Nicotine is highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke.
Nicotine is only found in individuals that have used or taken this drug. It is a highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke. [PubChem]Nicotine is a stimulant drug that acts as an agonist at nicotinic acetylcholine receptors. These are ionotropic receptors composed up of five homomeric or heteromeric subunits. In the brain, nicotine binds to nicotinic acetylcholine receptors on dopaminergic neurons in the cortico-limbic pathways. This causes the channel to open and allow conductance of multiple cations including sodium, calcium, and potassium. This leads to depolarization, which activates voltage-gated calcium channels and allows more calcium to enter the axon terminal. Calcium stimulates vesicle trafficking towards the plasma membrane and the release of dopamine into the synapse. Dopamine binding to its receptors is responsible the euphoric and addictive properties of nicotine.Nicotine also binds to nicotinic acetylcholine receptors on the chromaffin cells in the adrenal medulla. Binding opens the ion channel allowing influx of sodium, causing depolarization of the cell, which activates voltage-gated calcium channels. Calcium triggers the release of epinephrine from intracellular vesicles into the bloodstream, which causes vasoconstriction, increased blood pressure, increased heart rate, and increased blood sugar.
Top Gene Interactions
Nicotine Health Effects
- Autonomic nervous system paralytic
- Autonomic nervous system stimulant
- Anti estrogenic
- Anti feedant
- Anti fumitory
As nicotine enters the body, it is distributed quickly through the bloodstream and can cross the blood-brain barrier. On average it takes about seven seconds for the substance to reach the brain when inhaled. The half life of nicotine in the body is around two hours. 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. (L327) Route of Elimination: About 10% of the nicotine absorbed is excreted unchanged in the urine. Half Life: Cotinine has a half life of 15-20 hours, while nicotine has a half life of 1-3 hours
Nicotine is highly toxic alkaloid found in the nightshade family of plants (Solanaceae). (L327) NICOTROL Inhaler is indicated as an aid to smoking cessation for the relief of nicotine withdrawal symptoms. NICOTROL Inhaler therapy is recommended for use as part of a comprehensive behavioral smoking cessation program. It is used for the relief of nicotine withdrawal symptoms and as an aid to smoking cessation.
- Health Effects: Nicotine has mood-altering effects that may include relaxation, sharpness, calmness, and alertness. It may act as a stimulant or sedative/pain killer, depending on the dosage. (L327)
Symptoms of overdose include nausea, abdominal pain, vomiting, diarrhea, diaphoresis, flushing, dizziness, disturbed hearing and vision, confusion, weakness, palpitations, altered respiration and hypotension.
Other supportive measures include diazepam or barbiturates for seizures, atropine for excessive bronchial secretions or diarrhea, respiratory support for respiratory failure, and vigorous fluid support for hypotension and cardiovascular collapse. (L1712)
- Route of Exposure:
Oral (L327) ; Inhalation (L327) Absorption of nicotine through the buccal mucosa is relatively slow and the high and rapid rise followed by the decline in nicotine arterial plasma concentrations seen with cigarette smoking are not achieved with the inhaler. About 10% of absorbed nicotine is excreted unchanged in urine.
- Carcinogenicity: No indication of carcinogenicity to humans (not listed by IARC).
- Toxicity: LD50: 140 mg/kg (Dermal, Rat) LD50: 25 mg/kg (Subcutaneous, Rat) LD50: 5900 ug/kg (Intraperitoneal, Mouse) LD50: 2.8 mg/kg (Intravenous, Rat) (T80) LD50: 24 mg/kg (Oral, Mouse) (T18)
- Lethal Dose: 40 to 60 mg (<1 mg/kg) for an adult human. (T36)
Mechanism of Action
|Target Name||Mechanism of Action||References|
Steroid hormone receptor ERR1
Neuronal acetylcholine receptor subunit alpha-5
Neuronal acetylcholine receptor subunit beta-4
Cytochrome P450 19A1
Neuronal acetylcholine receptor subunit alpha-3
Neuronal acetylcholine receptor subunit beta-3
Neuronal acetylcholine receptor subunit alpha-6
Acetylcholine receptor subunit alpha
Acetylcholine receptor subunit beta
Acetylcholine receptor subunit delta
Acetylcholine receptor subunit epsilon
Acetylcholine receptor subunit gamma
|Nicotine binds to the nicotinic acetylcholine receptor. Stimulation of nicotinic receptors leads to a variety of cholinergic and adrenergic effects; tachycardia or bradycardia mediated by either stimulation or interference with sympathetic or parasympathetic pathways, stimulation of receptors in the carotic and aortic bodies, release of epinephrine from the adrenal medulla, and stimulation of the chemoreceptor-trigger zone. (L1062)||
Neuronal acetylcholine receptor subunit alpha-2
Neuronal acetylcholine receptor subunit alpha-4
Neuronal acetylcholine receptor subunit alpha-7
Neuronal acetylcholine receptor subunit beta-2
Neuronal acetylcholine receptor subunit alpha-9
Neuronal acetylcholine receptor subunit alpha-10
Metabotropic glutamate receptor 2
Metabotropic glutamate receptor 3
|Nicotine binds to the nicotinic acetylcholine receptor. Stimulation of nicotinic receptors leads to a variety of cholinergic and adrenergic effects; tachycardia or bradycardia mediated by either stimulation or interference with sympathetic or parasympathetic pathways, stimulation of receptors in the carotic and aortic bodies, release of epinephrine from the adrenal medulla, and stimulation of the chemoreceptor-trigger zone.||