QuestionSBA
QuestionChoice
This is the mechanism fo action of levodopa. Levodopa is converted into dopamine in the brain. Dopamine cannot cross the blood-brain barrier, but levodopa can. Once in the brain, it is converted to dopamine, increasing dopamine levels and improving motor symptoms.
10026686
b
Crosses the blood-brain barrier where it is converted to dopamine by decarboxylation in the presynaptic terminals of dopaminergic neurons
QuestionChoice
Selegiline is a selective and irreversible inhibitor of monoamine oxidase type B (MAO-B). MAO is an enzyme that breaks down dopamine in the brain. By inhibiting MAO-B, selegiline prevents the breakdown of dopamine, thereby increasing dopamine levels in the brain. It is usually used as an adjunct to Levodopa in the treatment of Parkinson's.
10026685
a
Binds to MAO-B receptor within the nigrostriatal pathways and blocks the microsomal metabolism of dopamine
QuestionChoice
This is the mechanism of action of selective serotonin reuptake inhibitors, such as sertraline.
10026689
e
Inhibits serotonin re-uptake
QuestionChoice
This is the mechanism of action of entacapone and tolcapone. COMT is an enzyme that metabolises levodopa in the brain. COMT inhibitors prevent the breakdown of levodopa, extending its duration of action. It is typically used with levodopa.
10026688
d
Prevents the peripheral degradation of levodopa, allowing a higher concentration to cross the blood-brain barrier
QuestionChoice
This is the mechanism of action or ropinirole or pramipexole. They directly activate dopamine receptors in the brain, mimicking the effects of dopamine. They are usually used as an adjunct to Levodopa in the treatment of Parkinson's but can be used alone.
10026687
c
Selectively stimulates dopamine (D2) receptors within the caudate putamen
Concept
Chapter
2693
5911
MAO inhibitors
Topic
172
Pharmacology of the Nervous System
17735
A 73-year-old male patient presents to the neurology clinic for a follow-up appointment. He has been started on levodopa, however, he is still experiencing some symptoms including bradykinesia and a resting tremor. The consultant prescribes selegiline.

What is the mechanism of action of selegiline?
a