$$\text{Tyrosine} \rightarrow \text{L-DOPA} \rightarrow \text{Dopamine} \rightarrow \text{Norepinephrine}$$

Question 1

Which enzyme is the rate-limiting step in catecholamine synthesis?

Accepted Answer

Tyrosine hydroxylase (TH)

Question 2

A patient is treated with a copper-chelating agent. Which neurotransmitter would you expect to be elevated in their synapses as a result?

Accepted Answer

Dopamine

Question 3

Which of the following drugs blocks the vesicular monoamine transporter VMAT2, leading to depletion of catecholamines?

Accepted Answer

Reserpine

Question 4

If a drug inhibits monoamine oxidase (MAO), what is the expected effect on catecholamine levels?

Accepted Answer

Catecholamine levels increase due to decreased degradation

Question 5

Which pathway originates in the substantia nigra and is primarily involved in motor control?

Accepted Answer

Nigrostriatal pathway

Question 6

AADC (aromatic amino acid decarboxylase) is found in all of the following EXCEPT:

Accepted Answer

Heart

Question 7

Which of the following is TRUE regarding the action of alpha-1 adrenergic receptors?

Accepted Answer

They activate phospholipase C via Gq proteins

Question 8

Which of the following drugs acts as a selective neurotoxin for the locus coeruleus noradrenergic system in rodents?

Accepted Answer

DSP-4

Question 9

Which dopamine receptor subtype is primarily metabotropic and activates adenylate cyclase?

Accepted Answer

D1

Question 10

A patient with Parkinson's disease is most likely to have degeneration of dopaminergic neurons in which brain region?

Accepted Answer

Substantia nigra

Question 11

Which of the following is a correct sequence for catecholamine synthesis?

Accepted Answer

$$	ext{Tyrosine} ightarrow 	ext{L-DOPA} ightarrow 	ext{Dopamine} ightarrow 	ext{Norepinephrine}$$

Question 12

Which of the following drugs is an irreversible MAO inhibitor?

Accepted Answer

Deprenyl

Question 13

Which neurotransmitter is primarily released in the nucleus accumbens during reward-related behaviors?

Accepted Answer

Dopamine

Question 14

A patient is given a drug that blocks AADC. What is the expected effect on catecholamine synthesis?

Accepted Answer

No production of dopamine or norepinephrine, accumulation of L-DOPA

Question 15

Which of the following statements about MAO subtypes is correct?

Accepted Answer

MAO-A degrades serotonin, norepinephrine, and dopamine; MAO-B degrades dopamine

Question 16

Which of the following drugs inhibits catecholamine reuptake and is commonly abused for its stimulant effects?

Accepted Answer

Cocaine

Question 17

Which G protein is associated with beta-adrenergic receptor activation, and what is its effect?

Accepted Answer

Gs, stimulates adenylate cyclase

Question 18

Which of the following is a clinical effect of alpha-2 adrenergic receptor stimulation?

Accepted Answer

Decreased synthesis of cAMP

Question 19

A knockout mouse lacking both D1 and D2 dopamine receptors will most likely:

Accepted Answer

Die within the second to third week of life

Question 20

Which of the following best describes the mechanism by which norepinephrine regulates sleep?

Accepted Answer

High norepinephrine levels promote wakefulness, low levels promote sleep

Catecholamine Biochemistry: Synthesis, Pathways, and Neuropharmacology

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