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Parkinson's disease
· A disease caused by the death of dopamine secreting neurones in the basal
ganglia (substansia nigra).
· Dopamine secreting neurones are neurones that secrete neurotransmitters
· Symptoms usually develop after 80% of the nerves die:
· Stiffness in the muscles
· Tremors of the muscles
· Slowness of movement
· Poor balance
· Walking problems
· Sometimes: depression, speech and breathing difficulty may arise.
Dopamine is mostly present in the frontal lobe which is to do with coordination and control, This is
why when the nerves secreting dopamine die the above symptoms develop.…read more

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Neurones that secrete
Motor cortex: where the dopamine is usually released. serotonin are situated
Axons of the dopamine- secreting
nerves spread over:
Brain stem
This is where the dopamine-
secreting neurones die which
causes Parkinson's disease.…read more

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· Dopamine agonists: Drugs that activate the dopamine receptor directly by
binding to receptors at the synapses and triggering action potentials. (usually
used in the early stages of the disease)
· L-dopa (levodopa) is used as an alternative to dopamine as it penetrates the
blood-brain barrier while dopamine cannot. It helps reduce symptoms by
relieving stiffness and slowness of movement as the remaining dopamine-
secreting nerves make as much dopamine as possible when L-dopa is present. L-
dopa is a precursor, once in the brain it is converted into dopamine.
· MAOB inhibitors (monoaminooxidase B inhibitor) inhibit the enzyme that breaks
down the dopamine in the brain synapses.
· Gene therapy: by adding genes to either stop the nerves from dying or enhance
the levels of dopamine.
· Stem cell therapy: using embryonic stem cells to replace failing dopamine-
producing cells in the brain.
· Surgical procedures.…read more

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· Depression is multifactorial and is thought to be genetic triggered by hardship
or stress. If two people have the same set of alleles for depression,
environmental factors are the determining factor.
· Serotonin is a neurotransmitter that plays a vital role in determining your mood.
As well as serotonin dopamine and noradrenaline are thought to be linked with
· Low levels of neurotransmitters in the brain result in less action potentials
triggered in nerve impulses around the brain, this usually occurs when the
person is suffering from depression.
· Symptoms:
· continuous low mood or sadness
· feeling hopeless and helpless
· feeling irritable and intolerant of others
· having no motivation or interest in things
· feeling anxious or worried
· having suicidal thoughts or thoughts of harming yourself…read more

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· MAO inhibitors which inhibits the enzymes that break down the
neurotransmitters in the synaptic clefts.
· SSRI (selective serotonin reuptake inhibitors), these are drugs that inhibit
the reuptake of protein, thus more serotonin remains in the in the synaptic
cleft and more action potentials are triggered.(relieving some of the
· TCAs (tricyclic antidepressants) this works to increase the levels of
serotonin and notradrenalin.…read more

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