NMDA receptor saturation (Chen et al 2001)

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Experiments and modeling reported in the paper Chen N, Ren J, Raymond LA, and Murphy T (2001) support the hypothesis that glutamate has a relatively lower potency at NMDARs than previously thought from agonist application under equilibrium conditions. Further information and reprint requests are available from Dr T.H. Murphy thmurphy at interchange.ubc.ca
1 . Chen N, Ren J, Raymond LA, Murphy TH (2001) Changes in agonist concentration dependence that are a function of duration of exposure suggest N-methyl-D-aspartate receptor nonsaturation during synaptic stimulation. Mol Pharmacol 59:212-9 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Synapse;
Brain Region(s)/Organism:
Cell Type(s):
Gap Junctions:
Receptor(s): NMDA;
Gene(s): NR2A GRIN2A; NR2B GRIN2B;
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Ion Channel Kinetics;
Implementer(s): Murphy, Tim H [THMurphy at interchange.ubc.ca];
Search NeuronDB for information about:  NMDA; Glutamate;
// The hoc files as received by the authors pop up some graphs so that each
// can be run separately.
// This file manages its own gui so the following declaration is introduced
// to allow the orginal files to pop up the graphs if those are run standalone.
mosinit = 1
// Modifications to  ndma2B.hoc were made to check if the above is
// declared. If so then gui statements are not executed.

// Since nmda2A.hoc, nmda2Aex.hoc, and nmda2B.hoc differ only slightly it is
// sufficient to load just one and functionally switch between them with
// fairly simple procedure calls.
ismenu = 1

proc nrn2a_model() { //copied from nmda2A.hoc
	Rb_NMDA5      = 5e-3    //    (/uM /ms)       : binding 
	Ru_NMDA5      = 0.025  //     (/ms)   : unbinding
	Rd_NMDA5      = 0.002   //    (/ms)   : desensitization
	Rr_NMDA5      = 0.001   //    (/ms)   : resensitization 
	Ro_NMDA5      = 0.15   //     (/ms)   : opening
	Rc_NMDA5      = 0.15   //     (/ms)   : closing
proc nrn2b_model() { //copied from nmda2B.hoc
	Rb_NMDA5      = 2e-3    //    (/uM /ms)       : binding 
	Ru_NMDA5      = 0.005  //     (/ms)   : unbinding
	Rd_NMDA5      = 0.004   //    (/ms)   : desensitization
	Rr_NMDA5      = 0.006   //    (/ms)   : resensitization 
	Ro_NMDA5      = 0.10   //     (/ms)   : opening
	Rc_NMDA5      = 0.04   //     (/ms)   : closing

//following now in start.ses
xpanel("Fig 3")
xbutton("1 uM", "PRE.cmax_glurel = 1e-3")
xbutton("30 uM", "PRE.cmax_glurel = 30e-3")
xbutton("1000 uM", "PRE.cmax_glurel = 1000e-3")
xbutton("1 ms", "PRE.dur_glurel = 1")
xbutton("20 ms", "PRE.dur_glurel = 20")
xbutton("2 s", "PRE.dur_glurel = 2000")
xvalue("cmax", "PRE.cmax_glurel(.5)", 1)
xvalue("dur", "PRE.dur_glurel(.5)", 1)
xradiobutton("NR2A model", "nrn2a_model()")
xradiobutton("NR2B model", "nrn2b_model()", 1)



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