C8H10N4O2
“Caffeine”

 

 

 

 

Metabolism

Caffeine is broken down in the liver by the 1A2 isozyme of cytochrome P450. into three methylxanthines listed below along with their effects. The following three bullets are taken directly from wikipedia:

• Paraxanthine (84%): Has the effect of increasing lipolysis, leading to elevated glycerol and free fatty acid levels in the blood plasma.
• Theobromine (12%): Dilates blood vessels and increases urine volume. Theobromine is also the principal alkaloid in cocoa, and therefore chocolate.
• Theophylline (4%): Relaxes smooth muscles of the bronchi, and is used to treat asthma. The therapeutic dose of theophylline, however, is many times greater than the levels attained from caffeine metabolism.

 

Action

The only likely mechanism of action of the methylxanthine is the antagonism at the level of adenosine receptors. [2]

The effects of caffeine on learning, memory, performance and coordination are rather related to the methylxanthine action on arousal, vigilance and fatigue. [2]

The half-life of caffeine “varies from several hours to several days, but for the average non-smoking adult it is about 3-4 hours.” It is lengthened for those who have certain liver diseases, are pregnant, or who are taking certain medications that interfere with the catabolism of caffeine. A great example would be oral contraceptives which generally increase the half-life to about 13 hours. [3]

Caffeine and Sleep

Now here comes the meat and ‘taters – hopefully I can make it easy to follow. Adenosine Triphosphate (ATP) is your body’s cellular resource for energy. During the day, the body uses a great amount of ATP and breaks this down to adenosine. As the day wears on there becomes an accumulation of adenosine in the brain. Adenosine promotes sleepiness and fatigue [4]. So where does caffeine come in? Well… since caffeine is an antagonist to the adenosine receptors (specifically addressing those in the brain), and your cells’ receptors for said ATP metabolite are taken up by Caffeine instead, the normal effects of adenosine-loaded sleep pressure are not felt… until the “crash”, that is. Once caffeine is broken down, all that built-up adenosine is taken up by the receptors that were temporarily holding onto caffeine until it expires through the body’s natural metabolism.

And that’s the way the cookie crumbles. Be sure to check out my sources to correct me where I may be wrong and to grasp a greater understanding.

Sources

[1]-http://en.wikipedia.org/wiki/Caffeine
[2]-http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=1356551&dopt=Abstract
[3]-http://www.erowid.org/chemicals/caffeine/caffeine_effects.shtml
[4]-http://www.sfn.org/index.cfm?pagename=brainBriefings_adenosineAndSleep