Basolateral pH-Sensitive K+ Channels Mediate Membrane Potential of Proximal Tubule Cells in Bullfrog Kidney.
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- KUBOKAWA Manabu
- Department of Physiology, Osaka Medical College
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- MORI Yoshiaki
- Department of Physiology, Osaka Medical College
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- FUJIMOTO Katsuhisa
- Department of Physiology, Osaka Medical College
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- KUBOTA Takahiro
- Department of Physiology, Osaka Medical College
Bibliographic Information
- Other Title
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- Basolateral pH-Sensitive K+Channels Med
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Abstract
The present study investigated basolateral K+ channels and their pH-sensitivity in isolated bullfrog proximal tubule cells by using the patch-clamp technique, and compared channel activity with the basolateral membrane potential (EM) and intracellular pH (pHi) monitored by using double-barreled H+-selective microelectrodes in perfused bullfrog proximal tubules. In the patch-clamp experiments, K+ channels with inward slope conductance of about 50 pS were observed in the basolateral membrane of isolated proximal tubule cells in cell-attached patches. Raising pH of the bath with HCO3--free HEPES Ringer solutions from 7.7 (control) to 8.2 in the presence of an H+ ionophore, FCCP (2 μM), enhanced channel activity to 126.4% of controls; lowering bath pH to 7.2 and to 6.7 reduced channel activity to 26.4 and to 1.7% of controls. Microelectrode experiments in bullfrog proximal tubules perfused with HCO3--free HEPES Ringer solutions showed that EM and pHi in control conditions of peritubular pH 7.7 without FCCP were −52.6mV and 7.45. Raising peritubular pH to 8.2 in the presence of FCCP (2μM) increased EM and pHi to −61.8mV and 7.73; lowering it to 7.2 and to 6.7 decreased EM and pHi to −28.6 mV and 7.25 and to −10.6 mV and 6.95. These results suggest that changes in EM in response to cellular alkalinization or acidification made by HCO3--free HEPES solutions are produced primarily by changes in activity of the pH-sensitive K+ channels.
Journal
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- The Japanese Journal of Physiology
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The Japanese Journal of Physiology 48 (1), 1-8, 1998
THE PHYSIOLOGICAL SOCIETY OF JAPAN
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Details 詳細情報について
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- CRID
- 1390282680018253440
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- NII Article ID
- 130004435651
- 30015529496
- 10008303808
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- NII Book ID
- AA00691224
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- COI
- 1:CAS:528:DyaK1cXivVKgsrw%3D
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- ISSN
- 18811396
- 0021521X
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- NDL BIB ID
- 4450304
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- PubMed
- 9538283
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- PubMed
- CiNii Articles
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- Abstract License Flag
- Disallowed