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Focal Ca2+ Transient Detection in Smooth Muscle
Published on: June 29, 2009
SCN5A is expressed in human jejunal circular smooth muscle cells
Y Ou1, S J Gibbons, S M Miller
1Department of Physiology and Biophysics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Neurogastroenterology and Motility
|October 3, 2002
Summary
The SCN5A gene encodes the tetrodotoxin-resistant sodium channel alpha-subunit in human jejunal smooth muscle cells. This finding expands the known distribution of SCN5A beyond cardiac tissue.
Area of Science:
- Molecular Biology
- Cardiovascular Physiology
- Gastrointestinal Physiology
Background:
- Tetrodotoxin-resistant sodium currents are present in human jejunal circular smooth muscle (HJCSM) cells.
- The specific molecular identity of the sodium channel alpha-subunit in these cells was previously unknown.
Purpose of the Study:
- To identify the pore-forming alpha-subunit of the sodium channel in HJCSM cells.
- To investigate the distribution of SCN5A expression within the human jejunum.
Main Methods:
- Degenerate primers and RT-PCR were used to identify and amplify cDNA fragments.
- Northern blot analysis confirmed full-length SCN5A expression.
- Laser capture microdissection isolated HJCSM cells for precise molecular analysis.
Main Results:
- A 1.5 kb cDNA fragment showed 99% homology to human cardiac SCN5A.
- Full-length SCN5A expression was confirmed in HJCSM cells via Northern blot.
- RT-PCR demonstrated SCN5A presence in circular but not longitudinal smooth muscle.
Conclusions:
- SCN5A encodes the alpha-subunit of the tetrodotoxin-resistant sodium current in HJCSM cells.
- The SCN5A gene is expressed in intestinal smooth muscle, indicating a broader distribution than previously recognized.
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