TTX-R Na+ current effect on cell response (Herzog et al 2001)

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"Small dorsal root ganglion (DRG) neurons, which include nociceptors, express multiple voltage-gated sodium currents. In addition to a classical fast inactivating tetrodotoxin-sensitive (TTX-S) sodium current, many of these cells express a TTX-resistant (TTX-R) sodium current that activates near -70 mV and is persistent at negative potentials. To investigate the possible contributions of this TTX-R persistent (TTX-RP) current to neuronal excitability, we carried out computer simulations using the Neuron program with TTX-S and -RP currents, fit by the Hodgkin-Huxley model, that closely matched the currents recorded from small DRG neurons. ..." See paper for more and details.
1 . Herzog RI, Cummins TR, Waxman SG (2001) Persistent TTX-resistant Na+ current affects resting potential and response to depolarization in simulated spinal sensory neurons. J Neurophysiol 86:1351-64 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Dorsal Root Ganglion (DRG) cell;
Channel(s): I Na,p; I Na,t; I K;
Gap Junctions:
Gene(s): Nav1.1 SCN1A; Nav1.6 SCN8A; Nav1.7 SCN9A; Nav1.8 SCN10A; Nav1.9 SCN11A SCN12A;
Simulation Environment: NEURON;
Model Concept(s): Ion Channel Kinetics; Nociception;
Implementer(s): Morse, Tom [Tom.Morse at];
Search NeuronDB for information about:  I Na,p; I Na,t; I K;
// inf_states.hoc
// graphs the states infinity values

objref v_vec
{v_vec=new Vector((40-(-120))/.25)}

{s = v_vec.size()}

objref tau_m_nattxs_vec, tau_h_nattxs_vec, m_nattxs_vec, h_nattxs_vec

objref m_nav1p9_vec, h_nav1p9_vec
objref tau_m_nav1p9_vec, tau_h_nav1p9_vec

// tau_m_nattxs_vec=new Vector(s)

{    m_nattxs_vec=new Vector(s)}
{    h_nattxs_vec=new Vector(s)}
{tau_m_nattxs_vec=new Vector(s)}
{tau_h_nattxs_vec=new Vector(s)}

{    m_nav1p9_vec=new Vector(s)}
{    h_nav1p9_vec=new Vector(s)}
{tau_m_nav1p9_vec=new Vector(s)}
{tau_h_nav1p9_vec=new Vector(s)}

for i=0,v_vec.size()-1 {
	{m_nattxs_vec.x[i]=soma.m_nattxs( 0.5 )}
	{h_nattxs_vec.x[i]=soma.h_nattxs( 0.5 )}
	{tau_m_nattxs_vec.x[i]=soma.tau_m_nattxs( 0.5 )}
	{tau_h_nattxs_vec.x[i]=soma.tau_h_nattxs( 0.5 )}

	{m_nav1p9_vec.x[i]=soma.m_nav1p9( 0.5 )}
	{h_nav1p9_vec.x[i]=soma.h_nav1p9( 0.5 )}
	{tau_m_nav1p9_vec.x[i]=soma.tau_m_nav1p9( 0.5 )}
	{tau_h_nav1p9_vec.x[i]=soma.tau_h_nav1p9( 0.5 )}

objref vbox    // three rows (of two columns)
objref hbox[3] // one hbox for each row, each will contain two graphs
objref g[6]    // six graphs total

{vbox = new VBox()}

  {hbox[0] = new HBox()}
    // first row is activation/inact curves for ttx-s, ttx-rp
    {g[0]=new Graph()}
	{g[0].exec_menu("View = plot")}

    {g[1]=new Graph()}
	{g[1].exec_menu("View = plot")}

  {hbox[1] = new HBox()}
    {g[2]=new Graph()}
	{g[2].exec_menu("View = plot")}
    {g[3]=new Graph()}
	{g[3].exec_menu("View = plot")}
  {hbox[2] = new HBox()}
    {g[4]=new Graph()}
	{g[4].exec_menu("View = plot")}
    {g[5]=new Graph()}
	{g[5].exec_menu("View = plot")}
{"fig 2 Herzog et al. 2001", 360, 15, 620, 580)}

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