A1 receptor

Target id: 18

Nomenclature: A1 receptor

Family: Adenosine receptors

Annotation status:  image of a green circle Annotated and expert reviewed. Please contact us if you can help with updates.  » Email us

Gene and Protein Information
class A G protein-coupled receptor
Species TM AA Chromosomal Location Gene Symbol Gene Name Reference
Human 7 326 1q32.1 ADORA1 adenosine A1 receptor 79,108,131
Mouse 7 326 1 E4 Adora1 adenosine A1 receptor 87,140
Rat 7 326 13q13 Adora1 adenosine A1 receptor 86
Previous and Unofficial Names
RDC7
adenosine receptor A1
A1-AR
A1R
Database Links
Specialist databases
GPCRDB aa1r_human (Hs), aa1r_mouse (Mm), aa1r_rat (Rn)
Other databases
ChEMBL Target
DrugBank Target
Ensembl Gene
Entrez Gene
GenitoUrinary Development Molecular Anatomy Project
KEGG Gene
OMIM
RefSeq Nucleotide
RefSeq Protein
UniProtKB
Wikipedia
Natural/Endogenous Ligands
adenosine

Download all structure-activity data for this target as a CSV file

Agonists
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Affinity Units Reference
[3H]CCPA Hs Full agonist 9.2 pKd 70,111
pKd 9.2 (Kd 6.31x10-10 M) [70,111]
5-Cl-5-deoxy-(±)-ENBA Hs Full agonist 9.3 pKi 31
pKi 9.3 (Ki 5.1x10-10 M) [31]
N(6)-cyclohexyladenosine Rn Agonist 9.1 pKi 20
pKi 9.1 (Ki 8.5x10-10 M) [20]
(R)-PIA Rn Agonist 8.9 pKi 20
pKi 8.9 (Ki 1.2x10-9 M) [20]
CCPA Rn Agonist 8.9 pKi 78
pKi 8.9 (Ki 1.3x10-9 M) [78]
(R,S)-PHPNECA Hs Full agonist 8.6 pKi 138
pKi 8.6 [138]
TCPA Hs Agonist 8.6 pKi 7
pKi 8.6 (Ki 2.8x10-9 M) [7]
GR79236 Rn Agonist 8.5 pKi 56
pKi 8.5 (Ki 3.1x10-9 M) [56]
NECA Rn Agonist 8.3 pKi 82
pKi 8.3 (Ki 5.1x10-9 M) [82]
tecadenoson Pig Agonist 8.2 pKi 56,96
pKi 8.2 (Ki 6.5x10-9 M) [56,96]
2-chloroadenosine Rn Agonist 8.2 pKi 20
pKi 8.2 (Ki 6.7x10-9 M) [20]
cyclopentyladenosine Hs Full agonist 6.5 – 9.4 pKi 18,21,36,47,56-57,111
pKi 6.5 – 9.4 [18,21,36,47,56-57,111]
CCPA Hs Full agonist 7.7 – 8.1 pKi 56,100
