
n.
A colorless, poisonous alkaloid, C10H14N2, derived from the tobacco plant and used as an insecticide. It is the substance in tobacco to which smokers can become addicted.
[French, from New Latin nicotiāna. See nicotiana.]
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American Heritage Dictionary:
nic·o·tine |

[French, from New Latin nicotiāna. See nicotiana.]
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Oxford Dictionary of Chemistry:
nicotine |
Britannica Concise Encyclopedia:
nicotine |
For more information on nicotine, visit Britannica.com.
Oxford Food & Fitness Dictionary:
nicotine |
A drug that acts as a stimulant on the central nervous system. See also smoking.
Oxford Companion to the Body:
nicotine |
Nicotine is a simple alkaloid produced by the tobacco plant. The history of chewing and smoking tobacco, and of taking snuff, is of great antiquity. All the acute effects of the tobacco habit are dependent on nicotine, which has complex actions, both on the central nervous system and in the rest of the body. Nicotine acts on certain cell membrane receptors, which were therefore given the name nicotinic receptors. Nicotine was found to mimic the actions of the neurotransmitter acetylcholine at these sites: at the neuromuscular junctions in skeletal (voluntary) muscle; at the synapses in the relay stations (the ganglia) of the autonomic nervous system; and in various parts of the brain and spinal cord. In many situations nicotine first activates the nicotinic receptors and then by its continued presence desensitizes them. Normally, at these nicotinic synapses, the transmitter (acetylcholine) is rapidly destroyed by the enzyme cholinesterase, so its action is evanescent; this is not the case with nicotine.
Nicotinic receptors are proteins which span the cell membrane (e.g. of a muscle cell or neuron) and when activated by acetylcholine or by nicotine undergo a conformational change that creates ion channels in the membrane. These channels allow the passage of sodium ions inwards and potassium ions outwards through the membrane, leading to excitation of the cell.
Increased levels of nicotine can be measured in the blood up to one hour after a cigarette. Nicotine-taking, in whatever form, is for self gratification and reward, requiring reinforcement at intervals. If nicotine is withdrawn, irritability and failure to concentrate is the result. The actions of nicotine are caused by effects in the brain. Repeated intake of nicotine leads to increased numbers of nicotinic receptors in the brain, which might be expected to reduce the need for nicotine rather than increase it. But it seems likely that many of the receptors are in a desensitized form and that the number of functional receptors is reduced, so that the addict requires increasing and repeated doses to maintain the effect. The claims that nicotine increases concentration, learning ability, and retention of learned information are well founded — numbers of performance tests have confirmed this. Nicotine produces a sense of alertness, but nevertheless of calm. This seems to be due to inhibition of reflex nerve loops in the spinal cord, with the effect of causing muscular relaxation.
The above actions all take place in the central nervous system. The effects of nicotine in the rest of the body are due to actions on the ganglia of the autonomic nervous system, predominantly on the sympathetic ganglia. Mimicking the effects of physiological sympathetic stimulation, they include increases in heart rate, cardiac output, and blood pressure, and reduction in gut motility and digestive functions. Because the adrenal medulla is a modified sympathetic ganglion — with secretion normally stimulated by acetylcholine — adrenaline and noradrenaline are released by the action of nicotine; these are likely to be responsible for most of the cardiovascular effects. Nicotine also releases antidiuretic hormone from the posterior pituitary gland, hence reducing the formation of urine.
Nicotine is not used therapeutically, except for nicotine patches and chewing gum, which are used to help smokers give up the habit. They do not have the dangers associated with constituents of tobacco smoke.
For some time nicotine enjoyed popularity as an insecticide. However, in its concentrated form it is highly poisonous, and it can be absorbed through the skin, so is no longer used for spraying on plants. Lobeline, another plant alkaloid from Lobelia species, has very similar actions to nicotine.
