The Journal of Membrane Biology

, Volume 180, Issue 2, pp 111–121 | Cite as

l-Arginine Effects on Na+ Transport in M-1 Mouse Cortical Collecting Duct Cells—A Cationic Amino Acid Absorbing Epithelium

  • D.P.J.  Howard
  • J.E.  Cuffe
  • C.A.R.  Boyd
  • C.  Korbmacher

Abstract.

The effect of l-arginine on transepithelial ion transport was examined in cultured M-1 mouse renal cortical collecting duct (CCD) cells using continuous short circuit current (ISC) measurements in HCO3/CO2 buffered solution. Steady state ISC averaged 73.8 ± 3.2 μA/cm2 (n= 126) and was reduced by 94 ± 0.6% (n= 16) by the apical addition of 100 μm amiloride. This confirms that the predominant electrogenic ion transport in M-1 cells is Na+ absorption via the epithelial sodium channel (ENaC). Experiments using the cationic amino acid l-lysine (radiolabeled) as a stable arginine analogue show that the combined activity of an apical system y+ and a basal amino acid transport system y+L are responsible for most cationic amino acid transport across M-1 cells. Together they generate net absorptive cationic amino acid flux. Application of l-arginine (10 mm) either apically or basolaterally induced a transient peak increase in ISC averaging 36.6 ± 5.4 μA/cm2 (n= 19) and 32.0 ± 7.2 μA/cm2 (n= 8), respectively. The response was preserved in the absence of bath Cl (n= 4), but was abolished either in the absence of apical Na+ (n= 4) or by apical addition of 100 μm amiloride (n= 6). l-lysine, which cannot serve as a precursor of NO, caused a response similar to that of l-arginine (n= 4); neither L-NMMA (100 μm; n= 3) nor L-NAME (1 mm; n= 4) (both NO-synthase inhibitors) affected the ISC response to l-arginine. The effects of arginine or lysine were replicated by alkalinization that mimicked the transient alkalinization of the bath solution upon addition of these amino acids. We conclude that in M-1 cells l-arginine stimulates Na+ absorption via a pH-dependent, but NO-independent mechanism. The observed net cationic amino acid absorption will counteract passive cationic amino acid leak into the CCD in the presence of electrogenic Na+ transport, consistent with reports of stimulated expression of Na+ and cationic amino acid transporters by aldosterone.

Key words: Renal collecting duct — Amiloride — Epithelial sodium channel (ENaC) — Nitric oxide (NO) — pH — Cationic amino acid transport — System y+— System y+L 

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Copyright information

© 2001 Springer-Verlag New York Inc.

Authors and Affiliations

  • D.P.J.  Howard
    • 1
  • J.E.  Cuffe
    • 1
  • C.A.R.  Boyd
    • 2
  • C.  Korbmacher
    • 1
  1. 1.University Laboratory of Physiology, Oxford University, Parks Road, Oxford, OX1 3PT, UKGB
  2. 2.Department of Human Anatomy and Genetics, Oxford University, South Parks Road, OX1 3QX, UKGB

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