title: Voltage-gated sodium channel expression and action potential generation in differentiated NG108-15 cells.
abstract: BACKGROUND
  The generation of action potential is required for stimulus-evoked neurotransmitter release in most neurons. Although various voltage-gated ion channels are involved in action potential production, the initiation of the action potential is mainly mediated by voltage-gated Na+ channels. In the present study, differentiation-induced changes of mRNA and protein expression of Na+ channels, Na+ currents, and cell membrane excitability were investigated in NG108-15 cells.
  
  
  RESULTS
  Whole-cell patch-clamp results showed that differentiation (9 days) didn't change cell membrane excitability, compared to undifferentiated state. But differentiation (21 days) induced the action potential generation in 45.5% of NG108-15 cells (25/55 cells). In 9-day-differentiated cells, Na+ currents were mildly increased, which was also found in 21-day differentiated cells without action potential. In 21-day differentiated cells with action potential, Na+ currents were significantly enhanced. Western blot data showed that the expression of Na+ channels was increased with differentiated-time dependent manner. Single-cell real-time PCR data demonstrated that the expression of Na+ channel mRNA was increased by 21 days of differentiation in NG108-15 cells. More importantly, the mRNA level of Na+ channels in cells with action potential was higher than that in cells without action potential.
  
  
  CONCLUSIONS
  Differentiation induces expression of voltage-gated Na+ channels and action potential generation in NG108-15 cells. A high level of the Na+ channel density is required for differentiation-triggered action potential generation.
authors.affiliation: Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
authors.forename: Jinxu
authors.initials: J
authors.lastname: Liu
authors.forename: Huiyin
authors.initials: H
authors.lastname: Tu
authors.forename: Dongze
authors.initials: D
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Zheng
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Li
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001703:Biophysics; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004558:Electric Stimulation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000502:physiology*; D006822:Hybrid Cells; D008297:Male; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013223:Statistics as Topic; D013779:Tetrodotoxin / Q000494:pharmacology; D061566:Voltage-Gated Sodium Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D026941:Sodium Channel Blockers; D061566:Voltage-Gated Sodium Channels; D013779:Tetrodotoxin; D002795:Choline O-Acetyltransferase