Page 191 - Encyclopedia of Chemical Compounds 3 Vols

CAFFEINE

Words to Know

ALKALOIDS Organic bases that contain the WATER OF HYDRATION Water that has
element nitrogen. combined with a compound by some
physical means.
DIURETIC A substance that increases the
flow of urine.

and two hydrogens to the theobromine molecule and convert-
ing it to caffeine.

COMMON USES AND POTENTIAL HAZARDS
Caffeine is used in foods and drinks and for medical
purposes. Its primary action is to stimulate the central ner-
vous system. People drink coffee, tea, or cola drinks to stay
awake and alert because caffeine creates a feeling of added
energy. It does this by increasing heart rate, improving blood
flow to the muscles, opening airways to aid breathing, and
releasing stored energy from the liver to provided added fuel
for the body. In large quantities, caffeine can also cause
nervousness, insomnia, and heart problems. The effects of
caffeine can linger in the body for more than six hours. In
medical applications, caffeine is sometimes used as a heart
stimulant for patients in shock, to treat apnea (loss of breath-
ing) in newborn babies, to counteract depressed breathing
levels as a result of drug overdoses, and as a diuretic.
Caffeine stimulates the brain in two ways. First, because
it has a chemical structure similar to that of adenosine, it
attaches to adenosine receptors in the brain. Adenosine is a
substance that normally attaches to those receptors, slowing
brain activity and causing drowsiness. By blocking those
receptors, caffeine increases electrical activity in the brain,
creating a feeling of alertness. Caffeine also works in the
brain like drugs such as heroin and cocaine, although in a
much milder way. Like those drugs, caffeine increases dopa-
mine levels. Dopamine is a chemical present in the brain that
increases the body’s feeling of pleasure.
Studies have shown that caffeine can become addictive.
People who use the compound eventually need to take more

140 CHEMICAL COMPOUNDS