Alcohol Flashcards
Which of these is used in beverages and which of these is found in formic acid:
a. Ethyl alcohol
b. Methyl alcohol
Ethyl alcohol found in beverages
Methyl alcohol found in formic acid
How is ethanol produced? (2 marks)
- Fermentation of sugars by yeasts.
- Fermentation causes yeast to die, distillation then increases alcohol concentration (can make spirits)
Due to alcohol being so calorific what organ in particular can it cause a lot of muslce degeneration of? (1 mark)
- Brain
What value of blood alcohol concentration is seen to cause a measurable behavioural effect?
0.02%
How does ingesting food before you drink slow the absorption of alcohol? (2 marks)
- Pyloric sphincter delays movement to small instestine which regulates the movement of material from stomach to intestine
- This delayed movement allows dehydrogenase to break down the alcohol
Why are women more prone to being more intoxicated than men even if they drink the same amount?
(1 mark)
- Men contian 60% more active alcohol dehydrogenase so they are able to break down alcohol faster
What does alcohol dehydrogenase convert alcohol to and where does this reaction take place?
(2 marks)
- In liver
- Converts it inot acetaldehyde and then this is converted by aldehyde dehydrogenase (ALDH) to acetate
What does a build in acetaldehyde dehydrogenase cause?
(1 mark)
- Flushing, nausea and vomitting
Enzymes from what family convert alcohol inot acetaldehyde?
(1 mark)
Cytochrome P450
How is ‘induction’ the basis for metabolic tolerance?
(2 marks)
- Alcohol consumed regularly - enzymes increase
- Get increase in rate of metabolism of alcohol
What the four different mehcanisms of tolerance? (8 marks)
- Acute tolerance: occurs on single exposure to alcohol - feel less intoxicated on declining limb of alcohol curve
- Metabolic tolerance: increase in P450 in liver microsomal enzymes that metabolise the alcohol. Quicker metabolism, blood levels of drug = reduced, so diminshed effects
- Pharmodynamic tolerance: neurons adapt to continued presence of alcohola and make compensatory changes in cell function (receptors exposed to alcohol will continually adapt)
- Behavioural tolerance: practising behaviours while under influence of alcohol allows adjustment and compensation
What are some of the symptoms of physical dependence after prolonged use of alcohol? (3 marks)
- May be due to residual acetaldehyde in the body
- Gastric irritation, rebound drop in blood sufar, excess fluid loss
- some alcoholics experience delirium - can include convulsions, hallucinations, disorientation, panic attacks and unstable blood pressure
What are some of the effects of alcohol at 0.15% and 0.35% blood alcohol concetration? (2 marks)
- 0.15% - start to vomit
- 0.35% - unconcious - can be seen as a mechanism of prevention to stop drinking
What sort of brain damaged is experienced from chronic drinking?
(5 marks)
- Deficiency for thiamine (Vitamin B1) - which is critical for brain glucose metabolism - causes cell death and Wernicke encepalopathy
- Wernicke Korsakoff syndrome: slective degeneration of diencephalon - causes confusion, disorientation
- Korsakoff syndrom: potenitally irreversible memory loss - anterograde amnesia
- Enlarged ventricles of the brain and extensive shrinkage of brain tissue
What sort of treatment can help stop degeneration (but not be able to reverse it)?
(1 mark)
Thiamine treatment
How can low to moderate daily dose of alcohol reduce the risk of heart disease?
(1 mark)
- Increases amount of good cholesterol in blood while reducing the bad
What happens in a fatty liver after chronic use of alcohol?
(3 marks)
- Causes inflammation in tissue along with increased breakdown of fats into fatty acids
- Changes in adipose tissue release fatty acid into the blood
- Contributes to increased deposit of triglycerides
What is alcohol hepatitis? (2 marks)
- Liver cell damage caused by accumulation of high levels of acetaldehyde
- Causes inflammation of liver, fever, jaundice and pain
What is alcoholic cirrhosis? (1 mark)
- Death of liver cells stimulates scar formation and blood vesses carrying O2 are cut off
What is foetal alcohol syndrome? (2 marks)
- Pre-natal alcohol exposure - (alcohol passes through placental barrier)
- Can cause withdrawal syndrome in foetus
What are some of the symptoms of foetal alcohol syndrome?
(4 marks)
- Mental retardation
- Low birthweight
- Neurological problems
- Distinctive cranial malformations
What are some of the non-specific affect of alcohol in the neuronal membrane?
(3 marks)
- Alters lipid composition
- Interacts with polar heads of phospholipid
- Disturbs relationship in protein membrane
What are some of the specific affects of alcohol in the neuronal membrane?
(3 marks)
- Acts at neurotransmitter binding site
- Modifies gating mechanism inside channel
- Stimulates G proteins linked to adenyl cyclase
How does alcohol affect glutamate function?
(3 marks)
- Effect NMDA receptor function so affects learning and memory - as glutamate release is reduced into hippocampus
- W/drawal symptoms of less glutamate in CNS: seizures and hyperexcitability
- Excessive Ca2+ influx - contributes to cell death
How does alcohol affect GABA function?
(5 marks)
- Binds to GABAA receptors opens channels and allows Cl- to enter cell and hyperpolarise membrane therfore increasing Cl- and stimulating GABA release
- Some of these receptors located extrasynaptically respond to more persistent action of GABA that remains in extracellular space to produce tonic inhibition
- Repeated exposure to ethanol reduces GABAA mediated Cl- flux
How does alcohol affect dopamine?
(3 marks)
- May increase mesolimbic firing indirectly secondary to its modulation of other NT in VTA e.g. those produced by GABA etc.
- Reinforcement
- Can have negative affect in terms of withdrawal
How are opioids affected by alcohol?
(3 marks)
- Acute administration of alcohol increase endogenous opioid production and release endorphins and enkephalins
- Chronic administration reduces production
- However - has been shown in animals that an antagonist for opioid reduces alcohol consumption
What is the difference between Type I and Type II alcoholics?
(2 marks)
Type I: (normally female)
- Generally begin drinking in later life and experience guilt and fear about their alcoholism
Type II: (normally male)
- Display thrill-seeking, antisocial and criminal activities; greater genetic vulnerability and start drinking at an early age
How does detoxification by benzodiapines/ diazepines work to prevent alcohol withdrawal?
(2 marks)
- Makes drinking unpleasant as dilsulfrin inhbits ALDH
- Reduce alcohol’s reinforcing qualities e.g. Naltrexone and Acamprosate
