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134 lines
2.9 KiB
134 lines
2.9 KiB
TITLE detailed model of Glycine receptors |
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COMMENT |
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----------------------------------------------------------------------------- |
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Kinetic model of Glycine-A receptors |
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==================================== |
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C -- C1 -- C2 -- O1 |
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D1 -- D2 -- D3 |
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----------------------------------------------------------------------------- |
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This Model is based on: |
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Gentet LJ, Clements JD Binding site stoichiometry and the effects of |
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phosphorylation on human alpha1 homomeric glycine receptors J Physiol (Lond) |
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2002 vol. 544 (Pt 1) pp. 97-106, Figure 7. |
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Written by Paul Manis, UNC Chapel Hill, 2009 |
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Kinetic values are estimated from VCN glycine receptors. |
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This model has desensitization states. |
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----------------------------------------------------------------------------- |
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This mod file does not include mechanisms for the release and time course |
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of transmitter; it is to be used in conjunction with a sepearate mechanism |
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to describe the release of transmitter and that provides the concentration |
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of transmitter in the synaptic cleft (to be connected to pointer C here). |
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----------------------------------------------------------------------------- |
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ENDCOMMENT |
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INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} |
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NEURON { |
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POINT_PROCESS GLYaGC |
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POINTER XMTR |
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RANGE C0, C1, C2, D1, D2, D3, O1, Open |
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RANGE g, gmax, f1, f2 |
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RANGE Erev |
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RANGE k1, km1, a1, b1, d1, r1, d2, r2, d3, r3, rd, dd |
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NONSPECIFIC_CURRENT i |
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} |
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UNITS { |
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(nA) = (nanoamp) |
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(mV) = (millivolt) |
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(pS) = (picosiemens) |
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(umho) = (micromho) |
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(mM) = (milli/liter) |
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(uM) = (micro/liter) |
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} |
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PARAMETER { |
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Erev = -70 (mV) : reversal potential |
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gmax = 500 (pS) : maximal conductance |
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: Rates |
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: bushy cell |
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k1 = 12.81 (/uM /ms) : binding |
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km1 = 0.0087 (/ms) : unbinding |
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a1 = 0.0194 (/ms) : opening |
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b1 = 1.138 (/ms) : closing |
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r1 = 5.19 (/ms) : desense 1 |
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d1 = 0.000462 (/ms) : return from d1 |
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r2 = 0.731 (/ms) : return from deep state |
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d2 = 1.641 (/ms) : going to deep state |
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r3 = 3.817 (/ms) : return from deep state |
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d3 = 1.806 (/ms) : going to deep state |
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rd = 1.0 (/ms) |
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dd = 1.0 (/ms) |
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} |
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ASSIGNED { |
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v (mV) : postsynaptic voltage |
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i (nA) : current = g*(v - Erev) |
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g (pS) : conductance |
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XMTR (mM) : pointer to glycine concentration |
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f1 (/ms) : binding |
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f2 (/ms) : binding |
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Open (1) |
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} |
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STATE { |
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: Channel states (all fractions) |
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C0 : unbound |
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C1 : single bound |
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C2 : double bound |
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D1 : desense, bound |
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O1 : open |
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D2 : Desense |
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D3 : Desense |
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} |
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INITIAL { |
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XMTR = 0 |
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C0 = 1 |
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C1 = 0 |
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C2 = 0 |
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O1 = 0 |
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D1 = 0 |
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D2 = 0 |
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D3 = 0 |
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} |
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BREAKPOINT { |
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SOLVE kstates METHOD sparse |
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Open = (O1) |
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g = gmax * Open |
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i = (1e-6) * g * (v - Erev) |
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} |
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KINETIC kstates { |
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f1 = k1 * (1e3) * XMTR |
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f2 = k1 * (1e3) * XMTR |
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~ C0 <-> C1 (f1,km1) |
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~ C1 <-> C2 (f2,12.5*km1) |
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~ C2 <-> O1 (a1,b1) |
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~ C1 <-> D1 (r1, d1) |
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~ C2 <-> D2 (r2, d2) |
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~ D1 <-> D2 (rd, dd) |
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~ D2 <-> D3 (r3, d3) |
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CONSERVE C0+C1+C2+D1+D2+D3+O1 = 1 |
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}
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