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71 lines
1.3 KiB
71 lines
1.3 KiB
NEURON { |
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SUFFIX capmp |
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USEION ca READ cao, ica, cai WRITE cai, ica |
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RANGE tau, width, cabulk, ica, pump0 |
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} |
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UNITS { |
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(um) = (micron) |
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(molar) = (1/liter) |
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(mM) = (millimolar) |
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(uM) = (micromolar) |
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(mA) = (milliamp) |
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(mol) = (1) |
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FARADAY = (faraday) (coulomb) |
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} |
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PARAMETER { |
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width = 0.1 (um) |
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tau = 1 (ms) |
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k1 = 5e8 (/mM-s) |
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k2 = 0.25e6 (/s) |
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k3 = 0.5e3 (/s) |
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k4 = 5e0 (/mM-s) |
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cabulk = 0.1 (uM) |
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pump0 = 3e-14 (mol/cm2) |
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} |
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ASSIGNED { |
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cao (mM) : 2 |
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cai (mM) : 100e-6 |
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ica (mA/cm2) |
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ica_pmp (mA/cm2) |
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ica_pmp_last (mA/cm2) |
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} |
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STATE { |
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cam (uM) <1e-6> |
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pump (mol/cm2) <1e-16> |
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capump (mol/cm2) <1e-16> |
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} |
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INITIAL { |
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ica = 0 |
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ica_pmp = 0 |
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ica_pmp_last = 0 |
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SOLVE pmp STEADYSTATE sparse |
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} |
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BREAKPOINT { |
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SOLVE pmp METHOD sparse |
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ica_pmp_last = ica_pmp |
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ica = ica_pmp |
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} |
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KINETIC pmp { |
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~ cabulk <-> cam (width/tau, width/tau) |
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~ cam + pump <-> capump ((1e7)*k1, (1e10)*k2) |
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~ capump <-> cao + pump ((1e10)*k3, (1e10)*k4) |
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ica_pmp = (1e-7)*2*FARADAY*(f_flux - b_flux) |
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: ica_pmp_last vs ica_pmp needed because of STEADYSTATE calculation |
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~ cam << (-(ica - ica_pmp_last)/(2*FARADAY)*(1e7)) |
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CONSERVE pump + capump = (1e13)*pump0 |
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COMPARTMENT width {cam} : volume has dimensions of um |
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COMPARTMENT (1e13) {pump capump} : area is dimensionless |
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COMPARTMENT 1(um) {cabulk} |
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COMPARTMENT (1e3)*1(um) {cao} |
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cai = (0.001)*cam |
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}
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