
where the asterisk denotes an internodal quantity and where
I
Na
= P
Na
m
3
huz(Na); I
Kf
= P
Kf
n
2
z(K); I
Ks
= P
Ks
sz(K);
I
IR
= P
IR
q(0.53z(Na) + 0.47z(K)); I
LK
= P
LK
z(Na) (21)
and
z(y) = (V
a
F
2
/RT)([y]
o
–[y]
i
exp(V
a
F/RT))/(1–exp(V
a
F/RT)) (22)
for y = Na, K (T = 310.16K; F, Faraday’s constant; R, universal gas
constant). The fraction activations are given by the differential
equation:
dy/dt = a
y
(1−y)−b
y
y for y = m, h, n, s, q (23)
where
A (ms
–1
) B(mV) C(mV)
a
m
1.872 −56.59 6.06
b
m
3.973 −61 9.41
a
h
0.550 −109.74 9.06
b
h
22.61 −26 12.5
a
n
0.129 −53 10
b
n
0.324 −78 10
s 0.00556 −60 22
q 0.00125 −110 −12
u −80 −12
and
a
m
, a
n
= A(V
a
−B)/(1 ...