin C (I271P23G24)
    Language English
    Publishing date 2016
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 3082-x
    ISSN 1432-1424 ; 0022-2631
    ISSN (online) 1432-1424
    ISSN 0022-2631
    DOI 10.1007/s00232-015-9866-x
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Calcium rapidly down-regulates human renal epithelial sodium channels via a W-7-sensitive mechanism.

    Robins, Gerard G / Sandle, Geoffrey I

    The Journal of membrane biology

    2014  Volume 247, Issue 8, Page(s) 729–737

    Abstract: Increases in intracellular calcium (Ca(2+)) inhibit renal sodium (Na(+)) absorption in cortical collecting ducts, but the precise mechanism is unclear. We, therefore, studied the effects of raising intracellular Ca(2+) (using 10 µmol/L A23187, a Ca(2+) ... ...

    Abstract Increases in intracellular calcium (Ca(2+)) inhibit renal sodium (Na(+)) absorption in cortical collecting ducts, but the precise mechanism is unclear. We, therefore, studied the effects of raising intracellular Ca(2+) (using 10 µmol/L A23187, a Ca(2+) ionophore) on wild-type and Liddle-mutated human epithelial Na(+) channels (hENaC) expressed in Xenopus oocytes, using the dual-electrode voltage clamp technique. A23187 decreased amiloride-sensitive Na(+) current by 55% in oocytes expressing wild-type hENaC, an effect prevented by co-exposure to 50 μmol/L W-7 (to inhibit the Ca(2+)/calmodulin complex). By contrast, co-exposure to 50 μmol/L calphostin (to inhibit protein kinase C) or 5 μmol/L KN-62 (to inhibit Ca(2+)/calmodulin-dependent protein kinase II) had no effect on the decrease in amiloride-sensitive Na(+) current elicited by A23187 alone. Whereas A23187 reduced amiloride-sensitive Na(+) current in oocytes expressing wild-type hENaC, it had no similar effect in those expressing Liddle-mutated hENaCs, suggesting that the activity of individual Na(+) channels in situ was unchanged by the rise in intracellular Ca(2+). These data suggest that the A23187-induced rise in intracellular Ca(2+) inhibited wild-type hENaC through a W-7-sensitive mechanism, which likely reflected enhanced removal of Na(+) channels from the cell membrane by endocytosis. We, therefore, propose that Na(+) absorption in cortical collecting duct cells is inhibited by Ca(2+), possibly when complexed with calmodulin.
    MeSH term(s) Animals ; Calcium/pharmacology ; Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors ; Cell Membrane/drug effects ; Cell Membrane/metabolism ; Endocytosis/drug effects ; Endocytosis/physiology ; Enzyme Inhibitors/pharmacology ; Epithelial Sodium Channels/chemistry ; Epithelial Sodium Channels/metabolism ; Female ; Humans ; Kidney/cytology ; Kidney/drug effects ; Kidney/metabolism ; Oocytes/cytology ; Oocytes/drug effects ; Oocytes/metabolism ; Patch-Clamp Techniques ; Sodium/metabolism ; Sulfonamides/pharmacology ; Xenopus laevis
    Chemical Substances Enzyme Inhibitors ; Epithelial Sodium Channels ; Sulfonamides ; W 7 (65595-90-6) ; Sodium (9NEZ333N27) ; Calcium-Calmodulin-Dependent Protein Kinases (EC 2.7.11.17) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2014-07-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 3082-x
    ISSN 1432-1424 ; 0022-2631
    ISSN (online) 1432-1424
    ISSN 0022-2631
    DOI 10.1007/s00232-014-9698-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article: Infective and inflammatory diarrhoea: mechanisms and opportunities for novel therapies

    Sandle, Geoffrey I

    Current opinion in pharmacology. 2011 Dec., v. 11, no. 6

    2011  

    Abstract: There have been significant advances in unravelling the cellular mechanisms of diarrhoea in common gut infections and colonic inflammation, as well as in the identification of targets for potential antidiarrhoeal drugs. Infective diarrhoea reflects ... ...

