• The Korean Journal of Physiology and Pharmacology
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• v.11 no.2
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• pp.37-43
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• 2007

Adenosine has been reported to provide cytoprotection in the central nervous systems as well as myocardium by activating cell surface adenosine receptors. However, the exact target and mechanism of its action still remain controversial. The present study was performed to examine whether adenosine has a protective effect against $A{\beta}$-induced injury in neuroglial cells. The astrocyte-derived human neuroglioma cell line, A172 cells, and $A{\beta}_{25{\sim}35}$ were employed to produce an experimental $A{\beta}$-induced glial cell injury model. Adenosine significantly prevented $A{\beta}$-induced apoptotic cell death. Studies using various nucleotide receptor agonists and antagonists suggested that the protection was mediated by $A_1$ receptors. Adenosine attenuated $A{\beta}$-induced impairment in mitochondrial functional integrity as estimated by cellular ATP level and MTT reduction ability. In addition, adenosine prevented $A{\beta}$-induced mitochondrial permeability transition, release of cytochrome c into cytosol and subsequent activation of caspase-9. The protective effect of adenosine disappeared when cells were pretreated with 5-hydroxydecanoate, a selective blocker of the mitochondrial ATP-sensitive $K^+$ channel. In conclusion, therefore we suggest that adenosine exerts protective effect against $A{\beta}$-induced cell death of A172 cells, and that the underlying mechanism of the protection may be attributed to preservation of mitochonarial functional integrity through opening of the mitochondrial ATP-sensitive $K^+$ channels.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.6
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• pp.753-761
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• 1998

Preconditioning of a heart with small doses of catecholamines induces a tolerance against the subsequent lethal ischemia. The present study was performed to find a specific receptor pathway involved with the catecholamine preconditioning and to test if adenosine plays a role in this cardioprotective effect. Isolated rat hearts, pretreated with small doses of ${\alpha}-\;or\;{\beta}-adrenergic$ agonists/antagonists, were subjected to 20 minutes ischemia and 20 minutes reperfusion by Langendorff perfusion method. Cardiac mechanical functions, lactate dehydrogenase and adenosine release from the hearts were measured before and after the drug treatments and ischemia. In another series of experiments, adenosine $A_1\;or\;A_2$ receptor blockers were treated prior to administration of adrenergic agonists. Pretreatments of a ${\beta}-agonist,\;isoproterenol(10^{-9}{\sim}10^{-7}\;M)$ markedly improved the post-ischemic mechanical function and reduced the lactate dehydrogenase release. Similar cardioprotective effect was observed with an ?-agonist, phenylephrine pretreatment, but much higher $concentration(10^{-4}\;M)$ was needed to achieve the same degree of cardioprotection. The cardioprotective effects of isoproterenol and phenylephrine pretreatments were blocked by a ${\beta}_1-adrenergic$ receptor antagonist, atenolol, but not by an ${\alpha}_1-antagonist,$ prazosin. Adenosine release from the heart was increased by isoproterenol, and the increase was also blocked by atenolol, but not by prazosin. A selective $A_1-adenosine$ receptor antagonist, 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX) blocked the cardioprotection by isoproterenol pretreatment. These results suggest that catecholamine pretreatment protects rat myocardium against ischemia and reperfusion injury by mediation of ${\beta}_1-adrenergic$ receptor pathway, and that adenosine is involved in this cardioprotective effect.

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.73-77
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• 1992

From the roots of Angelica dahurica Bentham et Hooker (Umbelliferae), five coumarin glucosides together with adenosine have been isolated and identified as nodakenin, 3'-hydroxymarmesinin, tert-O-$\beta$-D-glucopyranosyl-byakangelicin, sec-O-$\beta$-D-glucopyranosyl-byakangelicin and scopolin. This is the first report of the occurrence of these compounds in this plant.

