Dopaminergic neurotransmission Flashcards
Where in the CNS do dopaminergic neurons project?
frontal cortex
nucleus accumbens
ventral tegmental area
hippocampus
substantia nigra
striatum
What do dopaminergic neurons regulate?
reward system and movement
brain structures regulating behavior by inducing pleasurable effects
Where are dopaminergic neurons synthesized?
substantia negra
General scheme of dopaminergic nerve terminal
Scheme of Dopamine receptors
What metabolite appears in the urine in dopamine metabolism?
homovanillic acid
What does the amount of homovanillic acid appears tell you?
indicates the functional state of dopaminergic neurons
↓ Parkinsons disease
↑ schizophrenia
What is Parkinsons disease?
A deficiency in the neurotransmitter dopamine
What drugs can be used to treat Parkinson’s?
L-DOPA
Deprenyl
Dopamine receptor agonists
Why is L-DOPA used in conjuction with carbidopa?
L-DOPA can be converted to dopamine by dopa decarboxylase in the periphery and brain
We use a combination with Carbidopa which is an inhibitor of DOPA decarboxylase in the PERIPHERY but not in the BRAIN therefore we can saver the conversion in the brain but not in the periphery
Hence more L-DOPA enters the brain and can be converted to Dopamine
What is Schizophrenia a result of?
↑ dopaminergic activity in the brain and/or
↓ glutamatergic activity
- there is increased dopamine levels in the brain
- therefore there is also an increased number of D2 receptors
Increased levels of what metabolite can be found in the urine of a patient suffering from Schizophrenia?
homovanillic acid
Synthesis of dopamine (draw)
What are the enzymes responsible for the metabolism of dopamine?
MAO
Aldehyde dehydrogenase
COMT
(yields 3,4 dihydroxy phenylacetaldehyde DOPAC)
What is an inhibitor of MAO?
selegilin
deprenyl
