Adenosine A_2A receptor antagonists as novel anti-Parkinsonian agents: a review of structure-activity relationships

The adenosine A_2A receptor (AA2AR) has emerged as an attractive target for the treatment of Parkinson's disease. Evidence suggests that antagonists of the AA_2AR may be neuroprotective and may help to alleviate the symptoms of Parkinson's disease. During last decade, many efforts have been accomplished searching potent and selective AA_2AR antagonists. In this field, various xanthines and non-xanthine heterocyclic compounds of monocyclic, bicyclic and tricyclic nucleus possessing very good affinity with a broad range of selectivity have been proposed. The aim of this article is to summarize available data on different chemical classes of AA_2AR antagonists including those in clinical development, and briefly present an overview of the structure–activity relationships found for these compounds.