Nicotine: Psy 383 S01
1.  Nicotine is clearly dangerous to health.  In 1979 Surgeon G said:   "Cigarette smoking is  the single most important environmental factor contributing to premature  mortality in the United States."
2.  Epidemiology: What populations are most likely to smoke?
 a.  Less educated
 b.  Low socioeconomic group or unemployed.
 c.  Age: 1983 data shows slight decrease with age in 50s, great decrease in 60s.  Is that because people quit or because smokers are dead?
3.  Pharmacokinetics
 a.  Nicotine is active ingredient. Rapid delivery to lungs. Nicotine then goes directly to heart and then to brain.
 b.  absorbed rapidly from lungs.  Gets to brain in 7 sec.  Peak concentration in about 15 min.
 c. Half -life about 30 min.
 d.    smokeless tobacco absorbed from mucous membranes, not GI tract.
4.  Mechanism of action on central nervous system: activates nicotinic receptors in brain and peripherally.
 a.  nicotine binds to receptors on DA cells, causing DA release. In particular binds to DA receptors in ventral tegmental area and nucleus accumbens.
 b.   The receptor in brain that responds to nicotine has been cloned.  Knockout mice without this receptor do not find nicotine reinforcing.  In these mice nicotine does not increase DA levels.  Mice do respond normally to cocaine.
 c.   Smoking reduces monoamine oxidases, increasing the concentration of DA in the cleft. Withdrawal would increase MAO and decrease dopamine.  Therefore an MAOI may be useful in stopping smoking.
5. Health effects:
 a.  overall risks
  i.  Overall mortality rate 1.7 (70% more likely to die at any age).
  ii.  Shortens life expectancy by 8.1 yrs.(2pack a day)
  iii.  Mortality increases with amount smoked.
  iv.  It helps to quit. Approximately 15 years after quitting one's mortality rate same as non-smoker. Some cardiovascular effects decrease in 1-2 mos. Two years after quitting risk of myocardial infarction is same as that of non smoker.
 b.  nervous system
  i.  vomiting, nausea: stimulates chemoreceptor trigger zone. become tolerant to these effects.
  ii.  tremor and convulsion in overdose.
 c.  cardiovascular (200,000 deaths per year)
  i. nicotime increases workload of heart and hence oxygen consumption.  Nicotine gums or patches will not help with this.
  ii. CO decreases oxygen supply to all organs including the heart.
 d.  Respiratory system. damage to respiratory system causes 140,000 deaths per year
  i. lung cancer
   (1) tars: cause lung cancer due to effects on enzymes, immune system
   (2) tars: damage to cilia in bronchioles so hard to clear dust from lungs.  Study with magnetic dust indicates 5 times slower.
  ii. emphysema and other lung diseases  due to damaage to aveoli.
   (1) emphysema is distension and loss of elasticity of alveoli
   (2) eventually  alveoli rupture
6.  Human Performance. Smokers may  get significant benefits from nicotine, but this is controversial:
 a.  Improves performance on variety of tasks.  Must distinguish between nonsmokers and deprived smokers.
 b.  visual vigilance:  Smokers respond more accurately than nonsmokers to brief pauses in continuous movement of clock hand.  (task dull, would non smokers do better with candy sticks).
 c.  helps focus attention: ask people to name color of ink in which a word is written. (e.g. green written in blue ink).  Nicotine administered by mucous membrane reduces interference in both smokers and non smokers.
 d.  May reduce anxiety and decreases aggression. Some disagreement about whether due to withdrawal.  Irritability of smokers is at least partially due to withdrawal.
  i.  Experiment  put people in room with TV, simulated aircraft noise.  Asked how irritated they felt.  Had smoking and non smoking conditions.
   (1)  groups:
    (a)  smokers
    (b)  smokers trying to quit
    (c)  non smokers
    (d)  habitual light smokers. not irritable.  These are rare but interesting. not susceptible to nicotine addiction.
   (2)  When smoking not allowed, smokers and smokers trying to quit were most irritable.
   (3)  When smoke allowed, smokers were not irritable but smokers trying to quit were.
 e.  6 hr vigilance task, measured aggression at end.  Smokers did not show increase in aggression but deprived smokers and nonsmokers did.
 f.     There has been controversy about whether smoking can protect against alzheimer’s           disease, but recent longitudinal studies suggest that it does not. (Book says it can improve some aspects of cognitive function in people with Alzheimer’s disease, but this is controversial, too).
 g.    Smoking may accelerate mental deterioration in elderly. (people in this study did not have Alzheimer’s disease).  The researchers recorded the smoking and drinking habits of a sample of  people who were 65 years or older. They also assessed their intelligence with standard tests.   One year later they re-tested the participants. After adjusting for factors such as depression, general health, education levels and alcohol use, which can also impair intelligence,  the researchers found smokers had a much higher risk of intellectual decline than people who didn't smoke. They said their results are consistent with previous findings that show smoking contributes to the clogging and hardening of the arteries and impairs the blood flow to the brain and other parts of the body.
7.  Tobacco is addicting. Nicotine is the major addicting agent
 a.  Only 10% of smokers are occasional users.
 b.    88% of those who have used in the last year have used in the last month.  (comparable data for mj is 61%). data similar for older groups.
 c.  When tobacco is scarce as in WW II, nicotine addiction leads to antisocial behavior. May buy tobacco rather than food.
 d. Withdrawal symptoms (read): anxiety, craving, aggression, depression
 e. clearly a reinforcer, subjects inject more if concentration is lowered.
8.  Decrease the harms.
 a. Stop smoking therapy: nicotine patches, nasal spray or gum can prevent withdrawal symptoms.  Do not prevent cardiovascular effects of nicotine.
 b.  increase price
  i. has greatest effect on  younger smokers.
  ii. price much less elastic for older, established smokers.
  iii. price elasticity is greater long term. Perhaps higher price discourages people from starting.
 c. prevent advertising to children. People rarely start smoking after the age of 20. (Do you believe tobacco companieswhen they say they are not marketing to children)