MCQ Quiz: Brain Neurochemistry

Brain neurochemistry is the foundation of modern psychopharmacology. Understanding how neurotransmitters are synthesized, how they signal, and how they are cleared from the synapse is essential for grasping the mechanism of action of virtually every medication used to treat CNS disorders. This quiz will test you on the key characteristics of the major neurotransmitter systems that are the targets of brain therapeutics.

1. Which amino acid is the primary precursor for the synthesis of the catecholamine neurotransmitters (dopamine, norepinephrine, epinephrine)?

• a. Tryptophan
• b. Tyrosine
• c. Glutamine
• d. Histidine

Answer: b. Tyrosine

2. The primary mechanism for the termination of synaptic action for serotonin and dopamine is:

• a. Enzymatic degradation within the synapse.
• b. Reuptake into the presynaptic neuron via specific transporter proteins (SERT, DAT).
• c. Diffusion away from the synapse.
• d. Uptake by postsynaptic glial cells.

Answer: b. Reuptake into the presynaptic neuron via specific transporter proteins (SERT, DAT).

3. A drug that blocks the reuptake of serotonin would be expected to:

• a. Decrease the amount of serotonin in the synapse.
• b. Increase the amount of serotonin in the synapse.
• c. Inhibit the synthesis of serotonin.
• d. Block serotonin receptors.

Answer: b. Increase the amount of serotonin in the synapse.

4. Which neurotransmitter is primarily implicated in the “reward” pathway and is a key target in the treatment of both Parkinson’s disease and schizophrenia?

• a. Acetylcholine
• b. GABA
• c. Dopamine
• d. Glutamate

Answer: c. Dopamine

5. GABA (gamma-aminobutyric acid) is the main inhibitory neurotransmitter in the brain. It produces its effect by opening which type of ion channel?

• a. Sodium (Na+) channels
• b. Calcium (Ca2+) channels
• c. Potassium (K+) channels
• d. Chloride (Cl-) channels

Answer: d. Chloride (Cl-) channels

6. Monoamine Oxidase (MAO) is an enzyme responsible for the breakdown of which neurotransmitters?

• a. Acetylcholine and Glutamate
• b. Serotonin, Norepinephrine, and Dopamine
• c. GABA and Glycine
• d. Endorphins and Enkephalins

Answer: b. Serotonin, Norepinephrine, and Dopamine

7. A drug that acts as an antagonist at the D2 receptor is the primary mechanism for which class of medications?

• a. Antidepressants
• b. Anxiolytics
• c. Antipsychotics
• d. Mood stabilizers

Answer: c. Antipsychotics

8. Glutamate is the primary excitatory neurotransmitter. Its over-activity can lead to excitotoxicity, a process mediated largely by which receptor?

• a. AMPA receptor
• b. NMDA receptor
• c. Kainate receptor
• d. Metabotropic glutamate receptor

Answer: b. NMDA receptor

9. Alzheimer’s disease is associated with a deficiency of which neurotransmitter, crucial for memory and cognition?

• a. Dopamine
• b. Serotonin
• c. Norepinephrine
• d. Acetylcholine

Answer: d. Acetylcholine

10. What is the mechanism of action of acetylcholinesterase inhibitors like donepezil?

• a. They increase the production of acetylcholine.
• b. They block the enzymatic breakdown of acetylcholine in the synapse.
• c. They directly stimulate acetylcholine receptors.
• d. They block the reuptake of acetylcholine.

Answer: b. They block the enzymatic breakdown of acetylcholine in the synapse.

11. Benzodiazepines work by binding to an allosteric site on the GABA-A receptor, which results in:

• a. A decrease in GABA’s effect.
• b. An enhancement of GABA’s inhibitory effect.
• c. A direct opening of the chloride channel.
• d. A blockade of the GABA receptor.

Answer: b. An enhancement of GABA’s inhibitory effect.

12. The amino acid Tryptophan is the direct precursor for the synthesis of:

• a. Dopamine
• b. Norepinephrine
• c. Serotonin (5-HT)
• d. GABA

Answer: c. Serotonin (5-HT)

13. A drug that binds to a receptor and prevents the endogenous neurotransmitter from binding, without causing a response itself, is called a(n):

• a. Agonist
• b. Partial agonist
• c. Inverse agonist
• d. Antagonist

Answer: d. Antagonist

14. The “monoamine hypothesis” of depression suggests a deficiency in which group of neurotransmitters?

• a. Acetylcholine
• b. Glutamate and GABA
• c. Serotonin, norepinephrine, and dopamine
• d. Opioid peptides

Answer: c. Serotonin, norepinephrine, and dopamine

15. Which of the following is NOT a primary mechanism for removing a neurotransmitter from the synapse?

• a. Reuptake into the presynaptic neuron.
• b. Enzymatic degradation.
• c. Diffusion away from the synapse.
• d. Permanent binding to the postsynaptic receptor.

