Tobacco and Nicotine Addiction

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Tobacco and Nicotine Addiction

Adapted from a presentation by George Sanchez,
4th year Biomedical Science major, Texas AM
University
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Method of Delivery

• Tobacco products include cigarettes, cigars, and
  pipe tobacco, which are smoked snuff, which is
  inhaled into the nose and chewing tobacco, which
  is chewed but not swallowed.
• Inhalation of tobacco smoke is the fastest and
  most efficient way yet discovered to deliver
  nicotine to the brain.

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History of Tobacco

• Tobacco was first used by the peoples of the
  pre-Columbian Americas.
• Native Americans apparently cultivated the plant
  and smoked it in pipes for medicinal and
  ceremonial purposes.

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Tobacco Spreads to Europe
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Tobacco in the Colonies

• The first successful commercial crop was
  cultivated in Virginia in 1612 by Englishman John
  Rolfe.
• Within seven years, it was the colony's largest
  export.
• Over the next two centuries, the growth of
  tobacco as a cash crop fueled the demand in North
  America for slave labor.

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Early Discoveries of the Effects of SmokingThe
20th Century

• In 1930, researchers in Cologne, Germany, noticed
  that many cancer patients were smokers.
• Eight years later, Dr. Raymond Pearl of Johns
  Hopkins University reported that smokers do not
  live as long as non-smokers.
• By 1944, the American Cancer Society began to
  warn about possible ill effects of smoking,
  although it admitted that "no definite evidence
  exists" linking smoking and lung cancer.

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The Tobacco Industry Responded Swiftly

• By 1954 the major U.S. tobacco companies had
  formed the tobacco industry research council to
  counter the growing health concerns.
• Mass-marketing began for filtered and low-tar
  cigarettes that promised a "healthier" smoke (now
  we know smokers compensate by smoking more and
  inhaling longer).

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The Next Big Blow to Tobacco Industry

• 1964, Surgeon General's Advisory Committee on
  Smoking and Health put out a 387-page report
  stating that cigarette smoking is causally
  related to lung cancer.
• In 1965, Congress passed the Federal Cigarette
  Labeling and Advertising Act requiring the
  Surgeon General's warnings on all cigarette
  packages.

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Tobacco Industry on the Run
President Clinton announces Food and Drug
Administrations plan to regulate tobacco,
especially sales and advertising aimed at minors
Smoking is banned on all interstate buses and all
domestic airline flights lasting 6 hours or less
1971
1994
1990
1995
All broadcast advertising was banned
Mississippi files the first of 22 state lawsuits
seeking to recoup millions of dollars from
tobacco companies for smokers Medicaid bills
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Addiction to Smoking A Global Problem
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Smoking is Addictive

• 80 of attempts to quit smoking fail within a
  year.
• In the U.S., 70 of smokers say they would like
  to quit.
• 5 are successful each year.

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Smoking Kills

• Normal Lung Smokers
  Lung
• The complex mixture called tobacco tar, and
  carbon monoxide, are mainly responsible for most
  of the diseases that are associated with the
  long-term use of tobacco.

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Nicotine Addictive Component of Tobacco

• Nicotine produces effects that are commonly seen
  with other addictive drugs such as amphetamines
  and cocaine.
• Craving and self-administration
• Increase in movements
• Reinforces place reference (learned associations
  bars, restaurants, etc.)

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Structure of Nicotine
Click here to learn more about how molecules
interact with protein receptors on cell
membranes.
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The Idea of Molecular Receptors

• Drugs bind to cell membranes
• Regions on membrane where this binding occurs are
  called molecular receptors or binding sites
• Binding sites are proteins that are specific
  matches to the drug molecule (fit together like a
  key in a lock)
• Effect of the drug is achieved by this binding
  (like the key and lock, think of it as opening a
  function in the cell)

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Long-Term Use Leads to Cigarette Cravings

• Long-term use increases the number of molecular
  receptors in brains of humans.
• Increased number of receptors increases the
  demand for nicotine
• When receptors are unoccupied by nicotine, they
  complain Where is our nicotine?

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Why Do Smokers Crave Nicotine?

• Nicotine acts in nervous system circuits that
  release a reward chemical dopamine
• Brain learns to like the release of dopamine
• When nicotine is withdrawn, the brains reward
  system signals the craving to restore nicotine
  levels

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Craving for Nicotine

• Craving is high when nicotine is at low
  concentrations
• Craving is satisfied when nicotine levels are
  restored to levels to which nerve cells have
  become accustomed.
• Nerve cells learn that nicotine is normal, lack
  of nicotine is abnormal

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Craving Patterns

• After a night of abstinence, dopamine
  concentration in brain is at its lowest level.
• First cigarette strongly activates dopamine
  release. Greatest pleasure.
• Tolerance occurs quickly, because receptors adapt
  quickly.
• Throughout a day, episodes of cigarette smoking
  are separated by short periods of abstinence
  nicotine levels drop and receptors cry out for
  their nicotine fix.

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Addiction Process is Still a Mystery

• If an individual quits smoking for a few weeks,
  the number of nicotine receptors returns toward
  normal (like that of non smokers).
• BUT
• Craving can still exist even years after
  quitting.
• Long-term changes have occurred in neural
  circuits.
• Smokers remember the behaviors that were linked
  to sensory cues and reinforced.

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Think Before You Act
Smoking is the leading cause of premature death!