Adenosine receptor ligands in clinical trials

Adenosine and its receptors play different roles in normal and patho-physiological conditions. For these reasons, many laboratories have focused their attention on dissecting the molecular pathway underlying the mechanism of action of this nucleoside with the final goal being to design new drugs. Wide expression and overlapping functions have been the major problems to designing specific adenosine agonists and antagonists with few associated negative side effects. Engineered mice have helped to dissect the single adenosine receptor function in specific tissues and pathological conditions. All these efforts in the last 20 years have led to the design of more than 2000 compounds, some of them now in clinical trials for treating different pathologies. In this review, we highlight the mouse animal models that have been of use in designing new selective drugs as well as discuss the main adenosine receptor ligands in clinical trials.