Table 1.

Voltage and calcium dependence for steady-state (x_∞) and time constant (τ_x) functions for activation (m) and inactivation (h) gating variables

Cond.	m, h	x∞	τx (ms)
INa	m3	$\frac{1}{1+\exp \left[\frac{-\left(V+24.7\right)}{5.29}\right]}$	$1.32-\frac{1.26}{1+\exp \left[\frac{-\left(V+120\right)}{25}\right]}$
	h	$\frac{1}{1+\exp \left[\frac{V+48.9}{5.18}\right]}$	$\left\{\frac{0.67}{1+\exp \left[\frac{-\left(V+62.9\right)}{10}\right]}\right\}\times \left\{1.5+\frac{1}{1+\exp \left[\frac{V+34.9}{3.6}\right]}\right\}$
ICaT	m3	$\frac{1}{1+\exp \left[\frac{-\left(V+25\right)}{7.2}\right]}$	$55-\frac{49.5}{1+\exp \left[\frac{-\left(V+58\right)}{17}\right]}$
	h	$\frac{1}{1+\exp \left[\frac{V+36}{7}\right]}$	$AB:87.5-\frac{75}{1+\exp \left[\frac{-\left(V+50\right)}{16.9}\right]}$
			$PD:350-\frac{300}{1+\exp \left[\frac{-\left(V+50\right)}{16.9}\right]}$
ICaS	m3	$\frac{1}{1+\exp \left[\frac{-\left(V+22\right)}{8.5}\right]}$	$16-\frac{13.1}{1+\exp \left[\frac{-\left(V+25.1\right)}{26.4}\right]}$
INaP	m3	$\frac{1}{1+\exp \left[\frac{-\left(V+26.8\right)}{8.2}\right]}$	$19.8-\frac{10.7}{1+\exp \left[\frac{-\left(V+26.5\right)}{8.6}\right]}$
	h	$\frac{1}{1+\exp \left[\frac{V+48.5}{4.8}\right]}$	$666-\frac{379}{1+\exp \left[\frac{-\left(V+33.6\right)}{11.7}\right]}$
Ih	m	$\frac{1}{1+\exp \left[\frac{V+70}{6}\right]}$	$272+\frac{1499}{1+\exp \left[\frac{-\left(V+42.2\right)}{8.73}\right]}$
IK	m4	$\frac{1}{1+\exp \left[\frac{-\left(V+14.2\right)}{11.8}\right]}$	$7.2-\frac{6.4}{1+\exp \left[\frac{-\left(V+28.3\right)}{19.2}\right]}$
IKCa	m4	$AB:\left(\frac{\left[Ca\right]}{\left[Ca\right]+30}\right)\frac{1}{1+\exp \left[\frac{-\left(V+51\right)}{4}\right]}$	$90.3-\frac{75.09}{1+\exp \left[\frac{-\left(V+46\right)}{22.7}\right]}$
		$PD:\left(\frac{\left[Ca\right]}{\left[Ca\right]+30}\right)\frac{1}{1+\exp \left[\frac{-\left(V+51\right)}{8}\right]}$
IA	AB: m4 PD: m3	$\frac{1}{1+\exp \left[\frac{-\left(V+27\right)}{8.7}\right]}$	$11.6-\frac{10.4}{1+\exp \left[\frac{-\left(V+32.9\right)}{15.2}\right]}$
	h	$\frac{1}{1+\exp \left[\frac{-\left(V+56.9\right)}{4.9}\right]}$	$38.6-\frac{29.2}{1+\exp \left[\frac{-\left(V+38.9\right)}{26.5}\right]}$
IMI	m	$\frac{1}{1+\exp \left[\frac{-\left(V+12\right)}{3.05}\right]}$	0.5

Note that I_A activation is m⁴ in the AB cell and m³ in the PD cell. The variable [Ca] refers to the intracellular calcium concentration (see table 2).