Tobacco and Nicotine Addiction Adapted from a presentation by George Sanchez, 4th year Biomedical Science major, Texas A&M University

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.

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.

Tobacco Spreads to Europe Adventurers like Jean Nicot of France (where nicotine derives its name) popularize tobacco mid 1500’s 1556 Tobacco introduced to France Tobacco introduced to Portugal Tobacco introduced to Spain Tobacco introduced to England 1558 1559 1565

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.

Early Discoveries of the Effects of Smoking: The 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.

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).

The Next Big Blow to Tobacco Industry SURGEON GENERAL’S WARNING: Smoking Causes Lung Cancer, Heart Disease, Emphysema, And May Complicate Pregnancy. 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.

Tobacco Industry on the Run President Clinton announces Food and Drug Administration’s 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

Addiction to Smoking: A Global Problem One-third of the global adult population smokes. It is one of few causes of mortality that is increasing. Of those who smoke during adolescence and throughout life, one-half die from smoke-related diseases. Smoking causes one-third of deaths in men aged 35-69.

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.

Smoking Kills Normal Lung Smoker’s 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. The comma is confusing on this slide and needs to be fixed.

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.)

Structure of Nicotine Nicotine molecule has two rings of carbon and each ring has a nitrogen atom. The two diagrams show the structure in the two common ways that chemists describe molecules. On the right, black balls = carbon, white balls = hydrogen, blue balls = nitrogen. The three-dimensional diagram on the right helps to visualize how nicotine needs to find a place on cell membranes where it can fit, like a hand in a glove. See next slide Click here to learn more about how molecules interact with protein “receptors” on cell membranes.

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)

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?”

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 brain’s reward system signals the craving to restore nicotine levels

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

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.”

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.

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