TASK-3 dominates the background potassium conductance in rat adrenal glomerulosa cells

Mol Endocrinol. 2002 Mar;16(3):621-9. doi: 10.1210/mend.16.3.0788.


In a preceding study we showed that the highly negative resting membrane potential of rat adrenal glomerulosa cells is related to background potassium channel(s), which belong to the two-pore domain channel family. TWIK-related acid-sensitive K+ channel (TASK-1) expression was found in glomerulosa tissue, and the currents elicited by injection of glomerulosa mRNA (I(glom)) or TASK-1 cRNA (I(TASK-1)) showed remarkable similarity in Xenopus laevis oocytes. However, based on the different sensitivity of these currents to acidification, we concluded that TASK-1 may be responsible for a maximum of 25% of the weakly pH-dependent glomerulosa background K+ current. Here we demonstrate that TASK-3, a close relative of TASK-1, is expressed abundantly in glomerulosa cells. Northern blot detected TASK-3 message in adrenal glomerulosa, but not in other tissues. Quantitative RT-PCR experiments indicated even higher mRNA expression of TASK-3 than TASK-1 in glomerulosa tissue. Similarly to the glomerulosa background current, the current expressed by injection of TASK-3 cRNA (I(TASK-3)) was less acid-sensitive than I(TASK-1). Ruthenium red in the micromolar range inhibited I(glom) and I(TASK-3), but not I(TASK-1). Like I(TASK-1), I(TASK-3) was inhibited by stimulation of AT1a angiotensin II receptor coexpressed with the potassium channel. The high level of expression and its pharmacological properties suggest that TASK-3 dominates the resting potassium conductance of glomerulosa cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / pharmacology
  • Animals
  • Blotting, Northern
  • Cloning, Molecular
  • Electric Conductivity
  • Gene Expression
  • Hydrogen-Ion Concentration
  • Nerve Tissue Proteins*
  • Potassium / metabolism*
  • Potassium Channels / genetics
  • Potassium Channels / physiology*
  • Potassium Channels, Tandem Pore Domain*
  • RNA, Complementary
  • RNA, Messenger / analysis
  • Rats
  • Receptor, Angiotensin, Type 1
  • Receptors, Angiotensin / genetics
  • Receptors, Angiotensin / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transfection
  • Zona Glomerulosa / chemistry
  • Zona Glomerulosa / physiology*


  • Kcnk9 protein, rat
  • Nerve Tissue Proteins
  • Potassium Channels
  • Potassium Channels, Tandem Pore Domain
  • RNA, Complementary
  • RNA, Messenger
  • Receptor, Angiotensin, Type 1
  • Receptors, Angiotensin
  • Angiotensin II
  • potassium channel subfamily K member 3
  • Potassium