Overview of DA Action Flashcards
Where is the largest concentration of DA found?
Corpus striatum, limbic system and hypothalamus
What is DA synthesised from and where?
From tyrosine > dopa > dopamine
In the presynaptic terminal
What is the specific DA transporter ?
VMAT2
What is dopamine metabolised by? And what to?
But MAO-B and COMT
To DOPAC and HVA
How many subtypes of DA receptors are there?
5
How many major classes of DA are there?
2
Which subtypes make up the D1 class?
D1 and D5
Which subtypes make up the D2 class?
D2, D3, D4
Where are the D1 class of receptors found?
Brain and smooth muscle
What does activation of D1 class cause?
Stimulates adenylyl cyclase to produce cAMP
What does activation of D2 class cause?
Coupling with Gi to inhibit adenylyl cyclase activity
Where are D2 class receptors mostly found?
Brain and CV system
Which receptor subtype modulates DA release?
D3
Which receptor subtype is involved in biosynthesis and metabolism?
D2
What are the 3 main DA pathways?
Nigrostriatal
Mesolimbicocortical
Tuberohypophyseal
What is the main role of the nigrostriatal pathway?
Motor control
Where is the nigrostriatal pathway?
Substantia Nigra in the midbrain
What is the main role of the mesolimbicocortical system?
Emotion and reward
Where is the mesolimbicocortical system located?
VTA, synapsing in the cerebral cortex and striatum
What is the main role of the tuberohypophyseal system
Endocrine control
Where is the tuberohypophyseal system located?
Arcuate nucleus and periventricular area in hypothalamus
Synapses in ant pit, infundibulum
How is DA involved in the indirect pathway?
DA acts on D2 receptors in the enkaphalin-containing striatal pallidal neurons resulting in their inhibition
What goes wrong in PD?
Lack of DA so reduced action of the D1 and D2 receptors.
Reduced actions in the direct AND indirect pathways
