Table 1.

Ionic current parameters

Parameter	Description	Value	Reference
ISERCA,max	Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) maximum current	200/100 pA	See text
Kmf	Ca2+-ATPase constant for cytosolic or microdomain Ca2+	310 nM†	14
Kmr	Ca2+-ATPase constant for SR Ca2+	1.7 mM	41
nH	SR Ca2+-ATPase Hill coefficient	2†	37
νRyR	Ryanodine receptor (RyR) Ca2+ conductivity	12 s−1†	This study
Ka	RyR constant	0.3722 μM*	47
Kb	RyR constant	0.6360 μM*	47
Kc	RyR constant	0.0571 μM*	47
Kc−	RyR constant	0.1 s−1*	47
νIP3R	IP3R Ca2+ conductivity	10 s−1†	This study
νip3	Rate constant for IP3 production	1.85 s−1	12
[IP3ref]	Reference IP3 concentration	240 nM	11
α4	Feedback constant for Ca2+ stimulation of IP3 production	0.5	12
k4	Dissociation constant for Ca2+ stimulation of IP3 production	1.1 μM	11
Ir	Rate constant for IP3 consumption	1 s−1	11
d1	IP3 receptor dissociation constant	0.13 μM	11
a4	IP3 receptor binding constant	0.2 μM−1·s−1	11
d4	IP3 receptor dissociation constant	144.5 nM	11
a5	IP3 receptor binding constant	20 μM−1·s−1	11
d5	IP3 receptor dissociation constant	82.34 nM	11
GCaSOC,max	Maximum Ca2+ SOC current conductance	87 pS†	This study¶
KSOC	ISOC SR Ca2+ constant	100 μM	12
ΔCT	Chloride cotransport parameter	87.8251 mV*	22
JNaCl,max	Maximum flux though Na+-Cl− cotransporter	6.0 × 10−17 mol/s*	This study¶
JKCl,max	Maximum flux though K+-Cl− cotransporter	3.5 × 10−18 mol/s*	22
JNKCC,max	Maximum flux though Na+-K+-2Cl− cotransporter (NKCC)	6.0 × 10−17 mol/s*	This study¶
KNaNKCC	Na+ half-saturation constant for NKCC	46 mM*	43
KKNKCC	K+ half-saturation constant for NKCC	4 mM*	43
KCl,1NKCC	Cl− first half-saturation constant for NKCC	78 mM*	43
KCl,2NKCC	Cl− second half-saturation constant for NKCC	78 mM*	43
kon	Ca-Cl channel on-rate	3 μM−1·s−1*	24
koff	Ca-Cl channel off-rate	50 s−1*	24
α1	Ca-Cl kinetic constant	10 s−1*	24
α2	Ca-Cl kinetic constant	30 s−1*	24
α3	Ca-Cl kinetic constant	300 s−1*	24
β1, β2, β3	Ca-Cl kinetic constants	224 exp(−3.8 − 0.01Vmj) s−1*	24
GClCa,max	Ca-Cl channel maximum conductance	12 nS*	34
GK,b	K+ background current conductance	0.010 nS	51
GNa,b	Na+ background current conductance	0.010 nS	51
GCa,b	Ca+ background current conductance	0.012 nS	51
GCl,b	Cl− background current conductance	0.010 nS*	This study
GKir,max	Inward rectifier conductance	0.3 nS†	8
[K]ref	Reference K+ concentration	5.4 mM	51
GKv,max	Maximum IK,v conductance	9.8325 nS	51
GKATP,maxPATP	Maximum IK,ATP conductance at resting ATP concentration	1.036 nS	9
nATP	IK,ATP constant	0.463	9
GKCa,max	Maximum IK,Ca conductance	0.5 nS	51
τPF	Fast time constant for IK,Ca	0.5 ms	51
τPS	Slow time constant for IK,Ca	11.5 ms	51
INaK,α1,max	Maximum Na+/K+-ATPase α1-isoform current	1.95 μA/μF†	This study¶
INaK,α2,max	Maximum Na+/K+-ATPase α2-isoform current	0.30 mA/μF†	This study¶
Km,K	K+ half-saturation constant for Na+-K+-ATPase (both isoforms)	1.5 mM	12
Km,Na,α1	Na+ half-saturation constant for Na+-K+-ATPase α1-isoform	12 mM	12
Km,Na,α2	Na+ half-saturation constant for Na+-K+-ATPase α2-isoform	22 mM	12
INaCa,max	Maximum Na+/Ca2+ exchange current	14.13 μA/μF†	41
KmCai	Internal Ca2+ half-saturation constant for Na+/Ca2+ exchange	3.59 μM	41
KmCao	External Ca2+ half-saturation constant for Na+/Ca2+ exchange	1.3 mM	41
KmNai	Internal Na+ half-saturation constant for Na+/Ca2+ exchange	12.29 mM	41
KmNao	External Na+ half-saturation constant for Na+/Ca2+ exchange	87.5 mM	41
ksat	Na+/Ca2+ exchange saturation factor at negative potentials	0.27	41
γ	Constant for voltage dependence of Na+/Ca2+ exchange	0.35	41
KmCa,act	Constant for Na+/Ca2+ exchange	0.125 μM†	22
GVONa,max	Maximum IVONa conductance	2.86 nS	54
τm	IVONa activation time constant	0.1 mS	54
τh	IVONa inactivation time constant	1 mS	54
ICa,P,max	Maximum sarcolemmal Ca2+ pump current	1 μA/μF†	This study¶
Km,Ca,P	Half-saturation constant for sarcolemmal Ca2+ pump	0.17 μM†	15
GCaL,max	Maximum ICa,L conductance	1.4151 nS	51
[CM]tot	Total concentration of calmodulin binding sites available for Ca2+ binding in cytosol or microdomains	0.1 mM†	51
kCMon	Ca2+ on-rate for calmodulin	34 μM−1·s−1	41
kCMoff	Ca2+ off-rate for calmodulin	8.84 s−1†	Based on calmodulin dissociation constant (51)
[Bf]tot	Total concentration of other Ca2+-binding proteins in cytosol or microdomains	0.4 mM†	51
kBfon	Ca2+ on-rate for other binding proteins	100 μM−1·s−1	41
kBfoff	Ca2+ off-rate for other binding proteins	300 s−1†	Based on caltropin dissociation constant (29)
[Calseq]SRtot	Total concentration of calsequestrin sites available for Ca2+ binding in SR	140 μM	41
kCalseqon	Ca2+ on-rate for calsequestrin	100 μM−1·s−1	41
kCalseqoff	Ca2+ off-rate for calsequestrin	80,000 s−1†	Based on calsequestrin dissociation constant (48)

Unless otherwise indicated, parameter values are identical to those of the original model (12). SR, sarcoplasmic reticulum; VONa, voltage-activated sodium.

^¶Parameters were chosen so as to yield resting concentrations compatible with experimental observations.

^*New parameter;

^†revised parameter value.