Caffeine, also known as methyltheobromine, is a central nervous system stimulant that humans consume daily. Found in coffee, tea, and other caffeinated beverages, caffeine has many side effects. Although caffeine may make the user more alert, it presents health problems such as addiction and hypertension. Caffeine has a specific chemical structure that allows it to be easily absorbed by the stomach and intestines. It is derived from purines and is hydrophobic, allowing easy passage through cell membranes. (MOST POPULAR) For this reason, the oral route of administration is faster than the intramuscular route (PUB CHEM). Once caffeine passes through the stomach, it goes to the liver where it is metabolized. The liver breaks down caffeine into theobromine, theophylline, and paraxanthine, called metabolites. (MOST POPULAR) After ingestion, there are high levels of paraxanthin in the blood. When blood circulates through the liver again, paraxanthine is broken down into 1-methylxanthine. (MOST POPULAR) This process is crucial for the excretion of caffeine. Due to caffeine's permeability, it can easily pass from one side of the cell membrane to the other. This property makes it very difficult for caffeine to be excreted through the kidneys. By converting paraxanthine to 1-methylxanthine, 1-methylxanthine can no longer pass from the kidney membrane into the bloodstream. Without this process, caffeine would remain in the body for several days. (MOST POPULAR) As previously mentioned, caffeine is a central nervous system stimulant. Caffeine stimulates the central nervous system by acting against another molecule, adenosine. Adenosine is a type of purine attached to a ribose sugar molecule. Adenosine is part of...... middle of article...... The researchers concluded that the slow waves typical of rats were diminished from day thirty-one to forty-second. (DAILY) This meant that the rats slept less soundly and their sleep was less effective in developing synapses. (DAILY) Researchers also noted that lack of deep sleep impacted the rat's behavioral development. (DAILY) Generally, as rats get older, they become more curious. The population of rats participating in the experiment became more hesitant after consuming the coffee. (DAILY) Although the results of this experiment do not necessarily suggest that caffeine consumption among adolescents is dangerous, it raises a question that deserves further investigation. Previously mentioned, caffeine has been considered a substance that can be abused and users can become dependent on it. . Dr. Naoshi Ogawa conducted two case studies examining clinical caffeine addiction.