Nicotine: what it is, characteristics and how it affects our body

The World Health Organization (WHO) estimates that there are more than 1.3 billion tobacco smokers on the planet. Beyond this alarming figure, if we delve into medical terms things worsens drastically: up to half of those who consume it end up dying. Lung cancer clearly exemplifies this fact, since it is responsible for 25% of neoplastic processes in humans and claims more than 130,000 deaths annually.

As much as we all know the dangers of this addiction, in certain countries tobacco use is still completely normalized. Without going any further, it is estimated that in regions like Spain 24.5% of the adult population smokes, with all the psychological, social and physiological effects that this entails.

Beyond numbers, lung cancer, health and other topics, tobacco is fascinating from a physiological point of view. Today we tell you all about its key component: nicotine.

• Related article: "The Effects of Tobacco on the Brain"

What is nicotine?

Nicotine, chemically named (S) -3- (1-methylpyrrolidin-2-yl) pyridine, is

an alkaloid found primarily in the tobacco plant (Nicotiana tabacum). It is a secondary metabolite produced by the plant from amino acids, which is why it contains nitrogenous compounds in its chemical formula. Tobacco is not the only alkaloid known and used by humans: cocaine and caffeine are also examples of this.

Nicotine is stored mainly in the leaves of the plant, assuming 5% of the total dry weight of it. This has a clear biological function: the compound is a pesticide that prevents certain invertebrates from preying on the leaves. In addition to this, herbicidal properties are also attributed to it, which reduces the growth of other plants close to tobacco, thus causing a greater availability of resources in the plant.

In addition to the tobacco plant known to all (Nicotine tabacum), there are other plants that synthesize this alkaloid in variable concentrations. Among them, we find the following:

• Some plants that contain little nicotine include horsetail, celery, potato and even the papaya plant.
• The tobacco tree (Nicotina glauca) does not have much nicotine, although it is rich in the alkaloid anabasine, a nicotinic receptor agonist.
• The mapacho (Nicotina rustica) has higher amounts of nicotine than the normal tobacco plant. For this reason, the intake of its leaves in excess is considered dangerous.

As you can see, not only the typical tobacco plant contains nicotine. At the end of the day, we are talking about a pesticide and herbicide alkaloid that can bring many benefits to the plant when it comes to surviving in the environment.

An average cigarette contains 12 milligrams of nicotine, although these values ​​can range from 8 to 20 milligrams. As a curious fact, it should be noted that the content of 4 cigarettes (50 mg of nicotine) is capable of ending the life of a man, if the compound is injected intravenously. Therefore, we are not surprised to learn that there have been several serious poisonings in infants by directly ingesting the content of cigarettes.

Actions of nicotine on the body

According to studies, nicotine is a substance with stimulating properties and is responsible for dependence on cigarettes. The main human brain structures involved in this addiction mechanism are the nucleus accumbens, the prefrontal cortex, the hippocampus and the amygdala. This alkaloid produces direct (and indirect) actions on neurotransmitters, as the dopamine, acetylcholine, norepinephrine and serotonin.

When a low dose of nicotine is administered to humans, produces a feeling of instant gratification, as endorphins are released in brain gratification circuits. As with other drugs, feelings of reward and euphoria are positively correlated with the release of the neurotransmitter dopamine, which generates the compulsive urge to re-consume the drug.

In addition to these measurable brain effects, nicotine encompasses many more settings in the human body. Among them, we find the following:

• Decreases appetite: nicotine helps you lose weight because it interacts with enzymes related to appetite and intake. Many tobacco users dramatically gain weight after quitting the drug.
• Increases intestinal activity.
• It causes the formation of more saliva and phlegm: this is a product of irritation of the upper respiratory tract.
• Increase heart rate and blood pressure.
• Stimulates memory and wakefulness: For this reason, chronic smokers feel that they need to smoke in order to concentrate and be active.

