Table 1. Parameter values used in the... | Rockefeller University Press

Table 1.

Parameter values used in the kinetic model of P2X2R gating

Symbol	P2X2a values	P2X2b values	NMDG-only medium	Na-only medium
k₁	1 s⁻¹
k₂	60,000 (M · s)⁻¹
L₁	0.01 s⁻¹
L₂*	0.2 s⁻¹	0.3 s⁻¹
L₃	0.6 s⁻¹		0.3 s⁻¹	0.15 s⁻¹
L₄	0.3 s⁻¹
L₅	0.004 s⁻¹	0.1 s⁻¹	0.004, 0.1 s⁻¹^a
β₁	100 (s⁻² · µM⁻¹)
β₂	0.8 s²
β₃	0.02 s
β₄	2 (s · µM)⁻¹	0.2 (s · µM)⁻¹
σ	0.04 µM/s
k_x	0.1 s⁻¹
f (fraction of free calcium)	0.01^b		0^b	0^b
α (converting current to flux)	5 × 10⁻⁶ µM/(s · pA)
S ([Ca²⁺]_i contribution)	10⁻³^b
R (converting A to pA)	10¹²^b
k_c	0.04 s⁻¹
g₁₂ (Q₁ and Q₂ conductances)	8 × 10⁻⁸ A
g₃₄ (Q₃ and Q₄ conductances)	1.2 × 10⁻⁷ A
V (holding potential)	−0.06 V			−0.06 or 0.06 V
E₁₂ (reversal potential of Q₁ and Q₂)	−0.02 V		−0.075 V	−0.004 V
E₃₄ (reversal potential of Q₃ and Q₄)	0.02 V		−0.009 V	−0.002 V
WP (washout period)	250 s		NA	NA

Symbol	P2X2a values	P2X2b values	NMDG-only medium	Na-only medium
k₁	1 s⁻¹
k₂	60,000 (M · s)⁻¹
L₁	0.01 s⁻¹
L₂*	0.2 s⁻¹	0.3 s⁻¹
L₃	0.6 s⁻¹		0.3 s⁻¹	0.15 s⁻¹
L₄	0.3 s⁻¹
L₅	0.004 s⁻¹	0.1 s⁻¹	0.004, 0.1 s⁻¹^a
β₁	100 (s⁻² · µM⁻¹)
β₂	0.8 s²
β₃	0.02 s
β₄	2 (s · µM)⁻¹	0.2 (s · µM)⁻¹
σ	0.04 µM/s
k_x	0.1 s⁻¹
f (fraction of free calcium)	0.01^b		0^b	0^b
α (converting current to flux)	5 × 10⁻⁶ µM/(s · pA)
S ([Ca²⁺]_i contribution)	10⁻³^b
R (converting A to pA)	10¹²^b
k_c	0.04 s⁻¹
g₁₂ (Q₁ and Q₂ conductances)	8 × 10⁻⁸ A
g₃₄ (Q₃ and Q₄ conductances)	1.2 × 10⁻⁷ A
V (holding potential)	−0.06 V			−0.06 or 0.06 V
E₁₂ (reversal potential of Q₁ and Q₂)	−0.02 V		−0.075 V	−0.004 V
E₃₄ (reversal potential of Q₃ and Q₄)	0.02 V		−0.009 V	−0.002 V
WP (washout period)	250 s		NA	NA

Parameters with no values under P2X2bR, NMDG, and Na columns are identical to those listed under the P2X2aR column. NA, not applicable.

Left value is for P2X2aR, and right value is for P2X2bR.

Parameters without units are dimensionless.