Exploring the multifaceted roles of adenosine: A molecule with diverse functions

Adenosine is a ubiquitous molecule distributed in all eukaryotic cells of the human body. The function of adenosine varies depending on the cell type and receptor subtypes involved. For instance, adenosine 2A and 2B receptors couple with stimulatory G proteins, leading to increased intracellular cyclic adenosine 3’,5’-monophosphate (cAMP) levels upon activation. In contrast, adenosine 1 and 3 receptors couple with inhibitory G proteins, resulting in decreased intracellular cAMP levels. Consequently, an imbalance of adenosine receptor expression can affect several biological pathways and mechanisms. In the brain, where adenosine plays an important role, dysregulation of adenosine receptors has been linked to several neurological diseases, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, epilepsy, and Huntington’s disease. Adenosine also modulates cardiovascular function, influencing vasodilatation, blood pressure regulation, heart rate, and platelet activity. In addition, growing evidence highlights the impact of adenosine receptors on decision-making, habits, and goal-directed behaviors, linking them to stress-induced mood depression and other psychiatric disorders. Given the importance of adenosine modulation on human health, studying nutraceuticals and natural substances that influence adenosine could provide valuable insights. Considering the extensive physiological roles of adenosine, this review aims to summarize the diverse functions of adenosine receptors across various human tissues, emphasizing their connection to various diseases and the potential influence of external factors on their expression and functionality.