The Journal of Membrane Biology

, Volume 135, Issue 3, pp 289–295 | Cite as

Na+ and Cl conductances are controlled by cytosolic Cl concentration in the intralobular duct cells of mouse mandibular glands

  • A. Dinudom
  • J. A. Young
  • D. I. Cook


Our previously published whole-cell patch-clamp studies on the cells of the intralobular (granular) ducts of the mandibular glands of male mice revealed the presence of an amiloride-sensitive Na+ conductance in the plasma membrane. In this study we demonstrate the presence also of a Cl conductance and we show that the sizes of both conductances vary with the Cl concentration of the fluid bathing the cytosolic surface of the plasma membrane. As the cytosolic Cl concentration rises from 5 to 150 mmol/liter, the size of the inward Na+ current declines, the decline being half-maximal when the Cl concentration is approximately 50 mmol/liter. In contrast, as cytosolic Cl concentration increases, the inward Cl current remains at a constant low level until the Cl concentration exceeds 80 mmol/liter, when it begins to increase. Studies in which Cl in the pipette solution was replaced by other anions indicate that the Na+ current is suppressed by intracellular Br-, Cl and NO 3 - but not by intracellular I-, glutamate or gluconate. Our studies also show that the Cl conductance allows passage of Cl and Br- equally well, I-less well, and NO 3 - , glutamate and gluconate poorly, if at all. The findings with NO 3 - are of particular interest because they show that suppression of the Na+ current by a high intracellular concentration of a particular anion does not depend on actual passage of that anion through the Cl conductance. In mouse granular duct cells there is, thus, a reciprocal regulation of Na+ and Cl conductances by the cytosolic Cl concentration. Since the cytosolic Cl concentration is closely correlated with cell volume in many epithelia, this reciprocal regulation of Na+ and Cl conductances may provide a mechanism by which ductal Na+ and Cl transport rates are adjusted so as to maintain a stable cell volume.

Key words

Na+ and Cl conductance Amiloride Intralobular ducts Mouse mandibular glands 


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Copyright information

© Springer-Verlag New York Inc. 1993

Authors and Affiliations

  • A. Dinudom
    • 1
  • J. A. Young
    • 1
  • D. I. Cook
    • 1
  1. 1.Department of Physiology (F-13)University of SydneyAustralia

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