Neurotransmitters

Question 1

Gamma-aminobutyric acid

Answer 1

inhibitory neurotransmitter that acts to hyperpolarize nerve cells by binding ligand-gated ion channels or metabotropic receptors.

inhibitor of presynaptic transmission in the central nervous system that is formed by glutamate decarboxylation, a reaction catalyzed by glutamate decarboxylase.

Question 2

serotonin

Answer 2

• Tetrahydrobiopterin (BH4) is a cofactor in the synthesis of serotonin (a major neurotransmitter), tyrosine (a precursor of DOPA), and DOPA (the antecedent of the neurotransmitters dopamine, norepinephrine and epinephrine).
• Dihydropteridine reductase enzymatically reduces dihydrobiopterin (BH2) to tetrahydrobiopterin (BH4).
• Serotonin (5-hydroxytryptamine, or 5HT) is formed through hydroxylation and decarboxylation of the amino acid tryptophan.

Question 3

Acetylcholine

Answer 3

neuromuscular junction neurotransmitter synthesized from choline and acetyl-CoA by choline acetyltransferase.

Question 4

Glutamate

Answer 4

• excitatory neurotransmitter that is synthesized from glutamine by the enzyme glutaminase

Ketamine is an N-methyl-D-aspartate (NMDA) receptor noncompetitive antagonist that blocks glutamate, which can result in anesthesia, sedation, and memory loss.
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