Lecture: #17 ([Drugs and alcohol] Neurotransmitters and Complex Behavior)

Question 1

Ways that neurotransmitter functioning can be interfered with in one of the flowing ways or in multiple of the following ways:

Answer 1

1. Change the release of the neurotransmitter in the presynaptic cell
2. Change the rate of break-down of the neurotransmitter in the synaptic cleft
3. Changing the neurotransmitter binding to receptors

Question 2

Botulinum toxin – aka “botox”

Answer 2

Injected directly into a muscle, Botox enters the terminal button of nerve cells and breaks down a protein called SNAP-25. This protein plays a crucial role in allowing a vesicle containing acetylcholine to fuse with the cell membrane (when calcium rushes in after an action potential is fired). By cleaving SNAP-25, Botox makes it impossible for acetylcholine to be released into the synapse.

Change the release of the neurotransmitter in the presynaptic cell

Effect: This prevents the signal for the muscle to contract from reaching its destination, causing the muscle to relax and smoothing out wrinkles. Botox remains in the terminal button for months, effectively reducing muscle contractions with a single injection

Question 3

Caffeine

Answer 3

Caffeine mimics adenosine’s shape but doesn’t hinder neuron firing. By binding to adenosine receptors, caffeine prevents the accumulation of adenosine, maintaining brain activity and preventing the process of feeling tired.

Changing the neurotransmitter binding to receptors

Effect:This results in increased alertness and reduced fatigue.

Question 4

OxyContin

Answer 4

OxyContin binds to opioid receptors mimicking the effects of natural endorphins.

Changing the neurotransmitter binding to receptors

Effect: reduces the perception of pain.

Question 5

LSD

Answer 5

Mimics serotonin and its effects

Changing the neurotransmitter binding to receptors

Effect: hallucinogenic and increased feelings of serotonin

Question 6

Ecstasy

Answer 6

Blocks the reuptake of serotonin
Mimics serotonin (creates reaction)

Change
- release of NT in presynaptic cell
- NT binding to receptors

Effect: serotonin in the brain, contributing to the feelings of pleasure, increased energy

Question 7

Cocaine

Answer 7

Cocaine disrupts the normal process of dopamine reuptake. As a result, dopamine continues to stimulate the postsynaptic receptors each time the neuron fires, intensifying the feeling of pleasure.

Changing the neurotransmitter binding to receptors: Reuptake inhibitors

Effect: intensifying the feeling of pleasure

Question 8

Selective serotonin reuptake inhibitors (SSRIs)

Answer 8

Such as Prozac and Zoloft, are medications designed to inhibit the reuptake of serotonin, a neurotransmitter linked to mood regulation. By allowing more serotonin to stay active in the synapse between neurons, SSRIs can help improve mood. Their effects typically take weeks to manifest.

Changing the neurotransmitter binding to receptors: Reuptake inhibitors

Effect: induces contentment and reduces depression

Question 9

Adderall

Answer 9

Acts as a stimulant
* increases adrenaline production
* increases dopamine production

Blocks the reuptake of

• Adrenaline
• Dopamine
• Serotonin

Inhibits monoamine oxidase
* Monoamine oxidase is the enzyme that sweeps through the synapse, and cleans out the neurotransmitters in the synaptic cleft

Change
* release NT
* breakdown NT in cleft
* NT bind receptor

Effect: increased feelings of happiness, euphoria, and improves focus

Question 10

Crystal meth

Answer 10

significant release of dopamine and serotonin

*The exact mechanism of this release is still being studied

Effect: leading to intense feelings of pleasure.

Question 11

Alcohol

Answer 11

How it works

Alcohol mimics GABA, an inhibitory neurotransmitter that calms brain activity. This can temporarily reduce anxiety.
This binding does not create anything it simply blocks it from firing 
**Effect:** leading to relaxation and sedation. 

Alcohol increases dopamine levels, leading to a feeling of pleasure and motivation.

Alcohol stimulates the release of endorphins
**Effect:** pain-blocking properties.

Alcohol increases serotonin receptor activity
**Effect:** briefly alleviate symptoms of depression.

Alcohol blocks glutamate receptors, an excitatory neurotransmitter essential for functions like speech and reaction time. 
**Effect:** slurred speech and slowed reflexes contribute to its depressant effects

overview:

• the molecule ethanol
• Alcohol affects you by mimicking neurotransmitters
• Alcohol affects multiple neurotransmitter systems in the brain, including gamma-aminobutyric acid (GABA), glutamate, dopamine, and serotonin.

Question 12

How do our bodies process alcohol?

Answer 12

The first step in processing it involves an enzyme called alcohol dehydrogenase, produced by your liver. This enzyme breaks down ethanol by removing a hydrogen atom and adding an oxygen-hydrogen group, resulting in acetaldehyde. 

Acetaldehyde is a toxic byproduct, but another enzyme, aldehyde dehydrogenase, quickly converts it into acetic acid.

Acetic acid is a harmless molecule that your body can easily use for energy or expel through urine and sweat.

Question 13

There are two versions of the DRD4 gene (versions of the receptor):

Shorter Version (High Dopamine Sensitivity)

Answer 13

• Individuals with two copies of the shorter version experience stronger dopamine stimulation. This means their pleasure centers are easily activated by everyday activities.
• They tend to be more novelty-averse and less likely to seek out risky behaviors because they already receive sufficient dopamine. Engaging in risky activities wouldn’t provide a significant increase in pleasure since their baseline dopamine levels are high.

Question 14

There are two versions of the DRD4 gene (versions of the receptor):

Longer Version

Answer 14

• People with this version have reduced dopamine sensitivity. They require more stimulation to activate their pleasure centers compared to those with the shorter version.
• To compensate for lower baseline dopamine, they may be more motivated to engage in activities that trigger dopamine release, leading to increased novelty-seeking behaviors. This could involve trying new things, social risk-taking, or activities perceived as exciting (e.g., skydiving, fast driving).

(Low Dopamine Sensitivity)