Dopamine pathways

Question 1

What are dopaminergic pathways?

Answer 1

Dopaminergic pathways are neural pathways in the brain that transmit the neurotransmitter dopamine from one are of the brain to another.

Question 2

How many dopamine pathways are there?

Answer 2

5 main pathways

Question 3

What are the pathways and what are they involved in?

Answer 3

1. Nigrostriatal - motor function
2. Mesolimbic - reward
3. Mesocortical - cognitive control of behaviour
4. Median eminence to anterior pituitary - inhibition of prolactin
5. Chemoreceptor trigger zone (CTZ) - nausea and vomiting

Question 4

Are these pathways direct or indirect?

Answer 4

Can be either.

Direct pathways are excited by dopamine causing movement and reducing inhibitory effect of indirect

Indirect - inhibition of talamus by dopamine, less excitation, inhibits movement.

Question 5

What is the dopamine synthesis pathway?

Answer 5

Tyrosine –> L-DOPA –> Dopamine –> DOPAC/HVA

Question 6

What are the dopamine receptors?

Answer 6

Dopamine receptors are GPCRs. 2 classes:
- D1 (D1/D5) - coupled to adenylyl cyclase (activate Gs, stimulate AC, increase cAMP)
D2 (D2, D3, D4) - coupled to IP3 (activate Gi/o, inhibit AC, decrease cAMP)