Adenosine receptor

9 pmoles mg protein respectively. CGS 21680 is a potent inUbitor of platelet aggregaticH) in human and rabbit blood (17). An adenosine binding protein, a otin has been purified fi om human platelet membranes (18). NECA binds adenotin with a 

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Adenosine receptors are members of the P purinoceptor GPCR family and can be classified into four subtypes A, 3 ... 

Administration of dipyridamole-AMP to mice 5—25 min after 1 Gy (100 rad) of TBI y-kradiation is also protective, as indicated by plasma thymidine levels and the amount of saline soluble polynucleotides in the thymus (112). Adding dipyridamole-AMP to in vitro kradiated suspensions of thymocytes enhances the rejoining of DNA strand breaks (112). These post-kradiation effects ate presumably mediated by the activation of extraceUulat adenosine receptors. 

FIGURE 4.18 Affinity of adenosine receptor agonists in whole cells (dark bars) and membranes (cross-hatched bars, high-affinity binding site). Data shown for (1) 2-phenylaminoadenosine, (2) 2-chloro adenosine, (3) 5 -N-ethylcarboxamidoadenosine, (4) N6-cyclohexyladenosine, (5) (-)-(R)-N6-phenylisopropyladenosine, and (6) N6-cyclopentyladenosine. Data redrawn from [15],... 

FIGURE 9.14 Effects of adenosine receptor agonist 2-chloro-adenosine on vascular perfusion pressure of isolated perfused rat kidneys. Minor effects seen in untreated kidneys (filled circles) and pronounced vasoconstriction while vasodilatation in kidneys coperfused with subthreshold concentrations of a-adrenoceptor vasoconstrictor methoxamine and vasodilatatory activation of adenylyl cyclase with forskolin (open circles). Redrawn from [49]. 

Abscissae, 254f Absolute stoichiometry, 180 Adenosine receptor agonists, 70 Adenylate cyclase, 23, 25f 62-Adrenoceptor antagonists, 4 6-Adrenoceptors, 82 Adsorption process... 

Purinergic System Adenosine Receptors Sterol Transporters... 

Extracellular adenosine acts through a class of G protein-coupled receptors (GPCRs), defined across mammalian species as Ab A2a, A2B, and A3ARs (adenosine receptors). Adenosine has a cytoprotective role in the body, both in the periphery and in the central nervous system. Following binding of adenosine, or another naturally occurring agonist, the receptor... 

Adenosine Receptors. Figure 1 Structures of widely used AR agonists, both nonselective and selective. Affinities/potencies at the ARs are found in Table 2. (a) Nucleoside derivatives that are either nonselective or selective for A receptors (1-12). (b) Nucleoside derivatives that are selective for A2a. A2a/A2b (mixed), or A3 receptors (13-19). 

Adenosine Receptors. Table 1 Characteristics of the four subtypes of adenosine receptors (human, unless noted)... 

Adenosine Receptors. Table 2 Affinity of commonly used adenosine receptor agonists and antagonists for defining pharmacologically adenosine receptor subtypes... 

Adenosine Receptors. Figure 3 An alignment of the primary sequences of the four human AR subtypes. Regions of conservation are highlighted. indicates the most conserved (X.50) residue in each TM region. Bold residues correspond to those indicated in Table 1. The A2A receptor is truncated in the carboxy-terminal region. 

Akkari R, Burbiel JC, Hockemeyer J et al (2006) Recent progress in the development of adenosine receptor ligands as antiinflammatory drugs. Curr Top Med Chem 6 1375-1399... 

Jacobson KA, Gao ZG (2006) Adenosine receptors as therapeutic targets. Nat Rev Drug Discov 5 247-264... 

G-protein-coupled Receptors Dopamine System Adenosine Receptors Chemokine Receptors... 

Adenosine activates the atrial Ai-adenosine receptor, which opens the Ik Ado channel leading to... 

Activation of dopamine 1 receptors (fenoldopam) or inhibition of A1 adenosine receptors (CVT 124, KW-3902) are additional approaches that cause increased NaCl excretion at least in part by inhibition of proximal reabsoiption. 

Beyond Viagra, there are a number of other PDE inhibitors that are used clinically. In fact, the classic drugs papaverine and dipyridamole were used clinically before their effects on PDEs were known. Caffeine and theophylline (a compound found in tea) are also PDE inhibitors. However, all of these drugs most likely have multiple targets, making conclusions regarding the roles of PDEs in processes that are sensitive to these agents difficult to interpret. Certainly, some of their effects are due to their actions on adenosine receptors. 

PI (adenosine) receptors were explored as therapeutic targets before P2 receptors. Adenosine was identified early and is in current use to treat supraventricular tachycardia. A2a receptor antagonists are being investigated for the treatment of Parkinson s disease and patents have been lodged for the application of PI receptor subtype agonists and antagonists for myocardial ischaemia and reperfusion injury, cerebral ischaemia, stroke, intermittent claudication and renal insufficiency. 

Derivatives of 2,4-dioxopurine, which may act as adenosine receptor antagonists, depending on the chemical structure. 

Acyl-CoA Synthetase Adaptive Immunity Adaptor Proteins Addiction Addison s Disease Additive Interaction Adenosine Adenosine Receptors Adenoviruses Adenylate Cyclase Adenylyl Cyclases ADH ADHD... 

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