— Alan W. Cuthbert
See also acetylcholine; autonomic nervous system; neurotransmitters; membrane receptors; smoking.
Drug Info:
Nicotine |
Brand names: Commit, Habitrol®, Nicoderm CQ® Clear, Nicoderm®, Nicoderm® CQ, Nicorelief, Nicorelief Mint, Nicorette®, Nicorette® DS, Nicotrol®, Nicotrol® Step 1, Nicotrol® Step 2, Nicotrol® Step 3, Nicotrol® Transdermal System, Prostep®
Chemical formula:

Nicotine inhaler
What is nicotine inhaler?
NICOTINE (Nicotrol®) helps people stop smoking. By replacing nicotine found in cigarettes, physical withdrawal effects are less severe. Nicotine inhaler is most effective when used in combination with a supervised stop-smoking program. Nicotine inhaler is for use over short periods of time (not more than 3 months). Generic nicotine inhaler is not yet available.What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:How should I use this medicine?
You should stop smoking completely before using the inhaler. Follow the directions carefully. Use exactly as directed. To avoid the risk of infections, do not use the inhaler for more than one person.What if I miss a dose?
If you miss a dose, take it as soon as your remember. If it is almost time for your next dose, skip the missed dose. Do not double doses.What drug(s) may interact with nicotine?
bupropionWhat should I watch for while taking nicotine?
Always carry the inhaler with you. Do not smoke while you are using the nicotine inhaler.What side effects may I notice from using nicotine?
Side effects that you should report to your prescriber or health care professional as soon as possible:Where can I keep my medicine?
Keep out of the reach of children. Store the inhaler in a safe place where children and pets cannot reach it, and be careful about throwing the inhaler container away. If a child uses the nicotine inhaler, call your prescriber or health care professional or a poison control center at once.Last updated: 4/19/2004 10:05:00 AM
Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.
Oxford A-Z of Medicinal Drugs:
nicotine |
| nicotinamide, nicorandil, nicardipine | |
| nicotinic acid, nifedipine, nilotinib |
Oxford Dictionary of Sports Science & Medicine:
nicotine |
A poisonous alkaloid obtained from the tobacco plant, Nicotiana tobacum. The psychological and addictive effects of smoking cigarettes and chewing tobacco are attributed to nicotine. It is a cholinergic agonist stimulating the central nervous system and enhancing arousal, paradoxically. Users also believe it has relaxing properties. Nicotine is generally detrimental on physical performance because of the adverse effects it can have on the cardiovascular, respiratory, and endocrine systems.
Columbia Encyclopedia:
nicotine |
Nicotine, which mimics the affects of acetylcholine, acts primarily on the autonomic nervous system. In a dose of less than 50 mg, it can cause respiratory failure and general paralysis. Smaller toxic doses can cause heart palpitations, lowered blood pressure, nausea, and dizziness. A person who smokes inhales approximately 3 mg from one cigarette. This amount increases the heart rate, constricts the blood vessels, and acts on the central nervous system, imparting a feeling of alertness and well-being. Although not considered carcinogenic, nicotine probably contributes to the increased incidence of heart disease seen in smokers and may enhance the growth of tumors caused by carcinogens.
People who use tobacco products develop a physiological addiction to nicotine. Research has shown that nicotine increases the flow of the neurotransmitter dopamine in the brain, creating pleasurable feelings and a craving to keep in the bloodstream levels of nicotine that will maintain these feelings. Lack of nicotine causes withdrawal symptoms (heart rate and blood pressure changes, sleeping problems, brain wave disturbances, and anxiety) in smokers.
