NIDA for Teens: The Science Behind Drug Abuse
Find NIDA for Teens on: NIDAnews on Twitter NIDANIH on YouTube Facebook NIDA-NIH on Flickr Sara Bellum Blog RSS
  • The Brain's Response to Nicotine

    Hi, my name's Sara Bellum. Welcome to my magazine series exploring the brain's response to drugs. In this issue, we'll investigate the fascinating facts about nicotine. Some of this information was only recently discovered by leading scientists.

    For centuries, people have chewed and smoked tobacco, which comes from the plant nicotiana tabacum. The reason tobacco is used by so many people is because it contains a powerful drug known as nicotine.

    When tobacco is smoked, nicotine is absorbed by the lungs and quickly moved into the bloodstream, where it is circulated throughout the brain. All of this happens very rapidly. In fact, nicotine reaches the brain within 8 seconds after someone inhales tobacco smoke. Nicotine can also enter the bloodstream through the mucous membranes that line the mouth (if tobacco is chewed) or nose (if snuff is used), and even through the skin.

    Nicotine affects the entire body. Nicotine acts directly on the heart to change heart rate and blood pressure. It also acts on the nerves that control respiration to change breathing patterns. In high concentrations, nicotine is deadly, in fact one drop of purified nicotine on the tongue will kill a person. It's so lethal that it has been used as a pesticide for centuries.

    So why do people smoke? Because nicotine acts in the brain where it can stimulate feelings of pleasure.

  • How Does Nicotine Act in the Brain?

    Your brain is made up of billions of nerve cells. They communicate by releasing chemical messengers called neurotransmitters. Each neurotransmitter is like a key that fits into a special "lock," called a receptor, located on the surface of nerve cells. When a neurotransmitter finds its receptor, it activates the receptor's nerve cell.

    The nicotine molecule is shaped like a neurotransmitter called acetylcholine. Acetylcholine and its receptors are involved in many functions, including muscle movement, breathing, heart rate, learning, and memory. They also cause the release of other neurotransmitters and hormones that affect your mood, appetite, memory, and more. When nicotine gets into the brain, it attaches to acetylcholine receptors and mimics the actions of acetylcholine.

    Nicotine also activates areas of the brain that are involved in producing feelings of pleasure and reward. Recently, scientists discovered that nicotine raises the levels of a neurotransmitter called dopamine in the parts of the brain that produce feelings of pleasure and reward. Dopamine, which is sometimes called the pleasure molecule, is the same neurotransmitter that is involved in addictions to other drugs such as cocaine and heroin. Researchers now believe that this change in dopamine may play a key role in all addictions. This may help explain why it is so hard for people to stop smoking.

  • Easy to Start, Hard to Quit

    Did you know that nicotine is as addictive as heroin or cocaine? If someone uses nicotine again and again, such as by smoking cigarettes or cigars or chewing tobacco, his or her body develops a tolerance for it. When someone develops tolerance, he or she needs more drug to get the same effect. Eventually, a person can become addicted. Once a person becomes addicted, it is extremely difficult to quit. People who start smoking before the age of 21 have the hardest time quitting, and fewer than 1 in 10 people who try to quit smoking succeed.

    When nicotine addicts stop smoking they may suffer from restlessness, hunger, depression, headaches, and other uncomfortable feelings. These are called "withdrawal symptoms" because they happen when nicotine is withdrawn from the body.

  • America's Leading Preventable Killer

    Withdrawal may be bad, but long-term smoking can be much worse. It raises your blood pressure, dulls your senses of smell and taste, reduces your stamina, and wrinkles your skin. More dangerously, long-term smoking can lead to fatal heart attacks, strokes, emphysema, and cancer.

    You may be surprised to learn that tobacco use causes far more illnesses and death than all other addicting drugs combined. One out every six deaths in the United States is a result of smoking.

    But even when faced with risk of death, many people keep using tobacco because they are so addicted to nicotine. Believe it or not, half of the smokers who have heart attacks keep smoking, even though their doctor warns them to stop. That's a strong addiction!

    Smokeless tobacco also has harmful effects. Chewing tobacco can cause damage to gum tissue and even loss of teeth. It also reduces a person's ability to taste and smell. Most importantly, smokeless tobacco contains cancer causing-chemicals that can cause cancers of the mouth, pharynx, larynx, and esophagus. This can even happen in very young users of chewing tobacco. In fact, most people who develop these cancers were users of chewing tobacco.

  • Got A Match?

    The brain's best defense against nicotine is to think hard before using it. Start by trying to match the correct percentages to the statements located below.

    1. Percentage of smokers who start smoking in their teens

    2. Percentage of smokers age 17 or less who say they regret starting

    3. Percentage of youth smokers who will continue smoking and die early from a smoking-related disease

    A.   About 30%
    B.   80% - 90%
    C.   70%


    1. Percentage of smokers who start smoking in their teens
      B.   80% - 90%

    2. Percentage of smokers age 17 or less who say they regret starting
      C.   70%

    3. Percentage of youth smokers who will continue smoking and die early from a smoking-related disease
      A.   About 30%

  • The Search Continues

    The truth is, there's still a whole lot that scientists don't know about nicotine's effects on the brain. Maybe someday you'll make the next big discovery.

    Until then, join me - Sara Bellum - in the other magazines in my series as we explore how drugs affect the brain and nervous system.

    Mind Over Matter is produced by the National Institute on Drug Abuse, National Institutes of Health. These materials are in the public domain and may be reproduced without permission. Citation of the source is appreciated. NIH Publication No. 03-4248. Printed 1998, Reprinted 2000, 2003.

  • The NIDA Blog Team

    News reports are gaining attention on how bees have been dying in large numbers—much higher numbers than before 2006. Beekeepers and scientists have been mystified about why this is happening. Dying honeybees are a big problem for farmers, too, because the bees pollinate agricultural crops—okra, apples, cabbage, broccoli, and dozens more—and help them grow. So fewer bees means fewer crops, which is bad for food supplies and the economy.

    No, you haven’t accidentally clicked over to a blog for bee lovers. Believe it or not, the bee crisis—and possible solutions to it—may be closely connected to the subject of drugs.

    Getting their buzz on

    Some scientists think one cause of the bee crisis is a class of pesticides called neonicotinoids. These pesticides are chemically related to nicotine, the addictive substance in tobacco (and most e-cigarettes), and are used on many crops—crops that are then pollinated by bees.  This means that when bees pollinate the crops with this type of pesticide, they pick up some of it up.

    Some researchers speculate that bees are actually getting addicted to the pesticide—much like people get addicted to nicotine. Just like those addicted to cigarettes, bees may keep going back to neonicotinoids for another “hit.” Bye-bye, bee.

    In one recent study, bees preferred nectar laced with neonicotinoids to nectar without the pesticides. The researchers found that the bees couldn’t taste a difference between the two types of nectars (by using an electron microscope to see if the taste receptors in the bees’ mouths were stimulated).  This is why the researchers think the neonicotinoids might have hooked the bees’ brains.

    (For now, the Environmental Protection Agency has stopped approving new outdoor uses for neonicotinoids, while it waits to see results from additional studies on bees’ health.)

    Are we bee-brained?

    Does it matter if the human brain and the bee brain act in similar ways? Over at the NIDA website, Dr. Nora Volkow, NIDA’s director, says that the bee research suggests that studying the science behind addiction in people might also give us a better understanding of animal behavior. If it does, we may learn how to end the bee crisis.

    More research will reveal if, like people addicted to tobacco and other dangerous substances, bees are getting hooked on the same chemicals that could be killing them.

    Brain Science
    Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.