• IMMUNE NETWORK
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• v.9 no.6
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• pp.255-264
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• 2009

Background: Chronic low grade inflammation is closely linked to type II diabetes, obesity, and atherosclerosis. Macrophages play a key role in the regulation of pro- or anti-inflammatory actions at the lesion sites of disease. Components of cordyceps militaris, cordycepin and adenosine, have been used for the modulation of inflammatory diseases. The effects of cordycepin in the modulation of macrophages have yet to be be elucidated. We investigated the effects of cordycepin and adenosine on the morphological changes of macrophages under the inflammatory condition of LPS and an anti-inflammatory condition involving high concentrations of adenosine. Methods: We confirmed the mRNA levels of the M1/M2 cytokine genes through RT-PCR and morphological change. Results: LPS-activated macrophages returned to their inactivated original shape, i.e., they looked like naive macrophages, through the treatment with high concentrations of cordycepin ($40{\mu}g/ml$). LPS and adenosine activated macrophages also returned to their original inactivated shapes after cordycepin treatment; however, at relatively higher levels of cordycepin than adenosine. This change did not occur with relatively low concentrations of cordycepin. Adenosine down-regulated the gene expression of M1 cytokines (IL-$1{\beta}$, TNF-${\alpha}$) and chemokines (CX3CR1, RANTES), such as cordycepin. Additionally, M2 cytokines (IL-10, IL-1ra, TGF-${\beta}$) were up-regulated by both cordycepin and adenosine. Conclusion: Based on these observations, both cordycepin and adenosine regulated the phenotypic switch on macrophages and suggested that cordycepin and adenosine may potentially be used as immunomodulatory agents in the treatment of inflammatory disease.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.442-446
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• 2010

Adenosine 3',5'-cyclic monophosphate (cAMP) is a second messenger responsible for a multitude of cellular responses. In this study, we utilized $\beta$-cyclodextrin ($\beta$-CD) as an artificial receptor with a hydrophobic cavity to elucidate the inclusion kinetics of cAMP in a hydrophobic environment using the ultrasonic relaxation method. The results revealed that the interaction of cAMP with $\beta$-CD followed a single relaxation curve as a result of host-guest interactions. The inclusion of cAMP into the $\beta$-CD cavity was found to be a diffusion-controlled reaction. The dissociation of cAMP from the $\beta$-CD cavity was slower than that of adenosine 5'-monophosphate (AMP). The syn and anti glycosyl conformations of adenine nucleotides are considered to play an important role in formation of the inclusion complex. Taken together, our findings indicate that hydrophobic interactions are involved in the inclusion complex formation of cAMP with $\beta$-CD and provide insight into the interactions of cAMP with cAMP-binding proteins.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.312-317
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• 2001

7'-Aldehyde-nucleosides analogue (2a, 2c) were synthesized from 6-N-benzoyl-2',3'-O-isopropylideneadenosine and uridine. The condensation of 2 with ethoxycarbonylmethylene Wittig reagent produced the adenosine and uridine analogues containing extended conjugated diene and ethoxycarbonyl group, ethyl-1',5',6',7',8'-pentadeoxy-1'-(adenin-9-yl)-$\beta$-D-ribo-nona-5'(E),7'(E)-dienofuranuronate (4b) and ethyl-1'. 5',6',7',8'-pentadeoxy-1'-(uracil-1-yl)-$\beta$-D-ribo-nona-5'(E),7'-(E)-dienofuranuronate (4c). 9-[8',8'-dibromo-5',6',7',8' -tetradeoxy-$\beta$-D-ribo-octa-5'(E),7'(E)-diene]nucleosides (6b, 6c) were also prepared from 2 with similar method.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.16-24
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• 2002

Three alkaloids and two steroids were isolated from the sclerotia of Grifola umbellata. Structures of the isolated compounds were determined as 9-$\beta$-D-ribofuranosyladenine (adenosine), 1-$\beta$-D-ribofuranosyluracil (uridine), 2,4-pyrimidinedione (uracil), ergosta-4, 6, 8 (14), 22-tetraen-3-one and ergosta-5, 7, 22-tritene-$3\beta$-ol (ergosterol) respectively on the basis of spectroscopic data and chemical correlations.

• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.235-240
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• 1995

The development of selectable markers for transformation has been a major factor in the successful genetic manipulation of plant. We established a new selectable marker system for tobacco transformation using chimeric adenosine deaminase (ADA) gene, which confers resistance to cytotoxic adenosine analogues, 9-$\beta$-D-arabinofuranosyl adenine(Ara-A) and cordycepin. The transformants with the chimeric ADA gene in tobacco grew in the presence of normally lethal level of cytotoxic adenosine analogues, 100 $\mu$M Ara-A and 50 $\mu$M cordycepin. We successfully distinguished transformed shoot from non-transformed shoot on the same selectable media with cytotoxic adenosine analogues. In this selectable media, we were able to select seeds with/ without ADA gene from transgenic tobacco seeds. Theses results show that the mammalian ADA gene may serve as a new selectable marker for tobacco transformation.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.1-11
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• 1996

Since it has been reported that the depolarization-induced norepinephrine (NE) release is inhibited by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus, a large body of experimental data on the post-receptor mechanism of this process has been accumulated. But, the post-receptor mechanism of presynaptic $A_1-adenosine$ receptor on the NE release has not been clearly elucidated yet. Therefore, it was attempted to clarify the post-receptor mechanisms of the $A_1-adenosine$ receptor-mediated control of NE release in this study. Slices from rat hippocampus were equilibrated with $^3H-norepinephrine$ and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 $Vcm^{-1}$, 2 ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Adenosine, in concentrations ranging from $1{\sim}30{\mu}M$, decreased the NE release in a dose-dependent manner, without affecting the basal rate of release. The adenosine effects were significantly inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, $2{\mu}M$), a selective $A_1-receptor$ antagonist. The responses to N-ethylmaleimide (NEM, 10 & $30{\mu}M$), a SH-alkylating agent of G-protein, were characterized by increments of the evoked NE-release and the basal release, and the adenosine effects were completely abolished by NEM pretreatment. $4{\beta}-Phorbol$ 12,13-dibutyrate (PDB, $1{\mu}M$), a specific protein kinase C (PKC) activator, increased the evoked NE release, whereas polymyxin B sulfate (PMB,0.1 mg), a PKC inhibitor, decreased the release, and the adenosine effects were inhibited by these agents. Nifedipine $(1{\mu}M)$, a $Ca^{2+}-channel$ blocker of dihydropyridine analogue, did not affect the adenosine effect. Tetraethylammonium (TEA, 3 mM) increased the evoked NE release, and inhibited the adenosine effects, but glibenclamide, a ATP dependent $K^+-channel$ blocker, did not. Finally, 8-bromo cyclic AMP (100 & $300{\mu}M$), a membrane-permeable analogue of cAMP, did not alter the NE release, but adenosine effects were inhibited by pretreatment with 8br-cAMP. These results suggest that the decrement of the evoked NE-release by $A_1-adenosine$ receptor is mediated by the C-protein, which is coupled to protein kinase C, adenylate cyclase system and TEA sensitive $K^+-channel$, and that nifedipine-sensitive $Ca^{2+}-channel$ and glibenclamide-sensitive $K^+-channel$ are not involved in this process.

• Korean Journal of Pharmacognosy
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• v.27 no.1
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• pp.15-19
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• 1996

In the course of phytochemical studies of Chrysanthermi Flos(Chrysanthemum indicum L., Compositae), two compounds were isolated by repeated column chromatography. Compound 1 is identified as adenosine on the basis of spectroscopic means and comparison with an authentic standard. Compound 2 is determined to be a new alkyl alcohol glycoside, 1-octen-3-ol $3-O-{\beta}-D-xylopyranosyl(1{\rightarrow} 6)-{\beta}-D-glucopyranoside$ on the spectroscopic evidence. Compounds 1 and 2 are reported for the first time from this plant.