Question
Facilitatory presynaptic neurotransmitter is‑
| A. |
GABA |
| B. |
Glycine |
| C. |
Glutamate |
| D. |
Aspartate |
Show Answer
|
Correct Answer » C Explanation |
 |
- Glutamate is the major excitatory (facilitatory) neurotransmitter in the central nervous system.
- It facilitates synaptic transmission by depolarizing the postsynaptic membrane through activation of:
- N-Methyl-D-Aspartate (NMDA) receptors
- α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors
- Kainate receptors
- It plays a crucial role in:
- Learning
- Memory
- Synaptic plasticity
- Long-term potentiation (LTP)
Why Other Options are Incorrect
A. Gamma-aminobutyric acid (GABA)
- Major inhibitory neurotransmitter in the brain.
- Produces neuronal inhibition by increasing chloride ion influx through GABA-A receptors.
- Does not facilitate presynaptic transmission.
B. Glycine
- Major inhibitory neurotransmitter in the spinal cord and brainstem.
- Increases chloride ion conductance, causing neuronal hyperpolarization.
- Not a facilitatory neurotransmitter.
D. Aspartate
- Aspartate is an excitatory amino acid neurotransmitter.
- However, its physiological role is much less significant than glutamate.
- Glutamate is the principal facilitatory neurotransmitter in the CNS.
