Pflügers Archiv

, Volume 425, Issue 5–6, pp 552–554 | Cite as

Differential effects of tamoxifen and I on three distinguishable chloride currents activated in T84 intestinal cells

  • M. A. Valverde
  • G. M. Mintenig
  • F. V. Sepúlveda
Short Communication Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands


The whole-cell mode of the patch-clamp technique has been used to monitor ionic currents in T84 colonic carcinoma cells. The cells were stimulated by either a cAMP cocktail, ionomycin or hypotonicity. Sizeable currents with distinct kinetics were observed after the stimulation with the different agonists. These kinetically distinct Cl currents also presented a differential sensitivity to the anti-oestrogen Tamoxifen and to the halide I. Tamoxifen only inhibits the volume activated Cl current without affecting the other two. Substitution of extracellular Cl by I shifted the reversal potential towards more negative values both in the hypotonicity and ionomycin activated Cl currents. The cAMP activated current responded to the Cl substitution by I with a blockade of both outward and inward currents, in addition to the displacement of the zero current level towards positive values. Thus, the use of these two simple tools, I and tamoxifen, allows the distinction of Cl channels in epithelial cells.

Key words

Cl channels CFTR calcium-activated Cl channels volume regulated channels Iodide Tamoxifen T84 


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Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • M. A. Valverde
    • 1
  • G. M. Mintenig
    • 1
  • F. V. Sepúlveda
    • 1
  1. 1.Department of Cellular PhysiologyAFRC Babraham InstituteCambridge

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