After inhaling tobacco smoke, the concentration of nicotine in the blood increases rapidly and, in less than 20 seconds, it reaches the brain and activates the previously described reward mechanisms. As surprising as it may seem, inhaled through tobacco smoke this alkaloid reaches its destination earlier than if it is administered intravenously.

Unfortunately, nicotine works as fast as it goes away. This alkaloid reaches its peak of activity within 10 seconds, so it produces a short and quick gratification, but of a mild nature. For this reason, a smoker requires the consumption of several cigarettes a day to feel completely well and focus your attention on the relevant tasks.

When you stop smoking is when the neurological catastrophe occurs: continued tobacco use causes the exceptionally low levels of dopamine secretion as nicotine concentrations are depleted in the nervous system central. This, without a doubt, bases the dangerous dependency bases that this substance generates.

• You may be interested in: "The 14 most important types of addictions"

Physical and psychological addiction

To understand the mechanism of nicotine addiction, it is essential to differentiate the physical from the physiological, although the two fronts are widely interconnected.

Physical dependence is that which occurs when symptoms appear a few days / hours after the drug in question has been withdrawn of the patient's life. Mild clinical signs usually appear 2-3 hours after the last cigarette, reaching a peak within 2-3 days.

Among them we find headaches, tension, anxiety, depression, difficulty concentrating, and a strong need to put a cigarette in your mouth. It should be noted that physical dependence is conditioned, to a large extent, by tolerance: the lower the sensitivity of the body to the substance, the more it is needed.

On the other hand, psychological addiction refers to the need for the pleasure generated by the substance or, failing that, to how it helps the patient to cope with their problems. Both events are widely interconnected, as they lead to the same symptoms described previously.

Is it difficult to quit smoking?

Any of the readers who have tried (or succeeded) to quit tobacco will know how to answer this question in a blunt way. As shocking as it may sound, the chances of being dependent on tobacco (28%) are higher than on cannabis (8%) or cocaine (11%). While other drugs are more clearly deleterious in the short term, tobacco kills slowly but unstoppably.

Most smokers try to quit smoking an average of 2 times before finally succeeding. 25% of those who propose it, in addition, are not able to endure more than 24 hours without putting a cigarette in their mouth. Such is the degree of addiction that more than half of patients who have undergone lung cancer surgery return to smoking at some point in their life. In these cases, the addiction clearly prevails over the craving for life.

Resume

Undoubtedly, we are facing one of the most problematic drugs (if not the most) in today's society. The World Health Organization backs up this claim with data that falls like a vase of cold water: tobacco kills up to 1 in 2 people who use it.

For all these reasons, lung cancer is one of the most common malignant tumor processes worldwide. For greater concern, this type of cancer is one of the most deadly, since the patient's survival rate 5 years after diagnosis does not reach 20%. After reading these lines, there is little doubt that starting to use tobacco is one of the worst decisions that can be made in life.

Bibliographic references:

• Is nicotine addictive? National Institute of Drug Abuse (NIH). Picked up on January 29 at https://www.drugabuse.gov/es/publicaciones/serie-de-reportes/adiccion-al-tabaco/es-adictiva-la-nicotina.
• Campo, A. (2002). Nicotine dependence: approach to its pharmacological management. Rev. colomb. psychiatrist, 67 - 72.
• Nicotine, pfitzer.es Collected on January 29 at https://www.pfizer.es/salud/dejar_de_fumar/nicotina.html
• Nicotine and Tobacco, Medlineplus.gov. Picked up on January 29 at https://medlineplus.gov/spanish/ency/article/000953.htm
• Secades Villa, R., & Fernández Hermida, J. R. (2001). Effective psychological treatments for drug addiction: nicotine, alcohol, cocaine and heroin. Psicothema, 13 (3).
• Tobacco, WHO. Picked up on January 29 at https://www.who.int/es/news-room/fact-sheets/detail/tobacco