Table 1.

I _max, EC₅₀, and Hill slope values for ATP concentration–response curves of WT and W46 mutant P2X4Rs. I _max represents peak currents generated by 100 μM ATP. EC₅₀ and Hill slope values were determined from ATP concentration–response curves. Data shown are mean ± SEM, n = 4–11

Receptor	ATP
	I max	EC50 (μM)	Hill slope
WT P2X4	4,163 ± 1,504	6.05 ± 0.53	1.57 ± 0.22
W46Y	3,078 ± 816	3.77 ± 0.98	1.82 ± 0.40
W46F	4,847 ± 1,152	4.13 ± 1.12	2.08 ± 0.62
W46D	2,059 ± 373	1.24 ± 0.31*	1.09 ± 0.11
W46K	6,523 ± 962	1.97 ± 0.29*	0.75 ± 0.12*
W46N	3,711 ± 717	1.37 ± 0.45*	0.64 ± 0.07*
W46L	2,118 ± 241	3.59 ± 1.20	1.18 ± 0.27
W46V	2,394 ± 192	1.85 ± 0.21*	1.06 ± 0.15
W46A	2,593 ± 363	3.18 ± 0.52	0.97 ± 0.07*

^* P < 0.05 compared to the EC₅₀ values of WT P2X4R