Availability of low-threshold Ca2+ current in retinal ganglion cells (Lee SC et al. 2003)

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Accession:125378
"... we measured T-type current of isolated goldfish retinal ganglion cells with perforated-patch voltageclamp methods in solutions containing a normal extracellular Ca2+ concentration. The voltage sensitivities and rates of current activation, inactivation, deactivation, and recovery from inactivation were similar to those of expressed +1G (CaV3.1) Ca2+ channel clones, except that the rate of deactivation was significantly faster. We reproduced the amplitude and kinetics of measured T currents with a numerical simulation based on a kinetic model developed for an +1G Ca2+ channel. Finally, we show that this model predicts the increase of T-type current made available between resting potential and spike threshold by repetitive hyperpolarizations presented at rates that are within the bandwidth of signals processed in situ by these neurons."
Reference:
1 . Lee SC, Hayashida Y, Ishida AT (2003) Availability of low-threshold Ca2+ current in retinal ganglion cells. J Neurophysiol 90:3888-901 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Channel/Receptor;
Brain Region(s)/Organism: Retina;
Cell Type(s): Retina ganglion GLU cell;
Channel(s): I T low threshold;
Gap Junctions:
Receptor(s):
Gene(s): Cav3.1 CACNA1G;
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Ion Channel Kinetics;
Implementer(s): Hayashida, Yuki [yukih at cs.kumamoto-u.ac.jp];
Search NeuronDB for information about:  Retina ganglion GLU cell; I T low threshold;
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leeEtAl2003
readme.html
ca12dZUy.mod
cell.hoc
fig8b_setupgraph.ses
init.hoc
mosinit.hoc *
screenshot.jpg
                            
load_file("cell.hoc")
load_file("fig8b_setupgraph.ses")

xpanel("Figure 8B")
  xlabel("Press the below button to reproduce the simulation")
  xlabel("traces shown in Lee et al. 2003 figure 8B")
  xbutton("Start","fig8b()")
xpanel()

objref g

proc fig8b() {
  graph_stagger = 2.5e-4 // used to stagger voltage traces
  Graph[0].exec_menu("Erase")
  Graph[0].exec_menu("Keep Lines")
  for i=0,5 {
    seclamp.amp2=-62+i*5
    init()
    run()
    i_traces[i]=i_vec.c.sub(i*graph_stagger)
    i_vec.resize(0)
  }
  Graph[0].exec_menu("View = plot")
  g = new Graph()
  g.exec_menu("Keep Lines")
  for i=0,5 {
    i_traces[i].line(g,t_vec)
  }
  g.exec_menu("View = plot")
  g.unmap()
  g.view(0, -0.0021, 120, 0.0021, 437, 68, 289.92, 688)
  g.label(0.6,.2,"Figure 8B")
}

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