Nicotine-containing chewing gums and skin patches that administer nicotine to people who are trying to cease smoking have been developed. Although the rate of absorption is slower with these methods than with smoking-smoking delivers nicotine to the brain within six seconds-and although nicotine obtained in this way does not provide the same pleasurable results as smoking, the gums and patches do help relieve some of the symptoms of withdrawal. Combining the use of patches or gum with continued smoking can result in nicotine overdose and toxicity, causing nausea, palpitations, and headache. Nicotine nasal sprays and inhalers more closely mimic the delivery and intensity of nicotine obtained by smoking. Some researchers have suggested, however, that prolonged use of nicotine replacement, especially inhalers, beyond the few months recommended to break the cigarette habit could damage cells lining the blood vessels and lungs.
See also smoking.
Dictionary of Cultural Literacy: Health:
nicotine |
A poisonous chemical substance found in the tobacco plant.
Word Tutor:
nicotine |
Nicotine is deadly and is often used as a pesticide.
LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!
Oxford Dictionary of Biochemistry:
nicotine |
| nicotinate mononucleotide, nicotinate, nicotinamide-nucleotide adenylyltransferase | |
| nicotinic acid, nidogen, nif |
Saunders Veterinary Dictionary:
nicotine |
A very poisonous piperidine alkaloid that in its pure state is a colorless, pungent, oily liquid, having an acrid burning taste. It is a constituent of tobacco and is produced synthetically.
Mosby's Dental Dictionary:
nicotine |
A poisonous alkaloid found in tobacco and responsible for many of the effects of tobacco. It is first a stimulant (small doses) and then a depressant (larger doses).
Random House Word Menu:
categories related to 'nicotine' |

Rhymes:
nicotine |
Bradford's Crossword Solver's Dictionary:
nicotine |
Wikipedia on Answers.com:
Nicotine |
| Systematic (IUPAC) name | |
|---|---|
| 3-[(2S)-1-methylpyrrolidin-2-yl]pyridine | |
| Clinical data | |
| Trade names | Nicorette, Nicotrol |
| AHFS/Drugs.com | monograph |
| Pregnancy cat. | D(US) |
| Legal status | Unscheduled (AU) ? (UK) ? (US) |
| Dependence liability | Medium to high |
| Routes | smoked (as smoking tobacco, mapacho, etc.), insufflated (as tobacco snuff or nicotine nasal spray), chewed (as nicotine gum, tobacco gum or chewing tobacco), transdermal (as nicotine patch, nicogel or topical tobacco paste), intrabuccal (as dipping tobacco, snuffs, dissolvable tobacco or creamy snuff), vaporized (as electronic cigarette, etc.), directly inhaled (as nicotine inhaler), oral (as nicotini), buccal (as snus) |
| Pharmacokinetic data | |
| Bioavailability | 20 to 45% (oral) |
| Metabolism | hepatic |
| Half-life | 2 hours |
| Identifiers | |
| CAS number | 54-11-5 |
| ATC code | N07BA01 QP53AX13 |
| PubChem | CID 942 |
| DrugBank | DB00184 |
| ChemSpider | 80863 |
| UNII | 6M3C89ZY6R |
| KEGG | D03365 |
| ChEBI | CHEBI:17688 |
| ChEMBL | CHEMBL3 |
| Chemical data | |
| Formula | C10H14N2 |
| Mol. mass | 162.26 g/mol |
| SMILES | eMolecules & PubChem |
|
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| Physical data | |
| Density | 1.01 g/cm³ |
| Melt. point | -79 °C (-110 °F) |
| Boiling point | 247 °C (477 °F) |
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Nicotine is an alkaloid found in the nightshade family of plants (Solanaceae) that constitutes approximately 0.6–3.0% of the dry weight of tobacco,[1][2] with biosynthesis taking place in the roots and accumulation occurring in the leaves. It functions as an antiherbivore chemical with particular specificity to insects; therefore nicotine was widely used as an insecticide in the past,[3][4] and currently nicotine analogs such as imidacloprid continue to be widely used.
