Search PubMed⌕ Search

PubMed · 16375751

A2B adenosine receptor antagonists: recent developments.

Abstract

There are pharmacological evidences that A(2B) receptors are involved in inflammatory processes, such as asthma. For this reason, many efforts has been made for identifying selective A(2B) antagonists as anti-asthmatic agents. The updated material related to this field has been rationalised and arranged in order to offer an overview of the topic.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Barbara Cacciari, Giorgia Pastorin, Chiara Bolcato, Giampiero Spalluto, Magdalena Bacilieri, Stefano Moro. 2005. A2B adenosine receptor antagonists: recent developments.. https://doi.org/10.2174/138955705774933374

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Targeting adenosine receptors in the treatment of allergic rhinitis: a randomized, double-blind, placebo-controlled study.

BACKGROUND: There is evidence that adenosine plays a role in the pathogenesis of asthma and rhinitis; however, it is currently unclear whether adenosine receptors are useful therapeutic targets in the treatment of allergic airway diseases. OBJECTIVE: The study evaluated the efficacy of intranasal treatment with an adenosine A(2A) receptor agonist/adenosine A(3) receptor antagonist (50 micro g), administered twice daily for 7 days, to reduce nasal symptoms and release of inflammatory mediators following intranasal allergen challenge in patients with allergic rhinitis (AR). The compound was compared with twice-daily treatment with intranasal fluticasone proprionate nasal spray (FPANS) for 7 days. METHODS: A randomized, double-blind, double-dummy, placebo-controlled, three-way balanced, incomplete block, crossover study was conducted on 48 males with verified AR. Following intranasal challenge with either an extract from the house dust mite (HDM), Dermatophagoides pteronyssinus, rye grass or cat dander, nasal responses and the concentrations of albumin, tryptase, myeloperoxidase, eosinophilic cationic protein, epithelial neutrophil-activating protein-78 (ENA-78), IL-5 and IL-8 in nasal secretions were measured and treatment groups were compared. RESULTS: Drug improved nasal blockage but had no significant effect on rhinorrhoea, number of sneezes or peak nasal inspiratory flow measurements when compared with placebo. Drug reduced tryptase release after EAR but did not significantly reduce the levels of other mediators. CONCLUSION: A novel agonist/antagonist of adenosine A(2A) and A(3) receptors appears to have limited clinical benefit in both the early-phase and the late-phase response to intranasal allergen challenge. However, reduction of some pro-inflammatory mediators suggests that comparable, more selective compounds may have additional benefits meriting further investigation.

Adenosine A2 Receptor Antagonists↗

Forebrain adenosine A2A receptors contribute to L-3,4-dihydroxyphenylalanine-induced dyskinesia in hemiparkinsonian mice.

Adenosine A2A receptor antagonists provide a promising nondopaminergic approach to the treatment of Parkinson's disease (PD). Initial clinical trials of A2A antagonists targeted PD patients who had already developed treatment complications known as L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID) in an effort to improve symptoms while reducing existing LID. The goal of this study is to explore the effect of A2A antagonists and targeted A2A receptor depletion on the actual development of sensitized responses to L-DOPA in mouse models of LID in PD. Hemiparkinsonian mice (unilaterally lesioned with 6-OHDA) were treated daily for 3 weeks with a low dose of L-DOPA (2 mg/kg) preceded by a low dose of selective A2A antagonist (KW-6002 [(E)-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione] at 0.03 or 0.3 mg/kg, or SCH58261 [5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine] at 0.03 mg/kg) or vehicle intraperitoneally. In control mice, contralateral rotational responses to daily L-DOPA gradually increased over the initial week before reaching a persistent maximum. Both A2A antagonists inhibited the development of sensitized contralateral turning, with KW-6002 pretreatment reducing the sensitized rotational responses by up to threefold. The development of abnormal involuntary movements (a measure of LID) as well as rotational responses was attenuated by the postnatal depletion of forebrain A2A receptors in conditional (Cre/loxP system) knock-out mice. These pharmacological and genetic data provide evidence that striatal A2A receptors play an important role in the neuroplasticity underlying behavioral sensitization to L-DOPA, supporting consideration of early adjunctive therapy with an A2A antagonist to reduce the risk of LID in PD.

Adenosine A2 Receptor Antagonists↗

Injections of the selective adenosine A2A antagonist MSX-3 into the nucleus accumbens core attenuate the locomotor suppression induced by haloperidol in rats.

There is considerable evidence of interactions between adenosine A2A receptors and dopamine D2 receptors in striatal areas, and antagonists of the A2A receptor have been shown to reverse the motor effects of DA antagonists in animal models. The D2 antagonist haloperidol produces parkinsonism in humans, and also induces motor effects in rats, such as suppression of locomotion. The present experiments were conducted to study the ability of the adenosine A2A antagonist MSX-3 to reverse the locomotor effects of acute or subchronic administration of haloperidol in rats. Systemic (i.p.) injections of MSX-3 (2.5-10.0 mg/kg) were capable of attenuating the suppression of locomotion induced by either acute or repeated (i.e., 14 day) administration of 0.5 mg/kg haloperidol. Bilateral infusions of MSX-3 directly into the nucleus accumbens core (2.5 microg or 5.0 microg in 0.5 microl per side) produced a dose-related increase in locomotor activity in rats treated with 0.5 mg/kg haloperidol either acutely or repeatedly. There were no overall significant effects of MSX-3 infused directly into the dorsomedial nucleus accumbens shell or the ventrolateral neostriatum. These results indicate that antagonism of adenosine A2A receptors can attenuate the locomotor suppression produced by DA antagonism, and that this effect may be at least partially mediated by A2A receptors in the nucleus accumbens core. These studies suggest that adenosine and dopamine systems interact to modulate the locomotor and behavioral activation functions of nucleus accumbens core.

Adenosine A2 Receptor Antagonists↗