drugs Flashcards
cocaines effect
- stimulant effect on brains CNS, especially on the neurons of the brains main reward system
how does cocaine have the effect on cns
- it alters synaptic transmission involving different neurotransmitters
which neurotransmitters does cocaine effect
noradrenaline
serotonin
acetylcholine
dopamine
which neurotransmitter does cocaine effect the most
dopamine
cocaine increased release of dopamine
what does dopamine do
- a sense of pleasure
where is dopamine released
reward centers of brain
what does cocaine block the trip take of
dopamine
how does cocaine block the trip take of dopamine
- by binding with dopamine transporter molecules on the terminal buttons in the presynaptic neurons which are responsible for recycling dopamine back into the neuron that produced it
because cocaine blocks reuptake of dopamine what happens
- the synapse is flooded with surpless quantities of dopamine all available for binding with postsynaptic receptors
- this is why cocaine gives us a euphoric high
long term effects of cocaine
- after repeated use dopamine receptors become downregulated
- this explains withdrawal and craving for the drug and higher doses needed to get the same effects
downregulated
- fewer receipts are active, some are damaged and shut down so the quantity of dopamine produced declines
heroin effects
- depressant effects on cns slowing down its activity
- including activity of neuroses involved in pain = why it’s an analgesic
how is heroin taken
usually injected intravenously
once heroin reaches the brain how is it processed
most of it has processed into morphine
what does the morphine from the heroin bind do when it reaches the brain
- a specific opioid receptor at the synapse found in the cerebral cortex, limbic system and hypothalamus
why do these specific opioid receptors exist in the brain for heroin and morphine
the cns has its own opioid system
when heroin binds to the receptors of the natural opioid system what happens
endorphins and enkephalins are produced by the body as natural painkillers
what type of drug is heroin
agonist
why is heroin an agonist drug
it mimics the action of another natural biochemical
long term effects of heroin
- downregulation on neural transmission
- opioid receptors on postsynaptic neurones are constantly binding with morphine molecules which desensitisises them to effects of the drug
ecstasy
-cns stimulant that blocks reuptake of serotonin at the synapse
- causes neurons to increase their output of serotonin initially
what does the activity of ecstasy or mdma do ?
create a double whammy of serotonin enhancement
- greater quantities are made available in the synapse for binding to post synaptic receptors
evaluation - supporting points
- research supporting role of dopamine
- application to better treatments to addiction
- controlled experiments
- support from observational studies
- scientific evidence
drug evaluation points - drawbacks
- validity using non human animal studies
- limitations in studying synaptic transmission
- ethical and practical limitations
- oversimplifies brain complexity
scientific evidence - evaluation
- research is taken from multiple studies and support the same conclusions
- reinforced theory as it has multiple scientific backings
- more credible
oversimplifies brain complexity - evaluation
- brain has multiple neurotransmitters interacting
- reducing effects to only dopamine ignores these
- oversimplifies how drugs affect CNS
research supporting role of dopamine - evaluation
- supports view that cocaines effects are due to activity of dopamine in brains reward system
research supporting role of dopamine - procedure
- mesocortiolimbic pathway of mice brains were deliberately damaged
- so neuron can’t produce levels of dopamine usually associated with reward
- when this is done mice can’t intravenously self administer cocaine
- this doesn’t occur when the lesions are performed in other areas of the mice brain
validity using non human animal studies - evaluation
- mainly non human animal studies used to understand drug effects in human CNS transmission
- human brain is more complex than animal brains
how are human brains more complicated than animal brains and oversimplified
- isolating effects of 1 neurotransmitter oversimplifies process - it’s unlikely complexity of recreational drugs effect on transmission is due to one mode of action
- interactions of dopamine with other neurotransmitter systems aren’t well understood
- using non human animals should be taken cautiously
how can effects of drugs be taken from humans also
pet scans - which show similar results to the animal results
evaluation - application to better treatments for addiction
- as our knowledge on effect of CNS grows more treatments for addiction become available
how are treatments for heroin created
- once identified as an agonist which binds to opiate receptors
- other drugs were developed with a reverse mode of action
what treats addiction of heroin
naloxone
naloxone
- doesn’t produce a rewarding euphoria associated with heroin use so can help manage withdrawal process and reduce symptoms