In low concentrations (an average cigarette yields about 1 mg of absorbed nicotine), the substance acts as a stimulant in mammals and is the main factor responsible for the dependence-forming properties of tobacco smoking. According to the American Heart Association, nicotine addiction has historically been one of the hardest addictions to break, while the pharmacological and behavioral characteristics that determine tobacco addiction are similar to those determining addiction to heroin and cocaine. Nicotine content in cigarettes has slowly increased over the years, and one study found that there was an average increase of 1.6% per year between the years of 1998 and 2005. This was found for all major market categories of cigarettes.[5]
Research in 2011 has found that nicotine inhibits chromatin-modifying enzymes (class I and II histone deacetylases) which increases the ability of cocaine to cause an addiction.[6]
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Contents
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Nicotine is named after the tobacco plant Nicotiana tabacum, which in turn is named after Jean Nicot de Villemain, French ambassador in Portugal, who sent tobacco and seeds from Brazil to Paris in 1560 and promoted their medicinal use. Nicotine was first isolated from the tobacco plant in 1828 by physician Wilhelm Heinrich Posselt and chemist Karl Ludwig Reimann of Germany, who considered it a poison.[7][8] Its chemical empirical formula was described by Melsens in 1843,[9] its structure was discovered by Adolf Pinner and Richard Wolffenstein in 1893, and it was first synthesized by A. Pictet and Crepieux in 1904.[10]
Nicotine is a hygroscopic, oily liquid that is miscible with water in its base form. As a nitrogenous base, nicotine forms salts with acids that are usually solid and water soluble. Nicotine easily penetrates the skin. As shown by the physical data, free base nicotine will burn at a temperature below its boiling point, and its vapors will combust at 308 K (35 °C; 95 °F) in air despite a low vapor pressure. Because of this, most of the nicotine is burned when a cigarette is smoked; however, enough is inhaled to cause pharmacological effects.
Nicotine is optically active, having two enantiomeric forms. The naturally occurring form of nicotine is levorotatory with a specific rotation of [α]D = –166.4° ((−)-nicotine). The dextrorotatory form, (+)-nicotine is physiologically less active than (–)-nicotine. (−)-nicotine is more toxic than (+)-nicotine.[11] The salts of (+)-nicotine are usually dextrorotatory.
As nicotine enters the body, it is distributed quickly through the bloodstream and crosses the blood-brain barrier reaching the brain within 10–20 seconds after inhalation.[13] The elimination half-life of nicotine in the body is around two hours.[14]
The amount of nicotine absorbed by the body from smoking depends on many factors, including the types of tobacco, whether the smoke is inhaled, and whether a filter is used. For chewing tobacco, dipping tobacco, snus and snuff, which are held in the mouth between the lip and gum, or taken in the nose, the amount released into the body tends to be much greater than smoked tobacco.[clarification needed][citation needed] Nicotine is metabolized in the liver by cytochrome P450 enzymes (mostly CYP2A6, and also by CYP2B6). A major metabolite is cotinine.
Other primary metabolites include nicotine N'-oxide, nornicotine, nicotine isomethonium ion, 2-hydroxynicotine and nicotine glucuronide.[15] Under some conditions, other substances may be formed such as myosmine.[16]
Glucuronidation and oxidative metabolism of nicotine to cotinine are both inhibited by menthol, an additive to mentholated cigarettes, thus increasing the half-life of nicotine in vivo.[17]
Nicotine can be quantified in blood, plasma, or urine to confirm a diagnosis of poisoning or to facilitate a medicolegal death investigation. Urinary or salivary cotinine concentrations are frequently measured for the purposes of pre-employment and health insurance medical screening programs. Careful interpretation of results is important, since passive exposure to cigarette smoke can result in significant accumulation of nicotine, followed by the appearance of its metabolites in various body fluids.[18][19] Nicotine use is not regulated in competitive sports programs, yet the drug has been shown to have a significant beneficial effect on athletic endurance in subjects who have not used nicotine before.[20]
Nicotine acts on the nicotinic acetylcholine receptors, specifically the ganglion type nicotinic receptor and one CNS nicotinic receptor. The former is present in the adrenal medulla and elsewhere, while the latter is present in the central nervous system (CNS). In small concentrations, nicotine increases the activity of these receptors. Nicotine also has effects on a variety of other neurotransmitters through less direct mechanisms.
