Neurotransmitters MCQs

97 MCQs with clinical pearls · MBBS Biochemistry · Prof Jariya

Topics covered (15)

Neurotransmitters — 15 MCQs
GABA — 10 MCQs
Dopamine — 9 MCQs
Serotonin — 8 MCQs
Acetylcholine — 7 MCQs
Noradrenaline — 7 MCQs
Substance P and Opioids — 7 MCQs
Histamine — 6 MCQs
Neurotransmitter Integration — 5 MCQs
Catecholamine Degradation — 4 MCQs
Glutamate — 4 MCQs
Glycine — 4 MCQs
Nitric Oxide — 4 MCQs
Endocannabinoids — 4 MCQs
Adenosine — 3 MCQs

Sample MCQs with clinical pearls

A 70-year-old man complains that his blood pressure increases after eating stale food. Which of the following compounds in his food may be causing this problem?

A) Anserine

B) Carnosine

C) Fructosamine

D) Histamine

E) Tyramine ✔

TYRAMINE: formed from TYROSINE by bacterial decarboxylation in stale/fermented foods (cheese, wine, pickled fish, aged meats). Normally degraded by MAO in gut wall and liver. Tyramine -> displaces NOREPINEPHRINE from sympathetic nerve terminals -> hypertensive crisis. TYRAMINE is particularly dangerous in patients on MAO INHIBITORS (MAOIs) - cannot degrade tyramine -> CHEESE REACTION (hypertensive crisis, headache, stroke risk). HISTAMINE in stale fish causes scombroid poisoning (flushing, urticaria). Tyramine is a pressor amine. 📹 [VIDEO LINK]

An 80-year-old woman presents to the emergency department with raised blood pressure after consuming stale food. Tyramine in the stale food is likely to have caused release of which of the following?

A) Dopa

B) Dopamine

C) Epinephrine

D) Glutamate

E) Norepinephrine ✔

TYRAMINE MECHANISM: tyramine (structurally similar to catecholamines) is taken up by sympathetic nerve terminals via catecholamine transporter -> DISPLACES NOREPINEPHRINE from storage vesicles -> NE released into synapse -> stimulates alpha and beta adrenergic receptors -> HYPERTENSION + tachycardia. In MAO INHIBITOR patients: tyramine not metabolised in gut/liver (first-pass MAO) -> excessive tyramine absorbed -> massive NE release -> hypertensive emergency (can cause intracerebral haemorrhage). Treatment: phentolamine (alpha-blocker) for MAO-inhibitor induced tyramine crisis. 📹 [VIDEO LINK]

A 45-year-old schizophrenic patient frequently experiences psychotic episodes. Excessive amounts of which of the following neurotransmitters is likely to be present in his frontal lobes?

A) Dopamine ✔

B) Epinephrine

C) Melatonin

D) Norepinephrine

E) Serotonin

DOPAMINE HYPOTHESIS OF SCHIZOPHRENIA: HYPERACTIVITY of MESOLIMBIC dopamine pathway -> positive symptoms (hallucinations, delusions). Simultaneously: HYPOACTIVITY of MESOCORTICAL dopamine pathway in prefrontal cortex -> negative symptoms (flat affect, poverty of speech, cognitive deficits). Basis: (1) D2 receptor antagonists (antipsychotics) reduce positive symptoms, (2) Amphetamines (increase dopamine) worsen schizophrenia, (3) L-DOPA therapy in Parkinson's can induce psychosis. Modern atypical antipsychotics: D2 + 5HT2A blockade. 📹 [VIDEO LINK]

These are three of 97 MCQs in this section. Every question carries a clinical pearl explaining the reasoning.

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