pKi 7.7 – 8.1 [56,100]
MRS3558 Mm Agonist 7.8 pKi 78
pKi 7.8 (Ki 1.58x10-8 M) [78]
LUF5831 Hs Partial agonist 7.7 pKi 47
pKi 7.7 [47]
(R)-PIA Hs Full agonist 6.4 – 8.7 pKi 36,57,70,111,130
pKi 6.4 – 8.7 [36,57,70,111,130]
Cl-IB-MECA Mm Agonist 7.5 pKi 78
pKi 7.5 (Ki 3.5x10-8 M) [78]
piclidenoson Hs Agonist 7.3 pKi 56
pKi 7.3 (Ki 5.1x10-8 M) [56]
GS9667 Hs Agonist 7.3 pKi 29
pKi 7.3 (Ki 5.5x10-8 M) [29]
2-hexynyl-NECA Hs Full agonist 7.2 pKi 138
pKi 7.2 [138]
adenosine Rn Agonist 7.1 pKi 143
pKi 7.1 (Ki 7.3x10-8 M) [143]
apadenoson Hs Agonist 7.1 pKi 56
pKi 7.1 (Ki 7.7x10-8 M) [56]
adenosine Hs Agonist ~7.0 pKi 143
pKi ~7.0 (Ki ~1x10-7 M) [143]
MRS3558 Rn Agonist 7.0 pKi 78
pKi 7.0 (Ki 1.05x10-7 M) [78]
NECA Hs Full agonist 5.3 – 8.2 pKi 36,57,111,130,143
pKi 5.3 – 8.2 [36,57,111,130,143]
Cl-IB-MECA Hs Agonist 6.7 pKi 56
pKi 6.7 (Ki 2.2x10-7 M) [56]
MRS3558 Hs Agonist 6.6 pKi 56
pKi 6.6 (Ki 2.6x10-7 M) [56]
Cl-IB-MECA Rn Agonist 6.6 pKi 78
pKi 6.6 (Ki 2.8x10-7 M) [78]
HEMADO Hs Agonist 6.5 pKi 71,138
pKi 6.5 (Ki 3.3x10-7 M) [71,138]
PENECA Hs Full agonist 6.2 pKi 138
pKi 6.2 [138]
CGS 21680 Hs Full agonist 5.8 – 6.4 pKi 36,56
pKi 5.8 – 6.4 [36,56]
CGS 21680 Rn Agonist 5.7 pKi 78
pKi 5.7 (Ki 1.8x10-6 M) [78]
2-chloroadenosine Hs Full agonist 5.2 – 5.6 pKi 57,111
pKi 5.2 – 5.6 [57,111]
(S)-PIA Hs Full agonist 4.6 – 6.0 pKi 57,130
pKi 4.6 – 6.0 [57,130]
CP608,039 Hs Agonist 5.1 pKi 56
pKi 5.1 (Ki 7.3x10-6 M) [56]
BAY 60-6583 Hs Agonist <5.0 pKi 74
pKi <5.0 (Ki >1x10-5 M) [74]
regadenoson Hs Agonist <5.0 pKi 56
pKi <5.0 (Ki >1x10-5 M) [56]
MRS5151 Mm Agonist 5.0 pKi 90
pKi 5.0 (Ki 1.05x10-5 M) [90]
MRS5151 Hs Agonist 4.8 pKi 90
pKi 4.8 (Ki 1.49x10-5 M) [90]
binodenoson Hs Agonist 4.3 pKi 56
pKi 4.3 (Ki 4.8x10-5 M) [56]
View species-specific agonist tables
Agonist Comments
The role for adenosine as endogenous ligand for the A1 receptor is described in [32] and [33].

