$d V d time = − (i_Ca + i_K + i_K_Ca + i_K_ATP) / Cm$

$i_Ca = g_Ca m_infinity (V − V_Ca)$

$m_infinity = (1.0 + e (vm − V) / sm) -1.0$

$i_K = g_K n (V − V_K)$

$d n d time = (n_infinity − n) / tau_n n_infinity = (1.0 + e (vn − V) / sn) -1.0$

$i_K_Ca = g_K_Ca omega (V − V_K)$

$omega = c 5.0 / (c 5.0 + kD 5.0)$

$i_K_ATP = g_K_ATP a (V − V_K)$

$d a d time = (a_infinity − a) / tau_a a_infinity = (1.0 + e (r − c) / sa) -1.0$

$d c d time = fcyt (Jmem + Jer)$

$d c_er d time = − fer Vcyt_Ver Jer$

$Jmem = − (alpha i_Ca + kPMCA c)$

$J_SERCA = kSERCA c$

$Jleak = pleak (c_er − c)$

$JIP3 = O_infinity (c_er − c) O_infinity = (c / (d_act + c)) 3.0 (IP3 / (d_IP3 + IP3)) 3.0 (c / (d_inact + c)) 3.0$

$Jer = Jleak + JIP3 − J_SERCA$