Addiction to nicotine- Is it genetically inclined.

Cigarettes can damage the human body. Any amount of smoke is dangerous. They are perhaps the only legal product which is advertised and intended use--smoking-- is harmful to the body and causes cancer.

The nicotine in cigarette smoke causes an addiction to smoking. Nicotine is an addictive drug--just like heroin and cocaine--for 3 main reasons.

• When taken in small amounts, nicotine creates pleasant feelings that urges to smoke more
• Smokers usually become dependent on nicotine and suffer withdrawal symptoms when they stop smoking. These symptoms include nervousness, headaches, irritability, and difficulty in sleeping.
• Because nicotine affects the chemistry of the brain and central nervous system, it can affect the mood and nature of the smoker.

Some people think that switching from high tar and nicotine cigarettes to those with low tar and nicotine content makes smoking safer, but this is not always true. When people switch to lower tar and nicotine brands, they often smoke more cigarettes or more of each cigarette to get the same nicotine dose as before.

Nicotine is a poison and in large doses can kill a person by stopping their breathing muscles. Smokers usually take in small amounts that the body can quickly break down and get rid of. The first dose of nicotine causes a person to feel awake and alert, while later doses result in a calm, relaxed feeling. Nicotine can make new smokers, and regular smokers who get too much of it, feel dizzy or sick to their stomach. Nicotine plays an important role in increasing smokers' risk of heart diseaseand stroke.

Most people begin smoking as teens. Peer pressure and curiosity are the major reasons young people try smoking. Also, people with friends and parents who smoke are more likely to begin smoking than those who have nonsmoking parents. Those who begin to smoke at a younger age are more likely than late starters to develop long-term nicotine addiction. Another prevalent influence in our society is the tobacco industry's ads for its products. The tobacco industry spends billions of dollars each year to create and market ads that show smoking as an exciting, glamorous, healthy adult activity.
  
Now new reports have been showing that the nicotine addiction in an individual is actually in his or her genes. 

Many of the forbidden pleasures of the modern day-nicotine, alcohol and over-eating- appear to be linked by common genetic factors. Genetic variables appear to play a key role in every aspect of nicotine addiction, from the tendency to begin smoking, to the chances of quitting. 

One of the more interesting forms of regulation for the neuronal nicotinic receptor gene family is the paradoxical up-regulation seen in subjects chronically treated with nicotine. Chronic nicotine infusion in mice results in a dose-dependent and time-dependent tolerance to nicotine that is paralleled by dose-dependent increases in both [³H]nicotine and [¹²⁵I] -bungarotoxin binding, suggesting that both high and low affinity receptors are affected. Many other studies have replicated the increases in nicotinic receptor levels in rats, treated chronically with nicotine

In humans, far less is known about the relationship between nicotine abuse and receptor levels. Several studies suggest that brain tissues from smokers have more [³H]nicotine binding than is seen in non-smokers. It has been found that the number of [³H]nicotine binding sites is correlated with the number of cigarettes smoked per day. In the brains of smokers who had quit smoking for different periods of time before death, binding levels had returned to the normal range, suggesting that monitoring nicotinic receptor levels during smoking cessation might provide valuable information regarding responses to smoking cessation and relapse. 

A new study out of Canada suggests young people are more likely to become addicted to cigarettes if they carry a specific form of a gene that helps clear nicotine out of the liver. Those with the inactive form of the CYP2A6 gene were about three-times more likely to get hooked on the habit than those with the normal form. The interesting thing is they were also less likely to smoke as many cigarettes. In the study, which was carried out among seventh graders in 10 schools, kids with the normal gene averaged about 29 cigarettes a week, compared to just 12 for kids with the inactive form of the gene. Kids with a partially inactive version of the gene smoked about 17 cigarettes a week. The investigators believe the inactive gene causes nicotine to stay in the body longer, thus requiring people to smoke fewer cigarettes in order to satisfy their cravings. 

A whole cascade of neural transmitters, which leads to a number of [systemic] effects that nicotine increases metabolism by 5% to 8%, lessens irritability, improves mood, and enhances concentration. Consequently, when smokers quit, they are faced with a nervous system redesigned for nicotine and are unable to function well without the drug. Cigarette manufacturers are currently developing cigarettes that distill nicotine rather than burn tobacco and its harmful constituents. Like it or not, nicotine addiction won’t ever go away. 

Longer-term studies in the pipeline are looking at the safety and efficacy of methoxsalen and other potent inhibitors have found. For those who cannot seem to kick the habit, this may be their best hope.


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