Answer: d. Permanent binding to the postsynaptic receptor.

16. The nigrostriatal pathway is a dopamine pathway critical for motor control. Its degeneration is the primary cause of:

• a. Schizophrenia
• b. Depression
• c. Alzheimer’s disease
• d. Parkinson’s disease

Answer: d. Parkinson’s disease

17. The enzyme that converts levodopa to dopamine is:

• a. Tyrosine hydroxylase
• b. DOPA decarboxylase
• c. Dopamine beta-hydroxylase
• d. MAO-B

Answer: b. DOPA decarboxylase

18. A drug’s ability to cross the blood-brain barrier is primarily determined by its:

• a. Color and taste
• b. Lipophilicity and molecular size
• c. Cost
• d. Formulation as a tablet or capsule

Answer: b. Lipophilicity and molecular size

19. An “excitatory postsynaptic potential” (EPSP) is typically caused by the influx of which ion?

• a. Chloride (Cl-)
• b. Potassium (K+)
• c. Sodium (Na+)
• d. Bicarbonate (HCO3-)

Answer: c. Sodium (Na+)

20. An “inhibitory postsynaptic potential” (IPSP) is typically caused by the influx of which ion?

• a. Sodium (Na+)
• b. Calcium (Ca2+)
• c. Chloride (Cl-)
• d. Magnesium (Mg2+)

Answer: c. Chloride (Cl-)

21. A drug that blocks the vesicular monoamine transporter (VMAT) would:

• a. Increase the synaptic release of monoamines.
• b. Decrease the storage of monoamines in synaptic vesicles.
• c. Inhibit the breakdown of monoamines.
• d. Stimulate postsynaptic receptors.

Answer: b. Decrease the storage of monoamines in synaptic vesicles.

22. “Up-regulation” of receptors is a process where the number of receptors on a cell surface increases, often in response to:

• a. Chronic stimulation by an agonist.
• b. Chronic blockade by an antagonist.
• c. A single dose of a drug.
• d. An increase in neurotransmitter synthesis.

Answer: b. Chronic blockade by an antagonist.

23. The therapeutic delay of several weeks seen with many antidepressants is thought to be related to:

• a. Slow absorption of the drugs.
• b. The time it takes for receptor down-regulation and other neuroadaptive changes to occur.
• c. The need to reach a high plasma concentration.
• d. Patient non-adherence.

Answer: b. The time it takes for receptor down-regulation and other neuroadaptive changes to occur.

24. The term “neuroplasticity” refers to the brain’s ability to:

• a. Resist all change.
• b. Reorganize and form new synaptic connections.
• c. Only be affected by injury.
• d. Shrink over time.

Answer: b. Reorganize and form new synaptic connections.

25. Which of the following is NOT a primary target for CNS therapeutics?

• a. Receptors
• b. Enzymes
• c. Reuptake transporters
• d. The blood-brain barrier itself

Answer: d. The blood-brain barrier itself

26. The enzyme Catechol-O-methyltransferase (COMT) is involved in the metabolism of:

• a. Acetylcholine
• b. GABA
• c. Catecholamines like dopamine
• d. Serotonin

Answer: c. Catecholamines like dopamine

27. A drug’s affinity for a receptor describes:

• a. The maximum effect it can produce.
• b. The strength with which it binds to the receptor.
• c. Its half-life.
• d. Its rate of metabolism.

Answer: b. The strength with which it binds to the receptor.

28. A partial agonist is a drug that:

• a. Binds to a receptor but produces no effect.
• b. Binds to and activates a receptor but produces a submaximal response compared to a full agonist.
• c. Binds to a different site than the full agonist.
• d. Has a higher efficacy than a full agonist.

Answer: b. Binds to and activates a receptor but produces a submaximal response compared to a full agonist.

29. The synthesis of GABA from glutamate requires which enzyme?

• a. Glutamate decarboxylase
• b. GABA transaminase
• c. Tyrosine hydroxylase
• d. Tryptophan hydroxylase

Answer: a. Glutamate decarboxylase

30. The “mesolimbic pathway” is a dopamine pathway strongly associated with:

• a. Motor control
• b. Cognition and planning
• c. Reward, motivation, and addiction
• d. Hormone release from the pituitary

Answer: c. Reward, motivation, and addiction

31. Barbiturates differ from benzodiazepines in that at high doses, they can:

• a. Decrease the effect of GABA.
• b. Directly open the GABA-A chloride channel without GABA being present.
• c. Block the GABA-A receptor.
• d. Only enhance the effect of GABA.

Answer: b. Directly open the GABA-A chloride channel without GABA being present.

