Recreational Drugs And Synaptic Transmission Flashcards
What is synaptic transmission?
How the electrical impulse travels across a synapse and influences a response
What is dopamine responsible for?
Pleasure and reward
Describe how cocaine affects synaptic transmission
Cocaine increases the amount of dopamine in the reward areas of the brain including the nucleus accumbens and VTA.
The cocaine blocks the presynaptic re uptake channels so dopamine remains in the synapse for longer stimulating the CNS
As a result, individuals experience feelings of ‘euphoria’
The body then tries to balance out the dopamine levels by reducing its production
When dopamine levels are low, individuals experience withdrawal and negative emotions like ‘dysphoria’
Negative emotions and withdrawal motivates the individual to engage in drugs again leading to abuse or relapse.
What neurotransmitter does cocaine increase?
Dopamine
Where are the reward areas of the brain?
Nucleus accumbens and VTA
What do individuals experience when dopamine levels are high?
Euphoria
What do individuals experience when dopamine levels are low?
Dysphoria
Describe how recreational drugs generally affect synaptic transmission. (3 marks)
Most drugs impact the balance of dopamine levels through the reward pathways in the brain known as the Nucleus accumbens and VTA
Dopamine increases in the synapse leading to the user feeling euphoria
The brain then tries to counteract the increases dopamine levels by reducing its production
Therefore, the low dopamine levels means individuals feel withdrawal symptoms
Describe how Heroine affects synaptic transmission
Heroine breaks down into morphine in the synapse
Morphine attaches to opioid receptors on the post synaptic neurone (striatum)
Resulting in an analgesic effect on the body (pain killing)
Repeated use of the opioid receptors, means they become damaged and insensitive so will require more morphine for the same effect
More use is needed (tolerance) and the body cannot produce its own analgesic effect through the use of endorphins
How does Cocaine affect the synapses?
Blocks the re uptake of pre synaptic channels, therefore dopamine is in the synapse for longer stimulating the Central Nervous System instigating feelings of euphoria
How does Heroine affect the synapse?
Binds to the natural opioid post synaptic receptors,
Morphine is in the synapse by breakdown which has a depressing effect on the Central Nervous System
Discuss the effects of recreational drugs on transmission in the Central Nervous System (8 marks)
Discuss- no strengths/weaknesses
Recreational drugs tend to influence the balance of dopamine by increasing neurotransmitters levels in the reward pathways of the brain known as the Nucleus accumbens and VTA. As a result, dopamine increases in the synapses leading to feelings of euphoria and pleasure within the individual. The brain then tries to counteract this increase by reducing the production of dopamine, leaving the individual wanting more and instigating withdrawal symptoms.
Cocaine is a recreational drug that increases dopamine in the rewards areas of the brain, so the individual is subjected to feelings of euphoria. This is because cocaine blocks the re uptake channels of the pre synaptic neurone so dopamine is left in the synapse for longer, binding to the receptors more frequently. This continuously stimulates the Central Nervous System until the dopamine levels are reduced.
Additionally, heroine is a recreational drug that breaks down into morphine in the synapse. Consequently, there is more morphine binding to the natural opioid receptors in the striatum of the post synaptic neurone. This has a depressing impact on the Central Nervous System due to the analgesic (painkilling) effect on the body.
Repeated simulation of these receptors via the use of recreational drugs can lead to damage to the receptors site, the receptors then become less sensitive to the neurotransmitter. Consequently, more neurotransmitter activity is required to produce the same analgesic effect- known as tolerance.
Evaluate the effect of recreational drugs on synaptic transmission (8 marks)
Feasibility- Strength
Weinshenker and Schroeder
Conducted research on the Mesolimbic pathway in mice and found that preventing dopamine transmission in the reward pathway prevented further use of cocaine
They created lesions to the to the Mesolimbic pathway of mice, following this the mice did not seek further cocaine.
This only occurred when the lesions were in the Mesolimbic pathway and not other areas.
Volkow
Brain imaging scans of a cocaine user against a control group (non user)
The cocaine abuser has less activity compared to the control group because of the excess dopamine levels reducing the sensitivity to receptors.
There is a positive correlation between the cocaine consumed and metabolites released (which break down dopamine)
Feasibility- weakness
Animal research
Because it is unethical to encourage drug use in humans for testing purposes, rodents were used as they have a similar brain anatomy such as the Hippocampus/ Cerebral Cortex.
However, there is an issue with this due to size differences which can impact function.
Additionally, the human brain also has more connections, consequently drug use may impact human differently so cannot extrapolate findings.
Application- strength
Medications have been created based on existing research to help individuals quit (abstain) from an addiction, this is done by creating medications that have an opposite mode of action, this means that the individual will feel no analgesic effect.
For example, Naroxine is used to treat heroine addiction because it works in the opposite way by blocking opioid receptors.
What is the Mesolimbic pathway?
VTA and Nucleus Accumbens
