Synapse MCQs With Answer

Synapse MCQs With Answer is a targeted question set designed for B. Pharm students to master synaptic physiology, pharmacology, and clinical relevance. These synapse MCQs cover neurotransmitters, receptor types, synaptic transmission steps, vesicle cycle, synaptic plasticity (LTP/LTD), and drug actions affecting synapses. Ideal for exam prep, revision, and classroom practice, this collection emphasizes high-yield topics and application-based scenarios to strengthen understanding of drug–synapse interactions and therapeutic implications. Keywords: Synapse MCQs With Answer, B. Pharm, synaptic transmission, neurotransmitters, synaptic pharmacology, synaptic plasticity. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary event that triggers neurotransmitter release at a chemical synapse?

• Influx of sodium ions into the presynaptic terminal
• Depolarization of the postsynaptic membrane
• Influx of calcium ions into the presynaptic terminal
• Activation of postsynaptic GPCRs

Correct Answer: Influx of calcium ions into the presynaptic terminal

Q2. Which protein family is directly responsible for synaptic vesicle fusion with the presynaptic membrane?

• Kinases
• SNARE proteins
• Connexins
• Phosphatases

Correct Answer: SNARE proteins

Q3. Which neurotransmitter is primarily excitatory in the central nervous system?

• GABA
• Glycine
• Glutamate
• Serotonin

Correct Answer: Glutamate

Q4. Ionotropic receptors are characterized by which primary mechanism?

• Activation of second messenger cascades
• Direct opening of ion channels upon ligand binding
• Gene transcription modulation
• Long-term receptor internalization

Correct Answer: Direct opening of ion channels upon ligand binding

Q5. Which enzyme degrades acetylcholine in the synaptic cleft?

• Monoamine oxidase
• Acetylcholinesterase
• Choline acetyltransferase
• Tyrosine hydroxylase

Correct Answer: Acetylcholinesterase

Q6. Electrical synapses differ from chemical synapses primarily because they:

• Use neurotransmitters to signal
• Have longer synaptic delays
• Allow direct ionic current flow via gap junctions
• Require vesicle fusion for transmission

Correct Answer: Allow direct ionic current flow via gap junctions

Q7. Long-term potentiation (LTP) is most associated with which cellular change?

• Decreased postsynaptic AMPA receptor density
• Increased postsynaptic AMPA receptor insertion
• Reduced presynaptic calcium influx
• Loss of dendritic spines

Correct Answer: Increased postsynaptic AMPA receptor insertion

Q8. Miniature end-plate potentials (MEPPs) reflect:

• Action potential propagation along the axon
• Spontaneous quantal release of neurotransmitter
• Postsynaptic receptor desensitization
• Electrical coupling between neurons

Correct Answer: Spontaneous quantal release of neurotransmitter

Q9. Which ion contributes directly to the generation of an inhibitory postsynaptic potential (IPSP) in many neurons?

• Calcium (Ca2+)
• Potassium (K+)
• Sodium (Na+)
• Chloride (Cl-)

Correct Answer: Chloride (Cl-)

Q10. Botulinum toxin causes paralysis by which synaptic mechanism?

• Blocking postsynaptic receptors
• Inhibiting acetylcholinesterase
• Cleaving SNARE proteins and preventing vesicle fusion
• Blocking voltage-gated calcium channels on the postsynaptic membrane

Correct Answer: Cleaving SNARE proteins and preventing vesicle fusion

Q11. Which transporter is responsible for reuptake of serotonin into presynaptic terminals?

• DAT (Dopamine transporter)
• SERT (Serotonin transporter)
• NET (Norepinephrine transporter)
• VAChT (Vesicular acetylcholine transporter)

Correct Answer: SERT (Serotonin transporter)

Q12. Which statement best describes metabotropic receptors?

• They form ion channels that open instantly on ligand binding
• They couple to G-proteins and modulate intracellular signalling
• They always produce excitatory postsynaptic potentials
• They only exist at neuromuscular junctions

Correct Answer: They couple to G-proteins and modulate intracellular signalling

Q13. Quantal analysis in synaptic physiology measures:

• Frequency of action potentials
• Amplitude of single-vesicle (quantal) transmitter release events
• Ion channel conductance
• Postsynaptic receptor synthesis rates

Correct Answer: Amplitude of single-vesicle (quantal) transmitter release events

Q14. In the neuromuscular junction, safety factor refers to:

• The number of synapses per motor neuron
• Excess end-plate potential magnitude above threshold ensuring reliable transmission
• The speed of acetylcholinesterase activity
• Amount of calcium in the muscle fiber

Correct Answer: Excess end-plate potential magnitude above threshold ensuring reliable transmission

Q15. Which neurotransmitter system is primarily implicated in Alzheimer’s disease therapy targets?

• GABAergic system
• Cholinergic system
• Histaminergic system
• Glycinergic system

Correct Answer: Cholinergic system

Q16. Which drug class increases synaptic acetylcholine by inhibiting acetylcholinesterase?

