3.1.2 Effect of Recreational Drugs on CNS Flashcards
Identify 2 drugs that can affect the transmission process of the central nervous system.
1) Cocaine
2) Nicotine
Describe the effects taking cocaine has on the body.
People experience feelings of euphoria and pleasure
Describe how cocaine affects neurotransmitters.
- It blocks the dopamine transporters which would normally remove excess dopamine through reuptake into the pre-synaptic neuron
- Because of this there is excess dopamine in the synaptic gap which are constantly stimulating the dopamine receptors of the post-synaptic neuron
- This is what causes the euphoric feeling due to the high levels of dopamine
Describe why cocaine is addictive
- Due to the over-stimulation of the dopamine receptors they become desensitised
- This then means that more cocaine would need to be taken next time in order to achieve the same effect and level of happiness
- Once the dopamine levels return to normal it leads to depression and cravings to be stimulated again
Describe the effects taking nicotine has on the body
It makes people feel pleasure and relaxed as well as alert.
Describe how Nicotine affects NTs
- Nicotine enters the blood stream and travels to the brain and mimics the action of acetylcholine by binding to the acetylcholine receptors
- The acetylcholine receptor then stimulates the neuron and causes action potential
- The action potential tells the pre-synaptic neuron to release more dopamine
Describe why nicotine is addictive
- Overtime this can cause a decrease in dopamine receptors and can change the shape of the cell
- This means that there are less dopamine receptors on the post-synaptic neuron so more dopamine is required to stimulate it at a normal level
- This desensitisation leads to addiction as more nicotine is required to achieve a normal level of stimulation
EACH-Evidence
1S/1W
P - Olds and Milner (1954) support
E - Found that mice endured pain in order to receive stimulation of regions of the brain believed to contain the reward pathway
E - This demonstrates the idea of a reward pathway in the brain where desire for pleasure overrides effects of pain, provides evidence for the overstimulation of D2 receptors for the drug user to recieve the feelings of happiness and pleaure dueto desensitising their D2 receptors
P - Jones and Stones (1990) rejects
E - They gave regular cannabis users either marijuana or a placebo and found that there was no difference in effect
E - Therefore demonstrating that it is not the actual drug that affects neurotransmission so it must be factors other than biological
EACH-Application
P - Yes
E - Drug replacement therapy can be implemented by replacing harmful drugs such as heroin with less harmful substances that mimic the same effects such as methadone
E - This allows the user to reduce dosage and come off their addiction safely allowing the receptors to return to normal
EACH-Credibility
1S/1W
P - Highint validity
E - Observations and self-report data of drug-users often matches what the neurobiology of recreational drugs would predict such as the initial feeling of pleasure and then later desensitisation
E - This suggests that users become addicted for this reason, findings are valid due to consistency across observations and brain scanning techniques
P - Studying the process is complex
E - Although brain scanning as helped us to understand the process, they only study brain activity not the actual synaptic gap
E - This demonstrates the difficulty in study such complex areas, theory may be too simplistic and reductionist
EACH-How?
1S/1W
P - High internal validity
E - Research is conducted in highly controlled lab conditions
E - Therefore can establish a cause and effect relationship
P - Low generalisability
E - Research uses animals as ppts, such as rats whose CNS and brain have qualitative differences due to evolutionary discontinuity
E - Therefore cannot represent the complexity of drugs affecting human neurotransmision and behaviour
