1. Which two main groups of drugs are important in the treatment of Parkinsonism?

Drugs that increase dopamine activity such as Levodopa, DA agonist (such as bromocriptine, pramipexole, ropinirole and rotigone) and MAO inhibitors (rasagiline and seligiline). And also, drugs that decrease cholinergic activty such as biperidine, orphenadrine, trihexyphenidyl and benztropine. 

2. In what way does amantadine act as a antiparkinsonism drug?

It is a mettaffinoid potentiator of dopamine, so basically what it does is increase dopamine activity by increasing dopamine release and synthesis, and inhibits DA reuptake. And its NDMA antagonist properties is effective  with the symptoms that appear in parkinsonism

3. Discuss the mechanisms of action of the antiparkinsonism drugs that indirectly increase dopamine concentration.

Levodopa - Is a DA precursor that is transported into the CNS via active transport and is converted to DA and also converts to DA in the peripheral system.

DA agonists

• Bromocriptine - an ergot derivative that is a partial D2 agonist, stimulates the dopamine receptor.
• Pramipexole - non-ergot derivative that is a D3 agonist
• Ropinirole - a D2 agonist that stimulates the dopamine receptor, increasing dopamine activity. 

4. Which of the dopamine agonists are ergot derivatives and which are not?

Bromocriptine is an ergot derivatives and Pramipexole, Ropinirole are non-ergot derivatives.

5. List the specific dopamine receptors that are stimulated by each agonist.

Bromocriptine - partial D2 agonist

Pramipexole - direct D3 agonist

Ropinirole - D2 agonist

6. Which of these drugs are classified as neuron protecting drugs?  What does this mean?

Pramipexole is a neuroprotective drug is a drug that protects the neuron against cell death by inhibiting the cascade effects that occur that may lead to cell degradation; with PD it may delay the progression of parkinsonism. And the MAO-B drugs are also neuroprotective.

7. What is the importance of monoamine oxidase B (MAO-B) selective drugs in the treatment of Parkinsonism?

It is used to decrease disease progression and is used in first line treatment of younger patients with moderate parkinsonism.

8. How do the COMT-inhibitors act in Parkinsonism?

COMT-inhibitors such as Entacapone metabolize levodopa to 3-O methyldopa (3OMD) and extends the duration of action of levodopa when it is used in combination therapy(entacapone-levodpa-carbidopa) and decrease the peripheral conversion of L-dopa to DA. 

9. How does istradephyline act?

Istradephyline is a adenosine a2 antagonist, it is used in combination therapy with levodopa and it reduces the levodopa doses and reduces the side effects that would normally be experienced with combination therapy of levodopa and carbidopa. And it is used in patients who experience on and off episodes with the combination therapy of levodopa-carbidopa.

10.  Discuss the MOA of safinamide

Safinamide increases DA activity and decreases glutamate activity. It increases DA activity by inhibition of MAO-B and also inhibits the reuptake of dopamine.