• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1620-1624
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• 2011

Homologated analogues 3a and 3b of potent and selective A3 adenosine receptor ligands, IB-MECA and dimethyl-IB-MECA were synthesized from commercially available 1-O-acetyl-2,3,5-tri-O-benzoyl-${\beta}$-D-ribofuranose (4) via $Co_2(CO)_8$-catalyzed siloxymethylation as a key step. Unfortunately, homologated analogues 3a and 3b did not show significant binding affinities at three subtypes of adenosine receptors, indicating that free rotation, resulting from homologation, induced unfavorable interactions in the binding site of the receptor maybe due to the presence of many conformations.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.32-36
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• 1997

An adenosine deaminase inhibitor-producing bacterium was isolated from soil. An isolate exhibiting high adenosine deaminase inhibitory activity, was designated J-89, and classified as a strain of Bacillus subtilis on the basis of its morphological, phenotypic characteristics, the menaquinone content and cellular fatty acid composition. To confirm the taxonomic position of the strain we need more information such as DNA-DNA homology and other chemotaxonomic characteristics. In this paper we provisionally named strain J-89 as Bacillus sp. J-89 pending further chemotaxonomic study and analysis of adenosine deaminase inhibitor.

• Journal of Life Science
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• v.9 no.1
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• pp.64-68
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• 1999

The properties of purified intracellular adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) of Nocardioides sp. J-326TK isolated from soil have been studied. The enzyme deaminated adenosine and 2`-deoxyadenosine and the respective {TEX}$K_{M}${/TEX} values were 4.0×{TEX}$10^{-4}${/TEX} M and 5.0× {TEX}$10^{-4}${/TEX} M, but the enzyme was not active on 8-bromoadenosine, 6-methylaminopurine riboside, ATP, ADP, 2`-AMP, 3`-AMP, 5`-AMP, dAMP, cAMP, NAD, FAD, NADP and adenine. The enzyme activity was strongly inhibited by the addition of {TEX}$Hg^{2+}${/TEX} and {TEX}$Ag^{+}${/TEX}, {TEX}$Cu^{2+}${/TEX}, {TEX}$Co^{2+}${/TEX} and {TEX}$Mn^{2+}${/TEX} also inhibited the activity but much less extent. The effect of alkyl reagents, metal chelating reagents and certain other compounds on the enzyme activity were also examined. No reagent activated the enzyme. On the contrary, the enzyme reaction was slightly inhibited by o-phenanthroline and 6-benzyladenosine.

• Genomics & Informatics
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• v.11 no.4
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• pp.282-288
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• 2013

The molecular vibration-activity relationship in the receptor-ligand interaction of adenosine receptors was investigated by structure similarity, molecular vibration, and hierarchical clustering in a dataset of 46 ligands of adenosine receptors. The resulting dendrogram was compared with those of another kind of fingerprint or descriptor. The dendrogram result produced by corralled intensity of molecular vibrational frequency outperformed four other analyses in the current study of adenosine receptor agonism and antagonism. The tree that was produced by clustering analysis of molecular vibration patterns showed its potential for the functional classification of adenosine receptor ligands.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.365.1-365.1
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• 2002

Since adenosine A3 receptor has been cloned from rat brain. a number of compounds have been synthesized and evaluated for the binding affinity to this receptor. Among these. 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-methylcarboxamide (2-CI-IB-MECA) has been found to be one of the most selective agonists (Ki = 1.0 nM) for rat adenosine A3 receptor. On the basis of the high binding affinity of 2-CI-IB-MECA to adenosine A3 receptor. it was interesting to find out whether 2'-hydroxyl group of 2-CI-IB-MECA is essential for the binding affnity to the receptor. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.189.1-189.1
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• 2003

4-(4-Methoxyphenyl)-2-aminothiazole and 3-(4-methoxyphenyl)-5-aminothiadiazole derivatives have been synthesized and evaluated as selective antagonists for human adenosine A$_3$ receptors. A methoxy group in the 4-position of the phenyl ring and N-acetyl or propionyl substitutions of the aminothiazole and aminothiadiazole templates displayed great increases of binding affinity and selectivity for human adenosine A$_3$ receptors. The most potent A$_3$ antagonist of the present series, N-［3-(4-methoxy-phenyl)-［1,2,4］thiadiazol-5-yl］-acetamide exhibiting a K$\_$i/ value of 0.79 nM at human adenosine A$_3$ receptors, showed antagonistic property in functional assay of cAMP biosynthesis involved in one of the signal transduction pathways of adenosine A$_3$ receptors. (omitted)

• Biomolecules & Therapeutics
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• v.12 no.2
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• pp.68-73
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• 2004

