title: Expression and function of the Scn5a-encoded voltage-gated sodium channel NaV 1.5 in the rat jejunum.
abstract: BACKGROUND
  The SCN5A-encoded voltage-gated sodium channel NaV 1.5 is expressed in human jejunum and colon. Mutations in NaV 1.5 are associated with gastrointestinal motility disorders. The rat gastrointestinal tract expresses voltage-gated sodium channels, but their molecular identity and role in rat gastrointestinal electrophysiology are unknown.
  
  
  METHODS
  The presence and distribution of Scn5a-encoded NaV 1.5 was examined by PCR, Western blotting and immunohistochemistry in rat jejunum. Freshly dissociated smooth muscle cells were examined by whole cell electrophysiology. Zinc finger nuclease was used to target Scn5a in rats. Lentiviral-mediated transduction with shRNA was used to target Scn5a in rat jejunum smooth muscle organotypic cultures. Organotypic cultures were examined by sharp electrode electrophysiology and RT-PCR.
  
  
  RESULTS
  We found NaV 1.5 in rat jejunum and colon smooth muscle by Western blot. Immunohistochemistry using two other antibodies of different portions of NaV 1.5 revealed the presence of the ion channel in rat jejunum. Whole cell voltage-clamp in dissociated smooth muscle cells from rat jejunum showed fast activating and inactivating voltage-dependent inward current that was eliminated by Na(+) replacement by NMDG(+) . Constitutive rat Scn5a knockout resulted in death in utero. NaV 1.5 shRNA delivered by lentivirus into rat jejunum smooth muscle organotypic culture resulted in 57% loss of Scn5a mRNA and several significant changes in slow waves, namely 40% decrease in peak amplitude, 30% decrease in half-width, and 7 mV hyperpolarization of the membrane potential at peak amplitude.
  
  
  CONCLUSIONS
  Scn5a-encoded NaV 1.5 is expressed in rat gastrointestinal smooth muscle and it contributes to smooth muscle electrophysiology.
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: A
authors.initials: A
authors.lastname: Beyder
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Gibbons
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: A
authors.initials: A
authors.lastname: Mazzone
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Strege
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Saravanaperumal
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: L
authors.initials: L
authors.lastname: Sha
authors.affiliation: College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: S
authors.initials: S
authors.lastname: Higgins
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Eisenman
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Bernard
authors.affiliation: Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: A
authors.initials: A
authors.lastname: Geurts
authors.affiliation: The Dorothy M. Davis Heart and Lung Research Institute and Departments of Physiology & Cell Biology and Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
authors.forename: C F
authors.initials: CF
authors.lastname: Kline
authors.affiliation: The Dorothy M. Davis Heart and Lung Research Institute and Departments of Physiology & Cell Biology and Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Mohler
authors.affiliation: Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: G
authors.initials: G
authors.lastname: Farrugia
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003106:Colon / Q000378:metabolism*; D007150:Immunohistochemistry; D007583:Jejunum / Q000378:metabolism*; D008564:Membrane Potentials / Q000235:genetics / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D062554:NAV1.5 Voltage-Gated Sodium Channel; D012333:RNA, Messenger; C568322:Scn5a protein, rat
keywords: jejunum; rat; smooth muscle; sodium channel