    Abstract There have been significant advances in unravelling the cellular mechanisms of diarrhoea in common gut infections and colonic inflammation, as well as in the identification of targets for potential antidiarrhoeal drugs. Infective diarrhoea reflects activation of electrogenic Cl⁻ secretion, inhibition of electroneutral NaCl absorption and in some cases, downregulation of tight junctional proteins and increased apoptosis. In colonic inflammation, diarrhoea mainly reflects impairment of colonic Na⁺ and Cl⁻ absorption by inflammatory cytokines, leading to decreased water absorption. Stimulation of endogenous opiate-dependent pathways, manipulation of epithelial ion (Na⁺, K⁺ and Cl⁻) channels and suppression of proinflammatory cytokine production by a variety of drugs and novel molecules, offer opportunities to move evaluation of these potential antisecretory and anti-inflammatory agents from the laboratory into clinical trials.
    Keywords absorption ; anti-inflammatory agents ; apoptosis ; clinical trials ; cytokines ; diarrhea ; digestive system ; inflammation ; potassium ; proteins ; secretion ; sodium ; sodium chloride
    Language English
    Dates of publication 2011-12
    Size p. 634-639.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 2037057-X
    ISSN 1471-4973 ; 1471-4892
    ISSN (online) 1471-4973
    ISSN 1471-4892
    DOI 10.1016/j.coph.2011.09.005
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  8. Article ; Online: Cyclic AMP-induced K+ secretion occurs independently of Cl- secretion in rat distal colon.

    Sandle, Geoffrey I / Rajendran, Vazhaikkurichi M

    American journal of physiology. Cell physiology

    2012  Volume 303, Issue 3, Page(s) C328–33

    Abstract: cAMP induces both active Cl(-) and active K(+) secretion in mammalian colon. It is generally assumed that a mechanism for K(+) exit is essential to maintain cells in the hyperpolarized state, thus favoring a sustained Cl(-) secretion. Both Kcnn4c and ... ...

    Abstract cAMP induces both active Cl(-) and active K(+) secretion in mammalian colon. It is generally assumed that a mechanism for K(+) exit is essential to maintain cells in the hyperpolarized state, thus favoring a sustained Cl(-) secretion. Both Kcnn4c and Kcnma1 channels are located in colon, and this study addressed the questions of whether Kcnn4c and/or Kcnma1 channels mediate cAMP-induced K(+) secretion and whether cAMP-induced K(+) secretion provides the driving force for Cl(-) secretion. Forskolin (FSK)-enhanced short-circuit current (indicator of net electrogenic ion transport) and K(+) fluxes were measured simultaneously in colonic mucosa under voltage-clamp conditions. Mucosal Na(+) orthovanadate (P-type ATPase inhibitor) inhibited active K(+) absorption normally present in rat distal colon. In the presence of mucosal Na(+) orthovanadate, serosal FSK induced both K(+) and Cl(-) secretion. FSK-induced K(+) secretion was 1) not inhibited by either mucosal or serosal 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34; a Kcnn4 channel blocker), 2) inhibited (92%) by mucosal iberiotoxin (Kcnma1 channel blocker), and 3) not affected by mucosal cystic fibrosis transmembrane conductance regulator inhibitor (CFTR(inh)-172). By contrast, FSK-induced Cl(-) secretion was 1) completely inhibited by serosal TRAM-34, 2) not inhibited by either mucosal or serosal iberiotoxin, and 3) completely inhibited by mucosal CFTR(inh)-172. These results indicate that cAMP-induced colonic K(+) secretion is mediated via Kcnma1 channels located in the apical membrane and most likely contributes to stool K(+) losses in secretory diarrhea. On the other hand, cAMP-induced colonic Cl(-) secretion requires the activity of Kcnn4b channels located in the basolateral membrane and is not dependent on the concurrent activation of apical Kcnma1 channels.
    MeSH term(s) Animals ; Chlorides/metabolism ; Colforsin/pharmacology ; Colon/drug effects ; Colon/metabolism ; Cyclic AMP/metabolism ; Cystic Fibrosis Transmembrane Conductance Regulator/antagonists & inhibitors ; Cystic Fibrosis Transmembrane Conductance Regulator/metabolism ; Intermediate-Conductance Calcium-Activated Potassium Channels/antagonists & inhibitors ; Intermediate-Conductance Calcium-Activated Potassium Channels/metabolism ; Intestinal Mucosa/drug effects ; Intestinal Mucosa/metabolism ; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/antagonists & inhibitors ; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism ; Male ; Peptides/pharmacology ; Potassium/metabolism ; Pyrazoles/pharmacology ; Rats ; Rats, Sprague-Dawley ; Vanadates/pharmacology
    Chemical Substances Chlorides ; Intermediate-Conductance Calcium-Activated Potassium Channels ; Kcnma1 protein, rat ; Kcnn4 protein, rat ; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits ; Peptides ; Pyrazoles ; TRAM 34 ; Cystic Fibrosis Transmembrane Conductance Regulator (126880-72-6) ; Colforsin (1F7A44V6OU) ; Vanadates (3WHH0066W5) ; iberiotoxin (773HER9B6T) ; Cyclic AMP (E0399OZS9N) ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2012-05-30
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 392098-7
    ISSN 1522-1563 ; 0363-6143
    ISSN (online) 1522-1563
    ISSN 0363-6143
    DOI 10.1152/ajpcell.00099.2012
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article: Pathogenesis of diarrhea in ulcerative colitis: new views on an old problem.