• Beta blockers
• Acetylcholinesterase inhibitors
• Monoamine oxidase inhibitors
• Calcium channel blockers

Correct Answer: Acetylcholinesterase inhibitors

Q17. NMDA receptor activation requires which two events?

• Ligand binding and hyperpolarization
• Ligand binding and prior postsynaptic depolarization to remove Mg2+ block
• Only ligand binding
• cAMP increase and protein synthesis

Correct Answer: Ligand binding and prior postsynaptic depolarization to remove Mg2+ block

Q18. Which molecule loads acetylcholine into synaptic vesicles?

• Choline acetyltransferase (ChAT)
• Vesicular acetylcholine transporter (VAChT)
• Choline transporter (CHT)
• Acetylcholinesterase (AChE)

Correct Answer: Vesicular acetylcholine transporter (VAChT)

Q19. Synaptic delay (≈0.5–2 ms) is mainly due to:

• Action potential propagation along the axon
• Diffusion distance in the synaptic cleft and vesicle release processes
• Postsynaptic receptor desensitization
• Transcriptional delays

Correct Answer: Diffusion distance in the synaptic cleft and vesicle release processes

Q20. Which neurotransmitter is primarily inhibitory in the adult spinal cord?

• Glutamate
• GABA
• Dopamine
• Acetylcholine

Correct Answer: GABA

Q21. AMPA receptors are primarily permeable to which ion when activated?

• Calcium preferentially over sodium
• Sodium and potassium (Na+ influx, K+ efflux)
• Chloride
• Only potassium

Correct Answer: Sodium and potassium (Na+ influx, K+ efflux)

Q22. Which process retrieves synaptic vesicle membrane after exocytosis?

• Exocytosis
• Endocytosis
• Transcytosis
• Phagocytosis

Correct Answer: Endocytosis

Q23. Which disease is caused by autoantibodies against postsynaptic acetylcholine receptors?

• Parkinson’s disease
• Myasthenia gravis
• Multiple sclerosis
• Amyotrophic lateral sclerosis

Correct Answer: Myasthenia gravis

Q24. Tetanus toxin leads to spastic paralysis by:

• Blocking acetylcholine release at neuromuscular junction
• Cleaving inhibitory neurotransmitter release proteins, reducing GABA/glycine release
• Blocking sodium channels in motor neurons
• Enhancing acetylcholinesterase activity

Correct Answer: Cleaving inhibitory neurotransmitter release proteins, reducing GABA/glycine release

Q25. Which transporter packages monoamines (dopamine, norepinephrine) into synaptic vesicles?

• VMAT (Vesicular monoamine transporter)
• SERT
• GAT
• EAAT (Excitatory amino acid transporter)

Correct Answer: VMAT (Vesicular monoamine transporter)

Q26. Metabotropic glutamate receptors (mGluRs) typically modulate synaptic activity via:

• Direct ion permeation
• G-protein coupled second messenger pathways
• Proteolytic cleavage of neurotransmitters
• Electrical gap junctions

Correct Answer: G-protein coupled second messenger pathways

Q27. Which pharmacological agent blocks benzodiazepine binding effects at GABA-A receptors?

• Flumazenil
• Naloxone
• Atropine
• Propranolol

Correct Answer: Flumazenil

Q28. Synaptic plasticity that weakens synaptic strength over time is called:

• Long-term potentiation (LTP)
• Long-term depression (LTD)
• Facilitation
• Augmentation

Correct Answer: Long-term depression (LTD)

Q29. Which receptor type at the neuromuscular junction mediates rapid depolarization of the muscle end-plate?

• Muscarinic ACh receptor
• Nicotinic ACh receptor (ionotropic)
• Beta-adrenergic receptor
• NMDA receptor

Correct Answer: Nicotinic ACh receptor (ionotropic)

Q30. Which molecule synthesizes acetylcholine in the presynaptic neuron?

• Acetylcholinesterase
• Choline acetyltransferase (ChAT)
• Tyrosine hydroxylase
• Glutamic acid decarboxylase

Correct Answer: Choline acetyltransferase (ChAT)

Q31. Which is a major excitatory amino acid transporter that clears glutamate from the synaptic cleft?

• GAT-1
• EAAT (Excitatory amino acid transporter)
• DAT
• SERT

Correct Answer: EAAT (Excitatory amino acid transporter)

Q32. Which synaptic change is associated with associative learning?

• Reduced calcium entry into presynaptic terminals
• Coincidence detection at NMDA receptors leading to LTP
• Blockade of AMPA receptors
• Global downregulation of neurotransmitter synthesis

Correct Answer: Coincidence detection at NMDA receptors leading to LTP

Q33. Which drug type increases synaptic dopamine by blocking its reuptake transporter?

• SSRIs
• DAT inhibitors (e.g., cocaine)
• Cholinesterase inhibitors
• Benzodiazepines

Correct Answer: DAT inhibitors (e.g., cocaine)

Q34. Which statement about gap junctions is true?

