Adenosine is produced during inflammation and modulates different functional activities in macrophages. In murine bone marrow-derived macrophages, adenosine inhibits M-CSF-dependent proliferation with an IC50 of 45 microM. Only specific agonists that can activate A2B adenosine receptors such as 5'-N-ethylcarboxamidoadenosine, but not those active on A1 (N6-(R)-phenylisopropyladenosine), A2A ([p...

Fenton RA, Komatsu S, Ikebe M, Shea LG, Dobson JG, Jr. Adenoprotection of the heart involves phospholipase C-induced activation and translocation of PKC-ε to RACK2 in adult rat and mouse. Am J Physiol Heart Circ Physiol 297: H718–H725, 2009. First published June 12, 2009; doi:10.1152/ajpheart.00247.2009.—Adenosine protects the heart from adrenergic overstimulation. This adenoprotection includes...

Adenosine, acting via AI adenosine receptors, can inhibit adenylate cyclase activity in adipocytes. To assess the effects of chronic adenosine agonist exposure on the AI adenosine receptor system of adipocytes, rats were infused with (-)-phenylisopropyladenosine or vehicle for 6 days and membranes were prepared. Basal as wel1,as isoproterenol-, sodium fluoride-, and forskolin-stimulated adenyla...

In electrically driven left atria isolated from guinea pig and rat, a new milrinone analog, 6-ethyl-5-propionyl-1,2-dihydro-2-oxo-3-pyridine carbonitrile, produced a positive inotropic effect that was not dependent on adrenergic mechanisms and was more marked than that exerted by the parent compound. Its inotropic action was almost completely abolished by pretreatment of atria with adenosine de...

The impact of age on functional sensitivity to A(1)-adenosine receptor activation was studied in Langendorff-perfused hearts from young (1-2 mo) and old (12-18 mo) male Wistar rats. Adenosine mediated bradycardia in young and old hearts, with sensitivity enhanced approximately 10-fold in old [negative logarithm of EC(50) (pEC(50)) = 4.56 +/- 0.11] versus young hearts (pEC(50) = 3.70 +/- 0. 09)....

(R)-N6-Phenylisopropyladenosine (PIA) stimulates dopa production 3- to 5-fold in PC12 cells, with a half-maximal effective concentration (EC50) of 50 nM. This increase can be explained by a stable activation of tyrosine hydroxylase [TyrOHase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] when it is phosphorylated by a cAMP-dependent protein kinase. The a...

BACKGROUND Adenosine analogs have been shown to produce antinociception after intrathecal administration. To determine the adenosine receptor subtype involved in spinal antinociception, the effects of selective agonists and an antagonist on the evoked potentials recorded from a neonatal rat spinal cord were studied. The measured potentials are a slow ventral root potential (slow VRP), which is ...