TABLE 1.

General Pharmacology of P2X Receptors

Receptor	Kd/EC50	Preferred Substrates	References
P2X1	Kd(ATP) = 2–3 nM	No specific agonists for P2X1 only	102
	EC50(ATP) = 0.07 µM	BzATP > 2meSATP > ATP > αβmeATP	103
	EC50(BzATP) = 0.003 µM
P2X2	EC50(ATP) = 1.2 µM	BzATP > ATP = 2meSATP ≫ αβmeATP	103
	EC50(BzATP) = 0.75 µM
P2X3		2meSATP ≫ ATP > αβmeATP	104
	EC50(ATP) = 0.5 µM	BzATP > 2meSATP > ATP > αβmeATP	103
	EC50(BzATP) = 0.08 µM
P2X4	EC50(ATP) = 10 µM	BzATP > ATP = 2meSATP ≫ αβmeATP	103
	EC50(BzATP) = 7 µM
P2X5	EC50(ATP) = 10 µM	ATP = 2meSATP ≫ αβmeATP > BzATP	103
P2X6 (hetero)	EC50(ATP) = 12 µM	2meSATP ≥ ATP ≫ αβmeATP	103
	EC50(2meSATP) = 9 µM
P2X7	EC50(ATP) = 100 µM	BzATP > ATP = 2meSATP ≫ αβmeATP	103
	EC50(BzATP) = 20 µM