Caffeine is defined as a drug because it stimulates the central nervous system, causing increased heart rate, alertness, and is addictive. Caffeine is naturally produced in the leaves and seeds of many plants as is Cocaine. It’s also produced artificially and added to certain foods.
The principal action of caffeine is as an antagonist of adenosine receptors in the brain, because the caffeine molecule is structurally similar to adenosine, and binds to adenosine receptor on the surface of cells without activating them. Therefore, caffeine acts as a competitive inhibitor. The reduction in adenosine activity results in increased activity of the neurotransmitter dopamine, accounting for the stimulatory effect. This is why hallucinogenics and caffeine are often used together.
Recent research discovered that caffeine freely diffuses into cells and causes intracellular calcium release from the calcium stores in the Endoplasmic Reticulum. This would explain the higher percentage of osteoporosis among those older Americans who routinely drink caffeinated beverages.
Caffeine belongs to a group of stimulants called xanthines. Considering that it is readily available and a pick-me-up for many, caffeine is a very popular drug. According to the Center for Science in the Public Interest (CSPI), four out of five Americans have some caffeine on any given day, the average amount being about 200 milligrams a day (equivalent to that found in two 8-ounce cups of coffee, three to four 12-ounce cans of caffeinated soda, or four 8-ounce cup of tea). Globally, consumption of caffeine has been estimated at 120,000 tons per annum, making it the world’s most popular psychoactive substance. This number equates to one serving of a caffeinated beverage for every person on the planet on any given day.
Caffeine was on the International Olympic Committee list of prohibited substances for many years. Athletes who tested positive for more than 12 micrograms of caffeine per milliliter of urine could be banned from the Olympic Games. This level can be reached after drinking about 5 cups of coffee. However, caffeine was removed from the banned list in 2004.
