Vasopressin increases density of apical low-conductance K+ channels in rat CCD

Am J Physiol. 1993 Mar;264(3 Pt 2):F502-9. doi: 10.1152/ajprenal.1993.264.3.F502.

Abstract

The effect of arginine vasopressin (AVP) on the low-conductance K+ channel in the apical membrane of rat cortical collecting duct (CCD) principal cells from animals on a control and high-K+ diet was studied using patch-clamp techniques. AVP stimulated apical low-conductance K+ channel activity in both control and high-K+ animals: application of 110-220 pM AVP induced a significant increase in the density of low-conductance K+ channels. In the presence of phosphodiesterase inhibitor (3-isobutyl-1-methylxanthine), administration of 22 pM AVP also increased channel activity. The action of AVP on low-conductance K+ channel activity was mimicked by simultaneous application of forskolin and 3-isobutyl-1-methylxanthine. Exogenously applied N6,2'-O-dibutyryladenosine 3',5'-cyclic monophosphate (dibutyryl-cAMP, 0.4-0.8 mM) also increased apical low-conductance K+ channel activity. Since channel open probability (Po) was almost saturated in the absence of AVP, the increase of channel activity induced by AVP, forskolin, and dibutyryl-cAMP resulted predominantly from stimulating previously silent K+ channels. We conclude that AVP induces an increase of low-conductance K+ channel activity of principal cells in rat CCD by the stimulation of cAMP-dependent protein kinase. The AVP-induced increase of low-conductance K+ channel activity can thus significantly contribute to the hormone-induced K+ secretion in the rat CCD.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 1-Methyl-3-isobutylxanthine / pharmacology
  • Animals
  • Arginine Vasopressin / pharmacology*
  • Bucladesine / pharmacology
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism
  • Electric Conductivity
  • Female
  • Kidney Cortex / metabolism*
  • Kidney Tubules, Collecting / metabolism*
  • Kinetics
  • Male
  • Phosphorylation
  • Potassium Channels / drug effects
  • Potassium Channels / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Potassium Channels
  • Arginine Vasopressin
  • Colforsin
  • Bucladesine
  • Cyclic AMP
  • 1-Methyl-3-isobutylxanthine