Quinolinic acid

Quinolinic acid (also known as quinolinate or 2,3-Pyridinedicarboxylic acid) is a neurotoxin and metabolite of the kynurenine pathway, which metabolizes the amino acid tryptophan. It is a potent excitatory neurotransmitter at N-methyl-D-aspartate (NMDA) receptors in the central nervous system.

Chemistry

Quinolinic acid is a diketopiperazine that is derived from two molecules of alanine. It is a dicarboxylic acid and a member of the quinoline family. It is a conjugate acid of a quinolinate(1-).

Biosynthesis

Quinolinic acid is produced in the body by the kynurenine pathway, which is responsible for the conversion of the essential amino acid tryptophan into nicotinamide adenine dinucleotide (NAD+). The conversion involves several steps, with quinolinic acid being one of the intermediates.

Role in the body

In the central nervous system, quinolinic acid acts as a neurotoxin by binding to NMDA receptors and overstimulating them, causing neurodegeneration. This process is thought to be involved in several neurological diseases, including Huntington's disease, Alzheimer's disease, and depression.

Medical implications

Due to its neurotoxic properties, quinolinic acid has been studied in relation to various neurological disorders. Elevated levels of quinolinic acid have been found in the brains of individuals with Alzheimer's disease and Huntington's disease. It is also thought to play a role in the development of depression, as increased levels of quinolinic acid have been found in the cerebrospinal fluid of depressed individuals.

See also

• Kynurenine pathway
• Neurotoxin
• NMDA receptor

References

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  Synthesis Niacin I
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  Kynurenine pathway wordless