Sodium current in human jejunal circular smooth muscle cells

Adrian N. Holm, Adam Rich, Steven M. Miller, Peter Strege, Yijun Ou, Simon J. Gibbons, Michael G. Sarr, Joseph H. Szurszewski, James L. Rae, Gianrico Farrugia

Research output: Contribution to journalArticle

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Abstract

Background & Aims: Sodium channels are key regulators of neuronal and muscle excitability. However, sodium channels have not been definitively identified in gastrointestinal smooth muscle. The aim of the present study was to determine if a Na+ current is present in human jejunal circular smooth muscle cells. Methods: Currents were recorded from freshly dissociated cells using patch-clamp techniques. Complementary DNA (cDNA) libraries constructed from the dissociated cells were screened to determine if a message for α subunits of Na+ channels was expressed. Smooth muscle cells were also collected using laser-capture microdissection and screened. Results: A tetrodotoxin-insensitive Na+ channel was present in 80% of cells patch-clamped. Initial activation was at -65 mV with peak inward current at -30 mV. Steady-state inactivation and activation curves revealed a window current between -75 and -60 mV. The Na+ current was blocked by Iidocaine and internal and external QX314. A cDNA highly homologous to SCN5A, the α subunit of the cardiac Na+ channel, was present in the cDNA libraries constructed from dissociated cells and from smooth muscle cells collected using laser-capture microdissection. Conclusions: Human jejunal circular smooth muscle cells express a tetrodotoxin-insensitive Na+ channel, probably SCN5A. Whether SCN5A plays a role in the pathophysiology of human gut dysmotilities remains to be determined.

Original languageEnglish (US)
Pages (from-to)178-187
Number of pages10
JournalGastroenterology
Volume122
Issue number1
StatePublished - 2002

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Smooth Muscle Myocytes
Sodium
Laser Capture Microdissection
Complementary DNA
Sodium Channels
Tetrodotoxin
Gene Library
Patch-Clamp Techniques
Smooth Muscle
Muscles

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Holm, A. N., Rich, A., Miller, S. M., Strege, P., Ou, Y., Gibbons, S. J., ... Farrugia, G. (2002). Sodium current in human jejunal circular smooth muscle cells. Gastroenterology, 122(1), 178-187.

Sodium current in human jejunal circular smooth muscle cells. / Holm, Adrian N.; Rich, Adam; Miller, Steven M.; Strege, Peter; Ou, Yijun; Gibbons, Simon J.; Sarr, Michael G.; Szurszewski, Joseph H.; Rae, James L.; Farrugia, Gianrico.

In: Gastroenterology, Vol. 122, No. 1, 2002, p. 178-187.

Research output: Contribution to journalArticle

Holm, AN, Rich, A, Miller, SM, Strege, P, Ou, Y, Gibbons, SJ, Sarr, MG, Szurszewski, JH, Rae, JL & Farrugia, G 2002, 'Sodium current in human jejunal circular smooth muscle cells', Gastroenterology, vol. 122, no. 1, pp. 178-187.
Holm AN, Rich A, Miller SM, Strege P, Ou Y, Gibbons SJ et al. Sodium current in human jejunal circular smooth muscle cells. Gastroenterology. 2002;122(1):178-187.
Holm, Adrian N. ; Rich, Adam ; Miller, Steven M. ; Strege, Peter ; Ou, Yijun ; Gibbons, Simon J. ; Sarr, Michael G. ; Szurszewski, Joseph H. ; Rae, James L. ; Farrugia, Gianrico. / Sodium current in human jejunal circular smooth muscle cells. In: Gastroenterology. 2002 ; Vol. 122, No. 1. pp. 178-187.
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