This study was performed to investigate the regulatory mechanism of cerebral blood How of adenosine $A_2$ receptor agonist in the rats, and to define whether its mechanism is mediated by nitric oxide (NO), adenylate cyclase and guanylate cyclase. In pentobarbital-anesthetized, pancuronium-paralyzed and artificially ventilated male Sprague-Dawley rats, all drugs were applied topically to the cerebral cortex. Blood flow from cerebal cortex was measured using laser-Doppler flowmetry. Topical application of an adenosine $A_2$ receptor agonist [5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA; 4 umol/l)] increased cerebral blood flow. This effect of CPCA (4 umol/l) was blocked by pretreatment with NO synthase inhibitor [$N^G$-nitro-L-argine methylester (L-NAME; 140 umol/l)] and adenylate cyclase inhibitor [MDL-12,330 (20 umol/l)]. But the effect of CPCA (4 umol/l) was not blocked by pretreatment with guanylate cyclase inhibitor [LY-83,583 (10 umol/l)]. These results suggest that adenosine $A_2$ receptor increases cerebral blood How. It seems that this action of adenosine $A_2$ receptor is mediated via the NO and the activation of adenylate cyclase in the cerebral cortex of the rats.

• Biomolecules & Therapeutics
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• v.12 no.2
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• pp.108-113
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• 2004

This study was performed to investigate the regulatory mechanism of cerebral blood flow of adenosine $A_{2B}$ receptor agonist in the rats, and to define whether its mechanism is mediated by adenylate cyclase and guanylate cyclase. in pentobarbital-anesthetized, pentobrabital-paralyzed and artificially ventilated male Sprague-Dawley rats, all drugs were applied topically to the cerebral cortex. Blood How from cerebral cortex was measured using laser-Doppler flowmetry. Topical application of an adenosine $A_{2B}$ receptor agonist, 5'-N-ethylcar-boxamidoadenosine (NECA; 4 umol/l) increased cerebral blood flow. This effect of NECA (4 umol/l) was not blocked by pretreatment with adenylate cyclase inhibitor, MDL-12330 (20 umol/l). But effect of NECA (4 umol/l) was blocked by pretreatment with guanylate cyclase inhibitor, LY-83383 (10 umol/l). These results suggest that adenosine $A_{2B}$ receptor increases cerebral blood flow. It seems that this action of adenosine $A_{2B}$ receptor is mediated via the activation of guanylate cyclase in the cerebral cortex of the rats.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.499-504
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• 2000

We previously demonstrated that 6-paradol, a compound structurally related to capsaicin, showed to produce prolonged analgesia in experimental animals. The effects of 6-paradol on the release of adenosine were investigated in the rat spinal cord synaptosomes by high performance liquid chromatography. In the presence of $Ca^{++}$, adenosine was released from synaptosomes of rat spinal cord by 6-paradol and capsaicin in a dose dependent manner. Nifedifine, L-type voltage sensitive calcium channel blocker, was found to be ineffective in releasing adenosine by $10\;{\mu}M$ 6-paradol. After exposure to $10\;{\mu}M$ capsazepine, a novel capsaicin selective antagonist, the level of adenosine evoked by $10\;{\mu}M$ 6-paradol was decreased by 75%, and that evoked by $10\;{\mu}M$ capsaicin was blocked completely. These results suggest that the analgesic effect of 6-paradol might be mediated by the vanilloid (capsaicin) sensitive pathway, or the direct binding to the vanilloid receptor.

• Biomolecules & Therapeutics
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• v.14 no.2
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• pp.119-124
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• 2006

This study was performed to investigate the influence of the spinal adenosine $A_1$ receptors on the central regulation of blood pressure (BP) and heart rate (HR), and to define whether its mechanism is mediated by cyclic AMP (cAMP), cyclic GMP (cGMP) or potassium channel. Intrathecal (i.t.) administration of drugs at the thoracic level were performed in anesthetized, artificially ventilated male Sprague-Dawley rats. I.t. injection of adenosine $A_1$ receptor agonist, $N^6$-cyclohexyladenosine (CHA; 1, 5 and 10 nmol) produced dose dependent decrease of BP and HR and it was attenuated by pretreatment of 50 nmol of 8-cyclopentyl-1,3-dimethylxanthine, a specific adenosine $A_1$ receptor antagonist. Pretreatment with a cAMP analogue, 8-bromo-cAMP, also attenuated the depressor and bradycardiac effects of CHA (10 nmol), but not with cGMP analogue, 8-bromo-cGMP. Pretreatment with a ATP-sensitive potassium channel blocker, glipizide (20 nmol) also attenuated the depressor and bradycardiac effects of CHA (10 nmol). These results suggest that adenosine $A_1$ receptor in the spinal cord plays an inhibitory role in the central cardiovascular regulation and that this depressor and bradycardiac actions are mediated by cAMP and potassium channel.