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pH regulation of voltage-dependent K+ channels in canine pulmonary arterial smooth muscle cells

Authors
 D. Sun Ahn  ;  Joseph R. Hume 
Citation
 PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, Vol.433(6) : 758-765, 1997 
Journal Title
 PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY 
ISSN
 0031-6768 
Issue Date
1997
MeSH
Amphotericin B/pharmacology ; Animals ; Anti-Bacterial Agents/pharmacology ; Calcium/physiology ; Chloride Channels/drug effects ; Chloride Channels/metabolism ; Dogs ; Electrophysiology ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Ion Channel Gating/drug effects ; Ion Channel Gating/physiology ; Membrane Potentials/drug effects ; Membrane Potentials/physiology ; Muscle, Smooth, Vascular/drug effects ; Muscle, Smooth, Vascular/metabolism* ; Muscle, Smooth, Vascular/physiology ; Patch-Clamp Techniques ; Potassium Channels/drug effects ; Potassium Channels/physiology* ; Pulmonary Artery/drug effects ; Pulmonary Artery/metabolism* ; Pulmonary Artery/physiology
Abstract
Voltage-dependent K+ currents (Kv) may play a role in hypoxic pulmonary vaso constriction. The effects of changes in extracellular pH (pHo) and intracellular pH (pHi) on Kv currents in smooth muscle cells isolated from canine pulmonary artery were studied using the amphotericin B perforated-patch technique for whole-cell recording. Under these conditions, cellular mechanisms for pHi regulation remain intact, and the effects of pHo were examined by directly changing the pH of external solutions and changes in pHi were produced by external application of weak extracellular acids and bases and the cation/H+ ionophore, nigericin. Ca(2+)-free external solutions were used to isolate whole-cell Kv currents from contaminating Ca(2+)-activated K+ currents. Extracellular acidification (pHo = 6.4-7.0) reduced Kv currents, produced a positive voltage shift in steady-state activation and reduced maximum Kv conductance (gK). Extracellular alkalinization (pHo = 8.0-8.4) increased Kv currents, produced a small negative voltage shift in steady-state activation, and increased gK. Intracellular acidification produced by exposure of cells to external sodium butyrate (20 mM) or nigericin (5 micrograms/ml) increased Kv currents, produced a negative voltage shift in steady-state activation, and increased gK. Intracellular alkalinization produced by exposure of cells to external trimethylamine (20 mM) reduced Kv currents, produced a small positive voltage shift in steady-state activation and reduced gK. These results suggest that the effects of pHo and pHi on Kv currents are distinctly different, but are consistent with reported effects of pHo and pHi on hypoxic pulmonary vasoconstriction, suggesting that such modulation may be mediated in party by pH-induced alterations in Kv channel activity.
Full Text
https://link.springer.com/article/10.1007%2Fs004240050342
DOI
10.1007/s004240050342
Appears in Collections:
1. College of Medicine (의과대학) > Dept. of Physiology (생리학교실) > 1. Journal Papers
Yonsei Authors
Ahn, Duk Sun(안덕선) ORCID logo https://orcid.org/0000-0001-9351-6951
URI
https://ir.ymlib.yonsei.ac.kr/handle/22282913/177396
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