Adenosine is a naturally occurring nucleoside in the body that plays a crucial role in various physiological processes, particularly in the regulation of heart rhythm. It acts as a signaling molecule in cells, influencing processes such as energy metabolism, neurotransmission, and blood flow.

In medical practice, adenosine is primarily used as a medication to treat certain types of irregular heart rhythms, specifically supraventricular tachycardia (SVT). It works by slowing down the electrical conduction in the heart, which can help restore normal sinus rhythm