Effect of recreational drugs on the brain

What are recreational drugs

Stimulants, sedatives, hallucogens and opioids used for pleasure to alter neurotransmitter levels at the synapse

How does cocaine work

It blocks reuptake of dopamine by binding to dopamine transporter molecules on the terminal buttons of the presynaptic neuron, so the synapse has a surplus of dopamine available to bind to postsynaptic receptors

What is the effect of cocaine

It acts as a stimulant and creates a euphoric high

What is the long term effect of cocaine use

dopamine receptors become downregulated (damaged, shut down, less are active) and less dopamine is produced so more cocaine is needed to have the same effect- causing withdrawal

How does Heroin work

It is turned into morphine, which binds to and activates the mu-opioid receptor at the synapse, which is found in the cerebral cortex, limbic system

What is the effect of heroin

It is a depressant that acts as a painkiller by replacing endorphins and generally slows activity

What is the long term effect of heroin

Downregulation of opioid receptors

What is an agonist

A drug that activates a receptor to create a response

What is an antagonist

A drug that blocks the activity created by the agonist

How does Olds and Milner support the explanation of the way drugs work

rats who had wires connected to the reward pathways in their brains would give themselves pleasurable electric shocks and ignore other sources of pleasure such as food- just like drug addicts

How might the research for the workings of drugs not be generalisable

Much research has been done on rodents, which may not experience pleasure the same way as humans

How does this explanation have face validity

Observing drug addicts shows that excessive use leads to down regulation and dependence

How is this explanation useful

BY finding out about the synaptic use of drugs, drug treatment to counter or mimic this in safer ways could be developed e.g. methadone substitute prescribing

What does naloxone do

It’s an agonist that counters the effects of heroin so no euphoria is associated with it