Korean J Physiol Pharmacol.  2002 Oct;6(5):255-260.

Modulation of Inwardly Rectifying K+ Channel by Intracellular and Extracellular pH in Bovine Aortic Endothelial Cells

• Park KS
• Kong ID
• Lee JW
• Rhim HW
• Kim YC
• So IS
• Kim KW

Abstract

The effects of intracellular and extracellular pH on the inwardly rectifying K+ (IRK) channel of the bovine aortic endothelial cells (BAECs) were examined using whole-cell patch-clamp technique. The IRK current, efficiently blocked by Ba2+ (200microM), is the most prominent membrane current in BAECs, which mainly determines the resting membrane potential. The expression of Kir2.1 was observed in BAECs using reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Intracellular alkalinization, elicited by the extracellular substitution of NaCl with NH4Cl (30 mM), significantly augmented the amplitude of IRK current. On the contrary, the amplitude of IRK current was attenuated by the Na-acetate (30 mM)-induced intracellular acidification. The changes in extracellular pH also closely modulated the amplitude of IRK current, which was decreased to 40.2+/-1.3% of control upon switching the extracellular pH to 4.0 from 7.4. The extracellular pH value for half-maximal inhibition (pK) of IRK current was 5.11. These results demonstrate that the activity of IRK channel in BAECs, probably Kir2.1, was suppressed by proton at both sides of plasma membrane.

Keyword

Inwardly rectifying K+ channel; Intracellular pH; Extracellular pH

MeSH Terms

Cell Membrane
Endothelial Cells*
Hydrogen-Ion Concentration*
Membrane Potentials
Membranes
Patch-Clamp Techniques
Protons
Protons