Lysophosphatidyl choline modulates mechanosensitive L-type Ca2+ current in circular smooth muscle cells from human jejunum

Robert E. Kraichely, Peter R. Strege, Michael G. Sarr, Michael L. Kendrick, Gianrico Farrugia

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The L-type Ca2+ channel expressed in gastrointestinal smooth muscle is mechanosensitive. Direct membrane stretch and shear stress result in increased Ca2+ entry into the cell. The mechanism for mechanosensitivity is not known, and mechanosensitivity is not dependent on an intact cytoskeleton. The aim of this study was to determine whether L-type Ca2+ channel mechanosensitivity is dependent on tension in the lipid bilayer in human jejunal circular layer myocytes. Whole cell currents were recorded in the amphotericin-perforated-patch configuration, and lysophosphatidyl choline (LPC), lysophosphatidic acid (LPA), and choline were used to alter differentially the tension in the lipid bilayer. Shear stress (perfusion at 10 ml/min) was used to mechanostimulate L-type Ca2+ channels. The increase in L-type Ca2+ current induced by shear stress was greater in the presence of LPC (large head-to-tail proportions), but not LPA or choline, than in the control perfusion. The increased peak Ca 2+ current also did not return to baseline levels as in control conditions. Furthermore, steady-state inactivation kinetics were altered in the presence of LPC, leading to a change in window current. These findings suggest that changes in tension in the plasmalemmal membrane can be transmitted to the mechanosensitive L-type Ca2+ channel, leading to altered activity and Ca2+ entry in the human jejunal circular layer myocyte.

Original languageEnglish (US)
Pages (from-to)G833-G839
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume296
Issue number4
DOIs
StatePublished - Apr 2009

Keywords

  • Calcium channel
  • Gastrointestinal
  • Lipid bilayer tension
  • Lysophosphatidic acid
  • Shear stress

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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