Pressure-induced activation of membrane K+ current in rat saphenous artery

Viktor Berczi, William J. Stekiel, Stephen J. Contney, Nancy J. Rusch

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Pressurization of isolated arteries may result in Ca2+-dependent contraction and membrane depolarization. Because the open state probability of some vascular muscle K+ channels is augmented by rises in cytosolic Ca2+ and membrane depolarization, we investigated the possibility that increases in intraluminal pressure activate K+ channels in isolated, perfused rat saphenous arteries. Stepwise increases in intraluminal pressure from 5 to 205 mm Hg resulted in increasing, active arterial contraction, measured as smaller diameters in physiological salt solution than in Ca2+-free solution. Addition of 10 mM tetraethylammonium to the physiological salt solution to block arterial muscle K+ channels caused progressively greater diameter reductions at pressures above 25 mm Hg. Microelectrode measurements of membrane potential showed that tetraethylammonium depolarized arterial muscle more at 105 mm Hg (16±1 mV) than at 25 mm Hg (10±1 mV). The sensitivity of K+ current to tetraethylammonium was also demonstrated in patch-clamped vascular muscle cells from the same arteries. Peak whole-cell K+ current was suppressed 47% and 79% by 1 and 10 mM tetraethylammonium, respectively. This same current was enhanced 3.6-fold by the Ca2+ ionophore A23187 (10 μM), suggesting a Ca2+ dependence. We conclude that increases in intraluminal pressure progressively activate tetraethylammonium-sensitive K+ channels in the arterial muscle membrane. This can serve as a negative feedback mechanism to limit pressure-induced arterial constriction.

Original languageEnglish
Pages (from-to)725-729
Number of pages5
JournalHypertension
Volume19
Issue number6
DOIs
Publication statusPublished - Jun 1992

Keywords

  • blood pressure
  • calcium
  • potassium channels
  • tetraethylammonium compounds
  • vascular smooth muscle

ASJC Scopus subject areas

  • Internal Medicine

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