Inhibition of voltage-gated K+ current in rat intrapulmonary arterial myocytes by endothelin-1

Research output: Contribution to journalArticlepeer-review

Abstract

Although endothelin (ET)-1 is an important regulator of pulmonary vascular tone, little is known about the mechanisms by which ET-1 causes contraction in this tissue. Using the whole cell patch-clamp technique in rat intrapulmonary arterial smooth muscle cells, we found that ET-1 and the voltage-dependent K+ (K(V))-channel antagonist 4-aminopyridine, but not the Ca2+-activated K+-channel antagonist charybdotoxin (ChTX), caused membrane depolarization. In the presence of 100 nM ChTX, ET-1 (10-10 to 10-7 M) caused a concentration-dependent inhibition of K+ current (56.2 ± 3.8% at 10-7 M) and increased the rate of current inactivation. These effects of ET-1 on K+ current were markedly reduced by inhibitors of protein kinase C (staurosporine and GF 109203X) and phospholipase C (U-73122) or under Ca2+- free conditions and were mimicked by activators of protein kinase C (phorbol 12-myristate 13-actetate and 1,2-dioctanoyl-sn-glycerol). These data suggest that ET-1 modulated pulmonary vascular reactivity by depolarizing pulmonary arterial smooth muscle, due in part to the inhibition of K(V) current that occurred via activation of the phospholipase C-protein kinase C signal transduction pathway.

Original languageEnglish (US)
Pages (from-to)L842-L853
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume274
Issue number5 18-5
DOIs
StatePublished - May 1998

Keywords

  • Membrane potential
  • Patch clamp
  • Potassium ion
  • Protein kinase C

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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