Atrial natriuretic peptide enhances activity of potassium conductance in adrenal glomerulosa cells

M. B. Ganz, J. J. Nee, C. M. Isales, P. Q. Barrett

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Aldosterone secretion from the adrenal glomerulosa (AG) cells is inhibited by atrial natriuretic peptide (ANP). Inasmuch as alterations in K+ conductance can modulate aldosterone secretion, the effect of ANP on intracellular K+ homeostasis was investigated. Intracellular K+ concentration ([K+](i)) of AG cells was assessed by spectrofluorometry using the K+-sensitive dye, K+-binding benzofuran isophthalate. The resting value of [K+](i) in AG cells was determined to be 120 ± 1.2 mM (n = 37) in a HCO3-free, N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered medium. Exposure of AG cells to ANP led to a dose-dependent, transient decrease in [K+](i), from 21 ± 3.2% (n = 7) at 100 pM to 31 ± 2.3% at 1 μM (n = 7). In the continued presence of ANP, a rapid recovery to near basal values of [K+](i) was attained within 90 s. Measurements of membrane voltage using the potential sensitive dye 1-3 (-sulfonatopropyl)-4-{β-(-(di-n- butylamino)-6-naphthyl)vinyl}-pyridinium betaine documented an accompanying change in membrane potential. Pretreatment of AG cells with barium (0.5 mM), tetraethylammonium (0.1 mM), charybdotoxin (100 nM), or ethylene glycol- bis(β-aminoethylether)-N,N,N',N'-tetraacetic acid (0.5 mM) blunted the ANP- induced decrease in [K+](i). ANP-(7-23), the ANP-C-receptor selective agonist, which does not elevate guanosine 3',5'-cyclic monophosphate (cGMP) did not alter [K+](i) in contrast to cGMP (50 μM), which did. We conclude that ANP via the activation of the ANP A receptor alters K+ homeostasis through a Ca2+-activatable K+-conductive pathway likely to be the maxi-K channel.

Original languageEnglish (US)
Pages (from-to)1357-1365
Number of pages9
JournalAM.J.PHYSIOL.
Volume266
Issue number5 part 1
DOIs
StatePublished - May 13 1994

Keywords

  • intracellular potassium
  • membrane potential
  • potassium-binding benzofuran isophthalate

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

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