Table 1.

Radioligand binding affinity and angiotensin II type 2/AT₁ binding selectivity at cloned rat and human angiotensin II type 2 and AT₁ receptors (adapted from Smith and colleagues with permission¹⁰³).

Cloned rat receptors*	AT2R		AT1R		Binding affinity selectivity AT2R/AT1R
	Mean	SEM	Mean	SEM
Ligand	KD (nM)		KD (nM)
Angiotensin II	1.6	1.0	14.9	1.1	9.3
	IC50 (nM)		IC50 (µM)
EMA200	71.7	14.5	210.5	121.5	∼3000
EMA300	46.5	3.3	49.9	10.2	>1000
EMA400	75.2	10.0	2918	1270	>30,000
EMA401	39.5	5.2	408	335	>10,000
	2630	12
EMA402	804		85.4		106
Cloned human receptors
Ligand	IC50 (nM)		IC50 (nM)
Saralasin##	0.19		0.48		0.40
	Mean IC50 (nM)		Mean IC50 (µM)
EMA401#	39		n.c.		>10,000 but n.c.
EMA402#	1100		59		53.6
Compound 1530	25	9	>10		>400

^*n=3 to 4 separate experiments performed in duplicate except for EMA402 (R-enantiomer of EMA400), where n = 2 separate experiments each performed in duplicate.

For the human receptors, n = 1^# or 2^## performed in duplicate.

AT₂R, angiotensin II type 2 receptor; AT₁R, angiotensin II type 1 receptor; SEM, standard error of the mean; n.c., not calculable.