What is nicotine?
Everybody knows about the dangers of smoking. But what is nicotine from the point of view of chemistry and pharmacology, what properties does this infamous substance possess, the drop of which kills the horse?
The word "nicotine" originates from the Latin name of tobacco Nicotiana tabacum. They plant is obliged to the French ambassador at the court of Portugal, and concurrently with the scientist, Jean Nico, who recommended to Catherine de Medici tobacco, as a remedy for headache. Later, Nico brought a plant from Portugal to France and studied its properties.
In the Middle Ages, alchemists learned how to obtain pure nicotine by distilling tobacco leaves. Brown oily liquid was used to treat skin diseases, asthma, epilepsy, inflammation of the spleen.
The main scientific discoveries related to nicotine were made in the first half of the 18th century and belong to the German chemists Christian Wilhelm Posselt, Karl Ludwig Reimann, Louis Melsen, Adolf Piner. Chemically, nicotine was synthesized in 1893.
Nicotine - what is it?
Nicotine - what is this chemical? It belongs to the group of alkaloids - plant nitrogen-containing compounds with the properties of weak alkalis. This group includes strychnine, caffeine, quinine, cocaine and other medicines and poisons, isolated by humans from plants, and later synthesized by artificial means. Many alkaloids have a certain effect on the nervous system of humans and animals.
Nicotine is a colorless oily liquid with a pungent smell and burning taste. When stored, it becomes a yellowish brown color. In the Middle Ages, the alchemists called it "tobacco oil". The density of nicotine is approximately equal to the density of water, it mixes well with it. With acids, it also forms salts that are soluble in water. The chemical formula of nicotine: C10H14N2 (pyridin-3-N-methylpyrrolidine).
Nicotine is extremely toxic to cold-blooded animals and insects. In the early twentieth century, it was widely used to protect against pests as an insecticide. Later, due to the negative effect of the drug on humans and warm-blooded animals, artificial derivatives - imidacloprid, acetamiprid - came to replace it.
Where does nicotine
Nicotine is an alkaloid found in plants of the family of solanaceae (Solanaceae). The largest amount is found in tobacco leaves. Synthesis of matter is produced in the roots, and accumulation is in the leaves of the plant. The content of alkaloid in dry tobacco is 0.3-5% of the weight of the raw material. In smaller quantities it contains other plants of the family of the nightshade:
- green pepper.
- purgative acrid;
- / RTI & gt;
Does the human body produce nicotine? No, this substance does not participate in normal metabolism. True, under the influence of enzymes, it is oxidized to nicotinic acid, known as vitamin PP (antipellagric). Unfortunately, in the human body such an enzyme is absent and this transformation is impossible.
The effect of nicotine on the human body
Nicotine has a good affinity for all tissues of the human body. It is absorbed by the lungs from tobacco smoke, through the mucous membranes of the oral cavity, from the stomach and intestines, in contact with the skin. Entering the blood, it spreads rapidly across all organs, penetrates the brain barrier, through the placenta and other biological membranes.
When inhaled, this drug is found in the brain after 4-7 seconds. The peak concentration in the blood is reached 10 minutes after smoking a cigarette and is reduced in half in half an hour. During the same time, the brain is cleared of the drug.
How much nicotine stays in the blood and provides a narcotic effect? To the original quantity, its content is returned in 2-3 hours, and completely the substance is excreted from the body in about two days. After how much nicotine leaves the human body can be traced by the specific marker, which is - cotinine. The fact is that in the liver the drug is split into two molecules - cotinine and nicotine-H-oxide. The kidneys excrete these inactive metabolites with urine. A simple test has been developed that makes it possible to determine cotinine in urine 1.5-2 days after smoking a cigarette, which can serve as an indicator of the existence of a pernicious habit.
