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

DA agonists and the anticholinergic drugs.

In what way does amantadine act as a antiparkinsonism drug?

Amantadine is an adonesine A2 antagonist, adenosine inhibits D2 receptor function

Also a metaffinoid pontetiator of DA, amantadine increases the release of DA, the synthesis of DA and blocks DA reuptake.

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

Monoamine oxidase B inhibition, MAO-B  breaks down dopamine therefore MAO-B antagonism increases DA concentration in the CNS.

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

Bromocriptine is an ergot derivative, while promipaxole and ropirinole are non-ergot derivatives.

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

 Bromocriptine - D2 receptor (partial agonist)

Pramipaxole- D3 receptor

Ropirinole- D2 receptor

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

Pramipaxole and MAO-B inhibitors (Selegiline and rasagiline) are neuroprotective, they can alter the course of metabolic events after the onset of ischaemia and therefore have the potential to reduce stroke damage.

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

MAO-B  breaks down dopamine therefore MAO-B antagonism increases DA concentration in the CNS.

How do the COMT-inhibitors act in Parkinsonism?

COMT inhibitors extend the duration of action of L-dopa, decreases its metabolism and improves it's bioavalability. L-dopa is converted to DA by DOPA-decarboxylase, Increasing DA concentrations in the CNS.

How does istradephyline act?

Istradephyline is an adonesine A2 antagonist, adenosine inhibits D2 receptor function.

Discuss the MOA of safinamide

Safinamide is a novel dual MOA-B, a potent reversible inhibitor of MAO-B. It inhibits DA uptake  therefore increasing DA activity. Safinamide also decreases glutamate release.