Nicotine and Caffeine Chapter 12

Leaves of the Nicotiana tabacum plant Nicotine History

Nicotine Routes of Administration Inhalation Chewing Snorting Transdermal

Metabolism of Nicotine liver converts nicotine into metabolites cotinine half life: 2 hrs acute tolerance Nicotine

Site of action for nicotine Nicotinic cholinergic receptors (nAChR) –Basic functions of different receptors: Open Na+ channels  increase firing potential Allows Ca 2+ into cell  2 nd messengers Enhances NT release (presynaptic) Nicotine

Site of action for nicotine Nicotinic cholinergic receptors (nAChR) –Locations of receptors Neuromuscular junction at muscles –Low doses –High doses – depolarization block PNS CNS –Postsynaptic –Presynaptic membranes of other NT neurons Nicotine

Changes in cognitive function Nicotine-induced reduction of reaction time in a rapid visual information processing task Nicotine

Activation of mesolimbic dopamine system Time Nicotine

Activation of mesolimbic dopamine system Nicotine self-administration in rats first exposed to the drug during adolescence vs. adulthood Nicotine

Changes in mood Smokers Non-smokers Nicotine

Factors other than Nicotine Whole-body PET scans illustrating reduced MAO-B activity Nicotine

Tolerance - acute - chronic Withdrawal symptoms –Decrease heart rate and blood pressure –Irritability –Hunger –Sleep disturbances –GI complaints –Headache –Impairment of concentration Nicotine

Effects of smoking on general health Increased risk for: Cancer Cardiovascular disease Emphysema Chronic bronchitis Decreased birth weight in infants for mothers who smoked Nicotine

Why do people smoke? Nicotine resource model Deprivation reversal model Positive reinforcement (DA reward system) Substances other than nicotine Genetic factors? Nicotine

Treatment of nicotine dependence Nicotine