Smoking: Inserm succeeds in suppressing nicotine addiction thanks to light

French researchers have managed to control the activity of nicotine receptors in the brain through different lights. Explanations.

One more step against smoking. A new study by Inserm has shown that it is possible to manipulate nicotine addiction in mice quickly and reversibly.

"This innovative technology provides a better understanding of the role of different nicotinic receptors and neuronal pathways in setting up, maintaining nicotine addiction, but also in the processes of withdrawal and relapse. This is important for the identification of new therapeutic targets that are appropriate for combating nicotine addiction, "explains Alexandre Mourot, head of research.

Violet light helps to stop the attraction of nicotine

Nicotine, the main addictive agent of tobacco, acts on the brain by binding to nicotinic receptors. Starting from this premise, scientists have modified the nicotinic receptor in mice, in order to hang a chemical nano-switch reacting to light. Under the effect of the violet light, the switch folds in preventing the nicotine to fix: the receiver is "off". Under the effect of the green light, or in the dark, the switch is unfolded and will let the nicotine act: the receiver is "on".
Concretely, the violet light stops the attraction for nicotine. The team compared the time that mice spent in two compartments, with or without nicotine. Under green light, when nicotine can exert its effect, they observed that animals preferred the compartment with nicotine. Under violet light, however, the mice spent so much time in each compartment, proving that they were no longer attracted to nicotine.

A special nicotine receptor

For this study, the researchers focused on a particular nicotinic receptor, type b2, and a key area of ​​the reward circuit, delivering dopamine. In an intravenous injection of nicotine, dopamine neurons respond by increasing their electrical activity. The resulting release of dopamine is the key to setting up addiction.
Nicotine is a naturally occurring chemical found in tobacco plants, which is one of the alkaloids. Its properties for the plant are to remove parasites (fungicide, acaricide, insecticide). In humans, nicotine causes tobacco addiction and feelings of relaxation, pleasure, decreased anxiety and depression.
When smoking, there is an initial "peak" during which the concentration of nicotine in the body increases continuously until the total burning of the cigarette, or between 5 and 7 minutes. Then, this concentration decreases rapidly: after one hour, it decreases by half; after two hours, there remains in the blood more than a quarter of the initial peak.

The damage on the younger generations

There will still be some traces of nicotine in the body. After 4 days, the blood will have purged all the nicotine it contained. The other nicotine and tobacco derivatives, which are responsible for cravings (cotinine, anabasin and nornicotines) are much longer to eliminate in certain organs of the body, such as kidneys or adipose tissue. It takes on average three weeks to be completely virgin traces of nicotine, the evacuation of the product is mainly through the urine.
The damage to the younger generations can be considerable. According to a recent study, the arteries of teenagers who smoke begin to stiffen at the age of 17 years. Arterial stiffness indicates that the blood vessels are starting to be damaged, which makes the bed of future heart and vascular problems. We are talking about heart attacks or strokes.
"In France, more than 13 million people smoke," said the government last March, recalling that tobacco is a "major source of cancer, cardiovascular disease and respiratory failure, responsible for 73,000 deaths each year ". Every day in the world, 11 million cigarettes are sold, generating 39 billion profits, the equivalent of the GDP of Luxembourg.

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