• They are composed of connexin proteins forming channels between cells
• They require neurotransmitter release to function
• They only exist in peripheral nervous system synapses
• They degrade neurotransmitters in the synaptic cleft

Correct Answer: They are composed of connexin proteins forming channels between cells

Q35. Which mechanism contributes to short-term synaptic facilitation?

• Accumulation of presynaptic calcium from closely spaced action potentials
• Depletion of synaptic vesicles
• Postsynaptic receptor internalization
• Increased activity of acetylcholinesterase

Correct Answer: Accumulation of presynaptic calcium from closely spaced action potentials

Q36. MAO inhibitors affect synaptic transmission by:

• Blocking monoamine reuptake transporters
• Inhibiting monoamine breakdown in the presynaptic terminal
• Antagonizing postsynaptic receptors
• Enhancing vesicular packaging of monoamines

Correct Answer: Inhibiting monoamine breakdown in the presynaptic terminal

Q37. Which ion channel opening causes EPSP in most central synapses?

• Cl- channels
• K+ channels only
• Non-selective cation channels permeable to Na+
• Voltage-gated calcium channels on postsynaptic membrane

Correct Answer: Non-selective cation channels permeable to Na+

Q38. Which protein is essential for docking and priming synaptic vesicles at the active zone?

• Myosin
• Munc13/Munc18 and SNARE complex components
• Actin only
• Synaptotagmin exclusively

Correct Answer: Munc13/Munc18 and SNARE complex components

Q39. Desensitization of a receptor refers to:

• Permanently increasing receptor numbers
• Transient decrease in receptor responsiveness despite agonist presence
• Immediate cell death
• Enhanced neurotransmitter synthesis

Correct Answer: Transient decrease in receptor responsiveness despite agonist presence

Q40. Which synaptic pathology is directly targeted by pyridostigmine therapy?

• Botulism
• Myasthenia gravis by inhibiting AChE and increasing ACh at NMJ
• Tetanus by enhancing GABA release
• Parkinson’s disease by increasing dopamine synthesis

Correct Answer: Myasthenia gravis by inhibiting AChE and increasing ACh at NMJ

Q41. Which term describes the combined effect of multiple synaptic inputs arriving at the same location?

• Temporal summation
• Spatial summation
• Quantal analysis
• Reuptake

Correct Answer: Spatial summation

Q42. Which process reduces neurotransmitter action by transporting it back into glia or neurons?

• Exocytosis
• Reuptake via specific transporters
• Proteolysis in synaptic cleft
• Vesicle docking

Correct Answer: Reuptake via specific transporters

Q43. Which clinical agent blocks voltage-gated calcium channels at presynaptic terminals to reduce neurotransmitter release?

• Local anesthetics like lidocaine
• Alpha-latrotoxin
• Gabapentin/pregabalin (modulate calcium channel function)
• Atropine

Correct Answer: Gabapentin/pregabalin (modulate calcium channel function)

Q44. Which of the following is a neuromodulator rather than a classical fast neurotransmitter?

• Glutamate
• GABA
• Neuropeptide Y
• Acetylcholine at NMJ

Correct Answer: Neuropeptide Y

Q45. Which synaptic feature increases speed of neurotransmission in myelinated axons?

• Saltatory conduction between nodes of Ranvier
• Long unmyelinated stretches
• More chemical synapses per unit length
• Increased synaptic cleft width

Correct Answer: Saltatory conduction between nodes of Ranvier

Q46. Which postsynaptic event leads directly to hyperpolarization and inhibition?

• Opening of cationic non-selective channels
• Opening of potassium channels causing K+ efflux
• AMPA receptor activation with Na+ influx
• NMDA receptor-mediated Ca2+ influx

Correct Answer: Opening of potassium channels causing K+ efflux

Q47. Which is true about the vesicular cycle at synapses?

• Vesicles are released but never recycled
• Vesicles undergo docking, priming, fusion, and endocytosis for reuse
• Only newly synthesized vesicles are used for release
• Endocytosis occurs only in the postsynaptic cell

Correct Answer: Vesicles undergo docking, priming, fusion, and endocytosis for reuse

Q48. Which drug enhances GABAergic inhibition by increasing GABA-A receptor chloride channel opening frequency?

• Benzodiazepines
• SSRIs
• Tricyclic antidepressants
• Beta agonists

Correct Answer: Benzodiazepines

Q49. Which pathological change reduces cholinergic signaling in Alzheimer’s disease?

• Excessive synaptic vesicle recycling
• Loss of basal forebrain cholinergic neurons and reduced ACh levels
• Overexpression of nicotinic receptors
• Increased acetylcholine synthesis

Correct Answer: Loss of basal forebrain cholinergic neurons and reduced ACh levels

Q50. Which mechanism explains the action of selective serotonin reuptake inhibitors (SSRIs)?

• Inhibition of vesicular packaging of serotonin
• Blockade of serotonin reuptake transporters, increasing synaptic serotonin
• Direct agonism of serotonin receptors without altering synaptic levels
• Increasing acetylcholine release at synapses

Correct Answer: Blockade of serotonin reuptake transporters, increasing synaptic serotonin

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

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