Adenosine is an organic compound that relaxes as well as dilates the blood vessels. Occurring naturally, adenosine, which is found widely in nature, also has an effect on the electrical activity in our heart. Therapeutically, this substance is used to bring back the regular heartbeat in people enduring specific disorders related to the heart rhythm. This organic compound is also utilized in the process to check the stress on the heart.

It is worth mentioning here that adenosine is present in all the cells of humans and is also available in supplement/ drug form which are taken orally to deal with various symptoms as well as augment the energy levels. This organic compound is considered to be a variety of neurotransmitter and a purine nucleoside. Adenosine is made up of D-ribose and adenine.

Adenosine plays various roles in our body. Among these, the most important is considered to be its ability to help in the formation of other compounds such as adenosine monophosphate (AMP) - a constituent of DNA/RNA as well as adenosine triphosphate (ATP), which works in the form of a fuel source inside the cells. First, adenosine is changed to its base known as adenine. Subsequently, it is converted into adenosine monophosphate (AMP). Moreover, AMP also forms owing to the metabolism/ breakdown of adenosine triphosphate (ATP). The cells in our body use it for energy and also for biosynthesis in the liver.

Types of adenosine

Broadly speaking, there are three main types of adenosine - AMP, ADP and ATP. In addition, other adenosine types include adenosine deaminade (ADA) and S-Adenosyl-L-methionine (SAM). Adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP) are all vital participants in the process to generate energy within the cells and this energy helps the cells to continue working normally. In other words, these three compounds are essential to keep us alive. A brief description of the five types of adenosine is given below.

Adenosine triphosphate (ATP): This type of adenosine is the main energy-transmitting molecule found in all living organisms on this planet. ATP takes up chemical energy after the metabolism of molecules present in foods. It utilizes this energy to stimulate the cellular process. In fact, all the three micronutrients present in food - carbohydrates, fats and proteins - can be converted to adenosine triphosphate (ATP).

Adenosine diphosphate (ADP): This type of adenosine is basically a nucleotide comprising adenine, two phosphate units and ribose. Adenosine diphosphate is indispensable in photosynthesis as well as glycolysis. It is also the final product after adenosine triphosphate (ATP) drops one of the three phosphate groups. Adensine diphosphate can again be converted to adenosine triphosphate by a process known as ATP synthesis.

Adenosine monophosphate (AMP): This type of adenosine is actually a regulatory molecule that participates in metabolic processes such as gluconeogenesis and glycolysis. Adenosine monophosphate can also be converted to uric acid, a harmful substance that is excreted from our body through the kidneys and finally via urination.

Adenosine deaminase (ADA): This type of adenosine has a role in purine metabolism. It is essential for production of nucleic acids in our body tissues. Moreover, ADA supports the development as well as preservation of our immune system, as it converts toxic deoxyadenose into a substance known as lymphocytes. Newborns as well as children born with ADA gene mutation are likely to suffer from serious immune system malfunctions which can even prove to be fatal.

S-Adenosyl-L-methionine (SAM): This type of adenosine is a molecule which has important roles in a variety of biochemical reactions. As far as the most commonly used enzyme substrate is concerned, SAM comes next to ATP. A-Adyenosyl-L-methionine is actually the biosynthesized variety of adenosine triphosphate (ATP). SAM is necessary for the appropriate performance of our nervous system, cell membranes and neurotransmitters.

These organic compounds are different from each other and the basic difference is the group of phosphates each compound has. Each adenosine compound is made up of a nucleotide base known as adenine. Adenine is linked to ribose, a sugar molecule, and also with one, two or three groups of phosphates.

Physiological and pharmacological role of adenosine

Adenosine has a number of pharmacological and physiological roles in our body. Within our body, adenosine aids in transferring cellular energy by developing molecules such as adenosine diphosphate (ADP) and adenosine triphosphate (ATP). In addition, adenosine also plays a significant role in sending signals to various functions and pathways in our body by developing signal molecules such as adenosine monophosphate (cAMP).

Role of adenosine in our brain

Inside our brain, adenosine works in the form of an inhibitory neurotransmitter. In other words, adenosine possesses the ability to serve as a depressant for the central nervous system. In usual situations, adenosine helps to support sleep and curb arousal. When we are awake, adenosine levels in our brain continue to rise every hour.

Role of adenosine in our heart

Within the heart, adenosine works to dilate the coronary blood vessels resulting in an improved blood circulation to the heart. In addition, this organic compound also enhances the blood vessels' diameter in our peripheral organs.

Also, adenosine reduces the heart rate in our heart. When it is in our blood, it works to prevent formation of platelets. This action of adenosine prevents accumulation of platelets as well as their coagulation.

Role of adenosine in the blood

In our blood, the enzyme adenosine deaminase breaks down adenosine. Adenosine deaminase is present in walls of the blood vessels and also in the red blood cells (erythrocytes). The drug Dipyridamole works to inhibit the action of this enzyme, thereby increasing the adenosine levels in the blood. In turn, it leads to dilation of the blood vessels as well as improves the passage of blood through the coronary blood vessels which supply blood to the heart.

Role of adenosine in the liver, kidneys and lungs

Adenosine plays vital roles in our lungs, liver and kidneys. In the kidneys, this organic compound reduces the renal blood circulation, thereby reduces rennin production in the kidneys.

In the lungs, adenosine works to constrict the airways. Similarly, in the liver adenosine causes the blood vessels to constrict and, at the same time, it augments glycogen break down to form glucose.

