Recent studies of G protein-coupled receptors have highlighted two "new" and interactive elements involved in their function and regulation: their ability to localize to different cell surface and intracellular compartments and their ability to interact with partners other than their classic heterotrimeric G proteins. The effects mediated by these receptors can be markedly different depending o...

Bacterial meningitis is a disease worsened by neutrophil-induced damage in the subarachnoid space. In this study, the A2A adenosine receptors on human neutrophils were characterized, and the role of A2A receptors on the trafficking of leukocytes to the cerebrospinal fluid and on blood-brain barrier permeability (BBBP) was assessed in a rat meningitis model. Neutrophils bind the A2A selective an...

Accumulation of adenosine and of deoxyadenosine in the absence of adenosine deaminase activity (ADA) activity results in lymphocyte depletion and in severe combined immunodeficiency (ADA SCID), which is currently explained by direct cell death-causing effects of intracellular products of adenosine metabolism. We explored the alternative mechanisms of peripheral T-cell depletion as due to inhibi...

Prior studies indicate that adenosine and the adenosine A2A receptor play a role in hepatic fibrosis by a mechanism that has been proposed to involve direct stimulation of hepatic stellate cells (HSCs). The objective of this study was to determine whether primary hepatic stellate cells produce collagen in response to adenosine (via activation of adenosine A2A receptors) and to further determine...

Adenosine, released by cells in an injurious or hypoxic environment, possesses potent anti-inflammatory effects by inhibiting the production of proinflammatory cytokines and superoxide anions (O2-). We hypothesized that adenosine compounds also induced heterologous desensitization of chemokine receptors, which played a critical role in leukocyte trafficking. Our studies using adenosine receptor...

The exposure to supra-physiological levels of glucocorticoids in prenatal life can lead to a long-term impact in brain cytoarchitecture, increasing the susceptibility to neuropsychiatric disorders. Dexamethasone, an exogenous glucocorticoid widely used in pregnant women in risk of preterm delivery, is associated with higher rates of neuropsychiatric conditions throughout life of the descendants...

Introduction:Adenosine as a potent vasodilator has physiological role in regulation of regional cerebral blood flow (rCBF). Metod: Laser-Dِoppler flowmetry technique was used to study pial vessels blood flow responses to adenosine receptors agonists and antagonist. Male Sprague Dawley rats (250-350g) that were housed in standard conditions, were anesthetized with Urethane (1.5g/kg). Adenosine ...

BACKGROUND Adenosine is a potent coronary vasodilator and causes an increase of coronary blood flow by activation of A2A-adenosine receptors (A2A-AdoRs). The purpose of this study was to test the hypothesis that the high potency of adenosine and adenosine analogues to cause coronary vasodilation is explained by the presence of a large A2A-AdoR reserve ("spare receptors"). METHODS AND RESULTS ...

D1 receptors located on striatonigral neurons and D2 receptors located, together with A2A receptors, on striatopallidal neurons are known to interact functionally. Using in situ hybridization, we examined the effects of D1 and D2 agonists and of an A2A antagonist on c-fos mRNA in identified striatal neurons and in globus pallidus. The full D1 agonist, SKF 82958 (1 mg/kg), induced a homogenous i...

Adenosine either inhibits or facilitates synaptic transmission through A1 or A2A receptors, respectively. Since A2A receptor density increases in the limbic cortex of aged (24 mo) compared with young adult rats (2 mo), we tested if A2A receptor modulation of synaptic transmission was also increased in aged rats. The A2A receptor agonist, CGS21680 (10 nM), caused a larger facilitation of the fie...