Neurophysiology and special senses: pain transmission: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Neurophysiology and special senses: pain transmission

Sample item

In the dorsal horn, which neurotransmitters are released by primary nociceptive afferents onto second-order neurons?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Glutamate and substance P

Nociceptive afferents release glutamate for fast transmission and substance P for slow, sustained excitation. GABA, glycine and the opioid peptides act as inhibitors in the descending and local pain-modulating system.

Option by option

  • A. Serotonin and noradrenaline

    Serotonin and noradrenaline are descending modulating transmitters, not afferent transmitters.

  • B. GABA and glycine

    GABA and glycine are inhibitory interneuron transmitters.

  • C. Glutamate and substance P (correct)

    Correct. Glutamate and substance P excite dorsal horn neurons.

  • D. Enkephalin and dynorphin

    Enkephalin and dynorphin are inhibitory modulators of pain transmission.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, Glutamate and substance P. Nociceptive afferents release glutamate for fast transmission and substance P for slow, sustained excitation.

Why is "Serotonin and noradrenaline" not the answer?

Serotonin and noradrenaline are descending modulating transmitters, not afferent transmitters.

Why is "GABA and glycine" not the answer?

GABA and glycine are inhibitory interneuron transmitters.

Why is "Enkephalin and dynorphin" not the answer?

Enkephalin and dynorphin are inhibitory modulators of pain transmission.

What concept does this question test?

It tests Neurophysiology and special senses: pain transmission in Physiology. GABA, glycine and the opioid peptides act as inhibitors in the descending and local pain-modulating system.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neurophysiology and special senses: pain transmission?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.