Lighting and smoking a cigarette are actions that millions of people carry out on a regular basis every day, even knowing that smoking and tobacco consumption have a large number of harmful and detrimental effects on our survival.
Today, most people know 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 that are not usually taken into account by the population and that despite this are fundamental: for example, the effects of tobacco on the brain.
Throughout this article we are going to do a brief review of what smoking entails, how tobacco affects the brain and the effects and risks that tobacco consumption can have on the king organ.
Tobacco is a product made from the tobacco plant (Nicotiana tabacum), specifically its leaves and stem, which after being chopped or cut are prepared in different formats and some of which are mixed with other substances to make cigarettes. tobacco for rolling or for use in a pipe, and which is generally consumed by inhaling the smoke from 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, binding to the nicotinic acetylcholine receptors in our body. Despite this, with chronic consumption and the progressive habituation that this substance generates, the effects are increasingly less activating and tend to be perceived as depressants and even relaxants.
But habituation to nicotine ends up generating dependence on its acquisition externally, in such a way that little by little greater quantities are needed to obtain the same effects: with the passage of time, smoking becomes a necessity and smoking or dependence on nicotine or tobacco is established
Tobacco consumption and inhalation of its smoke also implies that other components are incorporated into the body, such as carbon monoxide, carcinogenic substances, 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).
Furthermore, this consumption has harmful effects on multiple parts of our body, regardless of whether we are talking about tobacco in the form of a cigarette or in other forms: inhalation of smoke is irritating and is deeply linked to respiratory problems (being one of the most common reasons). common causes of chronic obstructive pulmonary disease, emphysema and other respiratory problems) and the emergence of respiratory tumors or tumors of the intestinal and oropharyngeal tract.
It also affects, among others, the heart and vascular system, generating vasoconstriction and potentially facilitating severe problems in said system. It can cause liver and pancreas problems, cause eye and skin damage, and alter the metabolism and gastrointestinal system. It also reduces physical capacity due to lack of oxygenation.
How does smoking act on our brain?
Upon inhalation, Most of this substance is absorbed by the smoker through the lungs (and in much smaller quantities by the mucous membranes and the tongue), and after having been processed by the alveoli and taken to the blood in about eight seconds, it reaches our brain after having passed through the blood-brain barrier.
Once there, it fixes on the acetylcholine receptors called nicotinic, in which it generates the opening of calcium channels but 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 activation of the dopaminergic brain reward system. Nicotine affects different points of the brain, but some of the most relevant are the limbic system and the basal ganglia as well as the mesocortical and mesolimbic pathway.
This system is what causes tobacco consumption to gradually become palatable and encourage addiction. Dopamine in this area increases while other components of tobacco block the action of MAO, which would decrease it. It also affects the locus coeruleus, stimulating it and causing an increase in energy levels while contributing to generating feelings of tranquility in stressful situations.
Likewise, little by little, a desensitization of nicotinic receptors to this substance is generated through positive regulation, to which the body will respond by forming a greater number of receptors where the union between nicotine and receptor can occur. A tolerance is forming to the substance, something that will cause more and more nicotine to be needed to cause the same effects. And this tolerance also partly explains why chronic smokers, rather than becoming active, feel relaxation when they smoke: they are actually relieving the anxiety of withdrawal.
At the same time, it affects the hypothalamic-pituitary axis in a way that increases the release of adrenocorticotropic and corticotropin-releasing hormones, which in turn helps stimulate the adrenal glands in such a way that it causes the synthesis and emission of adrenaline or epinephrine. This hormone will generate vasoconstriction and increases in heart rate and pressure and in turn feeds back the activation of the body. It also hinders the synthesis of pancreatic enzymes.
Effects of tobacco on the brain
Beyond how it acts, it is also relevant to know some of its effects. In the short term and with the first consumption, it is common that the initial consumption of small doses can relieve depressive symptoms and increase mood.
Activation of the locus coeruleus also facilitates activation and there may appear to be increases in levels of wakefulness, ability to concentrate, and the feeling of knowing how to cope. However, it can also cause palpitations, dizziness and breathing problems.
However, as consumption becomes more frequent, worse and worse consequences are seen. Firstly, the progressive tolerance to nicotine results in a dependence on the substance eventually appearing, initially physical and later also psychological.
The lack of tobacco will lead to withdrawal, usually in the form of discomfort and anxiety Increases in appetite, apathy, headaches and sleep problems are also observed. Concentration problems may also appear in abstinence. It also alters the capacity for olfactory and gustatory perception, harming these senses.
The effect of nicotine on the neocortex has been observed, especially in the long term, as problematic and negative. Various studies suggest that tobacco consumption weakens and generates deterioration in the nerve cells of this part of the brain, and that it causes a reduction in their thickness due to the greater mortality of the nerve fibers. This factor may be linked to a higher likelihood of cognitive decline and even dementia. It has also been seen that the formation of new neurons is reduced
In the case of pregnancy, it has been observed that smoking can cause prematurity and low weight, as well as delays in the child’s growth and cognitive development.
They also greatly affect the vasoconstrictive abilities of nicotine, something that can facilitate the occurrence of stroke Now, nicotine (not smoking) seems to have positive effects in preventing Parkinson’s, although this is still being studied.
If we also take into account the possible effect of the presence of carbon monoxide (common in tobacco combustion), we also hinders oxygenation of the brain and can cause demyelination of the nervous system (loss of myelin, which results in loss of speed in the transmission of information between neurons)
Likewise, although in the initial moments it generated stimulation, in the long run it can generate problems such as depression. At a less biological and more psychological level, if unsuccessful efforts are made to quit, a feeling of helplessness or inefficiency may also occur, or one may even resort to other, more harmful substances.
