Special issue: G protein-coupled adenosine receptors: molecular aspects and beyond

Abstract

Adenosine is a purine nucleoside present in all human cells where it plays many different physiological roles: From being a building block for nucleic acids to a key constituent of the biological energy currency ATP. Indeed, more than 90 years ago, Drury and Szent-Györgyi reported that adenosine produces profound hypotension and bradycardia, and until the present time, the list of physiological effects of adenosine has expanded considerably. In addition, adenosine is a well-known neuromodulator in the brain and has effects on other tissues, thus exerting its physiological actions through four different subtypes of G protein-coupled adenosine receptors (i.e., A1R, A2AR, A2BR and A3R) which, as expected, are expressed in a large variety of cells throughout the body. Consequently, ARs are potential therapeutic targets in a variety of pathophysiological conditions, including cancer, cardiovascular diseases, neurological disorders, and inflammatory and autoimmune diseases.