title: Characterization of maturation of neuronal voltage-gated sodium channels SCN1A and SCN8A in rat myocardium.
abstract: BACKGROUND
  Sodium channels predominantly expressed in brain are expressed in myocardial tissue and play an important role in cardiac physiology. Alterations of sodium channels are known to result in neurological disease in infancy and childhood. It will be of interest to study the expression of brain-type sodium channels in the developing myocardium.
  
  
  METHODS
  The expression of neuronal sodium channels (SCN1A, SCN8A) and the cardiac isoform SCN5A in the developing rat myocardium was studied by rtPCR, Western blot, and immunohistochemistry at different stages of antenatal and postnatal development.
  
  
  RESULTS
  Significant changes of sodium channel expression during development were detected. Whereas SCN5A RNA increased to maximum levels on day 21 after birth, the highest SCN1A RNA levels were detected on day 1 to 7 after birth. SCN8A RNA was maximally expressed during embryonic development. At the protein level, the amount of SCN5A protein increased along with the RNA level. SCN1A protein level decreased after birth in contrast to RNA expression. Western blot could not detect SCN8A protein in the myocardium at any stage of development. Immunohistochemistry however proved the presence of SCN8A protein in the developing rat myocardium.
  
  
  CONCLUSIONS
  Heart- and brain-type sodium channels are differentially expressed during ontogenesis. The high expression level of SCN1A in the perinatal period and early infancy indicates its importance in preserving a regular cardiac rhythm in this early phase of life. Altered regulation of sodium channels might result in severe cardiac rhythm disturbances.
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg August University, Göttingen, Robert-Koch-Str. 40, 37099, Göttingen, Germany. ukrause1@gwdg.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Krause
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg August University, Göttingen, Robert-Koch-Str. 40, 37099, Göttingen, Germany. Christian@alflen.net.
authors.forename: Christian
authors.initials: C
authors.lastname: Alflen
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg August University, Göttingen, Robert-Koch-Str. 40, 37099, Göttingen, Germany. Michael.Steinmetz@med.uni-goettingen.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Steinmetz
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg August University, Göttingen, Robert-Koch-Str. 40, 37099, Göttingen, Germany. Matthias.mueller@med.uni-goettingen.de.
authors.forename: Matthias J
authors.initials: MJ
authors.lastname: Müller
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg August University, Göttingen, Robert-Koch-Str. 40, 37099, Göttingen, Germany. Thomas.Quentin@med.uni-goettingen.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Quentin
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, University Medical Center, Georg August University, Göttingen, Robert-Koch-Str. 40, 37099, Göttingen, Germany. tpaul@gwdg.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Paul
keywords: Developmental expression; Myocardium; Rat; SCN1A; SCN5A; SCN8A; Voltage-gated sodium channel