Caffeine's Vascular Mechanisms of Action
Caffeine is metabolized into mainly the following compounds: Paraxanthine, Theobromine, and Theophylline. The main metabolite of caffeine is Paraxanthine, which accounts for 72-80% of the metabolites formed. There are five main pathways of caffeine metabolism in adults. Three of them involve demethylation to make paraxanthine and theobromine. The fourth pathway forms uracil, and the fifth pathway is the elimination of the remaining caffeine that was not able to be metabolized. Based on multiple studies, it is difficult to determine if caffeine is beneficial or harmful to the heart because different studies of caffeine sometimes got contradicting results. Cardiovascular response to caffeine is different for each person because there are many factors that contribute to response to caffeine. Some factors include: amount consumed, time of day consumed, frequency it is consumed, amount of absorption, and liver metabolism.
Caffeine has a big effect on adenosine receptors. There are four types of adenosine receptors, and caffeine acts as an inhibitor of A1, A2a, and A2b receptors. Caffeine blocks these receptors as demonstrated in Sattin and Rall's experiment in 1970. In this experiment, when ATP was added, the effect of caffeine binding to the receptors and blocking them is reversed. Paraxanthine (metabolite of caffeine) is a even more powerful blocker of the receptors that caffeine blocks. The actual action or result of adenosine binding to its receptor depends on the type of receptor it binds to and the type of cell it is in.
This article has a lot of helpful information regarding how caffeine works in general and on the vascular system specifically. Since, in the experiment, blood pressure was tested, this article was helpful to get information about how caffeine would affect blood vessels. The article also has a lot of information going more in depth about how caffeine and adenosine receptors are related. Because we researched a lot about how caffeine works in the body on a molecular level, we did a lot of research about the adenosine receptors and how caffeine affects them.
Link to the article:
http://www.hindawi.com/journals/ijvm/2010/834060/
Caffeine has a big effect on adenosine receptors. There are four types of adenosine receptors, and caffeine acts as an inhibitor of A1, A2a, and A2b receptors. Caffeine blocks these receptors as demonstrated in Sattin and Rall's experiment in 1970. In this experiment, when ATP was added, the effect of caffeine binding to the receptors and blocking them is reversed. Paraxanthine (metabolite of caffeine) is a even more powerful blocker of the receptors that caffeine blocks. The actual action or result of adenosine binding to its receptor depends on the type of receptor it binds to and the type of cell it is in.
This article has a lot of helpful information regarding how caffeine works in general and on the vascular system specifically. Since, in the experiment, blood pressure was tested, this article was helpful to get information about how caffeine would affect blood vessels. The article also has a lot of information going more in depth about how caffeine and adenosine receptors are related. Because we researched a lot about how caffeine works in the body on a molecular level, we did a lot of research about the adenosine receptors and how caffeine affects them.
Link to the article:
http://www.hindawi.com/journals/ijvm/2010/834060/