scholarly journals Expression of Adenosine Receptors in Rodent Pancreas

2019 ◽  
Vol 20 (21) ◽  
pp. 5329 ◽  
Author(s):  
Hayashi
Keyword(s):  
Guinea Pig ◽  
Adenosine Receptor ◽  
Adenosine Receptors ◽  
Exocrine Pancreas ◽  
A2a Adenosine Receptor ◽  
Secretory Rate ◽  
Rat Pancreas ◽  
A2a Adenosine Receptors ◽  
Duct Cells ◽  
Adenosine Receptor Agonist

Adenosine regulates exocrine and endocrine secretions in the pancreas. Adenosine is considered to play a role in acini-to-duct signaling in the exocrine pancreas. To identify the molecular basis of functional adenosine receptors in the exocrine pancreas, immunohistochemical analysis was performed in the rat, mouse, and guinea pig pancreas, and the secretory rate and concentration of HCO3− in pancreatic juice from the rat pancreas were measured. The A2A adenosine receptor colocalized with ezrin, an A-kinase anchoring protein, in the luminal membrane of duct cells in the mouse and guinea pig pancreas. However, a strong signal ascribed to A2B adenosine receptors was detected in insulin-positive β cells in islets of Langerhans. The A2A adenosine receptor agonist 4-[2-[[6-Amino-9-(N-ethyl-β-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid (CGS 21680) stimulated HCO3−-rich fluid secretion from the rat pancreas. These results indicate that A2A adenosine receptors may be, at least in part, involved in the exocrine secretion of pancreatic duct cells via acini-to-duct signaling. The adenosine receptors may be a potential therapeutic target for cancer as well as exocrine dysfunctions of the pancreas.

Evidence for regulated coupling of A1 adenosine receptors by phosphorylation in Zucker rats

1995 ◽  
Vol 268 (4) ◽  
pp. E693-E704 ◽  
Author(s):  
D. A. Berkich ◽  
D. R. Luthin ◽  
R. L. Woodard ◽  
S. J. Vannucci ◽  
J. Linden ◽  
...  
Keyword(s):  
Adenosine Receptor ◽  
Adenosine Receptors ◽  
Receptor Agonist ◽  
High Sensitivity ◽  
Zucker Rats ◽  
Guanine Nucleotide ◽  
Agonist Binding ◽  
A1 Adenosine Receptor ◽  
Adenosine Receptor Agonist ◽  
A1 Adenosine Receptors

Studies were designed to find the molecular basis for previous observations that lipolysis is less active and A1 adenosine receptor signaling is more active in adipocytes from obese than from lean Zucker rats. With quantitative immunoblot procedures for detection, Gi alpha 1 and Gs alpha 45 levels were found anomalously low in obese compared with lean membranes (50 and 30%, respectively), but other G alpha subunit levels were normal. However, the sensitivity of the receptor-Gi protein to GTP was about 5- to 10-fold higher in obese compared with lean membranes when assessed from 1) the ability of GTP to inhibit forskolin-stimulated adenylyl cyclase in the presence of an adenosine receptor agonist and 2) the ability of a nonhydrolyzable guanine nucleotide analogue to alter A1 adenosine receptor agonist binding. Alkaline phosphatase treatment of isolated adipocyte membranes from obese but not lean animals decreased guanine nucleotide sensitivity of agonist binding. Surprisingly, solubilized adipocyte A1 adenosine receptors from all animals exhibited the same high sensitivity to guanine nucleotides as that of intact obese membranes, and this high sensitivity could be decreased 20-fold by treatment with alkaline phosphatase. These data suggest that protein phosphorylation may regulate coupling of the A1 adenosine receptor in rat adipocyte membranes.

Adenosine receptor gene expression in rat kidney

1992 ◽  
Vol 263 (6) ◽  
pp. F991-F995 ◽  
Author(s):  
D. R. Weaver ◽  
S. M. Reppert
Keyword(s):  
Adenosine Receptor ◽  
Rat Kidney ◽  
Renin Secretion ◽  
A1 Adenosine Receptor ◽  
A2a Adenosine Receptor ◽  
Excretory Function ◽  
A2a Adenosine Receptors ◽  
Receptor Mrna ◽  
Collecting Ducts ◽  
Receptor Mrnas

Adenosine is an important modulator of renal function. Adenosine produced and released within the kidney is thought to participate in the metabolic regulation of glomerular filtration (tubuloglomerular feedback), as well as in regulating renal excretory function and renin secretion. The recent cloning of cDNAs encoding the A1 and A2a adenosine receptors from rat brain allows direct examination of potential sites of adenosine action within the rat kidney. Northern blot analysis of rat kidney poly(A)+ RNA revealed that A1 adenosine receptor mRNA was more abundant in kidney than the A2a adenosine receptor transcript. In situ hybridization with 35S-labeled cRNA probes was used to localize A1 and A2a adenosine receptor mRNAs within the kidney. A1 adenosine receptor mRNA was most abundant in the collecting ducts of the papilla and inner medulla. Collecting ducts in the outermost portion of the inner stripe of the outer medulla and cells of the juxtaglomerular apparatus also expressed A1 adenosine receptor mRNA. A2a adenosine receptor mRNA was localized to the renal papilla. The distribution of A1 and A2a adenosine receptor mRNAs within the rat kidney supports previously postulated roles for adenosine in the regulation of renal hemodynamics, excretory function, and renin secretion.

