Nom du corpus

Corpus Systématique Animale

Titre du document

Basolateral electrogenic Na/HCO3 symport in the amphibian distal tubule

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Springer (journals)
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Mots-clés d'auteur
  • Distal tubule
  • Amphibian
  • Double selective microelectrodes
  • Methazolamide
  • Na/(HCO3) n >1 cotransport
  • Basolateral membrane
Nom du fichier dans la ressource
  • Gabrielle Planelles 1
  • Takis Anagnostopoulos 1
  • 1) INSERM U. 323, CHU Necker Enfants-Malades, 156 Rue de Vaugirard, F-75730, Paris Cédex 15, France

This study was carried out to assess whether the amphibian distal tubule possesses a basolateral Na/ (HCO3) n>1 cotransport. The experiments were performed in the kidney of Necturus maculosus in vivo, by means of double-barreled selective microelectrodes. Basolateral membrane potential (V m), intracellular pH (pHi), intracellular sodium activity (?Nai) and intracellular chloride activity (?Cli), were recorded during selected disturbances of peritubular fluid composition. The following results were obtained, (a) A sudden decrease of [HCO3]0 leads to V m depolarization, intracellular acidification and decrease of ?Nai. (b) A rapid fall of [Na]0 elicits V m depolarization and decreases pHi; these patterns are not substantially altered in the presence of millimolar amiloride concentrations or in the nominal absence of peritubular Cl. (c) An acute decrease of [Na]o does not alter ?Cli. (d) In the functional absence of CO2/ HCO3 buffer (nominally CO2-free solution plus methazolamide), the reduction of [Na]0 has no effect on V m and/or pHi. We conclude that the distal tubule basolateral cell membrane is endowed with an electrogenic chlorid-eindependent Na/base carrier, mediating Na and base efflux. The blockade of this carrier by carbonic anhydrase inhibitor indicates that the cotransported base is HCO3 or a related species.

Catégories Science-Metrix
  • 1 - health sciences
  • 2 - biomedical research
  • 3 - physiology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - biochimie analytique, structurale et metabolique
Catégories Scopus
  • 1 - Health Sciences ; 2 - Medicine ; 3 - Physiology (medical)
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Clinical Biochemistry
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Physiology
Catégories WoS
  • 1 - science ; 2 - physiology
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  • Batraciens
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