The effects of tobacco on the brain

Lighting and smoking a cigarette are actions carried out by millions of people regularly every day, knowing that smoking and smoking have many harmful and detrimental effects on our survival.

Today, most people know about the relationship between tobacco and lung cancer, respiratory problems, the aging of our tissues or the shortening of life expectancy. However, there are other organs and conditions which are generally not so taken into account by the population and which are nevertheless fundamental: for example, the effects of tobacco on the brain.

Throughout this article we will be doing a brief review of what smoking involves, how tobacco affects the brain and the effects and risks that tobacco use may have on the royal organ.

    Tobacco and nicotine

    Tobacco is a product made from the tobacco plant (Nicotiana tabacum), in particular its leaves and stem, which are then chopped or cut, are prepared in different formats and some of which are mixed with other substances to form cigarettes, bite or be used in pipe, and which is usually consumed by the suction of the fumes of its combustion.

    The main active ingredient in tobacco, which gives it its psychoactive properties, is nicotine. This substance has activating and stimulating effects on the body, Looking at the nicotinic acetylcholine receptors in our body. Despite this with chronic consumption and the gradual habituation that this substance generates, the effects are less and less activating and tend to be perceived as depressants and even relaxers.

    But nicotine addiction ends up generating dependence on its external acquisition, so that little by little more quantities are needed to achieve the same effects: over time, smoking becomes a necessity and smoking or nicotine or tobacco addiction is established.

    Using tobacco and inhaling its smoke also means that other components are incorporated into the body, such as carbon monoxide, carcinogens, free radicals and oxidants such as the hydroxyl radical, carcinogenic gases such as formaldehyde or nitric oxide or metals such as cadmium or beryllium (And even arsenic).

    In addition, this consumption has harmful effects on many parts of our body, whether we talk about tobacco in the form of cigarettes or in other ways: inhaling smoke is irritating and is deeply linked to respiratory problems (being one of the most common reasons common conditions of chronic obstructive pulmonary disease, emphysema and other respiratory problems) and the appearance of respiratory tumors or of the intestinal and buccopharyngeal tract.

    It also affects, among other things, the heart and the vascular system, causing vasoconstriction and can facilitate serious problems in this system. It can cause liver and pancreatic problems, damage the eyes and skin, and impair metabolism and the gastrointestinal system. It also reduces physical capacity due to lack of oxygenation.

    How does smoking work in our brain?

    When inhalation occurs, most of this substance is absorbed by the smoking subject through the lungs (And in much smaller amounts through the mucous membranes and tongue), and after being processed through the alveoli and carried into the bloodstream in about eight seconds, it reaches our brain after crossing the blood-brain barrier.

    Once there, it binds to acetylcholine receptors called nicotinics, in which it generates the opening of calcium channels but which prevents the acetylcholine already existing in the brain from entering. This will cause the body to try to generate higher levels of acetylcholine, which will also cause the brain dopaminergic reward system to activate. Nicotine causes damage at various points in the brain, however some of the most important are the limbic system and the basal ganglia, As well as the mesocortical and mesolimbic route.

    This system is at the origin of tobacco consumption which gradually becomes desirable and promotes dependence. Dopamine in this area increases at the same time that other components of tobacco block the action of MAO which would decrease it. It also affects the locus coeruleus, stimulating and causing increased energy levels while helping to generate feelings of calm in stressful situations.

    Also, a desensitization of the nicotinic receptors to this substance is gradually generated by positive regulation, to which the organism will respond by forming a greater number of receptors where the union between the nicotine and the receptor can occur. A tolerance to the substance is formed, Which will cause the need for more and more nicotine to cause the same effects. And this tolerance also partly explains why chronic smokers feel more relaxed when they smoke when they smoke: they actually relieve the anxiety inherent in abstinence.

    At the same time, it affects the hypothalamic-pituitary axis in order to increase the release of adrenocorticotropic hormones and corticotropin, which in turn contributes to the stimulation of the adrenal glands in such a way that it causes the synthesis and release of adrenaline or epinephrine. This hormone will generate vasoconstriction and increases in pressure and heart rate and in turn fuel the activation of the body. It also hinders the synthesis of pancreatic enzymes.

    Effects of tobacco on the brain

    Beyond how it works, it is also relevant to know some of its effects. In the short term and after the first few drinks, it is common for the initial consumption of small doses to alleviate depressive symptoms and increase mood.

    Activation of the locus coeruleus also facilitates activation and it may appear that there is an increase in arousal levels, the ability to concentrate and the feeling of knowing how to handle situations. However, it can also cause dizziness and breathing problems.

    However, as consumption becomes more frequent, the consequences worsen. In the first place, the progressive tolerance to nicotine results in an addiction to the substance, first physical and then mental.

    Lack of tobacco it will generate abstinence, usually in the form of discomfort and anxiety. Increases in appetite, listlessness, headaches, and sleeping problems are also seen. Problems concentrating can also occur during abstinence. It also impairs the ability to smell and taste, interfering with these senses.

    The effect of nicotine on the neocortex has been observed, especially in the long term, as problematic and negative. Several studies suggest that smoking weakens and causes deterioration of nerve cells in this part of the brain, and leads to a reduction in its thickness due to increased death of nerve fibers. This factor may be linked to an increased likelihood of cognitive impairment and even dementia. We have also seen that the formation of new neurons is reduced.

    In the case of pregnancy, it has been observed that smoking can lead to prematurity and low weight, as well as delays in the growth and cognitive development of the child.

    They also greatly affect the vasoconstrictor abilities of nicotine, something that may facilitate the onset of a stroke. However, nicotine (other than smoking) appears to have positive effects in preventing Parkinson’s disease, although this is still something under investigation.

    If one also takes into account the possible effect of the presence of carbon monoxide (common in the combustion of tobacco), also makes it difficult for the brain to oxygenate and can cause demyelination of the nervous system (loss of myelin, which results in a loss of speed in the transmission of information between neurons)

    Also, although in the first few moments it generated stimulation, in the long run it can generate problems such as depression. On a less biological and more psychological level, if unsuccessful efforts are made to stop it, they may also feel helpless or ineffective, or even resort to other more harmful substances.

    Bibliographical references:

    • Dani, JA (2001). Overview of nicotinic receptors and their role in the central nervous system. Biol. Psychiatry 49, 166–174.
    • Karama, S., Ducharme, S., Corley, J., Chouinard-Decorte, F., Starr, JM, Wardlaw, JM, Bastin, ME and Deary, IJ (2015). Smoking cigarettes and clearing up the cerebral cortex. Molecular Psychiatry, 20: 778-785.
    • Martín, A., Rodríguez, I., Rubio, C. Revert, C and Hardisson, A. (2004). Toxic effects of tobacco. Tower. Toxicol., 21: 63-71.
    • Tanja, AJ, Quintero, LCM (2015). Neurobiochemical effects of nicotine on the human brain. April 16 magazine; 54 (260): 31-41.

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