//genesis /* This is the main script for running the simulation designed for examining the effect of long (order of several seconds) depolarising conditioning prepulses on the action potential generated by a model cell containing a Hodgkin-Huxley type delayed rectifier potassium channel (rat channel data from Ref.*) and the RIIA sodium channel alpha subunit. The RIIA sodium channel shows prepulse potential and prepulse duration dependence, i.e., a kind of molecular memory. The RIIA sodium channel parameters has been quantified in a CHO surrogate system. All the basic parameters viz. m_inf, tau_m, h1_inf (fast inactivation gate), tau_h1 and tau_h2 (recovery from slow inactivation) increases/decreases in a periodic fashion. The fluctuation of the channel parameters could be fitted with a sum of 2/3 sin functions. The tabchannel object Rat_na_sm has been written to incorporate the effect of prepulse duration and prepulses potentials on the HH type voltage gated sodium channel. The author wellcomes improvement of this model by making it more real like system incorporating other types of ionic conductances viz. inward rectifier potassium channel, calcium activated potassium channels and calcium channels. Author: Sriparna Majumdar MBU, IISc '2002 */ echo =========================================================== echo echo A SIMPLE MODEL NEURON CONTAINING HH TYPE RAT BRAIN TRANSIENT echo SODIUM CHANNEL AND DELAYED RECTIFIER POTASSIUM CHANNEL echo echo ============================================================ //**************** // simulation time //**************** float tmax =0.22 // simulation time in sec float dt = 0.00005 // simulation time step in sec setclock 0 {dt} // ********************* // STARTUP SCRIPTS // ********************* include constants.g include channel.g include Rat_Na_sm.g include traub91chan.g include compartment.g include tools.g float Eleak = -0.0694 // leak membrane potential //------------------------------------------------------ // Making A Neuron with a Single Compartment called soma //------------------------------------------------------ create neutral /cell makecompartment /cell/soma {soma_l} {soma_d} {Eleak} setfield /cell/soma initVm {EREST} // initialize Vm to rest potential //provide current injection to soma //setfield /cell/soma inject 0.8e-9 //0.3 nA injection current //---------------------------------- // Adding channel to the compartment //---------------------------------- pushe /cell/soma //make_hhK make_Na_rat_sm //make_Na_hip_traub91 make_Kdr_hip_traub91 pope addmsg /cell/soma/Kdr_hip_traub91 /cell/soma CHANNEL Gk Ek addmsg /cell/soma /cell/soma/Kdr_hip_traub91 VOLTAGE Vm addmsg /cell/soma/Na_rat_sm /cell/soma CHANNEL Gk Ek addmsg /cell/soma /cell/soma/Na_rat_sm VOLTAGE Vm //------------------------ // GRAPHICS SECTION //------------------------ include graphics.g disk_output check reset