Cocaine/Amphetamine - dopamine system Flashcards
cocaine and amphetamine are both types of
psychostimulants
is reward the same as pleasure
no
effect of cocaine on dopamine
increases dopamine concentration
spatially –> increases distribution of dopamine
antagonises dopamine transporters
temporal –> causes dopamine to remain in synaptic cleft
3 types of monamine transporters
NET - Norepinephrine transporter
DAT - dopamine transporter
SERT - serotonin reuptake transporter
what normally takes up released dopamine
sodium coupled transporters
e.g. DAT
competitive agonist for dopamine receptors
amphetamine
precursor of dopamine
L-DOPA
problems caused by injecting cocaine
necrosis around injection site
vasoconstriction
cocathylene
toxic substance produced by liver when cocaine is interacts with alcohol
amphetamine compared to cocaine
much longer effects (1-2 hours) cheaper no harmful interactions with alcohol stereotyped repetitive movements doesnt last in your body as long
tyrosine to adrenaline pathway
tyrosine –> DOPA –> Dopamine –> Noradrenaline –> Adrenaline
dopamine receptors that activate adenyl cyclase (Gas)
D1 and D5
dopamine receptors that inhibit adenyl cyclase (Gai)
D2
D3
D4
5 dopaminergic pathways
nigrostriatal mesolimbic mesocortical tuberoinfundibular unknown
main reward pathway
mesolimbic
VTA
ventral tegmental area
in the midbrain
mesolimbic pathway connects
VTA to the nucleus accumbens
midbrain to forebrain
what type of neurotransmitter is dopamine
monoamine
2 areas of brain where dopamine is concentration
MIDBRAIN:
substantia nigra
ventral tegmental area
what does the nigrostriatal pathway connect
substantia nigra to the striatum
mesocortical pathway connects
VTA to cerebral cortex
dopamine transporter function
removes dopamine from synaptic cleft
simple reason why cocaine increases dopamine concentration
blocks dopamine re-uptake transporters
dopamine remains in synaptic cleft
causes constant impulses of dopamine (hyperactivity)
effect of cocaine on post synaptic receptors
constantly stimulated with increase of dopamine in synaptic cleft
numbers of receptors decrease to prevent over-stimulation
when cocaine is removed, less pleasure can be felt
reduction in D2 receptors leads to addiction
simple pharmacology of cocaine
increases spatial distribution and temporal concentration of dopamine by antagonising dopamine transporters
mechanism of dopamine transporters
co-transporters
Na+/Cl- travel down conc gradient
provide gradient for active transport of dopamine
why does amphetamine have less of an effect on general mood than cocaine
it doesnt affect serotonin
average time period cocaine lasts
30 minutes
short lasting
why can cocaine cause you to drop dead at 50
if you take cocaine with alcohol when you’re younger
produces cocathylene
neurotoxicity to the heart
lesions to the heart can manifest later in life
main nigrostriatal function
motor function
dysregulation leads to parkinsons
mesolimbic pathway associated with what behaviour
reward learning
e.g. reward prediction
mesocortical pathway associated with what behaviour
reward anticipation and reward consumption (how big is the reward?)
effects of tuberinfundibular pathway
release and secretion of prolactin hormone from anterior pituitary
short-term behavioural effects of dopamine stimulation
motivation
sustained behaviour that led to the cue
long term behavioural effect of dopamine stimulation
prediction of cue
