Parkinson's Disease and Schizophrenia Flashcards
Name the 3 monoamine neurotransmitters.
Dopamine
Noradrenalin
5-HT/Serotonin
What are the two catecholamines?
Dopamine and noradrenalin
What is the indolamine?
5-HT/Serotonin
Is dopamine ionotropic or metabotropic?
Metabotropic
Where are dopamine cell bodies located?
Substantia nigra.
Which part of the brain is the substantia nigra in?
Midbrain/mesencephalon
What colour are the dopamine cell bodies?
Black
Where do the dopamine cell bodies project dopamine to?
The striatum
What is the largest component of the basal ganglia?
The striatum
What is the basal ganglia?
Collections of subcortical nuclei deep in the cerebral hemisphere.
What are the two parts of the striatum?
Dorsal and ventral
What does the dorsal striatum contain?
The caudate nucleus and putamen
What does the ventral striatum contain?
Nucleus accumbens
What is the caudate nucleus responsible for?
Learning and inhibition
What is the putamen responsible for?
Motor skills and motor learning
What are the nucleus accumbens responsible for?
Reward, motivation, addiction and fear.
Which part of the brain is the basal ganglia in?
The forebrain/telencephalon
What does the nigrostriatal pathway do?
Connects dopamine neurons in the substantia nigra (midbrain) to the caudate nucleus and putamen -> dorsal striatum -> basal ganglia.
Also contains axons which allow dopamine neurons to travel from the ventral tegmental area to the nucleus accumbens -ventral striatum.
What is the MFB and what does it do?
Medial forebrain bundle. Takes dopamine neurons from the substantia nigra to the striatum
What does cardinal mean?
Most significant/important.
What are the three cardinal symptoms of Parkinson’s Disease?
- Rigidity
- Bradykinesia (slowness of movement)
- Tremors
Why does Parkinson’s disease occur?
Dopamine neurons in the substantia nigra degenerate.
What is it that causes the cardinal symptoms of Parkinson’s disease?
The loss of dopamine in the striatum.
What percentage of dopamine neurons have to be lost before symptoms of Parkinson’s start to appear?
80%
What is the main treatment of Parkinson’s disease?
Dopamine replacement therapy.
Describe the sequence of dopamine synthesis.
- Tyrosine converted to levodopa with tyrosine hydroxylase.
- Levodopa converted to dopamine with DOPA decarboxylase.
What is noradrenalin made from?
Dopamine
Which enzyme converts dopamine to noradrenalin?
Dopamine beta-hydroxylase.
What is the rate limiting step in dopamine synthesis?
The conversion of tyrosine to levodopa.
What does the mesocortical pathway do?
Projects dopamine from the ventral tegmental area to the cerebral cortex and limbic structures (nucleus accumbens) - linked to reward and motivation.
What is the VTA?
Ventral tegmental area - alternative site, near to the substantia nigra, where dopamine neurons collect.
What are the positive symptoms of schizophrenia?
+ Psychosis; hallucinations, delusions (of grandeur, control and persecution)
+ Thought disorder
What are the positive symptoms of schizophrenia associated with?
The excess dopamine (transmission)
What are the negative symptoms of schizophrenia?
- Lack of emotion
- Inability to experience pleasure.
- Social withdrawal
- Poverty of speech
What are the negative symptoms of schizophrenia associated with?
Prefrontal cortex damage.
What is the dopamine hypothesis of schizophrenia?
- Schizophrenia occurs as a result of the action of agonists and antagonists of dopamine.
- Positive symptoms result from excess dopamine transmission.
What is the drug that is used against the positive symptoms of schizophrenia?
Chlorpromazine - blocks dopamine D-@ receptors.
What is the effect that chlorpromazine has on neuroses and mood disorders?
Very little.
What are antipsychotic medicines also referred to?
Neuroleptics.
What can cause psychoses in people that do not even have schizophrenia?
Drugs which increase the transmission of dopamine. e.g Amphetamine.
What are the short term consequences of drug treatment in schizophrenia?
- Parkinson’s like symptoms
What are the long term consequences of drug treatment in schizophrenia?
Abnormal, involuntary movements, especially of the tongue and face.
= tardive dyskinesia.
What are the negative consequences of treating Parkinson’s disease?
- Dyskinesia
- Psychoses (visual & usually not scary)
