Dopaminergic Neurotransmission

Question 1

Mesolimbic Pathway

Answer 1

DA neurons go from the Tegmentum to the Nucleus accumbens
Important in reward
Antipsychotics act here

Question 2

Mesocortical pathway

Answer 2

DA neurons from tegmentum to prefrontal cortex
Important in cognition, motivation
Antipsychotics act here

Question 3

Nigrostriatal pathway

Answer 3

DA neurons from substantia nigra synapse in striatum
Important in coordination of movement
Drugs for Parkinson’s affect this pathway

Question 4

Tuberinfundibular pathway

Answer 4

DA pathway from hypothalamus to pituitary

Inhibits the release of prolactin leading to increased serum prolactin

Question 5

Dopamine Synthesis

Answer 5

L-Tyrosine –(tyrosine hydroxylase) –> L-DOPA –(DOPA decarboxylase)–> Dopamine

Question 6

D1 Receptor Family

Answer 6

Contains D1 and D5
Increases cAMP via Gs and Gq
Excitation occurs

Question 7

D2 Receptor Family

Answer 7

Contains D2/3/4
Decreases cAMP via Gi
Hyperpolarization and inhibition occurs

Question 8

Amantadine

Answer 8

Often combined with L-DOPA/Carbidopa therapy
Also an antiviral drug
Synergistic with L-DOPA
3 proposed mechanisms of action:
1. Inhibits DA re-uptake
2. Facilitate pre-synaptic DA release
3. Antagonize NMDA receptors