Why is so difficult to quit smoking?

Why is so difficult to quit smoking?
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Tobacco smokers, according to Xinhua Daily Telegraph reported that a long time without smoking, the nicotine gradually being removed, those that had previously been occupied nicotine receptors empty out, related to acetylcholine binding, transmission of nerve signals to hell broke loose, the body appeared unwell smokers to want to smoke as soon as possible, so that the number of receptors in vivo empty back to normal. So once smoking addiction, has not primarily in order to get a sense of pleasure, but in order to avoid uncomfortable.

Almost everyone knows that smoking is harmful to health, most people who have thought about quitting smoking, but only a few people will successfully quit smoking. America had a statistic: 80% of smokers thought about quitting, but if not using nicotine replacement therapy, only 3% -5% of people will successfully quit smoking. Why is so difficult to quit smoking? In addition to psychological and social factors, mainly just about nicotine, because nicotine is a drug similar to something that can be addictive. Why Nicotine is addictive it?

In the human brain inside, there is a region known as the reward center, to engage in some kind of survival, reproduction vital activities, such as drinking, eating, mating, socializing, the reward center will release something called dopamine substances, people have the feeling of pleasure, to motivate people to continue to engage in these beneficial activities. However, smoking, drug use, although these activities harmful than good, reward center will also be a large release of dopamine reward. For example, in smoking, smoking the first port, a few seconds later, the nicotine will reach the brain through the blood into the reward centers, stimulating it releases dopamine. This process is very fast, it can easily addictive. A teenager just smoked four cigarettes, it is possible lifelong addiction of smoking because the nicotine in tobacco inside kidnapped reward center of the brain, people have the illusion of smoking beneficial.

Mention inside contains a lot of tobacco carcinogens and other harmful substances, nicotine itself is a toxic substance, nicotine contained in cigarettes 4 if all be absorbed, it is enough to kill a person (Fortunately, when smoking only a small amount of nicotine is inhaled). Nicotine originally Solanaceae, including tobacco in order to prevent pests and herbivores evolved to eat them out of the natural insecticide. This natural insecticide is how the human brain’s reward kidnapped center it?

Contains a lot of nerve cells in the brain, if you read the nerve cells under a microscope, you will find them and other cells are very different in appearance, with long protrusions. Nerve cells through the mutual contact of these projections, the receive and transmit signals. Nerve cell processes parts in contact with each other, called synapses, if you look carefully, two nerve cell synapses are not linked together, leaving the middle of the gap. Signal passes through the gap how do? This need to use a class of chemical substances as a neurotransmitter. One of neuron nerve signals received after the release of its end projection neurotransmitters, neurotransmitter across the synaptic cleft, to the end of another nerve cell processes, the end of the membrane has a lot of specific receptors , a neurotransmitter associated with these receptors, signals pass over.

The earliest discovery of a neurotransmitter called acetylcholine, and its binding receptors called acetylcholine receptors. Acetylcholine receptor is actually a protein consisting of ion channels, the channel usually is turned off. Acetylcholine receptor, the ion channel is opened, the extracellular sodium ion, potassium ion, calcium ion into the nerve cells, triggering a series of reactions. If the reward centers, including those in the subsequent reaction to the release of dopamine. Then quickly degrade acetylcholine, removed, receptor ion channel is closed again, waiting for the next batch of acetylcholine binding.

Neurotransmitters and receptor binding, as a combination of key and lock, is very specific. But nicotine is like a forged key, happened to be with a certain type of acetylcholine receptor binding (such receptors called nicotinic acetylcholine receptors), open ion channels, stimulate dopamine release. Moreover, nicotine and acetylcholine receptor binding also was particularly tight, unlike acetylcholine be removed as quickly, it’s half-life (minus half the time) for up to two hours. However, it has been impossible to open ion channels, if the key has been inserted in the lock does not pull out, then the channel will be shut himself up. This process is called desensitization. Smokers continue to smoke in the process, the body has always contain nicotine, the result is that most of nicotinic acetylcholine receptors are occupied by nicotine, but in a state of desensitization can not react to acetylcholine.

But the nerve signals have to pass ah, how to do it? Nerve cells had to produce more acetylcholine receptors, so that they can combine with acetylcholine, to ensure normal transmission of nerve signals. So on nerve cells in smokers, the number of acetylcholine receptors much more than the average person, occupied most of the nicotine does not work, and the rest can work only acetylcholine receptor number and the average person almost. If smokers do not smoke for a long time, such as during sleep, or quit smoking, the nicotine gradually being cleared away, those that had previously been occupied nicotine receptors empty out, can also be combined with acetylcholine. This time on the problem, the empty lot more than usual receptors, are related to acetylcholine binding on the transmission of nerve signals messed up (acetylcholine receptors more than the number, can combine much is controlled by the number of receptors), physical discomfort appeared, there has been withdrawal reactions, smokers felt particularly uncomfortable, you want to suck one as soon as possible, so that the number of receptors in vivo empty back to normal. So once smoking addiction, has not primarily in order to get a sense of pleasure, but in order to avoid uncomfortable.

Fortunately, this process can be reversed. If you insist on smoking, excess acetylcholine receptor is gradually being removed, this is a long process: 6-12 weeks after quitting, the body of nicotine was only completely cleaned of excess acetylcholine receptors was only cleaned by body number was restored to normal levels, no longer appear withdrawal reactions. Withdrawal reactions usually last for two months, through this difficulty, be considered successfully quit smoking. Most people do not have the willpower, need the help of nicotine patches, nicotine gum and other nicotine replacement therapy, and gradually quit smoking.

Understanding of the principles of nicotine kidnapping reward center, we can devise a medication to help smokers quit. Another kind of counterfeit drugs is equivalent to the key that can compete with nicotine, the receptors of the “keyhole” account (but it does not cause massive release of dopamine), so that nicotine does not go, then even if smoking is also unable to get a sense of pleasure, not the desire to smoke. So use this smoking cessation drug more effective than nicotine replacement therapy, but it will still bind to its receptor cause a series of side effects, including headache, nausea, insomnia, depression, etc., can only be used under the guidance of a doctor, not long-term use.