Week 5: Alcohol Flashcards
What do we mean by alcohol?
The term describes a wide range of substances, only a few of which are consumed;
1. isopropyl alcohol - rubbing alcohol
2. methanol - wood alcohol - would make you go blind
3. ethanol - drinking alcohol
What are the 2 methods for making alcohol
- Fermentation - sugar + yeast = 15-20% alcohol + co2
- Distillation - boiling off the impurities of alcohol - to get 40-50% alcohol by volume
Origin and History of Alcohol
- has probably been part of the human diet for millions of years
- has a high fruit content, therefore, high sugar content. Also has yeast and always has some alcohol.
- alcohol has likely been associated throughout evolutionary history with food and nourishment
Was found nearly 9,000 years ago in china
The earliest law codes didn’t regulate fair commerce of alcohol and didn’t mention drunkenness
Egyptians, greeks, romans all drank moderately and later rome descended into insobriety
The British isles also had a long tradition of drinking. This was mostly mean, ale and cider as grapes didn’t grow well in this climate. Ditilled alcohol became popular in the 1600s (eg. whiskey) and we were faced with the gin epidemic
Gin Epidemic
Alcoholism was widespread amongst the poor in the 1700s, and the rise of the ‘gin craze’ became infamous. Gin was cheap and extremely strong, and for many people offered a quick release from the grinding misery of everyday life
Alcohol in the US over History
Colonists brought their inclinations for strong drink with them from England
Harvard Uni had a brewery and drafted rules to avoid ‘excesses, immoralities and disorders’ at commencement
workman received part of their wages in rum and employers would set aside certain days for inebriety
The Temperance Movement
After the American revolution, alcohol consumption increased until the temperence movement of the mid 1800s
This gained political traction as people realised that too much alcohol has bad implications
Prohibition
1917 - 1933
The prohibition passed as 18th amendment which outlawed alcohol
this drove a black market for alcohol with speakeasys and a lot of corrupt policing around alcohol
Neuropharmacology of Alcohol effects
Complex and involves a number of systems
alcohol intoxication occurs at concentrations 1,000 and 1,000,000 times greater than other drugs
stimulates multiple pathways at once
most effects are mediated by gaba and glut systems (but a few other transmitter too)
GABA effects of alcohol
GABAa receptors are responsible for maintaining constant inhibitory tone. Ethanol will bind to these receptors and increase the inhibitory action of GABA when it binds.
These alcohol sensitive GABAa receptors are common in the cerebellum hence the effects of alcohol on coordination - aka motor impairments
GLUT effects and Alcohol
Alcohol binds to NMDA receptors and blocks the ion channel - aka prevents excitation
The effects of alcohol on gaba and glutamate converge
- alcohol stimulates GABA receptors which inhibit neural activity
- alcohol also block normal functioning of glutamate (NMDA) receptors, which also inhibits neural activity
- together these effects throw off the delicate GABA/GLUT balance that is necessary for normal functioning of the CNS
- Prolonged blockage of NMDA receptors leads to compensatory upregulation which may be involved in alcohol withdrawal symptoms
Dopamine and Alcohol
Dopamine ass with all drugs, alochol produces its reinforcing effects through increasing dopamine activity in the mesolimbic dopamine system
Effects of alcohol on human behaviour and performance according to BAC (Blood alcohol level)
50-100 : More talkative; using a higher pitched voice; mild excitement
100-150 : Even more talkative and cheerful; often loud and boisterous : Later people become sleepy
>150: Nausea; Lethargy: Stupor
200-290 : Loss of understanding; memory blackout ; unconsciousness
There’s considerable variation between people for this and from situation to situation
Blackouts
Heavy drinking may cause periods of amnesia for events that occurred during intoxication
- Grayout;
- drinker only remembers bits and pieces of events that occurred during intoxication
- CAn recall if prompted or if they return to the location of the event
- Indicates the problem is with retrieval, the memories stored are intact but unable to be accessed after alcohol is cleared from the system - En bloc blackout
- a rarer occurrence; drinkers remember nothing that occurred during a drinking episode
- memories are not stores, they never return
- behaviours may appear to be quite normal during the blackout period
(the mechanism for this is not well understood)
Grayout
- Grayout;
- drinker only remembers bits and pieces of events that occurred during intoxication
- CAn recall if prompted or if they return to the location of the event
- Indicates the problem is with retrieval, the memories stored are intact but unable to be accessed after alcohol is cleared from the system
