Your Brain on Drugs: Nicotine

Your Brain on Drugs: Nicotine

Nicotine is one the most heavily used and addictive drugs in the United States. Nicotine is also the leading most preventable cause of disease, disability, and death in the United States. Cigarette smoking makes up 90% of lung cancer in the United States, and about 38,000 deaths per year can be contributed to secondhand smoke. Most cigarettes in the United States today contain about 10 milligrams or more of nicotine. The average smoker takes in 1 to 2 milligrams of nicotine per cigarette when inhaling.

What is nicotine?

Nicotine is one of the 4,000 chemicals found in the smoke form of tobacco products. Nicotine is the primary ingredient that acts on the brain. Smokeless tobacco products such as chewing tobacco and snuff also contain many toxins including high levels of nicotine. Nicotine is a naturally occurring colorless liquid that turns brown when it is burned. Nicotine also takes on the odor of tobacco when exposed to air.

Nicotine is absorbed through the skin and mucosal lining of the nose and mouth or in the lungs. Nicotine reaches its peak levels in the bloodstream and brain rapidly depending on how it is taken. Cigarette smoking results in nicotine reaching the brain within ten seconds. Nicotine is very addictive which is why those who smokers tend to do it regularly. Addiction is known as a compulsive drug seeking and uses even at risk of negative health consequences. Most smokers know that nicotine and tobacco is harmful and a lot of them try to quit to no avail.

Nicotine and Acetylcholine

Once nicotine reaches the brain, it triggers a series of responses that alters the way cells in the brain communicate with each other.

Nicotine mimics one of the major neurotransmitters in the brain called acetylcholine. Nicotine acts just like acetylcholine, by binding to receptors that increase the electrical activity of neurons, resulting in more signals transmitted to neighboring neurons. Because nicotine binds to the same receptors that bind acetylcholine, the acetylcholine receptor is often referred to as a nicotinic receptor.

However, when one uses a tobacco product or another nicotine containing product, there is more nicotine available in the synaptic spaces compared to acetylcholine. The nicotine competes with acetylcholine to bind to the nicotinic receptors and it wins. Now, with more nicotinic receptors activated by nicotine, a more intense response is produced.

So while acetylcholine normally provides the just the right amount of alertness when it binds to its receptors, nicotine produces a much more intense response (increased alertness, pleasurable feelings) due to its higher concentrations at the acetylcholine receptors.

How nicotine affects the brain

• Nicotine causes a rapid release of adrenaline. This causes the smoker to feel a rapid heartbeat, increased blood pressure, rapid, or shallow breathing. Nicotine also blocks the release of the hormone insulin. Nicotine can also increase the metabolic rate slightly too. The brain is the most important aspect for nicotine. Nicotine causes an increased release of acetylcholine from the neurons in the brain. This leads to heightened activity in pathways in the brain. This makes nicotine give someone the ability to pay attention and have a faster reaction time. This is what causes nicotine to give people the feeling of working better.
• Nicotine also causes a release of glutamate. Glutamate is imperative in learning and memory. When nicotine is used it glutamate creates a memory of the good feelings you get while smoking and further increases the drive and desire to use nicotine.
• Nicotine also causes your brain to make more endorphins. Endorphins are small proteins that are the body’s natural pain killer.  Endorphins can cause feelings of euphoria. This makes nicotine even more addictive without all the other added effects.
• Nicotine activates the circuitry that regulates feelings of pleasure; these are known as reward pathways. Nicotine increases the levels of dopamine in reward pathways.  This enhances nicotine’s addicting potential. Smoking a cigarette rapidly distributes nicotine to the brain. In fact nicotine levels peak within 10 seconds of inhaling from a cigarette but then also decrease rapidly. This is what causes smokers to have the need to smoke repeatedly throughout the day.

Quitting nicotine

Quitting nicotine is followed by withdrawal symptoms that can last up to a month or more. These symptoms can cause people to just end up smoking again. Nicotine withdrawal symptoms usually start in a few hours after the last cigarette and can include irritability, sleep disturbances, craving, cognitive and attention deficits, and increased appetite. Nicotine withdrawal symptoms usually peak within the first few days and will subside within a few weeks although for some people they can last much longer.

For some people, the feel, smell and sight of a cigarette and the ritual of obtaining, handling, lighting and smoking it are all associated with the pleasurable effects of smoking and can make withdrawal or craving worse. While nicotine gum and patches may alleviate the pharmacological aspects of withdrawal, cravings often persist.

More consequences of nicotine use

Nicotine and cigarette smoking has more consequences than those just on the brain. The medical consequences of nicotine result from the nicotine itself and how it is taken. Tobacco use accounts for 1/3^rd of all cancers. Here are some other medical consequences due to nicotine and cigarette smoking:

• Lung diseases such as chronic bronchitis and emphysema
• Worsening asthma symptoms
• Cancers of the mouth, kidney, esophagus, pharynx, larynx, stomach, pancreas, cervix, ureter, and bladder.
• Risk of heart disease including stroke, vascular disease, heart attack and aneurysm.
• Passive or secondary smoke increases risk for many diseases too.

If your loved one is in need of addiction treatment, please give us a call at 800-951-6135.

Sources:

http://science.howstuffworks.com/nicotine4.htm
http://rise.duke.edu/seek/pages/page.html?0105