The effect of nicotine on the human body is determined primarily by its effect on the nervous connections - synapses. At low concentrations, it stimulates the release of the mediator in acetylcholine receptors, which leads to a number of effects:
increased adrenaline production;
- increased heart rate;
- vasoconstriction and increased blood pressure;
- the supply of glucose from the liver to the blood;
- ejection of mediators in the brain, leading to a psycho-stimulating effect.
With increasing doses, it blocks nervous synapses, which is manifested by depression of the central nervous system and a number of negative symptoms .
Nicotine is a drug, it causes physical and mental dependence. To him develops rapid addiction - the requirement to increase the dose to achieve a drug effect. The question whether a person gets pleasure directly from the drug remains open, as the substance in a certain way affects the dopamine neurotransmitters in the brain responsible for the pain threshold and pleasure center. According to another version, this effect is not the drug itself, but the substances contained in tobacco smoke.
In patients with schizophrenia, increased cravings for tobacco are seen. The question is not completely clear - there are a number of hypotheses about the causes of this predilection.
This is a very toxic substance. The lethal dose of nicotine for humans is 0.5-1 mg / kg, for mice it is 0.8 mg / kg when administered to a vein and 5.9 mg / kg for intraperitoneal injection, for rats - 50 mg / kg by mouth and 140 mg / kg when applied to the skin. For comparison: the lethal dose of potassium cyanide is 1.7 mg / kg. When smoking, most of the drug evaporates with smoke, and in the lungs comes 20-30%. When chewing tobacco this percentage is higher, but the intake of toxin into the human body is slower, so the peak concentration in the blood is lower than that of smokers. On average, when a cigarette is smoked, a person receives 1 mg of nicotine. For teenagers and children, an attempt to smoke even half-packs of cigarettes in a short time (2-4 hours) can be fatal. The cause of death in an overdose of nicotine is a stoppage of breathing due to paralysis of the respiratory center, cardiac arrhythmia or severe suppression of the functions of the central nervous system (coma).
The nicotine poisoning in case of an overdose manifests itself as follows:
- apathy or overexcitement;
- cold sweat;
- dizziness, ringing in the ears, blurred vision;
- copious salivation;
- nausea, vomiting;
- superficial rapid breathing;
Harm of nicotine for the human body is very diverse. The nervous, cardiovascular, digestive system is affected, the general metabolism, respiratory organs suffers. Here are the diseases typical for smokers:
- cardiac ischemia;
- angina pectoris;
- myocardial infarction;
- obliterating endarteritis;
- peptic ulcer;
In combination with harmful substances of tobacco smoke, nicotine affects the respiratory system, causing such diseases:
- chronic inflammation of the larynx;
- laryngeal cancer;
- lungs' cancer.
Toxin contributes to the development of inflammation of the gums and oral mucosa, cancer of the tongue.
The Benefits of Nicotine
The substance is recognized by all, without exception, scientific communities, as a life-threatening toxin and drug. Is it possible to benefit from nicotine, as from a medicine? It's not a secret that many alkaloids of plant origin, including drugs, have been used before or are still used today as medical products. Currently, they are issuing funds designed to alleviate the withdrawal syndrome of former smokers - nicotine patches, chewing gum, and the like. They have many contraindications. So, they can not be used for pregnant and lactating patients with heart diseases and peptic ulcer.
A number of countries are conducting laboratory studies in which this alkaloid acts as a means for prevention and treatment:
attention deficit disorder;
- Alzheimer's disease;
- ulcerative bowel disease;
- Parkinson's disease.
So, probably, in the near future nicotine will be a part of medicines from a variety of diseases.
Summarizing all of the above, we can draw the following conclusions. Nicotine is an alkaloid of vegetable origin, which has a narcotic effect and affects the human nervous system through acetylcholine receptors of nerve compounds. What affects nicotine? He has a psycho-stimulating effect, is addictive and addictive. Smokers with experience develop pathologies of the nervous, cardiovascular, digestive and respiratory systems. The only reasonable and effective treatment for such diseases is to stop the drug from entering the body.