Caffeine is a naturally occurring alkaloid found in more than 60 plants 23. Caffeine methylxanthine is one of the most widely consumed stimulants in the world. It is a mild central nervous system stimulant, vasodilator and diuretic 22. Caffeine is present in a wide range of diet products such as coffee, tea, cola, candy bars, soft drinks and beverages. energizing. Additionally, a number of prescription and over-the-counter (OTC) medications, used for headaches, colds, allergies, and for pain relief and alertness, are often combined with caffeine. Here are some examples of these medications: No-Doz, No-Doz Plus and Cafergot 24, 25. Say no to plagiarism. Get a Tailored Essay on “Why Violent Video Games Should Not Be Banned”?Get the original essayAfter oral ingestion, caffeine is rapidly and almost completely absorbed from the gastrointestinal tract and reaches its peak plasma concentrations around 30 to 60 minutes after consumption. The volume of distribution is 0.6 L/Kg and 36% is protein bound. It crosses the blood-brain barrier and all biological membranes. It is metabolized in the liver by the cytochrome P450 (CYP) system to the stimulants dimethylxanthine, theobromine and theophylline. The elimination half-life is 4.5 hours in healthy non-smoking adults. Mechanism of action Adenosine A1 and A2A receptors are present in the basal ganglia. The basal ganglia are a group of structures that contribute to various motor controls. As shown in Table 1, A1 adenosine receptors are present in all areas of the brain, while A2A receptors are found more in dopamine-rich brain regions. There is evidence that A2A receptors interact with the dopamine system, which is involved in reward and arousal effects. 27. Caffeine acts as an antagonist of both types of receptors. The overall psychostimulant properties of caffeine in the brain depend on its ability to interact with neurotransmission in different brain regions. It has been indicated that caffeine particularly affects a group of projection neurons located in the striatum, which is the main receptor area of ​​the basal ganglia 29. Thus, caffeine blocks the inhibitory neurotransmitter adenosine, inhibits phosphodiesterase, and increases adenosine intracellular cyclic monophosphate (cAMP). 28. At low concentrations, it blocks adenosine receptors. However, at higher concentration, it inhibits phosphodiesterase and calcium mobilization. 27. Physiological Effects Keep in mind: This is just a sample. Get a personalized article from our expert writers now. Get a custom article essayIn a literature review by Glade, caffeine in moderate amounts was found to increase energy, decrease fatigue, improve physical, motor and cognitive performance, increase alertness, decrease mental fatigue , increases the precision of reactions and improves cognitive functioning abilities and neuromuscular coordination 30. The author did not specify the effective dose in the study. However, the medical website Rx-list mentioned that doses of 100 to 200 mg of caffeine can increase alertness, relieve drowsiness and improve thinking and that at doses of 250 to 700 mg/day, caffeine can cause anxiety, insomnia, nervousness, hypertension and insomnia 31. Additionally, an article by Pohler mentions that caffeine can affect all organ systems of the body if taken in excessive amounts ( painting 2) 32.