Adenosine is a naturally occurring nucleoside that plays a role in various physiological processes in the body [1].
How does adenosine affect the heart?
In the heart, adenosine acts as an endogenous regulator of coronary blood flow and myocardial oxygen supply and demand [2]. It causes vasodilation, which means it widens blood vessels, particularly in the heart. This effect is utilized clinically to help diagnose coronary artery disease [2]. Adenosine can also slow the heart rate and conduction through the atrioventricular node, which is the electrical gateway between the atria and ventricles [3]. This property is used to treat certain types of supraventricular tachycardia, a condition characterized by a rapid heart rate [3].
What else does adenosine do in the body?
Beyond its cardiac functions, adenosine is involved in neurotransmission and neuromodulation in the brain, influencing sleep, anxiety, and arousal [1]. It also plays a role in inflammation and immune responses [1]. Adenosine signaling is important in many cellular functions, including energy metabolism, where it is a component of ATP (adenosine triphosphate), the primary energy currency of cells [1].
Why is adenosine used in medical tests?
Intravenous adenosine is administered during cardiac stress tests to simulate the effects of exercise on the heart [2]. By causing vasodilation in healthy coronary arteries, it increases blood flow in these vessels. In areas of the heart with narrowed arteries due to blockages, blood flow does not increase proportionally, allowing imaging techniques to detect these differences and identify potential coronary artery disease [2].
Can adenosine have side effects?
When used medically, adenosine can cause transient side effects due to its rapid action. These may include flushing, chest discomfort, shortness of breath, dizziness, and a feeling of impending doom [3]. These effects are typically short-lived because adenosine is quickly metabolized in the body [2].