Action potential-evoked Na+ influx are similar in axon and soma (Fleidervish et al. 2010)

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Accession:136715
"In cortical pyramidal neurons, the axon initial segment (AIS) is pivotal in synaptic integration. It has been asserted that this is because there is a high density of Na+ channels in the AIS. However, we found that action potential-associated Na+ flux, as measured by high-speed fluorescence Na+ imaging, was about threefold larger in the rat AIS than in the soma. Spike-evoked Na+ flux in the AIS and the first node of Ranvier was similar and was eightfold lower in basal dendrites. ... In computer simulations, these data were consistent with the known features of action potential generation in these neurons."
Reference:
1 . Fleidervish IA, Lasser-Ross N, Gutnick MJ, Ross WN (2010) Na+ imaging reveals little difference in action potential-evoked Na+ influx between axon and soma. Nat Neurosci 13:852-60 [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: Neocortex;
Cell Type(s): Neocortex L5/6 pyramidal GLU cell; Neocortex L2/3 pyramidal GLU cell;
Channel(s): I Na,t; I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Simplified Models; Active Dendrites; Action Potentials;
Implementer(s): Fleidervish, Ilya [ilya.fleidervish at gmail.com];
Search NeuronDB for information about:  Neocortex L5/6 pyramidal GLU cell; Neocortex L2/3 pyramidal GLU cell; I Na,t; I K;
{load_file("nrngui.hoc")}
{load_file("variable_dt.ses")} // not used in original publication but
// has nearly the same results a lot faster Note: the number of 
// compartments and dt (when electing to use fixed time step uncheck 
// variable time step and set dt back to original value by unchecking 
// check mark in dt field of RunControl box) have also been reduced 
// from the amount used in the publication

// some choosen parameters:
{nai0_na_ion = 4}
{nao0_na_ion = 151}

proc set_ek() {
  forall ek=-85
}

proc load_3a() {
  {load_file("Fig3A.ses")}
  set_ek()
  PWManager[0].hide(pwmcnt-1)
}
proc load_4b10() {
  {xopen("Fig4B 10APs ver7a.ses")}
  set_ek()
  PWManager[0].hide(pwmcnt-1)
}
proc load_4b100() {
  {load_file("Fig4B 100APs ver7a.ses")}
  set_ek()
  PWManager[0].hide(pwmcnt-1)
}
proc load_6b() {
  {load_file("Fig6B.ses")}
  set_ek()
  PWManager[0].hide(pwmcnt-1)
}

{xpanel("Fleidervish et al. 2010")}
  {xbutton("Fig. 3A","load_3a()")}
  {xbutton("Fig. 4B 10APs ver7a", "load_4b10()")}
  {xbutton("Fig. 4B 100APs ver7a","load_4b100()")}
  {xbutton("Fig. 6B", "load_6b()")}
  {xlabel("After generating a paper figure from the above buttons you")}
  {xlabel("need to quit and restart to generate another paper")}
  {xlabel("figure.  You can select quit from the File menu in the Neuron ")}
  {xlabel("Main Menu, or by type Crtl-D at the oc> prompt")}
{xpanel()}

{pwmcnt = PWManager[0].count} // the initial gui should not be dismissed

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