Periodicity in Na channel properties alters model neuron excitability (Majumdar and Sikdar 2007)

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Accession:93416
"... We have shown earlier that the duration and amplitude of a prolonged depolarization alter all the steady state and kinetic parameters of rNav1.2a voltage gated Na channel in a pseudo-oscillatory fashion. In the present study, we show that the Hodgkin–Huxley voltage and time dependent rate constants of activation (am and bm) and fast inactivation (ah and bh), obtained from the analyses of Na currents and steady state activation and inactivation plots, following application of prepulses in both slow (1–100 s) and fast (100–1000 ms) ranges, vary with the duration of a prepulse in a pseudo-oscillatory manner. ..."
Reference:
1 . Majumdar S, Sikdar SK (2007) Periodicity in Na+ channel properties alters excitability of a model neuron Biochem Biophys Res Commun.
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):
Channel(s): I Na,t; I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: GENESIS;
Model Concept(s): Ion Channel Kinetics; Epilepsy;
Implementer(s):
Search NeuronDB for information about:  I Na,t; I K;
//genesis

/* FILE INFORMATION
** The 1991 Traub set of voltage and concentration dependent channels
** Implemented as tabchannels by : Dave Beeman
**      R.D.Traub, R. K. S. Wong, R. Miles, and H. Michelson
**	Journal of Neurophysiology, Vol. 66, p. 635 (1991)
*/

// CONSTANTS
float EREST_ACT = -0.080 /* hippocampal cell resting potl */
float ENA = 0.125 + EREST_ACT // 0.045
float EK = -0.015 + EREST_ACT // -0.095
float ECA = 0.140 + EREST_ACT // 0.080
float SOMA_A = 2.827e-9       // soma area in square meters

//========================================================================
//                Tabchannel K(DR) Hippocampal cell channel
//========================================================================
function make_Kdr_hip_traub91
        if ({exists Kdr_hip_traub91})
                return
        end

        create  tabchannel      Kdr_hip_traub91
                setfield        ^       \
                Ek              {EK}	\	           //      V
                Gbar            { 50.0*SOMA_A }    \      //      S
                Ik              0       \                  //      A
                Gk              0       \                  //      S
                Xpower  4       \
                Ypower  0       \
                Zpower  0

                setupalpha Kdr_hip_traub91 X               \
                           {16e3 * (0.0351 + EREST_ACT)}   \  // AA
                           -16e3                           \  // AB
                           -1.0                            \  // AC
                           {-1.0 * (0.0351 + EREST_ACT) }  \  // AD
                           -0.005                          \  // AF
                           250                             \  // BA
                           0.0                             \  // BB
                           0.0                             \  // BC
                           {-1.0 * (0.02 + EREST_ACT)}     \  // BD
                           0.04                               // BF

end

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