Alcohol

Question 1

What are sedative-hypnotics and anxiolytics?

Answer 1

a group of drugs that depress CNS and behaviour

e.g. alcohol, barbiturates

Question 2

What is alcohol?

Answer 2

a group of organic compounds that include ethanol, ethyl alcohol, methanol (toxic)
no current medical uses except antiseptic

Question 3

Why is methanol toxic?

Answer 3

alcohol dehydrogenase converts methanol into formaldehyde and then formic acid; interferes with cell metabolism

Question 4

How is alcohol produced?

Answer 4

fermentation; yeasts consume sugars producing ethanol and CO2 (up to 15% conc)
repeated distillation can produce higher concs

Question 5

How are different alcoholic beverages produced?

Answer 5

different sugars = different alcohol
beer; grains
wine; grapes
sake; rice

Question 6

What is the prevalence of alcohol use?

Answer 6

lifetime use; 83%
past year; 66%
past month; 51%
men show more frequent alcohol-related problems

Question 7

How is blood alcohol content measured?

Answer 7

grams of alcohol per 100ml of blood
legal driving limit; 0.08g/100ml
% is not entirely accurate as 1g of blood is not 1ml

Question 8

How does BAC affect the subjective effects of alcohol?

Answer 8

.03-.12; euphoria
.09-.25; excitement
.18-.30; confusion
.25-.40; stupor
.35-.50; coma
.45+; death

Question 9

How can alcoholism be modelled in animals?

Answer 9

very difficult to initiate drinking; sucrose fading procedure
slow absorption makes associative learning problematic
IV alcohol is readily SA
animals binge for a few days then stop for a while; similar pattern to humans

Question 10

What are the physiological effects of alcohol?

Answer 10

increased blood circulation; dilation of blood vessels, flushed face, feeling of warmth
inhibition of anti-diuretic hormone; dehydration
easier to fall asleep but interferes with REM

Question 11

What are the pharmacokinetics of alcohol?

Answer 11

alcohol is a small non-ionised molecule that rapidly crosses membranes
higher dose = more rapid absorption
90% absorbed in small intestine
food in stomach slows movement to intestine so more is degraded before absorption

Question 12

How is alcohol eliminated?

Answer 12

10% is expelled through sweat, urine, tears unmetabolised

most is broken down into carbon dioxide, water and energy

Question 13

How is alcohol metabolised?

Answer 13

alcohol + alcohol dehydrogenase = acetaldehyde
acetaldehyde + acetaldehyde dehydrogenase = acetic acid
acetic acid + oxidation reaction = CO2, H2O + energy

Question 14

How can genetic variation influence alcohol metabolism?

Answer 14

10% of asians have a gene that codes for an inactive form of acetaldehyde dehydrogenase, therefore there is a high conc of acetaldehyde; headache, flushing, nausea, heart rate

Question 15

What drugs can limit alcohol intake?

Answer 15

antabuse (disulfiram); inhibits acetaldehyde dehydrogenase

Question 16

What is acute tolerance?

Answer 16

the same level of alcohol produces reduced behavioural effects within a single session/exposure

Question 17

What is chronic tolerance?

Answer 17

tolerance that reflects metabolic changes
- increased expression of acetaldehyde dehydrogenase
- induction of liver enzymes responsible for ethanol oxidising
usually only 5/10% alcohol metabolism, up to 60% with chronic use

Question 18

What is a hangover?

Answer 18

dehydration, low blood sugar, irritated digestive system

mini withdrawal; drinking more can relieve symptoms

Question 19

Describe alcohol withdrawal

Answer 19

can be fatal

delirium tremens; seizures, hallucinations, tremors

Question 20

What are the mechanisms of alcohol action?

Answer 20

interacts with many targets; Ca2+. NMDA, glycine, 5HT3a, GABAaR

Question 21

How does alcohol interact with GABAa?

Answer 21

acute; enhanced flow of Cl-
chronic; decreased flow of Cl-
similar action to barbiturates

Question 22

How does alcohol interact with glutamate?

Answer 22

decreased flow of Ca2+, Na+ through NMDAR

Question 23

How does alcohol act at the CNS acutely then chronically?

Answer 23

increased dopamine in the accumbent, reduced firing and release
glut antagonism, up regulation of receptors
enhanced GABA-induced Cl- influx, decreased function

Question 24

Is alcohol having a pharmacological effect or is it a learned association?

Answer 24

beer flavour does not increase DA transmission, beer flavour + ethanol does

Question 25

What health problems can accompany heavy alcohol use?

Answer 25

cirrhosis of the liver
korsakoff syndrome; vitamin D1 deficiency
brain damage
foetal alcohol syndrome; lower birth and body weight, behavioural/learning problems
apoptosis; alcohol action at GABAaR and NMDAR

Question 26

What is absinthe?

Answer 26

wormwood macerated in alcohol then redistilled

lucid form of alcohol intoxication

Question 27

What is the key psychoactive ingredient in absinthe and its mechanism of action?

Answer 27

thujone; GABAa receptor antagonist

Question 28

What is the mechanism of action of thujone?

Answer 28

reversibly binds to GABAaR and blocks Cl- flow (antagonist); excitatory mechanism possibly responsible for psychoactive effects

Question 29

How do the acute effects of alcohol on GABA affect behaviour?

Answer 29

sedative effects; enhances GABA Cl- influx

Question 30

How do the chronic effects of alcohol on GABA affect behaviour?

Answer 30

tolerance, hyper excitability during withdrawal

Question 31

How do the acute effects of alcohol on glut affect behaviour?

Answer 31

memory loss

Question 32

How do the chronic effects of alcohol on glut affect behaviour?

Answer 32

brain damage, hyper excitability

Question 33

How do the acute effects of alcohol on dopamine affect behaviour?

Answer 33

reinforcement