Tecadenoson (CV-510) is a selective A1 agonist with potential therapeutic use in controlling paroxysmal supraventricular tachycardia [104].
Primary target mapping: we have tagged the adenosine A1 receptor as the primary target for this endogenous ligand as the affinity is marginally higher at this receptor isoform. However, adenosine is likely to exert clinical effects via other adenosine receptor family members.
Antagonists
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Affinity Units Reference
[3H]DPCPX Hs Antagonist 8.4 – 9.2 pKd 18,30,70,102,111,130
pKd 8.4 – 9.2 (Kd 1.2x10-9 – 6x10-10 M) [18,30,70,102,111,130]
xanthine amine congener Hs Antagonist 7.5 pKd 31
pKd 7.5 [31]
PSB36 Rn Antagonist 9.9 pKi 1
pKi 9.9 (Ki 1.24x10-10 M) [1]
DPCPX Rn Antagonist 9.0 – 9.7 pKi 67,72,139
pKi 9.0 – 9.7 (Ki 1x10-9 – 1.8x10-10 M) [67,72,139]
CPFPX Rn Antagonist 9.2 pKi 50
pKi 9.2 (Ki 6.3x10-10 M) [50]
LUF5981 Hs Antagonist 9.1 pKi 14
pKi 9.1 (Ki 9x10-10 M) [14]
derenofylline Hs Antagonist 9.0 pKi 61
pKi 9.0 (Ki 1x10-9 M) [61]
FR194921 Hs Antagonist 8.9 pKi 85
pKi 8.9 [85]
CPFPX Hs Antagonist 8.9 pKi 50
pKi 8.9 (Ki 1.26x10-9 M) [50]
tonapofylline Rn Antagonist 8.9 pKi 66
pKi 8.9 (Ki 1.3x10-9 M) [66]
rolofylline Rn Antagonist 7.9 – 9.7 pKi 106
pKi 7.9 – 9.7 (Ki 1.26x10-8 – 1.9x10-10 M) [106]
WRC-0571 Hs Antagonist 8.8 pKi 88
pKi 8.8 [88]
rolofylline Hs Antagonist 8.1 – 9.1 pKi 66,106
pKi 8.1 – 9.1 (Ki 8x10-9 – 7.2x10-10 M) [66,106]
derenofylline Rn Antagonist 8.6 pKi 61
pKi 8.6 (Ki 2.51x10-9 M) [61]
CGS 15943 Hs Antagonist 8.5 pKi 102
pKi 8.5 (Ki 3.5x10-9 M) [102]
DPCPX Hs Antagonist 7.4 – 9.2 pKi 21,53,100,111,139
pKi 7.4 – 9.2 (Ki 3.98x10-8 – 6.3x10-10 M) [21,53,100,111,139]
CGS 15943 Rn Antagonist 8.2 pKi 81
pKi 8.2 (Ki 6.4x10-9 M) [81]
tonapofylline Hs Antagonist 8.1 pKi 66
pKi 8.1 (Ki 7.4x10-9 M) [66]
MRS1754 Rn Antagonist 7.8 pKi 68
pKi 7.8 (Ki 1.68x10-8 M) [68]
8-cyclopentyltheophylline Hs Antagonist 7.5 – 8.0 pKi 18
pKi 7.5 – 8.0 [18]
FK-453 Hs Antagonist 7.7 pKi 56
pKi 7.7 (Ki 1.8x10-8 M) [56]
xanthine amine congener Hs Antagonist 7.6 pKi 57
pKi 7.6 [57]
vipadenant Hs Antagonist 7.2 pKi 41
pKi 7.2 (Ki 6.8x10-8 M) [41]
ST-1535 Hs Antagonist 7.1 pKi 93
pKi 7.1 (Ki 7.18x10-8 M) [93]
MRE 2029F20 Hs Antagonist 6.7 pKi 6,134
pKi 6.7 [6,134]
istradefylline Rn Antagonist 6.6 pKi 34
pKi 6.6 (Ki 2.3x10-7 M) [34]
AS70 Hs Antagonist 6.6 pKi 134
pKi 6.6 [134]
AS100 Hs Antagonist 6.5 pKi 134
pKi 6.5 [134]
ATL802 Hs Antagonist 6.4 pKi 68
pKi 6.4 (Ki 3.69x10-7 M) [68]
MRS1754 Hs Antagonist 6.4 pKi 68
pKi 6.4 (Ki 4.03x10-7 M) [68]
PSB-11 Rn Antagonist 6.4 pKi 103
pKi 6.4 (Ki 4.4x10-7 M) [103]
ZM-241385 Hs Antagonist 6.1 – 6.6 pKi 56,102
pKi 6.1 – 6.6 [56,102]
MRS928 Rn Antagonist 6.3 pKi 65
pKi 6.3 [65]
L-97-1 Hs Antagonist 6.2 pKi 100
pKi 6.2 [100]
MRS1041 Rn Antagonist 6.2 pKi 65
pKi 6.2 [65]