A novel small molecule A2A adenosine receptor agonist, indirubin-3′-monoxime, alleviates lipid-induced inflammation and insulin resistance in 3T3-L1 adipocytes

2019 ◽  
Vol 476 (16) ◽  
pp. 2371-2391 ◽  
Author(s):  
Saynaz A. Choudhary ◽  
Nikita Bora ◽  
Dipanjan Banerjee ◽  
Leena Arora ◽  
Anindhya Sundar Das ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Adenosine Receptor ◽  
In Vitro Study ◽  
A2a Adenosine Receptor ◽  
Insulin Resistant ◽  
Adenosine Receptor Agonist ◽  
Inflammatory State

Abstract Saturated free fatty acid-induced adipocyte inflammation plays a pivotal role in implementing insulin resistance and type 2 diabetes. Recent reports suggest A2A adenosine receptor (A2AAR) could be an attractive choice to counteract adipocyte inflammation and insulin resistance. Thus, an effective A2AAR agonist devoid of any toxicity is highly appealing. Here, we report that indirubin-3′-monoxime (I3M), a derivative of the bisindole alkaloid indirubin, efficiently binds and activates A2AAR which leads to the attenuation of lipid-induced adipocyte inflammation and insulin resistance. Using a combination of in silico virtual screening of potential anti-diabetic candidates and in vitro study on insulin-resistant model of 3T3-L1 adipocytes, we determined I3M through A2AAR activation markedly prevents lipid-induced impairment of the insulin signaling pathway in adipocytes without any toxic effects. While I3M restrains lipid-induced adipocyte inflammation by inhibiting NF-κB dependent pro-inflammatory cytokines expression, it also augments cAMP-mediated CREB activation and anti-inflammatory state in adipocytes. However, these attributes were compromised when cells were pretreated with the A2AAR antagonist, SCH 58261 or siRNA mediated knockdown of A2AAR. I3M, therefore, could be a valuable option to intervene adipocyte inflammation and thus showing promise for the management of insulin resistance and type 2 diabetes.

scholarly journals Discovery of A New Human A2A Adenosine Receptor Agonist, Truncated 2-Hexynyl-4′-thioadenosine

2010 ◽  
Vol 1 (9) ◽  
pp. 516-520 ◽  
Author(s):  
Xiyan Hou ◽  
Hea Ok Kim ◽  
Varughese Alexander ◽  
Kyunglim Kim ◽  
Sun Choi ◽  
...  
Keyword(s):  
Adenosine Receptor ◽  
Receptor Agonist ◽  
A2a Adenosine Receptor ◽  
Adenosine Receptor Agonist

Targeted deletion of A2A adenosine receptors attenuates the protective effects of myocardial postconditioning

2007 ◽  
Vol 293 (4) ◽  
pp. H2523-H2529 ◽  
Author(s):  
R. Ray Morrison ◽  
Xing Lin Tan ◽  
Catherine Ledent ◽  
S. Jamal Mustafa ◽  
Polly A. Hofmann
Keyword(s):  
Functional Recovery ◽  
Adenosine Receptor ◽  
Adenosine Receptors ◽  
Troponin I ◽  
Ischemia Reperfusion ◽  
Receptor Subtype ◽  
Protective Effects ◽  
Targeted Deletion ◽  
Beneficial Effects ◽  
A2a Adenosine Receptors

Endogenous adenosine is an important ligand trigger for the cardioprotective effects of postconditioning (POC), yet it is unclear which adenosine receptor subtype is primarily responsible. To evaluate the role of A2A adenosine receptors in POC-induced protection, global ischemia-reperfusion was performed with and without POC in isolated wild-type (WT) and A2A adenosine receptor knockout (A2AKO) mouse hearts. Injury was measured in terms of postischemic functional recovery and release of cardiac troponin I (cTnI). Activation of protective signaling with POC was assessed by Akt and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation. In WT hearts, POC improved recovery of postischemic developed pressure in early (81.6 ± 6.4% of preischemic baseline vs. 37.5 ± 5.6% for non-POC WT at 1 min) and late (62.2 ± 4.2% of baseline vs. 45.5 ± 5.3% for non-POC WT at 30 min) reperfusion, reduced cTnI release by 37%, and doubled the phosphorylation of both Akt and ERK1/2. These beneficial effects of POC were blocked by treatment with the selective A2A adenosine receptor antagonist ZM-241385 during reperfusion. Postischemic functional recovery, cTnI release, and phosphorylation of Akt and ERK1/2 were not different between non-POC WT and A2AKO hearts. In A2AKO hearts, POC did not improve functional recovery, reduce cTnI release, nor increase phosphorylation of Akt or ERK1/2. Thus the protective effects of POC are attenuated by both selective A2A receptor antagonism and targeted deletion of the gene encoding A2A adenosine receptors. These observations support the conclusion that endogenous activation of A2A adenosine receptors is an essential trigger leading to the protective effects of POC in isolated murine hearts.

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