32. The enzyme that converts norepinephrine to epinephrine is primarily found in the:

• a. Locus coeruleus
• b. Raphe nuclei
• c. Substantia nigra
• d. Adrenal medulla

Answer: d. Adrenal medulla

33. The action of a neurotransmitter is terminated when it is released from its receptor.

• a. True
• b. False

Answer: a. True

34. A “second messenger” system is typically activated by which type of receptor?

• a. Ligand-gated ion channels
• b. G-protein coupled receptors (metabotropic)
• c. Intracellular nuclear receptors
• d. Receptor tyrosine kinases

Answer: b. G-protein coupled receptors (metabotropic)

35. A pharmacist understanding that tramadol inhibits the reuptake of serotonin and norepinephrine is applying knowledge of:

• a. Neurochemistry and pharmacodynamics.
• b. Pharmacokinetics only.
• c. Pharmaceutics only.
• d. Pharmacy law.

Answer: a. Neurochemistry and pharmacodynamics.

36. Which of the following is NOT a criterion for a substance to be considered a neurotransmitter?

• a. It must be synthesized in the neuron.
• b. It must be released upon stimulation.
• c. It must have a specific receptor on the postsynaptic cell.
• d. It must be a large protein molecule.

Answer: d. It must be a large protein molecule.

37. The locus coeruleus is the principal site for brain synthesis of which neurotransmitter?

• a. Dopamine
• b. Serotonin
• c. Acetylcholine
• d. Norepinephrine

Answer: d. Norepinephrine

38. The raphe nuclei are the primary source of which neurotransmitter in the brain?

• a. Dopamine
• b. Serotonin
• c. GABA
• d. Histamine

Answer: b. Serotonin

39. A drug that is a “receptor antagonist” would be expected to have affinity but no intrinsic activity.

• a. True
• b. False

Answer: a. True

40. The term “pharmacodynamics” describes what the drug does to the body, including its interaction with neurotransmitter systems.

• a. True
• b. False

Answer: a. True

41. Which neurotransmitter system is the primary target for medications used to treat anxiety disorders?

• a. The dopaminergic system
• b. The GABAergic and serotonergic systems
• c. The cholinergic system
• d. The histaminergic system

Answer: b. The GABAergic and serotonergic systems

42. An imbalance in which neurotransmitter is most directly implicated in the motor symptoms of Huntington’s disease?

• a. A deficiency of GABAergic neurons and an excess of dopaminergic activity.
• b. A deficiency of serotonin.
• c. An excess of acetylcholine.
• d. A deficiency of norepinephrine.

Answer: a. A deficiency of GABAergic neurons and an excess of dopaminergic activity.

43. A “receptor subtype” (e.g., D1 vs. D2, 5-HT1A vs. 5-HT2A) allows for:

• a. The same neurotransmitter to have different effects in different parts of the brain.
• b. The development of more specific and targeted medications.
• c. Both a and b.
• d. Neither a nor b.

Answer: c. Both a and b.

44. The blood-brain barrier is composed of endothelial cells with what type of junctions?

• a. Gap junctions
• b. Loose junctions
• c. Tight junctions
• d. No junctions

Answer: c. Tight junctions

45. Which of the following is a primary role of glia cells (like astrocytes) in neurochemistry?

• a. Transmitting action potentials.
• b. Synthesizing neurotransmitters.
• c. Clearing neurotransmitters from the synapse and maintaining homeostasis.
• d. Forming the myelin sheath.

Answer: c. Clearing neurotransmitters from the synapse and maintaining homeostasis.

46. A drug’s ability to modulate a neurotransmitter system can affect:

• a. Mood
• b. Cognition
• c. Motor function
• d. All of the above

Answer: d. All of the above

47. The concept of “down-regulation” explains why:

• a. A drug becomes more effective over time.
• b. Tolerance may develop to a drug that is a chronic agonist.
• c. A drug’s side effects disappear immediately.
• d. A drug’s half-life increases.

Answer: b. Tolerance may develop to a drug that is a chronic agonist.

48. An understanding of neurochemistry is essential for which of the following pharmacy activities?

• a. Counseling a patient on expected side effects.
• b. Understanding a drug’s mechanism of action.
• c. Identifying potential drug-drug interactions.
• d. All of the above.

Answer: d. All of the above.

49. The overall goal of psychopharmacology is to:

• a. Use medications to correct perceived imbalances in brain neurochemistry.
• b. Cure all mental illness.
• c. Eliminate the need for psychotherapy.
• d. Create drugs with no side effects.

Answer: a. Use medications to correct perceived imbalances in brain neurochemistry.

50. The ultimate reason for a pharmacist to learn about brain neurochemistry is to:

• a. Be able to fundamentally understand how CNS medications work in order to ensure their safe and effective use.
• b. Pass a pharmacology exam.
• c. Be able to diagnose psychiatric conditions.
• d. Memorize all the receptor subtypes.

Answer: a. Be able to fundamentally understand how CNS medications work in order to ensure their safe and effective use.