By binding to nicotinic acetylcholine receptors, nicotine increases the levels of several neurotransmitters - acting as a sort of "volume control". It is thought that increased levels of dopamine in the reward circuits of the brain are responsible for the apparent euphoria and relaxation, and addiction caused by nicotine consumption. Nicotine has a higher affinity for acetylcholine receptors in the brain than those in skeletal muscle, though at toxic doses it can induce contractions and respiratory paralysis.[21] Nicotine's selectivity is thought to be due to a particular amino acid difference on these receptor subtypes.[22]
Tobacco smoke contains anabasine, anatabine, and nornicotine.[citation needed] It also contains the monoamine oxidase inhibitors harman and norharman.[23] These beta-carboline compounds significantly decrease MAO activity in smokers.[23][24] MAO enzymes break down monoaminergic neurotransmitters such as dopamine, norepinephrine, and serotonin. It is thought that the powerful interaction between the MAOI's and the nicotine is responsible for most of the addictive properties of tobacco smoking.[25] The addition of five minor tobacco alkaloids increases nicotine-induced hyperactivity, sensitization and intravenous self-administration in rats.[26]
Chronic nicotine exposure via tobacco smoking up-regulates alpha4beta2* nAChR in cerebellum and brainstem regions[27][28] but not habenulopeduncular structures.[29] Alpha4beta2 and alpha6beta2 receptors, present in the ventral tegmental area, play a crucial role in mediating the reinforcement effects of nicotine.[30]
Nicotine also activates the sympathetic nervous system,[31] acting via splanchnic nerves to the adrenal medulla, stimulates the release of epinephrine. Acetylcholine released by preganglionic sympathetic fibers of these nerves acts on nicotinic acetylcholine receptors, causing the release of epinephrine (and norepinephrine) into the bloodstream. Nicotine also has an affinity for melanin-containing tissues due to its precursor function in melanin synthesis or due to the irreversible binding of melanin and nicotine. This has been suggested to underlie the increased nicotine dependence and lower smoking cessation rates in darker pigmented individuals.[32]
By binding to ganglion type nicotinic receptors in the adrenal medulla nicotine increases flow of adrenaline (epinephrine), a stimulating hormone and neurotransmitter. By binding to the receptors, it causes cell depolarization and an influx of calcium through voltage-gated calcium channels. Calcium triggers the exocytosis of chromaffin granules and thus the release of epinephrine (and norepinephrine) into the bloodstream. The release of epinephrine (adrenaline) causes an increase in heart rate, blood pressure and respiration, as well as higher blood glucose levels.[33]
Nicotine is the natural product of tobacco, having a half-life of 1 to 2 hours. Cotinine is an active metabolite of nicotine that remains in the blood for 18 to 20 hours, making it easier to analyze due to its longer half-life.[34]
Nicotine's mood-altering effects are different by report: in particular it is both a stimulant and a relaxant.[35] First causing a release of glucose from the liver and epinephrine (adrenaline) from the adrenal medulla, it causes stimulation. Users report feelings of relaxation, sharpness, calmness, and alertness.[36] Like any stimulant, it may very rarely cause the often catastrophically uncomfortable neuropsychiatric effect of akathisia. By reducing the appetite and raising the metabolism, some smokers may lose weight as a consequence.[37][38]
When a cigarette is smoked, nicotine-rich blood passes from the lungs to the brain within seven seconds and immediately stimulates the release of many chemical messengers including acetylcholine, norepinephrine, epinephrine, vasopressin, arginine, dopamine, autocrine agents, and beta-endorphin.[39] This release of neurotransmitters and hormones is responsible for most of nicotine's effects. Nicotine appears to enhance concentration[40] and memory due to the increase of acetylcholine.[citation needed] It also appears to enhance alertness due to the increases of acetylcholine and norepinephrine.[citation needed] Arousal is increased by the increase of norepinephrine.[citation needed] Pain is reduced by the increases of acetylcholine and beta-endorphin. Anxiety is reduced by the increase of beta-endorphin. Nicotine also extends the duration of positive effects of dopamine[41] and increases sensitivity in brain reward systems.[42] Most cigarettes (in the smoke inhaled) contain 1 to 3 milligrams of nicotine.[43]
