Pflügers Archiv

, Volume 413, Issue 5, pp 562–564 | Cite as

Reciprocal effects of Ca2+ and Mg-ATP on the ‘run-down’ of the K+ channels in opossum kidney cells

  • Takako Ohno-Shosaku
  • Takahiro Kubota
  • Jun Yamaguchi
  • Masaaki Fukase
  • Takuo Fujita
  • Mamoru Fujimoto
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands Short Communication

Abstract

Using the patch clamp technique, we identified an inwardly rectifying K+ channel in the membrane of opossum kidney cells. The single channel conductance was about 90 pS for inward currents and 30 pS for outward currents under a symmetrical high-K+ condition. The activity of the channel was found to decrease with time during recording from inside-out patches. In the solution with submicromolar Ca2+, the activity disappeared within 4–20 min. Intracellular Ca2+ promoted the run-down of the channel activity at 0.1–1 mM, whereas millimolar Mg-ATP restored the activity after run-down. The run-down channels could never be reactivated by ATP in the absence of Mg2+, or by a nonhydrolyzable ATP analog, AMPPNP, even in the presence of Mg2+.

Key words

Patch clamp Kidney cell K+ channel Run-down Ca2+ ATP 

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Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Takako Ohno-Shosaku
    • 1
  • Takahiro Kubota
    • 1
  • Jun Yamaguchi
    • 1
  • Masaaki Fukase
    • 2
  • Takuo Fujita
    • 2
  • Mamoru Fujimoto
    • 1
  1. 1.Department of PhysiologyOsaka Medical CollegeOsakaJapan
  2. 2.Third Division, Department of MedicineKobe University School of MedicineKobeJapan

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