chapter 1 - alcohol. alcohol absorption 20% absorbed through stomach 80% absorbed through small...
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Alcohol Absorption
• 20% absorbed through stomach• 80% absorbed through small intestine• Equilibration: alcohol is absorbed and
distributed evenly throughout the body• Before equilibration: higher concentration in
brain than in blood• Food in stomach: main influence on
absorption. No food:1 hr. Food:2 hrs.
Alcohol Elimination
• 95% metabolized before excretion• 5% eliminated unchanged-urine and lungs• Most – metabolized by liver• Alcohol dehydrogenase (ADH) breaks down
alcohol into acetaldehyde• Acetaldehyde is broken down by acetaldehyde
dehydrogenase into acetate-then excreted
• Accumulation of acetaldehyde-nausea (Antabuse)
• approx. 1 drink per hour• Drink more that 1 per hour: liver metabolizes
other drugs faster (Plavix, Tylenol)• Cross tolerance: barbiturates
Acute Exposure
• Different effects-different people• 1-4 drinks-judgment, reaction time, motor
coordination• 4-12 drinks-motor coordination, reflexes• 12-16 drinks-voluntary responses to stimuli• 16-24 drinks- sensations, movement
Effects on Brain Cells
• Lesioning in animals• CNS depressant• Biphasic action-low doses-activates some
cells-feel stimulated• GABA – inhibitory• Glutamate – excitatory• NMBA – subtype of glutamate receptor-
essential for new memories
• Dopamine-increases release in reward centers• Only when blood alcohol levels are rising• When levels go down, drink more
• Memory: blackouts; not only in heavy drinkers; college students-40%-sex, fights, driving
• Hangover: headache-bloodvessels and fluid balances in body
• Take pain reliever before bed• Nausea-harder to treat• Coffee-may upset stomach; dehydration
Violence and Aggression
• 50-60% murders; 40% male sexual aggression; 60-70% male instigated domestic violence
Chronic Effects
• Brain shrinkage? Yes-long-term heavy use• Stop drinking-volume can return• Frontal Lobe-executive functions; especially
vulnerable• Mammillary bodies-base of brain-memory• hippocampus-new memories• New studies-moderate drinking can kill cells• Binging-brain damage
Effects on Mental Function
• Memory formation-new memories• Abstract thinking• Problem solving-lack mental flexibility• Attention and concentration• Perception of emotions• Will problems go away?
Other Brain Problems
• Wernicke’s disease-confusion, abnormal eye movements, lack of coordination
• Deficiency of thiamine• About 15% respond well to vitamin therapy and
abstinance• Korsakoff’s psychosis-can’t form new
memories; old memories are patchy; about 20% completely recover;60% partially; 20% institutionalization
Liver Disease
• Fatty liver-reversible• Alcoholic hepatitis-reversible• Cirrhosis-later stages-not reversible• Social drinkers-pattern of drinking is
important; the more alcohol each session, the higher the chance of problems
• 3 drinks per day-substantial risk of developing permanent cognitive impairments
Tolerance and Dependence
• Alcohol dependence (alcoholism)-abnormal seeking, lack of control, withdrawal
• Alcohol abuse-health problems, social problems, or both
Fetal Effects
• FAS-Fetal Alcohol Syndrome: slower growth0prenatal and postnatal; facial abnormalities; CNS abnormalities (mental retardation.
• FAE-Fetal Alcohol Effects: more moderate drinking; behaviors similar to ADD
• FASD-Fetal Alcohol Spectrum Disorders: includes all neurological, cognitive, behavioral,and learning problems
Why Addiction?
• Genetic Factors: family studies, twins, adoption
• Concordance rate-identical twins-58%• No study has conclusively demonstrated a
genetic basis for alcoholism• Men-sons of alcoholic fathers-seem more
affected by pleasurable effects-likely to continue drinking
Type I• After 25 • Infrequent ability to abstain• Infrequent fights and arrests• Infrequent dependence (loss of
control)• Frequent fear and guilt about
alcoholism• Male and female• Extent of genetic influences-moderate• Extent of environmental influences-
high• Serotonin abnormalities in the brain-
absent
Type II• Before 25• Frequent• Frequent
• Frequent
• Infrequent
• Male only• Extent of genetic influences-high• Extent of environmental influences-low • Serotonin abnormalities in the brain-
present
Special Considerations-Women
• Usually smaller; larger % of body fat=higher concentrations in blood
• Less alcohol dehydrogenase• May have blood alcohol levels 25-30% higher than
men after drinking same amount• Birth control pills-slow down elimination• Greater risk-liver damage, even drinking less• Greater risk-pancreatic damage;damaged
pancreas;enzymes leak out; start to digest pancreas
• More likely-high blood pressure; 2-3 drinks per day-40% greater risk
• Breast cancer-2-4 drinks per day-41% increased risk
• More sensitive to brain effects• Divorce rate-higher for alcoholic women• At greater risk for domestic violence and
sexual assault
Children and Adolescents
• “Binge drinking”: Men-5+ drinks; Women-4+• Brain-not fully developed-mid twenties
(especially frontal lobe)• More susceptible to effects on learning and
memory; smaller hippocampus; cells don’t develop as quickly
• Earlier start-more problems later
Interactions With Other Drugs
• Addition: two drugs in combination produce a greater effect than either drug separately
• Synergism: greater than an additive effect• Potentiation: a synergistic interaction; one drug
combined with another produces enhanced effect when one of the drugs alone would have no effect
• Antagonism: effect of a drug is diminished when used with another
• Drug A = 0• Drug B = 20• Drug C = 35• Drug A combined with Drug B = 30• Drug B combined with Drug C = 55• Drug A combined with Drug C = 15• Drug B combined with Drug C = 85
• Synergistic effects: Alcohol with barbiturates, heart meds, insulin, anti-inflammatory drugs, painkillers, tranquilizers, some antibiotics, Tagamet (heartburn)
• Antagonistic effects: Morphine with naloxone or naltrexone; some antidepressants with bran, oatmeal, high fiber foods
Health Benefits?• Relax; reduce stress• Light drinkers-reduced risk for coronary artery disease; 1-1 ½
drinks/day• Harvard Medical School Study-22,000 men;ages 40-84; 10 years;
those who drank 2-4 drinks per week: less likely to die with heart problems than men who drank <1
• Also fewer cancers• Death rate: 2+ a day-51% higher• Conclusion: 2 drinks/week, good; 2 drinks/day, bad• Large studies-Asia & Europe-light/moderate drinking may diminish
risk of death-middle aged men• Interpret results with caution