Which pair constitutes the major amino acid neurotransmitters in the CNS?

Which pair constitutes the major amino acid neurotransmitters in the CNS?

• A. Glutamate and GABA
• B. Dopamine and Norepinephrine
• C. Acetylcholine and Neuropeptides
• D. Serotonin and Dopamine

Answer: (A)

Glutamate and GABA are the primary amino acid neurotransmitters in the CNS. Glutamate serves as the main excitatory signal, driving fast excitatory transmission through receptors like NMDA, AMPA, and kainate. GABA provides the major inhibitory signal, mainly via GABA-A ionotropic receptors and GABA-B metabotropic receptors, helping to dampen neural activity and prevent overexcitation. These two amino acids cover the bulk of fast synaptic communication in the brain, maintaining the balance between excitation and inhibition that underpins neural networks, plasticity, and overall CNS function. Glutamate is produced from glutamine and released by glutamatergic neurons, while GABA is synthesized from glutamate by glutamate decarboxylase and packaged into vesicles for release by GABAergic neurons. The other options describe neurotransmitters that are not amino acids—dopamine and norepinephrine are catecholamines, acetylcholine is a cholinergic transmitter, serotonin is a monoamine, and neuropeptides are short chains of amino acids but not the classic amino acid neurotransmitters of CNS transmission.

Glutamate and GABA are the primary amino acid neurotransmitters in the CNS. Glutamate serves as the main excitatory signal, driving fast excitatory transmission through receptors like NMDA, AMPA, and kainate. GABA provides the major inhibitory signal, mainly via GABA-A ionotropic receptors and GABA-B metabotropic receptors, helping to dampen neural activity and prevent overexcitation. These two amino acids cover the bulk of fast synaptic communication in the brain, maintaining the balance between excitation and inhibition that underpins neural networks, plasticity, and overall CNS function. Glutamate is produced from glutamine and released by glutamatergic neurons, while GABA is synthesized from glutamate by glutamate decarboxylase and packaged into vesicles for release by GABAergic neurons. The other options describe neurotransmitters that are not amino acids—dopamine and norepinephrine are catecholamines, acetylcholine is a cholinergic transmitter, serotonin is a monoamine, and neuropeptides are short chains of amino acids but not the classic amino acid neurotransmitters of CNS transmission.