TABLE 8.

Binding affinity of agonists and antagonists at rat adenosine receptor subtypes (K_i values with 95% confidence intervals or ±S.E.M. in parentheses)

	A₁	A_2A	A₃	Reference
Agonists with unmodified ribose
R-PIA	1.2 (±0.16)	124 (±9)		—^a
	1.3 (1.1–1.6)	730 (690–770)		—^b
	0.51			—^c
			220 (±43)	—^d
			160 (±52)	—^e
S-PIA	49 (±2.4)	1,800 (±380)		—^a
	29			—^f
			920 (±310)	—^e
CPA	0.59 (±0.02)	460 (±15)		—^a
	0.8 (0.6–1.0)	2,000 (1,400–2,900)		—^b
			240 (±36)	—^e
CCPA	0.4 (0.2–0.7)	3,900 (2,500–4,700)		—^b
	0.23			—^c
			240 (±71)	—^e
ADAC	0.85 (±0.35)			—^w
2-Cl-adenosine	9.3 (±0.58)	63 (±7.5)		—^a
			1,900 (±900)	—^e
DPMA	140 (±23)	4.4 (±0.2)		—^u
			3,600 (±1,700)	—^e
(S)-ENBA	0.3 (±0.02)	1,400 (±150)		—^v
Agonists with 5_-modified ribose
NECA	6.3 (±0.52)	10 (±0.5)		—^a
	11 (7.0–17)	22 (20–25)		—^f
	3.7			—^c
			260 (±36)	—^d
CGS 21680	3100 (±470)	22 (±4.3)		—^g
			580 (±32)	—^e
HENECA	136 (95–195)	3.8 (1.5–9.9)		—^f
PENECA	698 (611–798)	120 (112–128)		—^h
PHPNECA	2.5 (2.2–2.9)	0.9 (0.7–1.3)		—ⁱ
AB-MECA	430 (±45)	1,600 (±180)	14 (±3)	—^j
IB-MECA	54 (±5)	56 (±8)	1.1 (±0.3)	—^j
IAB-MECA	18 (±5)	200 (±84)	1.3 (±0.18)	—^j
Cl-IB-MECA	820 (±570)	470 (±370)	0.33 (±0.08)	—^k
Antagonists: xanthines
DPCPX	0.3	340		—^l
	0.18^* (0.16–0.20)			—^l
			>10,000	—^e
XAC	2.8 (1.9–4.2)			—^m
	3.5	24		—^l
	4	50		—ⁿ
			>100,000	—^o
MRS1754	17 (±3.6)	610 (±290)		—^o
MSX-2	900 (±10)	8 (±3)		—^p
Theophylline	11,000	32,000		—^b
			>100,000	—^o
Antagonists: non-xanthines
CGS 15943	21 (±3.5)	3.3 (±1.8)		—^q
	22	3		—ⁿ
	6.4 (6.2–6.6)	1.2 (1.1–1.3)		—^r
			>100,000	—^o
SCH 58261	120 (100–140)	2.3 (2.0–2.7)		—^r
ZM 241385	2,000 (1,500–2,700)	0.30 (0.10–0.95)	150,000 (87,000–210,000)	—^s
MRE 3008F20	>10,000	2,000 (±220)	>10,000	—^t

Data from saturation experiments; where confidence limits are missing, they are within 0.15 log units.

Bruns et al., 1986; brain membranes (A₁), striatum (A_2A); radioligands [³H]CHA (A₁), [³H]NECA (A_2A).

Lohse et al., 1988; brain membranes (A₁), striatum (A_2A); radioligands [³H]PIA (A₁), [³H]NECA (A_2A).

Klotz et al., 1991; brain membranes; radioligand [³H]DPCPX.

Olah et al., 1994; transfected CHO cells; radioligand ¹²⁵I-AB-MECA.

van Galen et al., 1994; transfected CHO cells; radioligand ¹²⁵I-APNEA.

Cristalli et al., 1992; brain membranes (A₁), striatum (A_2A); radioligands [³H]DPCPX (A₁), [³H]NECA (A_2A).

Hutchison et al., 1989; rat brain; radioligands [³H]CHA (A₁), [³H]NECA (A_2A). Given are IC₅₀ values; based on the experimental conditions K_i values should be about 0.5– 0.7 and 0.9 times the IC₅₀ values for A₁ and A_2A, respectively.

Cristalli et al., 1995; brain membranes (A₁), striatum (A_2A); radioligands [³H]CHA (A₁), [³H]CGS 21680 (A_2A).

ⁱ

Camaioni et al., 1997; brain membranes (A₁), striatum (A_2A); radioligands [³H]CHA (A₁), [³H]CGS 21680 (A_2A).

Gallo-Rodriguez et al., 1994; rat brain (A₁), rat striatum (A_2A), transfected CHO cells (A₃); radioligand [³H]PIA (A₁), [³H]CGS 21680 (A_2A), ¹²⁵I-AB-MECA (A₃).

Kim et al., 1994; rat brain (A₁), rat striatum (A_2A), transfected CHO cells (A₃); radioligand [³H]PIA (A₁), [³H]CGS 21680 (A_2A), ¹²⁵I-AB-MECA (A₃).

Lohse et al., 1987; brain membranes (A₁), striatum (A_2A); radioligands [³H]PIA (A₁), [³H]NECA (A_2A).

Jacobson et al., 1986; rat brain, radioligand [³H]XAC.

ⁿ

Jarvis et al., 1989; rat brain; radioligands [³H]CHA (A₁), [³H]CGS 21680 (A_2A).

Kim et al., 2000; transfected HEK 293 cells (A₁), rat striatum (A_2A); radioligands [³H]PIA (A₁), [³H]CGS 21680 (A_2A).

Sauer et al., 2000; brain cortex (A₁), striatum (A_2A); radioligand [³H]CHA (A₁), [³H]CGS 21680 (A^2A).

Williams et al., 1987; brain (A₁), striatum (A_2A); radioligands [³H]CHA (A₁), [³H]NECA (A_2A). Given are IC₅₀ values; based on the experimental conditions K_i values should be about 0.5– 0.7 and 0.9 times the IC₅₀ values for A₁ and A_2A, respectively.

Baraldi et al., 1994; rat brain (A₁), rat striatum (A_2A); radioligand [³H]CHA (A₁), [³H]CGS 21680 (A_2A).

Poucher et al., 1995; brain cortex (A₁), PC 12 cells (A_2A), transfected CHO cells (A₃); radioligands [³H]PIA (A₁), [³H]NECA (A_2A) ¹²⁵I-AB-MECA (A₃). Given are IC₅₀ values; based on the experimental conditions K_i values should be about 0.1, 0.2, and 0.5 times the IC₅₀ values for A₁, A_2A, and A₃, respectively.

Varani et al., 2000; brain cortex (A₁), striatum (A_2A), transfected CHO cells (A₃); radioligands [³H]DPCPX (A₁), [³H]SCH 58261 (A_2A), ¹²⁵I-AB-MECA (A₃).

Bridges et al., 1988; brain (A₁), striatum (A_2A); radioligand [³H]CHA (A₁), [³H]NECA (A_2A); DPMA or PD 125944 is compound 16 in this paper.

Trivedi et al., 1989; brain (A₁), striatum (A_2A); radioligand [³H]CHA (A₁), [³H]NECA (A_2A).

Jacobson et al., 1987; brain (A₁), radioligand [³H]PIA (A₁).