nicotine and caffeine chapter 12. leaves of the nicotiana tabacum plant nicotine history
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Nicotine and CaffeineChapter 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 Ca2+ into cell 2nd messengers
• Enhances NT release (presynaptic)
Nicotine
Site of action for nicotine• Nicotinic cholinergic receptors (nAChR)
– Locations of receptors• Neuromuscular junction at muscles
• PNS
• CNS– Postsynaptic
– Presynaptic membranes of other NT neurons
Nicotine
Changes in cognitive functionNicotine-induced reduction of reaction time in a rapid visual information processing task
Nicotine
Activation of mesolimbic dopamine system
Time
Nicotine
Activation of mesolimbic dopamine systemNicotine self-administration in rats first exposed to the drug during adolescence vs. adulthood
Nicotine
Changes in mood
• Smokers
• Non-smokers
Nicotine
Factors other than NicotineWhole-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
http://scienceblogs.com/retrospectacle/upload/2007/04/caffeine.jpg http://www.caffeinemedia.com.au/images/Caffeine-Holding-Page_03.jpg
Caffeine
Absorption and Metabolism
Caffeine
Mechanism of action
• Adenosine antagonist
Caffeine
Withdrawal and ToleranceTime course of caffeine withdrawal in regular users (Part 1)
Caffeine
Withdrawal and ToleranceTime course of caffeine withdrawal in regular users (Part 2)
Caffeine
Withdrawal and ToleranceTime course of caffeine withdrawal in regular users (Part 4)
Caffeine
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