Time-dependent stimulation by aldosterone of blocker-sensitive ENaCs in A6 epithelia

Sandy I. Helman, Xuehong Liu, Kieron Baldwin, Bonnie L. Blazer-Yost, Willem J. Els

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

To study and define the early time-dependent response (≤6 h) of blocker-sensitive epithelial Na+ channels (ENaCs) to stimulation of Na+ transport by aldosterone, we used a new modified method of blocker-induced noise analysis to determine the changes of single-channel current (i(Na)) channel open probability (P(o)), and channel density (N(T)) under transient conditions of transport as measured by macroscopic short-circuit currents (I(sc)). In three groups of experiments in which spontaneous baseline rates of transport averaged 1.06, 5.40, and 15.14 μA/cm2, stimulation of transport occurred due to increase of blocker-sensitive channels. N(T) varied linearly over a 70-fold range of transport (0.5-35 μA/cm2). Relatively small and slow time-dependent but aldosterone-independent decreases of P(o) occurred during control (10-20% over 2 h) and aldosterone experimental periods (10-30% over 6 h). When the P(o) of control and aldosterone-treated tissues was examined over the 70-fold extended range of Na+ transport, P(o) was observed to vary inversely with I(sc), falling from ~0.5 to ~0.15 at the highest rates of Na+ transport or ~25% per 3-fold increase of transport. Because decreases of P(o) from any source cannot explain stimulation of transport by aldosterone, it is concluded that the early time- dependent stimulation of Na+ transport in A6 epithelia is due exclusively to increase of apical membrane N(T).

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume274
Issue number4 43-4
StatePublished - Apr 1998
Externally publishedYes

Fingerprint

Epithelial Sodium Channels
Aldosterone
Epithelium
Short circuit currents
Noise
Tissue
Membranes
Experiments

Keywords

  • Amiloride
  • Cortical collecting ducts
  • Electrophysiology
  • Epithelial sodium channels
  • Kidney
  • Noise analysis
  • Tissue culture

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology
  • Physiology (medical)

Cite this

Helman, S. I., Liu, X., Baldwin, K., Blazer-Yost, B. L., & Els, W. J. (1998). Time-dependent stimulation by aldosterone of blocker-sensitive ENaCs in A6 epithelia. American Journal of Physiology - Cell Physiology, 274(4 43-4).

Time-dependent stimulation by aldosterone of blocker-sensitive ENaCs in A6 epithelia. / Helman, Sandy I.; Liu, Xuehong; Baldwin, Kieron; Blazer-Yost, Bonnie L.; Els, Willem J.

In: American Journal of Physiology - Cell Physiology, Vol. 274, No. 4 43-4, 04.1998.

Research output: Contribution to journalArticle

Helman, SI, Liu, X, Baldwin, K, Blazer-Yost, BL & Els, WJ 1998, 'Time-dependent stimulation by aldosterone of blocker-sensitive ENaCs in A6 epithelia', American Journal of Physiology - Cell Physiology, vol. 274, no. 4 43-4.
Helman, Sandy I. ; Liu, Xuehong ; Baldwin, Kieron ; Blazer-Yost, Bonnie L. ; Els, Willem J. / Time-dependent stimulation by aldosterone of blocker-sensitive ENaCs in A6 epithelia. In: American Journal of Physiology - Cell Physiology. 1998 ; Vol. 274, No. 4 43-4.
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