Research suggests that, when smokers wish to achieve a stimulating effect, they take short quick puffs, which produce a low level of blood nicotine.[44] This stimulates nerve transmission. When they wish to relax, they take deep puffs, which produce a high level of blood nicotine, which depresses the passage of nerve impulses, producing a mild sedative effect. At low doses, nicotine potently enhances the actions of norepinephrine and dopamine in the brain, causing a drug effect typical of those of psychostimulants. At higher doses, nicotine enhances the effect of serotonin and opiate activity, producing a calming, pain-killing effect. Nicotine is unique in comparison to most drugs, as its profile changes from stimulant to sedative/pain killer in increasing dosages and use.
Technically, nicotine is not significantly addictive, as nicotine administered alone does not produce significant reinforcing properties.[45] However, after coadministration with an MAOI, such as those found in tobacco, nicotine produces significant behavioral sensitization, a measure of addiction potential. This is similar in effect to amphetamine.[25]
Nicotine gum, usually in 2-mg or 4-mg doses, and nicotine patches are available, as well as smokeless tobacco, nicotine lozenges and electronic cigarettes.
Modern research shows that nicotine acts on the brain to produce a number of effects. Specifically, research examining its addictive nature has been found to show that nicotine activates the Mesolimbic pathway ("reward system") —the circuitry within the brain that regulates feelings of pleasure and euphoria.[48]
Dopamine is one of the key neurotransmitters actively involved in the brain. Research shows that by increasing the levels of dopamine within the reward circuits in the brain, nicotine acts as a chemical with intense addictive qualities. In many studies it has been shown to be more addictive than cocaine and heroin.[49][50][51] Like other physically addictive drugs, nicotine withdrawal causes down-regulation of the production of dopamine and other stimulatory neurotransmitters as the brain attempts to compensate for artificial stimulation. As dopamine regulates the sensitivity of nicotinic acetylcholine receptors decreases. To compensate for this compensatory mechanism, the brain in turn upregulates the number of receptors, convoluting its regulatory effects with compensatory mechanisms meant to counteract other compensatory mechanisms. An example is the increase in norepinephrine, one of the successors to dopamine, which inhibit reuptake of the glutamate receptors,[52] in charge of memory and cognition. The net effect is an increase in reward pathway sensitivity, the opposite of other addictive drugs such as cocaine and heroin, which reduce reward pathway sensitivity.[42] This neuronal brain alteration can persist for months after administration ceases.
A study found that nicotine exposure in adolescent mice retards the growth of the dopamine system, thus increasing the risk of substance abuse during adolescence.[53]
Because of the severe addictions and the harmful effects of smoking, vaccination protocols have been developed. The principle is under the premise that if an antibody is attached to a nicotine molecule, it will be prevented from diffusing through the capillaries, thus making it less likely that it ever affects the brain by binding to nicotinic acetylcholine receptors.
These include attaching the nicotine molecule to a hapten such as Keyhole limpet hemocyanin or a safe modified bacterial toxin to elicit an active immune response. Often it is added with bovine serum albumin.
