effect of recreational drugs Flashcards
what are recreational drugs?
drugs are biochemicals that have specific effects on the functioning of the body’s systems.
- they may be used for physiological or psychological purposes.
what are drugs used for psychological treatments called?
psychoactive
- they affect transmission in the central nervous system altering an individuals mental process.
what effect does cocaine have on the CNS?
cocaine has a stimulant effect on the CNS especially on the neurons of the brains main reward system
- the drug achieves its effects by altering synaptic transmission involving several neurotransmitters, such as noradrenaline.
what is the role of dopamine in cocaine?
all recreational drugs increase dopamine release in the reward centres of the brain and this creates a sense of pleasure when activated.
- cocaine blocks the reuptake of dopamine by binding with dopamine transporter molecules on the terminal button of the presynaptic neuron which are responsible for recycling dopamine back into the neuron that produced it
what are the long-term effects of repeated cocaine use?
dopamine receptors become downregulated. fewer receptors are active - some damaged and shut down and the quantity of dopamine produced declines. this explains withdrawal
what are the effects of heroin on the CNS?
heroin has depressant effects on the CNS - it slows down the activity of neurons involved in pain
heroin is usually injected and once it reaches the brain, most of it is processed into a closely related opioid called morphine.
the receptors exist for heroin/morphine is that the CNS has its own opioid system
- endorphines are produced as natural painkillers that heroin taps into.
what type of drug is heroin?
it is an agonist drug because it mimics the action of another natural biochemical.
naloxone is an antagonist that blocks opiate receptors
what are the long-term effects of heroin use?
the long-term effects of repeated heroin use on neural transmission includes downregulation
- regular use of heroin over time means that opioid receptors on postsynaptic neurons are constantly binding with morphine molecules which desensitises them to the effects of the drug
what is a strength of the explanation?
a strength is the explanation are supported with research using non-human animals
-one commonly used procedure involves deliberately damaging the mesocorticolimbic pathway in mice brains
this means neurons are unable to produce levels of dopamine normally associated with reward
when this is done, the mice then fail to self-administer cocaine intravenously and this does not occur when the damage is performed in other parts of the mouse brain
what is a weakness of non-human animals studies?
problems with using mainly non-human animals studies to understand drug effects on human CNS transmission
- the basic transmission processes in mammals are similar but some differences arise because the human brain is more complex than that of a rat.
isolating the effects of one neurotransmitter greatly oversimplifies the process
what is the competing argument?
evidence of drug effects on CNS transmission comes from studies of humans as well
- Nora volkow (1997) used PET scans to track the activity of dopamine transporters during a cocaine-induced HIGH
they found that the extent to which cocaine occupied dopamine transporters correlated positively with the course of the subjective experience.
subjective experience intensified as more dopamine transporters were occupied by cocaine and declined as they became less active
how can you apply the effect of recreational drugs?
our knowledge of drug effects on CNS transmission grows, more treatments for addiction become available.
- once heroin was identified as an agonist that binds to opiate receptors, other drugs were developed with a reverse mode of action