SCH 58261 Hs Antagonist 6.1 – 6.3 pKi 56,102,130
pKi 6.1 – 6.3 [56,102,130]
AS99 Hs Antagonist 6.1 pKi 134
pKi 6.1 [134]
galangin Rn Antagonist 6.1 pKi 65
pKi 6.1 [65]
PSB-10 Rn Antagonist 6.1 pKi 98
pKi 6.1 (Ki 8.05x10-7 M) [98]
istradefylline Hs Antagonist 6.1 pKi 34
pKi 6.1 (Ki 8.41x10-7 M) [34]
MSX-2 Rn Antagonist 6.1 pKi 116
pKi 6.1 (Ki 9x10-7 M) [116]
MRS1042 Rn Antagonist 6.0 pKi 65
pKi 6.0 [65]
preladenant Hs Antagonist <6.0 pKi 95
pKi <6.0 (Ki >1x10-6 M) [95]
MRE 3008F20 Hs Antagonist 5.9 – 6.0 pKi 56,134-135
pKi 5.9 – 6.0 [56,134-135]
SCH442416 Hs Antagonist 5.9 pKi 56
pKi 5.9 (Ki 1.11x10-6 M) [56]
PSB-11 Hs Antagonist 5.8 pKi 103
pKi 5.8 (Ki 1.64x10-6 M) [103]
PSB-10 Hs Antagonist 5.8 pKi 103
pKi 5.8 (Ki 1.7x10-6 M) [103]
KF26777 Hs Antagonist 5.7 pKi 112
pKi 5.7 (Ki 1.8x10-6 M) [112]
CVT-6883 Hs Antagonist 5.7 pKi 28
pKi 5.7 (Ki 1.94x10-6 M) [28]
MRS1093 Rn Antagonist 5.7 pKi 65
pKi 5.7 [65]
PSB1115 Rn Antagonist 5.7 pKi 97
pKi 5.7 (Ki 2.2x10-6 M) [97]
MRS1132 Rn Antagonist 5.6 pKi 65
pKi 5.6 [65]
MSX-2 Hs Antagonist 5.6 pKi 116
pKi 5.6 (Ki 2.5x10-6 M) [116]
LAS38096 Hs Antagonist 5.6 pKi 27,136
pKi 5.6 (Ki 2.821x10-6 M) [27,136]
flavone Rn Antagonist 5.5 pKi 65
pKi 5.5 [65]
isobutylmethylxanthine Hs Antagonist 5.1 pKi 57
pKi 5.1 [57]
sakuranetin Rn Antagonist 5.1 pKi 65
pKi 5.1 [65]
theophylline Hs Antagonist 4.9 – 5.2 pKi 30,57,70,134
pKi 4.9 – 5.2 [30,57,70,134]
ATL802 Mm Antagonist 5.0 pKi 68
pKi 5.0 (Ki 9.583x10-6 M) [68]
MRS1191 Hs Antagonist <5.0 pKi 78
pKi <5.0 (Ki >1x10-5 M) [78]
MRS1523 Hs Antagonist <5.0 pKi 78
pKi <5.0 (Ki >1x10-5 M) [78]
VUF5574 Rn Antagonist >5.0 pKi 133
pKi >5.0 (Ki <1x10-5 M) [133]
PSB603 Hs Antagonist <5.0 pKi 10
pKi <5.0 (Ki >1x10-5 M) [10]
PSB603 Rn Antagonist <5.0 pKi 10
pKi <5.0 (Ki >1x10-5 M) [10]
PSB1115 Hs Antagonist <5.0 pKi 46
pKi <5.0 (Ki >1x10-5 M) [46]
theophylline Rn Antagonist 4.8 – 5.1 pKi 54,97
pKi 4.8 – 5.1 (Ki 1.4x10-5 – 8.74x10-6 M) [54,97]
morin Rn Antagonist 4.9 pKi 65
pKi 4.9 [65]
MRS1523 Rn Antagonist 4.8 pKi 78
pKi 4.8 (Ki 1.56x10-5 M) [78]
caffeine Hs Antagonist 4.3 – 5.0 pKi 1,23,54
pKi 4.3 – 5.0 (Ki 4.49x10-5 – 1.07x10-5 M) [1,23,54]
MRS923 Rn Antagonist 4.6 pKi 65
pKi 4.6 [65]
CSC Rn Antagonist 4.6 pKi 55
pKi 4.6 (Ki 2.8x10-5 M) [55]
MRS1065 Rn Antagonist 4.5 pKi 65
pKi 4.5 [65]
MRS1086 Rn Antagonist 4.5 pKi 65
pKi 4.5 [65]
flavanone Rn Antagonist 4.5 pKi 65
pKi 4.5 [65]
MRS1066 Rn Antagonist 4.4 pKi 65
pKi 4.4 [65]
MRS1084 Rn Antagonist 4.4 pKi 65
pKi 4.4 [65]
MRS1191 Rn Antagonist 4.4 pKi 78
pKi 4.4 (Ki 4.01x10-5 M) [78]
caffeine Rn Antagonist 4.4 – 4.4 pKi 19,45
pKi 4.4 – 4.4 (Ki 4.4x10-5 – 4.1x10-5 M) [19,45]
MRS1062 Rn Antagonist 4.3 pKi 65
pKi 4.3 [65]
View species-specific antagonist tables
Antagonist Comments
Reference [23] does not use a transfected cell system but measures binding to the human hippocampus.