Additionally, because of concerns with the unique immune systems of individuals being liable to produce antibodies against endogenous hormones and over the counter drugs, monoclonal antibodies have been developed for short term passive immune protection. They have half-lives varying from hours to weeks. Their half-lives depend on their ability to resist degradation from pinocytosis by epithelial cells.[54][citation needed]
| NFPA 704 |
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The LD50 of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 40–60 mg (0.5-1.0 mg/kg) can be a lethal dosage for adult humans.[55][56] Nicotine therefore has a high toxicity in comparison to many other alkaloids such as cocaine, which has an LD50 of 95.1 mg/kg when administered to mice. It is unlikely that a person would overdose on nicotine through smoking alone, although overdose can occur through combined use of nicotine patches or nicotine gum and cigarettes at the same time.[57] Spilling a high concentration of nicotine onto the skin can cause intoxication or even death, since nicotine readily passes into the bloodstream following dermal contact.[58]
Historically, nicotine has not been regarded as a carcinogen and the IARC has not evaluated nicotine in its standalone form and assigned it to an official carcinogen group. While no epidemiological evidence supports that nicotine alone acts as a carcinogen in the formation of human cancer, research over the last decade has identified nicotine's carcinogenic potential in animal models and cell culture.[59] [60] Nicotine has been noted to directly cause cancer through a number of different mechanisms such as the activation of MAP Kinases.[61] Indirectly, nicotine increases cholinergic signalling (and adrenergic signalling in the case of colon cancer[62]), thereby impeding apoptosis (programmed cell death), promoting tumor growth, and activating growth factors and cellular mitogenic factors such as 5-LOX, and EGF. Nicotine also promotes cancer growth by stimulating angiogenesis and neovascularization.[63][64] In one study, nicotine administered to mice with tumors caused increases in tumor size (twofold increase), metastasis (nine-fold increase), and tumor recurrence (threefold increase).[65]
Though the teratogenic properties of nicotine may or may not yet have been adequately researched, women who use nicotine gum and patches during the early stages of pregnancy face an increased risk of having babies with birth defects, according to a study of around 77,000 pregnant women in Denmark. The study found that women who use nicotine-replacement therapy in the first 12 weeks of pregnancy have a 60% greater risk of having babies with birth defects, compared to women who are non-smokers.[citation needed]
Effective April 1, 1990, the Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency added nicotine to the list of chemicals known to the state to cause developmental toxicity, for the purposes of Proposition 65.[66]
The primary therapeutic use of nicotine is in treating nicotine dependence in order to eliminate smoking with the damage it does to health. Controlled levels of nicotine are given to patients through gums, dermal patches, lozenges, electronic/substitute cigarettes or nasal sprays in an effort to wean them off their dependence.
However, in a few situations, smoking has been observed to apparently be of therapeutic value. These are often referred to as "Smoker’s Paradoxes".[67] Although in most cases the actual mechanism is understood only poorly or not at all, it is generally believed that the principal beneficial action is due to the nicotine administered, and that administration of nicotine without smoking may be as beneficial as smoking, without the higher risk to health due to tar and other ingredients found in tobacco.
