Nicotine (Nicotine) is a common name, nicotine, exists in the Solanaceae (nightshade) in alkaloid, it is also an important component of tobacco, or on behalf of N cholinergic receptor agonists, N1 and N2 receptors and central nervous system had no effect, the value of clinical application.
Nicotine can be addictive or addictive (one of the most difficult to get rid of), it is often difficult to restrain themselves, repeated use of nicotine also increases heart rate and high blood pressure and reduce appetite. High doses of nicotine can cause vomiting and nausea. Tobacco contains nicotine, which makes many smokers unable to quit smoking.
When nicotine enters the body, it can be transmitted through the blood and through the blood-brain barrier, which takes only 7 seconds to reach the brain. The half-life of nicotine in the human body is about 2 hours. Nicotine and smoking body via, affected by many factors, including tobacco quality, whether sucking, whether the use of filters are the reasons of influence. Chewing type, buccal type and inhaled tobacco through contained in the lip and nose gums direct inhalation, high efficiency of nicotine into the body. The liver is the main organ of metabolism of nicotine, decomposition enzyme (mainly CYP2A6 Cytochrome P450, CYP2B6 has effects on nicotine, cotinine) metabolic products (cotnine).
Effect of nicotine on nicotinic acetylcholine receptor, especially the receptors on autonomic nervous system ((alpha 1) 2 (beta 4) 3) receptors and central nervous system ((alpha 4) 2 (beta 2) 3), the former is located in the adrenal medulla and other locations, which is located in the central nervous system. At low concentrations, nicotine increases the activity of these receptors, and nicotine has a direct effect on other neurotransmitters. High concentration inhibition.
Central nervous system
Nicholas Ding Ke and nicotinic acetylcholine receptors with increased neurotransmitter, dopamine in the brain, increase happiness and sense of relaxation, and finally may be due to smoking addiction phenomenon.
Tobacco smoke contains a monoamine oxidase inhibitor (Monoamine oxidase inhibitor), monoamine oxidase breaks down monoamine neurotransmitters, dopamine, norepinephrine and serotonin.
Nicotine, which is exposed to nicotine in cigarette smoke for a long time, is a direct regulator of alpha 4 beta nicotinic acetylcholine receptors in the cerebellum and brain stem.
Peripheral nervous system
Nicotine can stimulate the sympathetic nerve, by stimulation of the splanchnic nerve of the adrenal medulla, the release of epinephrine. The parasympathetic preganglionic fibers release acetylcholine, which acts on nicotinic acetylcholine receptors to release epinephrine and norepinephrine into the blood.
The adrenal medulla
Nicotine increases the levels of epinephrine in the blood after binding to the nicotinic receptors in the adrenal medulla. Through the results and the receiver, the nicotine depolarization of the cells by the calcium channel, calcium ion inflow, calcium ion to promote neuronal exocytosis way, release epinephrine and norepinephrine into the blood, the blood epinephrine increases, resulting in increased heart rate, blood pressure, respiratory rate, high blood glucose as the case. Cotinine is a byproduct of nicotine metabolism, can persist for 48 hours in the blood, can be used to test whether a person smoking material.