Characteristics of purine-regulated receptors (Dec 2008)

Receptor		Main distribution	Agonists	Antagonists	Transduction mechanisms
P1 adenosine)	A1	Brain, spinal cord, testis, heart, autonomic nerve terminals	CCPA>R-PIA=S-ENBA; CVT-510; GR79236	DPCPX, N-0840, MRS1754, N-0840, WRC-0571	Gi/Go ¯cAMP
	A2A	Brain, heart, lungs, spleen	HENECA>CGS 21680=CVT-3146; ATL-146e	KF17837, SCH58261, ZM241385, KW 6002	GS cAMP
	A2B	Large intestine, bladder	Bay60-6583	Enprofylline, MRE2029-F20, MRS1754, MRS1706, PSB1115, Alloxazine, MRE-2029-F20	GS cAMP
	A3	Lung, liver, brain, testis, heart	IB-MECA>2-Cl-IB-MECA; DBXRM; VT160	MRS1220, L-268605, MRS1191, MRS1523(rat), VUF8504, VUF5574, MRS1220	Gi/Go, Gq/G11, ¯cAMP, PLC-b activation
P2X	P2X1	Smooth muscle, platelets, cerebellum, dorsal horn spinal neurons	ATP = 2-MeSATP≥a,b-meATP=L-b,g-meATP (rapid desensitization)	TNP-ATP, IP5I, NF023, NF449, RO1, MRS2159	Intrinsic cation channel (Ca^2+ and Na^+)
	P2X2	Smooth muscle, CNS, retina, chromaffin cells, autonomic and sensory ganglia	ATP³ATPgS³2-MeSATP>>a,b-meATP (pH + zinc sensitive)	Suramin, isoPPADS, RB2, NF770, NF279, NF778	Intrinsic ion channel (particularly Ca^2+)
	P2X3	Sensory neurones, NTS, some sympathetic neurons	2-MeSATP³ATP³a,b-meATP³Ap5A (rapid desensitization)	TNP-ATP, PPADS, A317491, Ip5I, NF110, phenol red, RO4, RO51, RN-1838, Spinorphin	Intrinsic cation channel
	P2X4	CNS, testis, colon	ATP>>a,b-meATP=2-MeSATP=CTP Ivermectin potentiation	TNP-ATP (weak), BBG (weak), phenolphthalein, Paroxetine	Intrinsic ion channel (especially Ca^2+)
	P2X5	Proliferating cells in skin, gut, bladder, thymus, spinal cord	ATP=2-MeSATP= ATPgS>a,b-meATP	Suramin, PPADS, BBG	Intrinsic ion channel
	P2X6	CNS, motor neurons in spinal cord	- (functions poorly as a homomultimer)	-	Intrinsic ion channel
	P2X7	Apoptotic cells in, for example, immune cells, pancreas, skin	BzATP³2-MeSATP≥ATP >>a,b-meATP	KN62, KN04, MRS2427, O-ATP, Coomassie BBG, RN-6189, Az11645373, A-740003, A-438079, N’-aryl acyl hydrazides, A-804598	Intrinsic cation channel and a large pore with prolonged activation
P2Y	P2Y1	Epithelial and endothelial cells, platelets, immune cells, osteoclasts	MRS2365>2-MeSADP=Ap5(γB)=ADPbS> 2-MeSATP=ADP>ATP	MRS2179, MRS2500, MRS2279, PIT	Gq/G11; PLC-b activation
	P2Y2	Immune cells, epithelial and endothelial cells, kidney tubules, osteoblasts	2-thio-UTP>UTP=ATP>UTPgS; INS 37217; INS 365; MRS2498; Ap4A; Up4-phenyl ester	Suramin > RB2, AR-C126313; PSB-716	Gq/G11 and possibly Gi/Go; PLC-b activation
	P2Y4	Endothelial cells, placenta, spleen, thymus	UTP>ATP>Up4U>UTPgS; INS 37217	RB2 > suramin	Gq/G11 and possibly Gi; PLC-b activation
	P2Y6	Some epithelial cells, placenta, T cells, thymus, microglia (activated)	3-phenacyl-UDP>UDPbS>UDP>UTP>>ATP; α,β-methylene-UDP	MRS2578, MRS2567, MRS2575 (human)	Gq/G11; PLC-b activation
	P2Y11	Spleen, intestine, granulocytes	AR-C67085MX>BzATP=ATPgS>ATP; NF546; NAD^+; NAADP^+	Suramin > RB2, NF157, 5’-AMPS NF340	Gq/G11 and GS; PLC-b activation
	P2Y12	Platelets, glial cells	2-MeSATP≥2-MeSADP>ADP>ATP	CT50547, AR-C69931MX, INS49266, AZD6140, PSB0413, ARL66096, 2-MeSAMP, Carba-nucleosides, MRS2395	GaI; inhibition of adenylate cyclase
	P2Y13	Spleen, brain, lymph nodes, bone marrow, erythrocytes	ADP=2-MeSADP>>2-MeSATP>ATP	MRS2211, 2-MeSAMP	Gi/Go
	P2Y14	Placenta, adipose tissue, stomach, intestine, discrete brain regions	UDP glucose≥UDP-galactose; MRS2690	-	Gq/G11

Abbreviations: Ap₅(γB), Adenosine pentaphosphate γ-boranophosphate; BBG, Brilliant blue green; BzATP, 2’-&3’-O-(4-benzoyl-benzoyl)-ATP; cAMP, cyclic AMP; CCPA, chlorocyclopentyl adenosine; CPA, cyclopentyl adenosine; CTP, cytosine triphosphate; IP₃, inosine triphosphate; Ip₅I, di-inosine pentaphosphate; 2-MeSADP, 2-methylthio ADP; 2-MeSATP, 2-methylthio ATP; NECA, 5'-N-ethylcarboxamido adenosine; PLC, phospholipase C; RB2, reactive blue 2; P2X receptor subtype agonist potencies based on rat preparations, while P1 and P2Y receptor subtype agonist potencies are based on human preparations.