For instance, recent studies suggest that smokers require less frequent repeated revascularization after percutaneous coronary intervention (PCI).[67] Risk of ulcerative colitis has been frequently shown to be reduced by smokers on a dose-dependent basis; the effect is eliminated if the individual stops smoking.[68][69] Smoking also appears to interfere with development of Kaposi's sarcoma in patients with HIV,[1].[70]
Nicotine reduces the chance of breast cancer among women carrying the very high risk BRCA gene,[71] preeclampsia,[72] and atopic disorders such as allergic asthma.[73] A plausible mechanism of action in these cases may be nicotine acting as an anti-inflammatory agent, and interfering with the inflammation-related disease process, as nicotine has vasoconstrictive effects.[74]
Tobacco smoke has been shown to contain compounds capable of inhibiting monoamine oxidase, which is responsible for the degradation of dopamine in the human brain. When dopamine is broken down by MAO-B, neurotoxic by-products are formed, possibly contributing to Parkinson's and Alzheimers disease.[75] Many such papers regarding Alzheimer's disease[76] and Parkinson's Disease[77] have been published. Recent studies find no beneficial link between smoking and Alzheimer's disease and in some cases, suggest it may actually result in an earlier onset of the disease.[78][79][80][81] However, nicotine has been shown to delay the onset of Parkinson's disease in studies involving monkeys and humans.[82][83][84] However a study has shown a protective effect of nicotine itself on neurons due to nicotine activation of α7-nAChR and the PI3K/Akt pathway which inhibits AIF release and mitochondrial translocation, cytochrome c release and caspase 3 activation.[85]
Recent studies have indicated that nicotine can be used to help adults suffering from autosomal dominant nocturnal frontal lobe epilepsy. The same areas that cause seizures in that form of epilepsy are responsible for processing nicotine in the brain.[86]
Studies suggest a correlation between smoking and schizophrenia, with estimates near 75% for the proportion of schizophrenic patients who smoke. Although the nature of this association remains unclear, it was recently argued that the increased level of smoking in schizophrenia may be due to a desire to self-medicate with nicotine.[87][88] More recent research has found that mildly dependent users got some benefit from nicotine, but not those who were highly dependent.[89] All of these studies are based only on observation, and no interventional (randomized) studies have been done. Research on nicotine as administered through a patch or gum is ongoing.
Nicotine appears to improve ADHD symptoms. Some studies are focusing on benefits of nicotine therapy in adults with ADHD.[90]
Nicotine (in the form of chewing gum or a transdermal patch) is being explored as an experimental treatment for OCD. Small studies show some success, even in otherwise treatment-refractory cases.[91][92][93]
The relationship between smoking and inflammatory bowel disease is now firmly established but remains a source of confusion among both patients and doctors. It is negatively associated with ulcerative colitis but positively associated with Crohn's disease. In addition, it has opposite influences on the clinical course of the two conditions with benefit in ulcerative colitis but a detrimental effect in Crohn's disease.[94][95]
When the metabolites of nicotine were isolated and their effect on first the animal brain and then the human brain in people with schizophrenia were studied, it was shown that the effects helped with cognitive and negative symptoms of schizophrenia. Therefore, the nicotinergic agents, as antipsychotics which do not contain nicotine but act on the same receptors in the brain are showing promise as adjunct antipsychotics in early stages of FDA studies on schizophrenia. The prepulse inhibition (PPI) is a phenomenon in which a weak prepulse attenuates the response to a subsequent startling stimulus. Therefore, PPI is believed to have face, construct, and predictive validity for the PPI disruption in schizophrenia, and it is widely used as a model to study the neurobiology of this disorder and for screening antipsychotics.[96] Additionally, studies have shown[weasel words] that there are genes predisposing people with schizophrenia to nicotine use.[97]
Therefore with these factors taken together the heavy usage of cigarettes and other nicotine related products among people with schizophrenia may be explained and novel antipsychotic agents developed that have these effects in a manner that is not harmful and controlled and is a promising arena of research for schizophrenia.
Mechanisms of Disease: nicotine—a review of its actions in the context of gastrointestinal disease
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Translations:
Nicotine |
Français (French)
n. - nicotine
Ελληνική (Greek)
n. - (χημ.) νικοτίνη
Português (Portuguese)
n. - nicotina (f)
Español (Spanish)
n. - nicotina
Svenska (Swedish)
n. - nikotin
中文(简体)(Chinese (Simplified))
烟碱, 尼古丁
中文(繁體)(Chinese (Traditional))
n. - 煙鹼, 尼古丁
العربيه (Arabic)
(الاسم) نيكوتين : مادة سامه في التبغ
עברית (Hebrew)
n. - ניקוטין, תרכובת חנקן מרעילה הנמצאת בטבק
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| nicotin– (prefix) | |
| piperidine alkaloids | |
| cotinine |
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