Disclosed are (N)-methanocarba adenine nucleosides, e.g., of the formula (I): as A3 adenosine receptor agonists, pharmaceutical compositions comprising such nucleosides, and a method of use of these nucleosides, wherein A, a, R2, and R3 are as defined in the specification. These nucleosides are contemplated for use in the treatment a number of diseases, for example, inflammation, cardiac ischemia, stroke, asthma, diabetes, and cardiac arrhythmias. Also disclosed are conjugates comprising a dendrimer and one or more ligands, which are functionalized congeners of an agonist or antagonist of a receptor of the G-protein coupled receptor (GPCR) superfamily. Such conjugates are have the potential of being used as dual agonists, dual antagonists, or agonist/antagonist combinations.
