Nicotine is an alkaloid of vegetable origin, particularly concentrated in tobacco leaves ( Nicotiana tabacum ). Its name derives from that of the French ambassador Jean Nicot, who in 1550 introduced the seeds of the plant to Europe, while the term tabacum refers to the pipe used by the North American Indians to smoke their leaves.
The effects of nicotine are however complex, linked to the dosage of intake and extended to different organs and systems. At high doses it is a powerful poison, so much so that 60 mg injected into a vein are generally sufficient to pass to a better life; in the past it was used as an excellent pesticide.
The nicotine taken through cigarette smoking is metabolized with a certain speed, which is greater in the habitual smoker than in the novice.
The risk of overdose is low, as the user tends unconsciously to adjust cigarette consumption to his own nicotine plasma levels. Some additional problems may be present for patients treated with transdermal patch replacement therapy, especially when they are not used according to the instructions of the doctor or pharmacist.
Effects of nicotine
At low doses, nicotine has a stimulating effect: it slightly increases the heart rate and blood pressure, causes slight sweating, improves concentration, increases metabolism, suppresses hunger and reduces stress. All right, in short, if it weren't for a small detail: repeated nicotine doses increase the concentration of its receptors in the brain, generating dependence. It is precisely the interaction with nicotinic acetylcholine receptors that increases the release of adrenaline, the hormone responsible for the stimulating properties described above.
At high doses, on the other hand, nicotine blocks these receptors, with opposite effects to those listed (hypotension, vasodilation, diarrhea, arrhythmias, drowsiness, headache), leading to complete paralysis of the respiratory muscles.
Heavy smokers suffer from unpleasant sensations when they come into abstinence. In these cases, symptoms such as depression, constipation, anxiety, nervousness, bulimia, reduction in heart rate and blood pressure are readily corrected by taking the substance.
Beyond the concentration in nicotine, which in itself is toxic but not carcinogenic, the harmful effects related to smoking are mainly due to the substances that develop during the burning of the cigarette; among the 4000 found in tobacco smoke there are at least sixty carcinogens (we recall nitrosamines, benzopyrene and various aromatic compounds), and other poisonous, such as arsenic and cyanide, or irritants, see ammonia and formaldehyde. What are the repercussions on health? To say it is enough to remember that, on average, a smoker has a life expectancy of 8 years less than that of a non-smoker.
Smoking during pregnancy can cause growth, mental and pulmonary development of the child.
Nicotine is excreted in breast milk in quantities directly proportional to the tobacco smoked, so that excessive consumption of cigarettes by the nurse can cause a whole series of disorders to the baby, such as restlessness, loss of appetite, tachycardia, vomiting and diarrhea.
increases gastric acidity and inhibits the secretion of pancreatic bicarbonates: it is a dangerous effect especially for those suffering from gastritis, gastroesophageal reflux and gastric or duodenal ulcers.
Slightly increases blood pressure: this is the reason why hypertensive and heart patients should not smoke.
Determines peripheral vasoconstriction: rather dangerous effects for those suffering from peripheral vasculopathies.
However, as mentioned, the toxicity of nicotine at the usual doses is, after all, modest; far more serious are the side effects attributable to the thousands of toxic and carcinogenic substances present in tobacco smoke (see: damage to smoke).
