Modulation of Inwardly Rectifying K<SUP>⁢</SUP> Channel by Intracellular and Extracellular pH in Bovine Aortic Endothelial Cells
Modulation of Inwardly Rectifying K<SUP>⁢</SUP> Channel by Intracellular and Extracellular pH in Bovine Aortic Endothelial Cells
- Kyu-Sang Park In Deok Kong Joong Woo Lee Hyewhon Rhim Young Chul Kim Insuk So Ki Whan Kim
- 대한생리학회-대한약리학회
- The Korean Journal of Physiology & Pharmacology
- 제6권 제5호
- 등재여부 : KCI등재
- 2002.01
- 255 - 260 (6 pages)
<P> The effects of intracellular and extracellular pH on the inwardly rectifying K<SUP>⁢</SUP> (IRK) channel of the bovine aortic endothelial cells (BAECs) were examined using whole-cell patch-clamp technique. The IRK current, efficiently blocked by Ba<SUP>2⁢</SUP> (200μM), 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 NH<SUB>4</SUB>Cl (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.