Tobacco Flashcards
Reproduction
- smoking women are 1.7-3.2 time more likely to be infertile than non-smokers
- babies more likely to be low birth weight, premature, have illness and die
- also caused by environmental tobacco smoke from other smokers in the home
- if all mother stopped smoking, infant death rate would decrease by 10%
- living with a smoker increases risk of sids
Environmental tobacco smoke
- 2nd hand smoke
- maintstream smoke = inhaled smoke
- sidestream = inhaled smoke but burns at lower temp
- has more carcinogens
- children most vulnerable
- causes bronchitis and pneumonia
- SIDS
-also 3rd hand smoke on clothes, fabrics
Patterns of smoking in canada
- 10% of Canadians use tobacco daily
- avg cigarettes per day is 13.9
- more people quitting than starting
Smoking patterns
- used as a hallucinogen by native North Americans
- sacred plant used occasionally at high doses but not continuously
- cig consumption greatest after lunch and dinner
- lowest on weds an sun
- greatest on say
- stimulated by presence of other smokers/cigs
- chippers: occasional use without dependence
Neural response
- activated VTA
- DA neurons contribute to addiction
- nicotinic receptors affected by tobacco same
- same as VTA —> dA release
Impact of nicotine on receptors
- activation, desensitization, recovery
- need a period of abstinence to become active again
- 2-3 hours to recover
- repeated administration leads to upregulation
- opposite of regular agonists
Nicotine pharmocokinetics
- rate of absorption and elimination impacted by route of administration
- half life approx 2 hours
- metabolized by CYP2A6
- variability is associated with patterns of usage
- metabolites excreted in urine
-area postrema limits the dosage range
1988 surgeon general report
-cigs and tobacco addiction due to nicotine
What makes a substance addictive
- self administration
- voluntarily administered to a greater extent than inactive placebo
- capable of producing compulsive patterns of use
- withdrawal
- cessation following prolonged use produces unpleasant symptoms
Nicotine as treatment for colitis
-patients with colitis received nicotine treatments over several months and none showed withdrawal symptoms
Hypothesis 4:
- individual differences in the extent to which nicotine and non-nicotine factors contribute to tobaccos addictive properties
- smokers appear to differentials response to NRTs and denicotinized tobacco
- denicotinized tobacco appears to be more effective in reducing cravings in highly dependent smokers
DSM and substance use disorders
- tobacco is the only drug that can cause an addiction without causing intoxication
- all withdrawal symptoms are psychological compared to other drugs that have both psychological and physical
Insula and tobacco addiction
- insular damage associated with dramatic reductions in smoking and conscious urges to smoke
- believed to be involved in bringing interoceptive signals into conscious awareness
- posterior insula believed to be involved in processing sensory and interoceptive inputs (eg nicotine effects; withdrawal)
- anterior insula thought to transmit these signals to brain regions involved in planning and evaluation of goal directed behaviour such as ACC
AI-ACC connectivity
- strong resting state functional connectivity between AI and ACC has been associated with enhanced smoking cue reactivity but not to changes in tonic craving in non-abstinent smokers
- abstinence/withdrawal associated with increased rsFC between insula and ACC relative to satiation
- extend to which changes in co-activation result from nicotine administration, changes in craving or withdrawal or combination are still unclear
Actual vs perceived nicotine administration
-nicotines acute effects on subjective withdrawal depends partly on the belief that nicotine has been ingested
-nicotine induced craving reduction and associated reduction in insular activity were only evidence when nicotine was both expected and administered
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