The effect of recreational drugs Flashcards
Name four types of recreational drugs?
Stimulants
Sedatives
Hallucinogens
Opioids
What type of drug is Cocaine?
Stimulant
What effect does Cocaine have on the CNS?
Alters synaptic transmission involving several neurotransmitters.
Greatest impact is on the activity of dopamine.
Increases the release of dopamine in the reward centre of the brain.
Cocaine blocks the reuptake of dopamine by binding with dopamine receptors.
The synapse is flooded with dopamine, all available for binding with the receptors which causes the ‘high’.
What are the long term effects of repeated Cocaine use?
Dopamine receptors become downregulated (fewer are active).
This explains withdrawal, craving for the drug and the higher doses needed to get the same effects.
What type of drug is Heroin?
Opioid
What kind of effect does Heroin have on the CNS?
It has a depressant effect, it slows down activity (including activity of neurons involved in pain).
How is Heroin usually taken?
Injected
Is Heroin an agonist or antagonist drug?
Agonist because it mimics the action of another natural biochemical.
What is the body’s natural opioid system?
Endorphins and Enkephalins are produced by the body as natural painkillers.
Which drug is used to manage withdrawal symptoms?
Naloxone - it is an antagonist that blocks opiate receptors.
What are the long term effects of Heroin on the CNS?
The basis of tolerance - Opioid receptors on postsynaptic neurons constantly bind with morphine molecules, desensitising them to the effects of the drug.
What is a strength of the effects of recreational drugs?
The support for dopamine from research using non-human animals.
Deliberately damaging the mesocorticolimbic pathway in the brains of mice.
Neurons cannot produce levels of dopamine normally associated with reward so the mice then fail to self-administer Cocaine.
This finding supports the view that Cocaine’s effect are due to the activity of dopamine in the brain’s reward system.
What is a weakness of the effects of recreational drugs?
The validity of non-human animal studies.
Transmission processes in mammals are similar but there are differences because the human brain is more complex than mouse brain.
This means that extrapolation from non-human animals to humans is risky and should be done with caution.
Who provided supporting evidence of drug effects on humans?
Volkow et al (1997)
Used PET scans to track the activity of dopamine transporters during a cocaine-induced high.
The extent to which cocaine occupied dopamine transporters correlated positively with the course of the subjective experience.
This supports the view that evidence from animal models is valid, as human studies produce similar results.
What is the application value of studying the effects of recreational drugs?
Knowledge leads to more and better addiction treatments.
For example, once heroin was identified as an agonist that binds to opiate receptors, other drugs were developed with a reverse mode of action, such as Naloxone which helps with the withdrawal process of Heroin.
