Chapter 10: Alcohol

Question 1

Describe the process of alcohol metabolism.

Answer 1

About 95% is metabolized by the liver at a rate of 1 to 1.5 ounces per hour and about 5% is excreted by the lungs.

The enzyme alcohol dehydrogenase metabolizes alcohol into acetaldehyde. Acetaldehyde (which is toxic) is degraded by the enzyme aldehyde dehydrogenase into acetic acid. Acetic acid is then oxidized into carbon dioxide, water, and energy.

Question 2

What is acute alcohol tolerance?

Answer 2

Acute tolerance occurs within a single drinking episode and may lead to dangerous driving when binge drinkers perceive that they are less inoxicted on the descending limb of the blood alcohol curve.

Question 3

How does the body adapt to chronic alcohol use?

Answer 3

1. Causes metabolic tolerance by increasing cytochrome P450 enzymes
2. Pharmacodynamic tolerance by producing compensatory changes in neuron function
3. Behavioural tolerance of the operant type where performance improves when tasks are practiced while under the influence
4. Behavioural conditioning of the classical conditioning type where repeated alcohol use in the same environment produces a compensatory response only in that environment
5. Physical dependence
6. Cross-tolerance with other sedative-hypnotic drugs

Question 4

Describe alcohol withdrawal.

Answer 4

After chronic alcohol use withdrawal lasts for several days and includes tremor, anxiety, high BP and HR, sweating, rapid breathing, and nausea and vomiting. Severe effects are called delirium tremens. they are characterized by hallucinations, convulsions, disorientation, and intense anxiety.

Question 5

Explain the behaviour effects of alcohol.

Answer 5

They are directly related to BAC but at low doses, the environment and expectations of effects also have significant effects.

Question 6

What body organ systems does alcohol affect?

Answer 6

1. Central nervous system
2. Cardiovascular system
3. Renal-urinary system
4. Reproductive system
5. GI system
6. Liver

Question 7

What effects does alcohol have on the central nervous system?

Answer 7

The effects are dose-dependent and include:

1. relaxation
2. reduced anxiety
3. intoxication
4. impaired judgment
5. impaired memory
6. sleep
7. coma (high doses)
8. death (high doses)

Question 8

What vitamin deficiency does alcohol cause.

Answer 8

Vitamin B1 which leads to neurotoxic effects and brain damage caused by cell death in the periaqueductal gray, medial thalamus, and mammillary bodies. This B1 deficiency can cause Wernicke’s encephalopathy and Korsakoff syndrome.

Question 9

What neurotransmitters does alcohol affect?

Answer 9

1. glutamate
2. GABA
3. dopamine
4. opioids

Question 10

How does acute alcohol use affect glutamate?

Answer 10

inhibits transmission by reducing glutamate release and reducing its effects at the NMDA receptor

Question 11

How does chronic alcohol use affect glutamate?

Answer 11

1. up-regulates NMDA receptors

2. increases glutamate release

Question 12

How does acute alcohol use affect GABA?

Answer 12

Works on GABA-A receptors to stimulate GABA release which increases chloride entry and hyperpolarization of the cell. This requires high levels of intoxication.

Question 13

How does chronic alcohol use affect GABA?

Answer 13

Down-regulates GABA-A receptors

Question 14

How does acute alcohol use affect dopamine?

Answer 14

Activates dopaminergic cells in the VTA causing the release of dopamine in the nucleus accumbens. This provides the positive reinforcement that leads to repeated drug taking.

Question 15

What role does dopamine play in alcohol withdrawal?

Answer 15

1. reduces firing rate of mesolimbic neurons
2. decreases dopamine release in the nucleus accumbens
3. causes rebound depression of reinforcement mechanisms

Question 16

How does acute alcohol use affect opioid systems?

Answer 16

increases opioid release and increases gene expression of opioid peptides

Question 17

How does chronic alcohol use affect opioid systems?

Answer 17

reduces gene expression and lower levels of opioid peptides

Question 18

Explain alcohol use disorder.

Answer 18

It is a form of substance use that involves compulsive alcohol seeking and use despite damaging health and social consequences. Frequency and pattern of drinking are as important as the quantity consumed.

Question 19

What are the risk factors for alcoholism?

Answer 19

1. personality
2. stress
3. vulnerability (i.e. family history, genetics, ACEs)
4. novelty seeking (e.g. drinking before age 13, aversion to delayed gratification)

Question 20

What is the genetic contribution toward risk for alcoholism?

Answer 20

Genetics explains 50-60% of the variance of risk for alcohol dependence. Some people have genes for an inactive form of the enzyme aldehyde dehydrogenase which gives them low risk for AUD because they experience unpleasant effects from alcohol consumption.

Question 21

What are the two major pharmacotherapeutic approaches for treating alcoholism?

Answer 21

1. disulfiram

2. naltrexone

Question 22

How does disulfiram work to treat alcoholism?

Answer 22

Disulfiram inhibits the enzyme aldehyde dehydrogenase which converts acetaldehyde into acetic acid. The result of this is that consuming alcohol causes very unpleasant effects such as nausea and vomiting, which discourages drinking.

Question 23

How does naltrexone work to treat alcoholism?

Answer 23

Naltrexone is an opioid receptor antagonist. It reduces the positive feelings caused by alcohol and has the effect of reducing alcohol consumption and craving.

Question 24

What is the most effective treatment for alcohol dependence?

Answer 24

Medical management along with either naltrexone or combined behavioural intervention.