Alcohol Flashcards
(33 cards)
What are sedative-hypnotics and anxiolytics?
a group of drugs that depress CNS and behaviour
e.g. alcohol, barbiturates
What is alcohol?
a group of organic compounds that include ethanol, ethyl alcohol, methanol (toxic)
no current medical uses except antiseptic
Why is methanol toxic?
alcohol dehydrogenase converts methanol into formaldehyde and then formic acid; interferes with cell metabolism
How is alcohol produced?
fermentation; yeasts consume sugars producing ethanol and CO2 (up to 15% conc)
repeated distillation can produce higher concs
How are different alcoholic beverages produced?
different sugars = different alcohol
beer; grains
wine; grapes
sake; rice
What is the prevalence of alcohol use?
lifetime use; 83%
past year; 66%
past month; 51%
men show more frequent alcohol-related problems
How is blood alcohol content measured?
grams of alcohol per 100ml of blood
legal driving limit; 0.08g/100ml
% is not entirely accurate as 1g of blood is not 1ml
How does BAC affect the subjective effects of alcohol?
.03-.12; euphoria .09-.25; excitement .18-.30; confusion .25-.40; stupor .35-.50; coma .45+; death
How can alcoholism be modelled in animals?
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
What are the physiological effects of alcohol?
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
What are the pharmacokinetics of alcohol?
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
How is alcohol eliminated?
10% is expelled through sweat, urine, tears unmetabolised
most is broken down into carbon dioxide, water and energy
How is alcohol metabolised?
alcohol + alcohol dehydrogenase = acetaldehyde
acetaldehyde + acetaldehyde dehydrogenase = acetic acid
acetic acid + oxidation reaction = CO2, H2O + energy
How can genetic variation influence alcohol metabolism?
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
What drugs can limit alcohol intake?
antabuse (disulfiram); inhibits acetaldehyde dehydrogenase
What is acute tolerance?
the same level of alcohol produces reduced behavioural effects within a single session/exposure
What is chronic tolerance?
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
What is a hangover?
dehydration, low blood sugar, irritated digestive system
mini withdrawal; drinking more can relieve symptoms
Describe alcohol withdrawal
can be fatal
delirium tremens; seizures, hallucinations, tremors
What are the mechanisms of alcohol action?
interacts with many targets; Ca2+. NMDA, glycine, 5HT3a, GABAaR
How does alcohol interact with GABAa?
acute; enhanced flow of Cl-
chronic; decreased flow of Cl-
similar action to barbiturates
How does alcohol interact with glutamate?
decreased flow of Ca2+, Na+ through NMDAR
How does alcohol act at the CNS acutely then chronically?
increased dopamine in the accumbent, reduced firing and release
glut antagonism, up regulation of receptors
enhanced GABA-induced Cl- influx, decreased function
Is alcohol having a pharmacological effect or is it a learned association?
beer flavour does not increase DA transmission, beer flavour + ethanol does
