Table 1.

Main model parameters and variables.

Parameter	Description	Typical value	Units
i	Ion index (i = Na, K, Cl, Ca, H, M)
${\mathit{\text{D}}}_{{\mathit{\text{o}}}_{\mathit{\text{i}}}}$	Free diffusion coefficient for ion i	1.0 × 10−9	$\frac{{\text{m}}^{\text{2}}}{\text{s}}$
t	Time	10	s
x, y	Spatial coordinates	500	μm
h	System height	10	μm
$\mathrm{\Delta }{\mathit{\text{G}}}_{\mathit{\text{ATP}}}^{\mathit{\text{o}}}$	Standard free energy of ATP hydrolysis	37	kJ/mol
T	Temperature	310	K
F	Faraday’s constant	96,485	C/mol
R	Ideal gas constant	8.3145	J/K mol
q	Electron charge constant	1.6 × 10−19	C/ion
kb	Boltzmann constant	1.38 × 10−23	J/K
vcell, vecm	Cell and extracellular volume	7.85 × 10−16	m3
σcell, σmem, σecm	Cell, membrane and extracellular surface area	3.14 × 10−10	m2
cmem	Membrane capacitance	0.022	F/m2
cself	Electrolyte-induced self-capacitance	0.86	F/m2
αpump	Maximum rate constant for pump	2.0 × 10−7	1/s m2
ν1/2GJ	GJ voltage-gating half-closed parameter	15	mV
dmem	Cell membrane thickness	7.5 × 10−9	m
dgj	Intercellular spacing	26.0 × 10−9	m
μ	Water viscosity	5.0 × 10−3	Pas
Variable	Description	Typical value	Units
${\mathit{\text{c}}}_{{\mathit{\text{i}}}_{\mathit{\text{ext}}}}$	Extracellular concentration	1 to 150	$\frac{\text{mol}}{{\text{m}}^{\text{3}}}$
${\mathit{\text{c}}}_{{\mathit{\text{i}}}_{\mathit{\text{int}}}}$	Intracellular concentration	1 to 150	$\frac{\text{mol}}{{\text{m}}^{\text{3}}}$
${\mathit{\text{D}}}_{{\mathit{\text{mem}}}_{\mathit{\text{i}}}}$	Membrane diffusion coefficient for ion I	1.0 × 10−18	$\frac{{\text{m}}^{\text{2}}}{\text{s}}$
${\mathit{\text{P}}}_{{\mathit{\text{mem}}}_{\mathit{\text{i}}}}$	Membrane permeability for ion i	0.13	$\frac{\text{nm}}{\text{s}}$
Vcell, Venv	Voltage in cell and environment	−10 to −80	mV
Vmem	Transmembrane voltage	−10 to −80	mV
${\overrightarrow{\mathrm{\Phi }}}_{\mathit{\text{i}}}$	Mass flux of ion i	1.0	$\frac{\mathrm{\mu }\text{mol}}{\text{s}{\text{m}}^{\text{2}}}$
ρe	Ionic charge density	600	$\frac{C}{{\text{m}}^{\text{3}}}$
$\overrightarrow{\mathit{\text{J}}}$	Ionic current density	10–500	$\frac{\mathrm{\mu }\text{A}}{{\text{cm}}^{\text{2}}}$
${\mathrm{\beta }}_{\mathit{\text{GJ}}}^{\mathit{\text{o}}}$	GJ diffusion scaling-coefficient	5.0 × 10−7
βTJ	TJ diffusion scaling-coefficient	1.0 × 10−7
DNaV, DKV	Max membrane diffusion for voltage-gated channel	1.0 × 10−14	$\frac{{\text{m}}^{\text{2}}}{\text{s}}$
$\overrightarrow{\mathit{\text{E}}}$	Electric field	1 × 105	V/m