Nicotine as a toxic agent

Nicotine, active and addictive ingradient of tobacco, is a mild central nervous system stimulant and a stronger cardio vascular system stimulant. Overall it constricts blood vessels, resulting in an increase in blood pressure, and ultimately stimulating the heart and raises the blood fat levels. In it’s liquid form nicotine is a powerful poison which can bring fatality. It is the nicotine, not the smoke, that causes people to continue to smoke cigarettes. It, besides, is a potent parasympathomimetic stimulant and an alkaloid in nature found in the leaves of Nicotiana rustica, in amount of 2-14%; in the tobacco plants, Nicotiana tabacum abundantly. 

In our body nicotine acts as an agonists at most nicotinic acetylcholine receptors(nAChRs). Nicotine constitutes approximately 0.6-3.0% of the dry weight of tobacco which is the first and foremost ingredient of cigarettes, cigars, chewing tobacco, e-cigarettes, snuff, pipe tobacco and snus, so, imagine how dangerous it is or how much toxicity can be produced! However it mainly found in solanaceae family like eggplants,potatoes, and tomatoes etc. The actual mechanism is not yet understood, still, I am trying to give possible explanation, anyway, when a cigarette is smoked, nicotine-rich blood passes from the lungs to the brain within seven seconds and immediately stimulates nAChRs leading release of many chemical massengers such as acetylcholine, norepinephrine, arginine, vasopressine, serotonin, dopamine and betaendorphin in parts of the brain. Nicotine causes different physiological and physiochemical changes in our body, of which, I have attached a diagram explaining all the damages. It causes depression, psychosocial changes like bad Impact in education, socioeconomic status, employment status, osteoporosis, spinal degerative disc disease, impaired bone healing, impaired wound healing. This type of diseases, especially, found after frequent uses. It occures many neurological disorders like nAChR desenstization, nAChR upregulations, neuroplasticicity in pain pathways, nicotine withdrawl,  neuroendocrine changes etc. Now it's upto you what you decide. Any of these damage will permanantly disable you.