Potassium current in circular smooth muscle of human jejunum activated by fenamates

Gianrico Farrugia, J. L. Rae, M. G. Sarr, J. H. Szurszewski

Research output: Contribution to journalArticle

Abstract

Thirty-eight cells, freshly isolated from circular smooth muscle of normal human jejunum obtained from nine patients undergoing weight-reduction surgery for morbid obesity, were patch clamped using a perforated patch-clamp technique. A highly potassium-selective voltage-dependent outward current was present in all cells. The current was carried by a 220-pS channel that activated near -75 mV and reached unit open probability at about +10 mV. Blockade of the current by quinidine (50 μM) and tetraethyl-ammonium (25 mM) was accompanied by membrane depolarization to 0 to -3 mV, suggesting that this current was the major determinant of the membrane potential. Flufenamic and mefenamic acid at concentrations comparable with blood levels reached when these drugs are used in clinical therapy as nonsteroidal anti- inflammatory agents, activated the potassium outward current and hyperpolarized the membrane potential. The shift in the membrane potential for 250 μM flufenamic acid was -36 ± 24 (SD) mV. Activation was rapid (seconds) and reversible. It was concluded that normal human jejunal circular smooth muscle cells have a highly potassium-selective outward current, which is the major determinant of the membrane potential and which is activated by fenamates.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume265
Issue number5 28-5
StatePublished - 1993

Fingerprint

Fenamates
Jejunum
Membrane Potentials
Smooth Muscle
Potassium
Flufenamic Acid
Mefenamic Acid
Quinidine
Morbid Obesity
Patch-Clamp Techniques
Non-Steroidal Anti-Inflammatory Agents
Ammonium Compounds
Smooth Muscle Myocytes
Weight Loss
Membranes
Pharmaceutical Preparations

Keywords

  • patch clamp
  • potassium channels

ASJC Scopus subject areas

  • Physiology
  • Gastroenterology

Cite this

Potassium current in circular smooth muscle of human jejunum activated by fenamates. / Farrugia, Gianrico; Rae, J. L.; Sarr, M. G.; Szurszewski, J. H.

In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 265, No. 5 28-5, 1993.

Research output: Contribution to journalArticle

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