imbalances of neurotransmitters in brain causing disease Flashcards
recap: whatre neurotransmitters?
chemicals that transmit nerve impulses across synapses
what is parkinsons and what is it caused by?
it is: a disorder that affects the co-ordination of movement
caused by: a loss of neurones in some parts of the brain
symptoms of parkinsons
-difficulties with balance
-changes to speech
-tremors to specific parts of the body and involuntary movement
-slow movement
-stiff and inflexible muscles
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what can serotonin affect
mood, anxiety and sleep
what can dopamine affect
movement/muscle control, pleasure
link between depression and serotonin
-serotonin transmits nerve impulses to areas of the brain that control mood
-lower levels linked to depression
how can SSRIs be used to treat depression?
selective serotonin reuptake inhibitors
-prevent reuptake of of serotonin on presynaptic neurone membrane
-more serotonin to activate receptors on postsynaptic neurone membrane
-impulse can be spread by serotonin
how can MAOB inhibitors be used to treat depression?
monoamine oxidase B
-inhibit enzymes from breaking serotonin down
-more serotonin can be reuptaken by presynaptic neurone to be used for future action potentials
how do the lost neurones in parkinsons sufferers lead to a loss of muscle control?
these neurones usually produce dopamine
dopamine is involved in muscle control
why are tremors a symptom of parkinsons?
fewer action potentials generated leads to slowmovement and tremors
-due to loss of neurones theres lower levels of dopamine produced in brain
-dopamine transmits impulses, impulse transmitted to postsynaptic neurones will be lower
-fewer calc ion channels will be opened
-impulse in neurone wont be high enough to reach threshold value as fewer calcium ions in axon
-threshold potential not reached then sodium ion channels wont be opened-depolarisation of neurone wont happen
-fewer action potentials generated
How can TCAs be used to treat depression?
tricylic antidepressants
increase levels of serotonin and noradrenaline in the brain
how can agonists be used as treatment for parkinsons
bind to receptors where dopamine usually would, same action produced-activate dopamine receptors
how could gene therapy and stem cells POTENTIALLY be used as treatment for parkinsons
stem cell therapy=could be used to replace lost dopamine-producing cells in the brain
gene therapy=additon of genes to affected cells to increase dopamine production or prevent destruction of dopamine-producing cells
state the neurotransmitter problem thats responsible for the symptoms of parkinsons
loss of neurons that produce dopamine, dopamine is involved in muscle control.
Explain how L-dopa works to treat the symptoms of Parkinson’s
L-dopa is converted to dopamine in the brain by dopa-decarboxylase
this increases levels of dopamine in the brain
dopamine can transmit impulses to effector organs, increasing control of movement
State the neurotransmitter problem that is responsible for the symptoms of depression
low levels of serotonin
serotonin transmits nerve impulses to areas of the brain that control mood
Explain how SSRIs are work to treat the symptoms of depression
prevent reuptake of serotonin on presynaptic neurone membrane
larger amount of serotonin can then bind to and activate receptors on postsynaptic neurone impulse for mood control can be spread, more receptors activated more sodium ion channels opened, threshold potential more likely to be reached, depolarising neurone and more action potentials produced, impulse spread further and can reach effectors that control mood
Explain the action of MDMA at the synapses
-increases amount of serotonin released from presynaptic neurone- more serotonin in brain
-inhibits reuptake of serotonin into presynaptic neurone
Explain why users of MDMA may experience symptoms of depression
reuptake into presynaptic neurone inhibited so less available for future action potentials
potentially not enough serotonin available to transmit impulse to control mood.
