Activation of calcium-sensitive potassium channels in L6 skeletal myocytes by arginine vasopressin requires extracellular calcium

Martin Gosling, J.W. Smith, David R. Poyner

Research output: Contribution to journalArticle

Abstract

The effects of extracellular application of arginine vasopressin (AVP) upon membrane currents in L6 skeletal myocytes was investigated using the whole-cell configuration of the patch-clamp technique. At O mV AVP produced large amplitude, transient outward currents that reversed when the clamping potential was changed to -100 mV (negative to EK) The effects of alterations in the extracellular K+ concentration upon the current reversal potential suggested that the current elicited by AVP was carried mainly by K+ ions. Intracellular dialysis with 10 μM inositol 1,4,5-trisphosphate (InsP3) elicited similar currents but only in 6/14 cells. Inclusion of 5 mg ml-1 heparin in the intracellular solutions was ineffective at inhibiting the current responses to AVP. The AVP-induced current was totally abolished when the intracellular EGTA concentration was increased from 0.05 mM to 10 mM or Ca2+ was removed from the extracellular perfusing solution. These results suggest that AVP produces activation of a Ca2+-sensitive K+ conductance in L6 skeletal myocytes by a process dependent upon extracellular Ca2+ and not intracellular Ca2+ release. © 1995 Academic Press. All rights reserved.

Original languageEnglish
Pages (from-to)1163-1168
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume217
Issue number3
DOIs
Publication statusPublished - 26 Dec 1995

Keywords

  • animals
  • arginine vasopressin calcium cells
  • cultured chelating agents
  • egtazic acid
  • extracellular epace membrane potentials
  • muscles
  • patch-clamp techniques
  • potassium channels
  • rats

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