Whole cell current and membrane potential regulation by a human smooth muscle mechanosensitive calcium channel

Adrian N. Holm, Adam Rich, Michael G. Sarr, Gianrico Farrugia

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26 Scopus citations

Abstract

Mechanotransduction is required for a wide variety of biological functions. The aim of this study was to determine the effect of activation of a mechanosensitive Ca2+ channel, present in human jejunal circular smooth muscle cells, on whole cell currents and on membrane potential. Currents were recorded using patch-clamp techniques, and perfusion of the bath (10 ml/min, 30 s) was used to mechanoactivate the L-type Ca2+ channel. Perfusion resulted in activation of L-type Ca2+ channels and an increase in outward current from 664 ± 57 to 773 ± 72 pA at +60 mV. Membrane potential hyperpolarized from -42 ± 4 to -50 ± 5 mV. In the presence of nifedipine (10 μM), there was no increase in outward current or change in membrane potential with perfusion. In the presence of charybdotoxin or iberiotoxin, perfusion of the bath did not increase outward current or change membrane potential. A model is proposed in which mechanoactivation of an L-type Ca2+ channel current in human jejunal circular smooth muscle cells results in increased Ca2+ entry and cell contraction. Ca2+ entry activates large-conductance Ca2+-activated K+ channels, resulting in membrane hyperpolarization and relaxation.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume279
Issue number6 42-6
StatePublished - 2000

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Keywords

  • Patch clamp
  • Small intestine
  • Stretch activation

ASJC Scopus subject areas

  • Gastroenterology
  • Physiology
  • Physiology (medical)

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