TABLE 2.

Standard parameters in calcium release simulations

Symbol	Description	Value	References/comments
rT	ER tubule radius	190–300 nm	Limited by computational time
rC	Cytosolic depth from the ER tubule membrane	2 μm	Swillens et al., 1998
zT	Length of the ER tubule segment ≡ distance between two release sites	0.75–1.5 μm	Horne and Meyer, 1997;Callamaras and Parker, 1999
BT,fix	Total concentration of the stationary buffer	120–300 μM	Clapham, 1995; Swillens et al., 1998; Haddock et al., 1999
KB,fix	Dissociation constant of the stationary buffer	10 μM	Swillens et al., 1998
	On-rate constant of the stationary buffer	108 M−1 s−1	Clapham, 1995
BT,mob	Total concentration of the mobile buffer (EGTA)	40–100 μM	Relatively low level, to minimize the slowing down effects on calcium release (Horne and Meyer, 1997)
KB,mob	Dissociation constant of the mobile buffer (EGTA)	170–670 nM	Pape et al., 1995; Naraghi and Neher, 1997
	On-rate constant of the mobile buffer (EGTA)	1.5–2.5 μM−1 s−1	Pape et al., 1995; Naraghi and Neher, 1997
[K+]ext	Constant cytosolic [K+] at r > rC	140 mM	Nguyen et al., 1998
[Ca2+]ext	Constant cytosolic [Ca2+] at r > rC	450 nM	Nguyen et al., 1998
[ATP]	Constant cytosolic [ATP]	3 mM	Nguyen et al., 1998
[IP3]	Constant cytosolic [IP3]	3 μM	Nguyen et al., 1998
	Diffusion coefficient of Ca2+ ions in the cytosol	200–220 μm2 s−1	Clapham, 1995; Naraghi and Neher, 1997
	Diffusion coefficient of Ca2+ ions in the lumen	20–50 μm2 s−1	Kargacin, 1994; Clapham, 1995. One order lower than to correct for buffers and extremely tortuous ion pathway
	Diffusion coefficient of K+ ions in the cytosol	1500–2000 μm2 s−1	Hille, 1992
	Diffusion coefficient of K+ ions in the lumen	50–160 μm2 s−1	One order lower than as for Ca2+
	Diffusion coefficient of EGTA in the cytosol	170–220 μm2 s−1	Pape et al., 1995; Naraghi and Neher, 1997
	Capture radius of the Ca2+ channel	4–12 nm	Chosen to yield a saturating Ca2+ current ≅0.1 pA at 500 μM [Ca2+]ER (Bezprozvanny and Erlich, 1994; Swillens et al., 1998); corresponds roughly to the dimen sion of the square-shaped mouth of the channel (Swillens et al., 1998)
	Capture radius of the K+ channel	0.3–4 nm	Hille, 1992
gCa	Single-channel conductance of the Ca2+ channel	113 pS	Mak and Foskett, 1997
gK	Single-channel conductance of the K+ channel	15–20 pS	Vergara et al., 1998
KP	Smooth ER Ca2+ pump's activation constant	0.1–1 μM	De Young and Keizer, 1992; Dupont and Goldbeter, 1994
T	Temperature	298 K