This output shows the exact constants and equations used for the simulation shown in Fig. 9A. In this a zero stimulus current was applied for 0.1 ms followed by a stimulus current of 1.6 nA. The full worksheet is available for download in the additional files.

Constants

Stimulus current, in nA, at 0.1 ms goes from zero to 1.6 nA

60

*Istim* := if(*t* < 0.100, 0, 1.600)

Octopamine ligand gated current

*I*_*OA* := 0.000

Capacitance in microF

* Cm* := 0.004

Equilibrium voltages, mV

Sodium, Potassium, Leak

28

*vNa* := 35

*vK* := -67

*vLeak* := -20

Fixed leak conductance

*gLeak* := 0.020

Sodium current

maximum conductance, m and h components

with max value and time constant as functions of voltage

*gbarNa* := 7.000

Sustained Potassium current

maximum conductance, NA and NB components

with max value and time constant as functions of voltage

*gbarKA* := 1.440

*tauNA* := *v* → 0.038 - 0.000 *v*

*gbarKB* := 2.880

*tauNB* := *v* → 0.006 - 0.000 *v*

Transient Potassium current

maximum conductance, a and b components

with max value and time constant as functions of voltage

*gbarA* := 12

*taua* := *v* → 0.002 - 0.000 *v*

*taub* := *v* → 0.026 + 0.000 *v*

Initial conditions, start from equilibrium voltage (-52.5 mV)

*v0* := -52.500

Sodium current

*m0* := 0.028

*h0* := 0.998

Sustained Potassium current

*NA0* := 0.017

*NB0* := 0.015

Transient Potassium current

*a0* := 0.055

*b0* := 0.057

Current equations

Sodium current

Sustained Potassium current

Transient Potassium current

Leak current

Total ionic current

*INa* := 7.000 (v(*t*) - 35) m(*t*)^{3} h(*t*)

*IK* := (v(*t*) + 67) (1.440 NA(*t*)^{2} + 2.880 NB(*t*))

*IA* := 12 (v(*t*) + 67) a(*t*)^{4} b(*t*)

*ILeak* := 0.020 v(*t*) + 0.0400

*ITotal* := 7.000 (v(*t*) - 35) m(*t*)^{3} h(*t*) + (v(*t*) + 67) (1.440 NA(*t*)^{2} + 2.880 NB(*t*))

+12 (v(*t*) +67) a(*t*)^{4} b(*t*) + 0.020 v(*t*) + 0.400

Differential equations

ODEs for Sodium current

ODEs for Sustained Potassium current

ODEs for Transient Potassium current

ODE for Voltage as function of current

Stimulus and octopamine ligand gated currents included here

*odev* :=
v(*t*) = 285.714 if(*t* < 0.100, 0, 1.600) - 114.286

- 2000.000 (v(*t*) - 35) m(*t*)^{3} h(*t*)

- 285.714 (v(*t*) + 67) (1.440 NA(*t*)^{2} + 2.880 NB(*t*))

- 3428.571 (v(*t*) + 67) a(*t*)^{4} b(*t*) - 5.714 v(*t*)

Solve system of ODEs

*sol100* := **proc**(*x*_*lsode*) ... **end proc**

Plotting...

Setup plot

*maxT* := 1.100

*mazPT* := 2000

"'if(t <. 1,0,1.6)"

"7.0"

*sHead* :="Stimulus: 'if(t < 1,0,1.6) gNaMax: 7.0"

Plotting voltage vs time

[*odeplot*]

{Fig. 9A is generated and shown here}

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