Adenosine foods and sources

There are a number of foods that can enhance adenosine triphosphate (ATP) in our body. In effect, all micronutrients lend a hand to increase production of ATP. Nevertheless, a diet that contains specific nutrients is more helpful in increasing production of ATP. If you seek to augment the level of ATP in your body it is advisable that you eat specific foods that are rich in copper, CoQ10, D-ribose, L-methionine, omega-3 fatty acids and protein. While protein provides the body with the essential amino acids, L-methionine helps to promote production of SAMe. Copper is an important essential mineral that helps to promote ATP production. This essential mineral has a role in several metabolic processes and is necessary for synthesizing adenosine triphosphate. Deficiency of copper in our body can lead to very slow metabolism, poor energy levels and various signs of reduced metabolic health.

Foods that provide our body with the above mentioned micronutrients include nuts and seeds, free-range eggs, legumes and 100 percent whole grains and grass-fed meat, organ meats like kidneys and liver as well as pastured poultry. In addition, seafood and wild-caught fish are also essential to provide the nutrients mentioned above. Sea food that help to boost the ATP levels in the body include cod, sardines, tuna, salmon, halibut, pike, whitefish, ling, haddock and sunfish. Various vegetables and fruits such as sea vegetables - spirulina and algae - also help to promote the production of adenosine triphosphate (ATP) in the body.

It is vital to take a balanced diet as it helps to maintain elevated levels of energy. This is because each of the micronutrients mentioned above have different consequences of adenosine triphosphate. For instance, when you consume carbs, you actually consume glucose, which is transformed into energy and stored in your muscles as glycogen. Subsequently, glycogen is converted into ATP through a process known as glycolysis. In effect, fats too can be used to enhance production of ATP, particularly when enough carbohydrate is not available in the body.

In addition to the above, we also require oxygen for production of adenosine triphosphate (ATP). It is obvious that our body gets oxygen when we inhale, particularly when we take deep breaths or do deep breathing exercises. This is because when we undertake any physical activity we actually breathe faster and inhale more air from the atmosphere.

Uses and benefits associated with adenosine

Adenosine triphosphate is a small storehouse of energy located inside the cells and it releases energy whenever required, particularly when an individual is undergoing rigorous physical activity. In fact, ATP is a key determinant in one's energy levels, metabolism as well as the body weight since it helps in converting the ingested foods to fuel which can be used by our cells, organs, and muscles.

Therefore, you may wonder what role does adenosine plays while one is enjoying a restful sleep. The answer is that when adenosine attaches itself to A1 receptors in our brain, we feel calmer as well as sleepier. When this happens, the muscles feel more relaxed and the brain is less attentive. In addition, adenosine also has the capability to bind itself to A2A receptors in our brain, thereby obstructing release of neurotransmitters that have an impact on our mood, especially dopamine.

While we sleep during the night, the molecules adenosine undergo metabolism. As a result, when we wake up in the morning, we feel refreshed. In fact, adenosine and caffeine are competitors and, hence, this explains why adenosine makes us feel tired and sleepy, while caffeine helps us to remain awake. Caffeine keeps us awake by blocking adenosine from attaching to specific types of receptors in our brain.

ATP is also beneficial for our skin, but what is its role. Adenosine monophosphate (AMP) can be administered into the muscle tissues through injection to promote healing of wounds. ATP is useful because it supports healthy circulation, decreases fluid retention, thereby reducing swelling; and, at the same time, lessens symptoms such as redness, itching and ulcer formation.

Therapeutically, ATP is used to cure shingles. Findings of some studies reveal that adenosine can also be effectual in decreasing the symptoms related to cold sores and herpes. However, further studies are necessary to corroborate this claim.

Adenosine triphosphate is used as a supplement to promote endurance and muscle recovery. This action of ATP is partially attributed to its benevolent effects in reducing pain and promoting circulation. In fact, physicians sometimes inject adenosine into the muscles to lessen swelling and, at the same time, treat conditions like bursitis and tendonitis.

Side effects and cautions

Despite the several therapeutic benefits of adenosine, it must be used with caution as this organic compound has a number of side effects. The negative effects of this organic compound are inferior to the triggering of adenosine receptors present on vascular tissues and it may result in vasodilation.

People who have been administered adenosine have reported side effects such as nausea, light-headedness, nervousness, sweating, skin flushing, a sense of impending doom, numbness and other symptoms. However, all the above mentioned side effects of adenosine are short-lived and passing - all secondary to the short half-life of adenosine.

Use of adenosine may sometimes also lead to more severe symptoms such as those related to the cardiac system and also include cardiac arrhythmia, which includes premature ventricular contractions and premature arterial contractions, cardiac ischemia, development of AV block, prolonged aystole and hypotension. Prior to administrating adenosine, it is important that the clinician talks to the patient about these adverse effects of using this organic compound.

While the therapeutic use of adenosine has several less severe side effects, it is important that the physician should review the specific drug interactions related to the use of this organic compound. Hence, the physician should ask the patient about the other problems they are enduring and what medications they are using to treat those conditions. Moreover, theophylline and caffeine may block the effect of administering adenosine. Theophylline is a member of the group of drugs known as methylxanthines, which are derived from a different purine base known as xanthine. The chemical structure of xanthine is somewhat comparable to adenosine's chemical structure. Xanthine possesses the ability to bind to adenosine receptors, thereby working as a viable rival of adenosine. Patients who are already taking these drugs are likely to require larger doses of adenosine.