    Sandle, Geoffrey I

    Journal of clinical gastroenterology

    2005  Volume 39, Issue 4 Suppl 2, Page(s) S49–52

    Abstract: Background: Whereas water movement into the intestinal lumen occurs secondary to Cl secretion in secretory diarrheal diseases, defects in key transport processes lead to profound decreases in colonic Na, Cl, and water absorption in ulcerative colitis.!## ...

    Abstract Background: Whereas water movement into the intestinal lumen occurs secondary to Cl secretion in secretory diarrheal diseases, defects in key transport processes lead to profound decreases in colonic Na, Cl, and water absorption in ulcerative colitis.
    Studies and results: Recent studies indicate reduced expression/activity of apical Na channels and basolateral Na, K-ATPase, leading to loss of electrogenic Na absorption in the distal colon and rectum. There is also likely to be a decrease in electroneutral NaCl cotransport, which is present throughout the colon. Preliminary work on basolateral K channel abundance and activity in colonic epithelial cells suggests that whole-cell K conductance is decreased in ulcerative colitis, leading to epithelial cell depolarization, and further limitation of Na absorption. In addition, there is a marked reduction in colonic epithelial resistance, which reflects a decrease in the integrity of intercellular tight junctions and the presence of apoptotic foci.
    Conclusions: Impaired Na and Cl transport, combined with enhanced epithelial "leakiness," results in a profound decrease in the capacity of the inflamed colon to absorb salt and water. Transport abnormalities in ulcerative colitis may at least partly reflect the effects of proinflammatory cytokines, raising the possibility of novel approaches to the restoration of colonic absorptive capacity in this disease.
    MeSH term(s) Biological Transport ; Chlorides/metabolism ; Colitis, Ulcerative/complications ; Colitis, Ulcerative/physiopathology ; Diarrhea/etiology ; Diarrhea/physiopathology ; Humans ; Intestinal Absorption/physiology ; Potassium/metabolism ; Sodium/metabolism ; Water-Electrolyte Balance
    Chemical Substances Chlorides ; Sodium (9NEZ333N27) ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2005-01-28
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 448460-5
    ISSN 1539-2031 ; 0192-0790
    ISSN (online) 1539-2031
    ISSN 0192-0790
    DOI 10.1097/01.mcg.0000155520.04253.37
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Parallel intermediate conductance K

    Rehman, Shabina / Narayanan, Karthikeyan / Nickerson, Andrew J / Coon, Steven D / Hoque, Kazi Mirajul / Sandle, Geoffrey I / Rajendran, Vazhaikkurichi M

    American journal of physiology. Gastrointestinal and liver physiology

    2020  Volume 319, Issue 2, Page(s) G142–G150

    Abstract: Transepithelial ... ...

    Abstract Transepithelial K
    MeSH term(s) Animals ; Chloride Channels/genetics ; Chloride Channels/metabolism ; Chlorides/metabolism ; Colon/physiology ; Female ; Intestinal Mucosa/metabolism ; Ion Transport ; Male ; Patch-Clamp Techniques ; Potassium/metabolism ; Potassium Channels/genetics ; Potassium Channels/metabolism ; Protein Transport ; Rats ; Rats, Sprague-Dawley
    Chemical Substances Chloride Channels ; Chlorides ; Potassium Channels ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2020-06-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 603840-2
    ISSN 1522-1547 ; 0193-1857
    ISSN (online) 1522-1547
    ISSN 0193-1857
    DOI 10.1152/ajpgi.00011.2020
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top