You are able to fix the problem identified above to continue your experiment. Phew!

You are now able to record changes in membrane potential in the neuron in the NTS.

You recorded Excitatory Postsynaptic Potential (EPSPs) in the neuron.

This is mostly likely due to release of an excitatory neurotransmitter from the synaptic afferents terminals.

Which neurotransmitter is most likely to result in this observation:

Question

You are able to fix the problem identified above to continue your experiment. Phew!

You are now able to record changes in membrane potential in the neuron in the NTS.

You recorded Excitatory Postsynaptic Potential (EPSPs) in the neuron.

This is mostly likely due to release of an excitatory neurotransmitter from the synaptic afferents terminals.

Which neurotransmitter is most likely to result in this observation:

BlackTom AI · Accepted Answer

Glutamate is the principal fast excitatory neurotransmitter in the central nervous system and is therefore the most likely cause of the recorded EPSPs.

Relevant knowledge points and concepts:
- EPSPs (excitatory postsynaptic potentials) are depolarizing events produced when excitatory neurotransmitters open postsynaptic cation channels, increasing inward Na+ (and sometimes Ca2+) current.
- Fast excitatory transmission in the brain and brainstem is primarily mediated by glutamate acting at ionotropic receptors (AMPA and NMDA) and metabotropic glutamate receptors (mGluRs).
- The nucleus tractus solitarius (NTS) receives visceral afferent input (e.g., from vagal and glossopharyngeal nerves) whose primary excitatory transmitter is glutamate.

Step-by-step reasoning:
1. You observed EPSPs—these are depolarizations produced by opening of cation-permeable channels on the postsynaptic neuron.
2. The fastest, most common mechanism for such rapid EPSPs is activation of AMPA receptors by glutamate, allowing Na+ influx and membrane depolarization. NMDA receptors can contribute slower, voltage-dependent components via Na+ and Ca2+ flux.
3. In the NTS, afferent terminals from visceral sensory fibers are glutamatergic; experimental literature shows glutamate release from these terminals produces the recorded EPSPs.
4. Therefore, the neurotransmitter most likely responsible for the EPSPs you recorded is glutamate.

Why the other choices are incorrect (briefly):
- GABA: The main inhibitory transmitter in the brain; GABA-A receptors open Cl- channels producing inhibitory postsynaptic potentials (IPSPs), not EPSPs.
- Glycine: Acts as an inhibitory transmitter in the spinal cord and brainstem via Cl- channels, producing IPSPs rather than EPSPs.
- Nitric oxide (NO): A gaseous neuromodulator and retrograde messenger; it diffuses and modulates synaptic function but is not a fast, classical transmitter that directly produces rapid EPSPs through ligand-gated ion channels.

Conclusion: The correct answer is Glutamate, which matches the provided answer.

类似问题

Identify the ONE correct statement about synaptic transmission.

Identify the ONE correct statement about synaptic transmission. 找出关于突触传递的唯一正确说法。

Which one of the following statements about neurotransmission is correct?

Within the CNS, the release of neurotransmitter from a terminal bouton at a chemical synapse is dependent upon which of the following?

Match the experimental manipulation with the effect it would have on synaptic transmission: 1: Deplete extracellular magnesium 2: Deplete extracellular calcium 3: Prevent protein synthesis 4: uncontrolled increase in cellular calcium

Which one of the following statements about neurotransmission is correct? 关于神经传递，下列哪一项陈述是正确的？

Which ONE of the following statements about neurotransmitter release at chemical synapses is CORRECT?

Which ONE of the following statements about chemical neurotransmission is CORRECT?

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