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.

The Brain’s Response to

Nicotine

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, 

U.S. Department of Health and Human Services. 

These materials are in the public domain and may be 

reproduced without permission. Citation of the source is 

appreciated. NIH Publication No. 06-4248. Printed 1998. 

Reprinted 2000, 2003, 2005, 2006.

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 of 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.

MOUTH CANCER

PHARYNX CANCER

LARYNX CANCER

ESOPHAGUS CANCER

LOSS OF TEETH

HEART ATTACK

STROKE

EMPHYSEMA

CANCER

National Institute on Drug Abuse

National Clearinghouse for Alcohol and Drug Information,

P.O. Box 2345, Rockville, MD 20847

1-800-729-6686

For more information, visit:

www.drugabuse.gov
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.

How Does Nicotine Act in the Brain?

A distant

view

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.

A. About 30%

B. 80%-90%

C. 70% 

1. Percentage of smokers who start 

smoking in their teens.

2. Percentage of smokers age 17 or 

under who say they regret starting.

3. Percentage of youth smokers who 

will continue smoking and die early 

from a smoking-related disease. 

Answers:

1. B- 80%-90%

2. C- 70%

3. A- About 30%

?