Overview of DA Action

Question 1

Where is the largest concentration of DA found?

Answer 1

Corpus striatum, limbic system and hypothalamus

Question 2

What is DA synthesised from and where?

Answer 2

From tyrosine > dopa > dopamine

In the presynaptic terminal

Question 3

What is the specific DA transporter ?

Answer 3

VMAT2

Question 4

What is dopamine metabolised by? And what to?

Answer 4

But MAO-B and COMT

To DOPAC and HVA

Question 5

How many subtypes of DA receptors are there?

Answer 5

5

Question 6

How many major classes of DA are there?

Answer 6

2

Question 7

Which subtypes make up the D1 class?

Answer 7

D1 and D5

Question 8

Which subtypes make up the D2 class?

Answer 8

D2, D3, D4

Question 9

Where are the D1 class of receptors found?

Answer 9

Brain and smooth muscle

Question 10

What does activation of D1 class cause?

Answer 10

Stimulates adenylyl cyclase to produce cAMP

Question 11

What does activation of D2 class cause?

Answer 11

Coupling with Gi to inhibit adenylyl cyclase activity

Question 12

Where are D2 class receptors mostly found?

Answer 12

Brain and CV system

Question 13

Which receptor subtype modulates DA release?

Answer 13

D3

Question 14

Which receptor subtype is involved in biosynthesis and metabolism?

Answer 14

D2

Question 15

What are the 3 main DA pathways?

Answer 15

Nigrostriatal
Mesolimbicocortical
Tuberohypophyseal

Question 16

What is the main role of the nigrostriatal pathway?

Answer 16

Motor control

Question 17

Where is the nigrostriatal pathway?

Answer 17

Substantia Nigra in the midbrain

Question 18

What is the main role of the mesolimbicocortical system?

Answer 18

Emotion and reward

Question 19

Where is the mesolimbicocortical system located?

Answer 19

VTA, synapsing in the cerebral cortex and striatum

Question 20

What is the main role of the tuberohypophyseal system

Answer 20

Endocrine control

Question 21

Where is the tuberohypophyseal system located?

Answer 21

Arcuate nucleus and periventricular area in hypothalamus

Synapses in ant pit, infundibulum

Question 22

How is DA involved in the indirect pathway?

Answer 22

DA acts on D2 receptors in the enkaphalin-containing striatal pallidal neurons resulting in their inhibition

Question 23

What goes wrong in PD?

Answer 23

Lack of DA so reduced action of the D1 and D2 receptors.

Reduced actions in the direct AND indirect pathways