Quinolinic acid

Quinolinic acid (abbreviated QUIN or QA), also known as pyridine-2,3-dicarboxylic acid, is a dicarboxylic acid with a pyridine backbone. It is a colorless solid. It is the biosynthetic precursor to nicotine.

Quinolinic acid is a downstream product of the kynurenine pathway, which metabolizes the amino acid tryptophan. It acts as an NMDA receptor agonist.

Quinolinic acid has a potent neurotoxic effect. Studies have demonstrated that quinolinic acid may be involved in many psychiatric disorders, neurodegenerative processes in the brain, as well as other disorders. Within the brain, quinolinic acid is only produced by activated microglia and macrophages.

History

In 1949 L. Henderson was one of the earliest to describe quinolinic acid. Lapin followed up this research by demonstrating that quinolinic acid could induce convulsions when injected into mice brain ventricles. However, it was not until 1981 that Stone and Perkins showed that quinolinic acid activates the N-methyl-d-aspartate receptor (NMDAR). After this, Schwarcz demonstrated that elevated quinolinic acid levels could lead to axonal neurodegeneration.