Istradefylline pKi values are derived from unpublished data (Müller et al.).
Allosteric Modulators
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Affinity Units Reference
VPC171 Hs Positive - - 5,52
[5,52]
PD81723 Hs Positive - - 12
[12]
Allosteric Modulator Comments
In vitro, VPC171 enhances A1R agonist ((R)-PIA)-induced ERK1/2 phosphorylation with a 2.4-fold positive cooperativity, and enhances [35S]GTPγS binding with a 6.9-fold positive cooperativity under the same conditions [52].
Primary Transduction Mechanisms
Transducer Effector/Response
Gi/Go family Adenylate cyclase inhibition
References:  16,57
Secondary Transduction Mechanisms
Transducer Effector/Response
Gs family
Gq/G11 family
Adenylate cyclase stimulation
Phospholipase C stimulation
References:  16
Tissue Distribution
Brain > heart, kidney, lung.
Species:  Human
Technique:  Northern blotting.
References:  114
Spermatozoa.
Species:  Human
Technique:  immunocytochemistry.
References:  91
Adopicytes.
Species:  Human
Technique:  Northern blotting.
References:  13
Jejunum, ileum, colon.
Species:  Human
Technique:  RT-PCR.
References:  15
Brain (cerebral cortex, hippocampus), spinal cord and trigeminal ganglia.
Species:  Human
Technique:  Immunohistochemistry.
References:  118
Kidney: medullary tubular structures.
Species:  Mouse
Technique:  RNAse protection and RT-PCR.
References:  137
Jejunum.
Species:  Mouse
Technique:  RT-PCR.
References:  39
Brain: cerebral cortex.
Species:  Mouse
Technique:  Autoradiography.
References:  80
Brain: cortex, cerebellum, hippocampus > olfactory bulb, mesencephalon, striatum.
Species:  Rat
Technique:  Northern blotting.
References:  86
Kidney: medullary tubular structures.
Species:  Rat
Technique:  RNAse protection and RT-PCR.
References:  137
CNS: spinal cord lumbar dorsal horn.
Species:  Rat
Technique:  Immunohistochemistry.
References:  123
Testes: Sertoli cells >> spermatogonia, spermatocytes.
Species:  Rat
Technique:  in situ hybridisation.
References:  110
Spermatozoa.
Species:  Rat
Technique:  immunocytochemistry.
References:  91
Spleen, stomach, heart, testis.
Species:  Rat
Technique:  Northern blotting.
References:  86
Expression Datasets

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Log average relative transcript abundance in mouse tissues measured by qPCR from Regard, J.B., Sato, I.T., and Coughlin, S.R. (2008). Anatomical profiling of G protein-coupled receptor expression. Cell, 135(3): 561-71. [PMID:18984166] [Raw data: website]

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Functional Assays
Measurement of cAMP levels in CHO cells transfected with the mouse A1 receptor.
Species:  Mouse
Tissue:  CHO cells.
Response measured:  Inhibition of cAMP accumulation.
References:  140
Measurement of cAMP levels in CHO.K1 cells transfected with the human A1 receptor.
Species:  Human
Tissue:  CHO.K1 cells.
Response measured:  Inhibition of cAMP accumulation.
References:  131
Measurement of cAMP levels in CHO cells transfected with the rat A1 receptor.
Species:  Rat
Tissue:  CHO cells.
Response measured:  Inhibition of cAMP accumulation.
References:  86
Measurement of extracellular-regulated kinase 1/2 (ERK1/2) phosphorylation in CHO cells transfected with the human A1 receptor.
Species:  Human