Ph 2.5 Dopamine (5)

Which statement best describes dopamine in dopaminergic neurones?

A neurotransmitter formed as an intermediate in catecholamine synthesis

Which best describes the role of tyrosine hydroxylase?

Converts tyrosine into L-DOPA in the dopamine synthesis pathway

What is the function of aromatic amino acid decarboxylase?

Converts L-DOPA into dopamine inside the cytosol

What is the definition of the vesicular monoamine transporter 2 (VMAT2)?

A transporter that moves dopamine into synaptic vesicles for storage

What happens when dopamine remains in the cytosol rather than vesicles?

It undergoes oxidation and becomes chemically unstable

What is the role of dopamine transporters (DAT)?

Reuptake dopamine from the cleft back into presynaptic neurones

What is homovanillic acid (HVA)?

The main metabolite produced from dopamine breakdown

Which statement best describes dopamine receptors?

Metabotropic receptors divided into D1-like and D2-like families

D1-like receptors (D1 and D5) are mainly associated with:

Memory, attention, impulse control and locomotion

D2-like receptors (D2, D3, D4) are mainly associated with:

Sleep, learning, memory and extrapyramidal activity

Which statement best defines the nigrostriatal pathway?

Pathway projecting from substantia nigra to basal ganglia to control movement

Which dopaminergic pathway regulates prolactin secretion?

Tuberoinfundibular pathway

The mesolimbic pathway is strongly associated with:

Reward, addiction and positive symptoms of schizophrenia

What is the primary dopaminergic abnormality in Parkinson’s disease?

Loss of dopaminergic neurones in the nigrostriatal pathway

What is the definition of levodopa (L-DOPA)?

A metabolic precursor converted into dopamine in the brain

Why is carbidopa combined with levodopa?

To block peripheral conversion of L-DOPA into dopamine

What is the mechanism of COMT inhibitors in Parkinson’s disease?

Inhibit methylation of L-DOPA and dopamine, increasing availability

What is the main clinical purpose of COMT inhibitors?

Increase levodopa bioavailability and reduce off-time

What is the definition of monoamine oxidase (MAO)?

An enzyme that breaks down monoamine neurotransmitters

Which drugs selectively inhibit MAO-B in Parkinson’s disease?

Selegiline and rasagiline

What best describes dopamine agonists?

Drugs that directly stimulate dopamine receptors

Which dopamine agonists are commonly used in Parkinson’s disease?

Pramipexole and ropinirole