tabacco and alcohol

Question 1

how many deaths per year is tabacco responsible for

Answer 1

5 million deaths/ year

Question 2

how does smoking affect lifespan?

Answer 2

smokers die on average 10 years younger
cessation at 50 halfs risk
cessation at 30 almost removes added risk

Question 3

how longs does it take nicoteine to reach brain?

Answer 3

10 seconds from when absorbed into bloodstream

affects are displayed in a few minutes

Question 4

where are nAch receptors found?

Answer 4

neuromuscular junctions, autonomic ganglia, throughout the CNS

Question 5

what are the different types of nAch subunits and where are they found?

Answer 5

at neuromuscular junction: alpha1, beta1, gamma, delta and epsilon

at neurone: alpha 2-10 (8 does not exist in humans)
beta 2-4

Question 6

what type of nAch have been implicated in mediating addictive effects of nicotine ? and how is this shown in mice?

Answer 6

ones with alpha4 and beta2 subunits

mice with deletion of gene for nAch subunit beta2 have reduced self administration of nicotine

Question 7

where are muscular and neuronal nAchRs located with respect to synapse

Answer 7

muscular: postsynaptic
neuronal: pre and postsynaptic

Question 8

when nicotine acts on nAchRs what does it cause release of? and what are theyre effects

Answer 8

dopamine noradrenaline GABA and endorphins
dopamine: psychoactive effects
noradrenaline: increased attentiveness
GABA and endorphins: anxiolytic effects (inhibits anxiety)

Question 9

where is dopamine released after smoking

Answer 9

the mesolimbic dopamine pathway (reward centre)
dopamine releasing cells are in the ventral tegmental area (top of brainstem)
relay pleasure messages to the nucleus accumbens
which then relay messages to cerebral cortex

Question 10

what are the physiological effects of smoking?

Answer 10

effects on ANS: increases heart rate, blood pressure, sweating and decreased GI motility, release of adrenaline and noradrenaline from adrenal medulla

effects on CNS: symptoms of stimulation and arousal, alleviates stress and anxiety, may enhance learning and sensory performance

relaxation of skeletal muscle (due to effects in spinal cord not NMJ)

Question 11

what is the tolerance and withdrawal symptoms of nicotine:

Answer 11

tolerance: higher doses required to produce same effect

withdrawal symptoms when stopping: irritability, hunger, restlessness, attentional deficits, sleep disturbances

Question 12

what is relapse rate in smokers who try to stop?

Answer 12

half of smokers who stop for 6 weeks will relapse within 6 months

20% of smokers who stop for 6 months will relapse within a year

Question 13

name and describe smoke cessation therapies

Answer 13

nicotine replacement therapy (patches gum etc): relieves withdrawal symptoms, lower concentration than present in smoking, no carcinogens that are present in smoking

bupropion: has been used as an antidepressant, not clear on how it helps smoking cessation, may involve effects on dopamine and noradrenaline transmission

nicotine replacement and bupropion are most cost effective methods

varenicline: partial agonist of alpha4beta2 nAchRs, cause a moderate and sustained increase in mesolimbic dopamine levels
competitive binding with nicotine may reduce rewarding properties of nicotine during relapse

nicotine vaccine (still in development): nicotine conjugated to carrier protien acts as antigen to stimulate antibody production, antibodies against nicotine stop it reaching brain.

Question 14

how much is a unit of alcohol in pure ethanol?

Answer 14

10mls of pure ethanol

Question 15

as of 2016 what is the recommended weekly alcohol intake for men and women

Answer 15

do not exceed 14 units/ week for both men and women spread over at least three days

Question 16

how much does a unit of alcohol raise blood alcohol levels by?

Answer 16

1 unit of alcohol raises blood alcohol by 15mg/100ml

Question 17

what is rate of alcohol metabolism by body

Answer 17

15mg/100mls of blood per hour, irrespective of blood alcohol concentration

Question 18

what are the physiological effects of alcohol

Answer 18

alcohol promotes: vasoconstriction, gastric secretion, urine production, liver damage, male impotence

CNS depression, intellectual performance and sensory discrimination impaired.

alcohol stimulates mesolimbic dopamine pathway

Question 19

what are the positive and negative reinforcements of alcohol

Answer 19

positive: pleasure and happy feelings
negative: relief of stress

Question 20

how does alcohol cause liver damage?

Answer 20

fatty liver is first stage of liver deterioration in heavy drinkers. Chronic alcohol consumption can lead to accumulation of fatty acids. Accumulation of fatty acids can lead to formation of fibrous scar tissue (fibrosis) which can lead to permanent damage (cirrhosis).

Question 21

which receptors does alcohol effect?

Answer 21

there is evidence for modulation of functional properties of nAchRs, ATP receptors, 5HT receptors, GABA receptors etc.

Question 22

how is alcohol absorbed

Answer 22

ethanol is highly lipid soluble, absorbed by stomach and small intestine.

Question 23

what is the metabolism pathway of alcohol? and what is antabuse

Answer 23

ethanol is converted to ethanal by alcohol dehydrogenase, ethanal is converted into ethanoic acid by aldehyde dehydrogenase. NAD is used as a cofactor in both reactions

Antabuse is a drug which is given to alcoholics which prevents conversion of ethanal to ethanoic acid, build up of ethanal makes them sick whenever they have alcohol.

Question 24

what is the tolerance and withdrawal symptoms of alcohol

Answer 24

greater quantaties of alcohol are required for same effect since alcohol dehydrogenase is an inducible enzyme.

withdrawal symptoms: tremor, sweating, nausea, hallucinations, confusion.