Dorsal root ganglion (DRG) neuronal model (Kovalsky et al. 2009)

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Accession:140038
This model, diverged from oscillatory parameters seen in live cells and failed to produce characteristic ectopic discharge patterns. Here we show that use of a more complete set of Na+ conductances--which includes several delayed components--enables simulation of the entire repertoire of oscillation-triggered electrogenic phenomena seen in live dorsal root ganglion (DRG) neurons. This includes a physiological window of induction and natural patterns of spike discharge. An INa+ component at 2-20 ms was particularly important, even though it represented only a tiny fraction of overall INa+ amplitude. With the addition of a delayed rectifier IK+ the singlet firing seen in some DRG neurons can also be simulated. The model reveals the key conductances that underlie afferent ectopia, conductances that are potentially attractive targets in the search for more effective treatments of neuropathic pain.
Reference:
1 . Kovalsky Y, Amir R, Devor M (2009) Simulation in sensory neurons reveals a key role for delayed Na+ current in subthreshold oscillations and ectopic discharge: implications for neuropathic pain. J Neurophysiol 102:1430-42 [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 K; I Sodium; Late Na;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Bursting; Ion Channel Kinetics; Pathophysiology;
Implementer(s): Devor, Marshall [marshlu at vms.huji.ac.il];
Search NeuronDB for information about:  I K; I Sodium; Late Na;
objectvar save_window_, rvp_
objectvar scene_vector_[3]
objectvar ocbox_, ocbox_list_, scene_, scene_list_
{ocbox_list_ = new List()  scene_list_ = new List()}
{pwman_place(0,0,0)}
{
xpanel("RunControl", 0)
v_init = -80
xvalue("Init","v_init", 1,"stdinit()", 1, 1 )
xbutton("Init & Run","run()")
xbutton("Stop","stoprun=1")
runStopAt = 5
xvalue("Continue til","runStopAt", 1,"{continuerun(runStopAt) stoprun=1}", 1, 1 )
runStopIn = 1
xvalue("Continue for","runStopIn", 1,"{continuerun(t + runStopIn) stoprun=1}", 1, 1 )
xbutton("Single Step","steprun()")
t = 0
xvalue("t","t", 2 )
tstop = 5
xvalue("Tstop","tstop", 1,"tstop_changed()", 0, 1 )
dt = 0.025
xvalue("dt","dt", 1,"setdt()", 0, 1 )
steps_per_ms = 40
xvalue("Points plotted/ms","steps_per_ms", 1,"setdt()", 0, 1 )
screen_update_invl = 0.05
xvalue("Scrn update invl","screen_update_invl", 1,"", 0, 1 )
realtime = 0
xvalue("Real Time","realtime", 0,"", 0, 1 )
xpanel(1640,0)
}

objref vboxC
vboxC = new VBox()
strdef read_paraV2_file, BatchRun

{sprint(read_paraV2_file,"%sIO_read_paraV2.txt",DirIO)}
{sprint(BatchRun,"%sbatch_run.txt",DirIO)}

vboxC.intercept(1)

sprint(IO_fileName,"%sIO_funcs_V1.txt",DirIO)
sprint(Func_dev_FileName,"%sFuncs_dev_V1.txt",DirFuncs)
sprint(Modelhoc,"%sModels.txt",DirModels)
sprint(DC_file,"%smakeDC1_test.hoc",DirFibers)
sprint(DR_file,"%smakeDR_test.hoc",DirFibers)


{// ------------- GRAPH CONTROL PANEL --------
xpanel("Function Load Control",0)
xlabel("Load function file")

xbutton("Load IO_funcs","xopen(IO_fileName)")

xlabel("-------------------------")
xlabel("Under development functions")
xbutton("Funcs dev load","xopen(Func_dev_FileName)")
xbutton("Load all V data","data_load_prerun()")
xbutton("Read parameters","xopen(read_paraV2_file)")
xbutton("Read batch run","xopen(BatchRun)")

xlabel("-------------------------")
xbutton("Load DC model","xopen(Modelhoc)")
xbutton("Load DC 8.7","{prebuildDC(8.7)}")
xbutton("Make DC fiber","{xopen(DC_file)}")
xbutton("Load DC 11.5","{prebuildDC(11.5)}")
xbutton("Make DC fiber","{xopen(DC_file)}")
xlabel("-------------------------")
xbutton("Load DR 11.5","{prebuildDR(15.0,11.5)}")
xbutton("Make DR fiber","{xopen(DR_file)}")
xlabel("-------------------------")
xbutton("Load SingleShot","{xopen(SingleShot)}")

xlabel("-------------------------")
xbutton("Remove DC fiber","{remove_DC()}")
xbutton("Remove DR fiber","{remove_DR()}")
xlabel("-------------------------")
xlabel("Run functions")
xbutton("Get all data ready","{get_ready()}")
xbutton("Move fibers","move_fibers()")
xbutton("Save x coordi","run_func1()")
xbutton("Load 32 channel pulse","load_pulse_wave()")
xvalue("  Amp ","Amp",1,"Assign_pulse_ext1(secDC_DC1)",0,0)

xvalue("Recording dt","DT",1,"",0,0)
xcheckbox(" Voltage recording",&Vrecord,"Record_voltage(Vrecord,DT)")
xcheckbox(" h gate recording",&Hrecord,"Record_hgate(Hrecord,DT)")
xcheckbox(" m gate recording",&Mrecord,"Record_mgate(Mrecord,DT)")

xlabel("-------------------------")
xlabel("Saving data")
xvarlabel(DataFileName)
xvarlabel(HeaderFileName)
xbutton("Save data now","Save_all_data()")
xpanel(0)
}
vboxC.intercept(0)
vboxC.map("Function Load Control",700, 0, 207, 570)



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