Electrophysiological Aspects of Adenosine Receptor Function

Abstract

Within the past decade, the importance of adenosine as a regulator of cellular activity in a variety of physiological systems has become increasingly apparent. Although some of adenosine’s actions were recognized over 50 years ago (Drury and Szent-Györgyi, 1929), it has only been relatively recently that the nature of these actions, the receptors that are involved, and the mechanisms by which receptor occupation is translated into physiological responses have been explicitly described. Although adenosine receptors have now been found in many different tissues, much of the early interest in this area focused around the central nervous system (CNS), in part because of the high concentrations of adenosine receptors in the brain, and because of the profound physiological actions of purines on the activity of the CNS. Historically, the observation by Sattin and Rall (1970) that adenosine stimulated the formation of cyclic adenosine 3′, 5′-monophosphate in brain slices, and that methylxanthines, such as theophylline and caffeine, were competitive pharmacological antagonists of this response, was instrumental in stimulating much of the recent interest in adenosine.