Basolateral pH-Sensitive K+ Channels Mediate Membrane Potential of Proximal Tubule Cells in Bullfrog Kidney.

• KUBOKAWA Manabu

  Department of Physiology, Osaka Medical College

• MORI Yoshiaki

  Department of Physiology, Osaka Medical College

• FUJIMOTO Katsuhisa

  Department of Physiology, Osaka Medical College

• KUBOTA Takahiro

  Department of Physiology, Osaka Medical College

書誌事項

タイトル別名

• Basolateral pH-Sensitive K+Channels Med

抄録

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 (E_M) and intracellular pH (pH_i) 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 E_M and pH_i 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 E_M and pH_i to −61.8mV and 7.73; lowering it to 7.2 and to 6.7 decreased E_M and pH_i to −28.6 mV and 7.25 and to −10.6 mV and 6.95. These results suggest that changes in E_M 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.

収録刊行物

• The Japanese Journal of Physiology

  The Japanese Journal of Physiology 48 (1), 1-8, 1998

  一般社団法人　日本生理学会

キーワード

• proximal tubule
• K<SUP>+</SUP> channel
• membrane potential
• intracellular pH
• FCCP

詳細情報

• CRID: 1390282680018253440
• NII論文ID: 130004435651
• NII論文ID: 30015529496
• NII論文ID: 10008303808
• NII書誌ID: AA00691224
• DOI: 10.2170/jjphysiol.48.1
• COI: 1:CAS:528:DyaK1cXivVKgsrw%3D
• ISSN: 18811396
• ISSN: 0021521X
• NDL書誌ID: 4450304
• PubMed: 9538283
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4450304
• Web Site: https://search.jamas.or.jp/link/ui/1998212434
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • PubMed
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可