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TOPIC 8 REVIEW – TOBACCO
Tobacco is the most dangerous substance in the world
- kills more people than
- industrial chemicals
- tobacco is basically linked to all forms of death listed above. In fact, 1/3 of all cancer deaths are associated with
the use of tobacco.
- the number one risk factor associated with stroke is tobacco smoke!
- tobacco kills 420, 000 per year in North America
- estimated that 6 billion deaths/year, more specifically in third world countries where as much as 70%
History of Tobacco
Columbus discovers tobacco 1492
- Natives drank smoke from tobbagos (name of tobacco for the natives Colombus saw on his trip to the Caribbean)
- first shipments to Spain from Tobago
- theory that “tobacco” comes from the shipment to Spain from the island “Tobago”
Jean Nicot introduced tobacco to France
- “l’herbe nicotaine”
- Jean Nicot introduced tobacco to France. He used it as an herbal medicine – in fact, one of the first treatments of
asthma was tobacco!
Tobacco was used to revive drowning victims
Tobacco smoking in clubs
- smoking a long time ago was expensive and unpleasant (tobacco was very harsh because of the acids in it).
- people consumed tobacco primarily using a pipe with a long stem
- point is to have the acid gas to cool down in the long stem to allow smoking to be possible
- crude processing of tobacco back then
Water pipes popular in Eastern countries
- water pipes is a way to smoke tobacco in Eastern countries.
- while it may prevent some organic substances going into the smoke, it is not MUCH safer
Snuff became popular with aristocracy
- snuff = powdered tobacco leaves
- you had to be rich because the supply of tobacco back then was low
Chewing tobacco popular with the masses
First depiction of cigarette smoking
- Cigarette is in fact a relatively new invention (late 1700s)
- cigarettes were originally rolled by hand
- making them expensive
- Bonsack machine reduced production cost
- first machine to manufacture cigarettes!
- drove down the cost dramatically
Flue-curing reduced harshness of smoke
- flue-curing = heating up tobacco in an oven.
- when you heat it rapidly in this flue process, it is not acidic anymore (i.e. it does not hurt your throat
anymore). Now possible to smoke in a modern way (without the long stem!)
Cigarettes become dangerous!
- machine manufacturing reduced cost
- could afford to smoke a lot
- flue curing reduced irritants in smoke
- smoke brought deep into lungs
- cigarettes now addictive
- these two factors increase exposure to toxic substances
- risk = toxicity x exposure
- early cigarette ads emphasized “mildness”
Cigarette smoking today
Average smoker smokes 10, 000 cigarettes each year
- data from today
- cigarette consumption then and now:
- late 1800s:
- 80 cigarettes a year
- did not inhale
- 10,000 cigarettes a year
- inhale deeply
- hold smoke in lungs
How It Works
Nicotine is the addictive substance
- 2 mg per cigarette required to addict smoker
- as a result, cigarettes (or nicorette gums for ex) typically contain 2 mg per cigarette or per gum
- therefore cigarette delivers 2 mg nicotine to addict
Nicotine acts on acetylcholine receptors
- nicotine = acetylcholine agonist
- messenger-receptor interaction
- 2nd messenger system signal transduction to go from the receptor to the biological response
- agonist at low doses, resulting in excitatory signal without the presence of acetylcholine
- agonist sends message without the normal messenger
- antagonist at how doses
- blocks chemical messages
- smokers regulate the dose
- if you want to get stimulated, you puff on the cigarette, but to get relaxed, you inhale deeply
- nicotine stimulates dopamine release
- remember, dopamine is involved in the “reward” system of the brain
- part of the reason why nicotine is so addictive!
- smoking cues add to the addiction
- “ritual” or “cue” of smoking
- ex: coffee in the morning = cigarette!
- nicotine use as a pesticide
- lethal dose is 60 mg
- cigar, however, contgains 120 mg! Why people don’t die – temperature of the cigar smoke causes
thermal decomposition of nicotine to a biologically safe level
- common form of poisoning in children