Fachbereich Veterinärmedizin


Service-Navigation

    Publikationsdatenbank

    Characterisation of an Anion Channel in the Rumen Epithelium (2008)

    Art
    Vortrag
    Autoren
    Stumpff, F
    Martens, H
    Gäbel, G
    Kongress
    18. Tagung der DVG-Fachgruppe Physiologie und Biochemie
    Leipzig, 09. – 11.03.2008
    Quelle
    Proceedings 18. Tagung der DVG-Fachgruppe Physiologie und Biochemie
    Leipzig, 2008 . Leipziger Blaue Hefte — S. 41
    Sprache
    Englisch
    Verweise
    URL (Volltext): http://www.vetmed.uni-leipzig.de/blaue-hefte/archiv/0004_DVG18-PhysiolBioch/free-online/LBH_DVG18-PhysiolBioch-Webversion.pdf
    Kontakt
    Institut für Veterinär-Physiologie

    Oertzenweg 19 b
    14163 Berlin
    +49 30 838 62600
    physiologie@vetmed.fu-berlin.de

    Abstract / Zusammenfassung

    Problem: Uptake of anions such as chloride and bicarbonate across the wall of the ovine and bovine
    rumen is essential for the maintanance of ruminal homeostasis and for balancing the salivary inflow of
    buffer. In a previous publication, we identified an anion conductance in isolated cells of the ruminal
    epithelium (Am J Physiol Gastrointest Liver Physiol 289: 3, G508-20, 2005). In the current study, we tried
    to characterize this conductance in more detail.
    Material and methods: Ruminal epithelial cells were isolated from ruminal tissue and cultured
    according to established methods. Whole cell and single channel currents were measured with the
    patch-clamp technique.
    Results: Cells were filled with a Na-gluconate solution and perfused with equimolar NaCl solution.
    When chloride was replaced with gluconate, outward current at 100 mV dropped to 33 ± 4% of the
    original value (n = 25) and cells were depolarised from -32 ± 1.2 mV to 2.9 ± 0.8 mV (p < 0.0001).
    Replacement of chloride with nitrate (130 mM or 65 mM) had no effect on outward current (105 ± 16%, n
    = 9 and 104 ± 11%, n = 4) or reversal potential (p > 0.05). Conversely, replacement of chloride by HCO3
    reduced outward current to 60 ± 6% and reduced reversal potential to -21 ± 2 mV (n = 6; p = 0.01 versus
    NaCl and p = 0.001 versus Na-gluconate). DIDS (1 mM and 100 &#956;mol) blocked outward current in NaCl
    solution to 44 ± 13% and 82 ± 7% (n = 16 and n = 5, respectively; p = 0.02 and p = 0.03). Excised inside
    out patch-clamp experiments in symmetrical and assymetrical NMDG-anion solutions revealed channels
    with a conductance of 350 ± 7 pS for chloride (n = 5).
    Conclusion: We conclude that isolated ruminal epithelial cells express anion channels with p(Cl-) &#8776;
    p(NO3-) > p(HCO3-) > p(gluconate-). We propose that these channels may play a role in the efflux of
    chloride and HCO3- across the basolateral membrane of the ruminal epithelium.