HQA

Homoquinolinic acid

Clinical data
ATC code	None
Identifiers
IUPAC name 3-(Carboxymethyl)-2-pyridinecarboxylic acid
Synonyms	Homoquinolinate
CAS Number	490-75-5
PubChem CID	3080554
ChemSpider	2338312
ECHA InfoCard	100.164.902
Chemical and physical data
Formula	C8H7NO4
Molar mass	181.145 g/mol
3D model (Jmol)	Interactive image
SMILES c1cc(c(nc1)C(=O)O)CC(=O)O
InChI InChI=1S/C8H7NO4/c10-6(11)4-5-2-1-3-9-7(5)8(12)13/h1-3H,4H2,(H,10,11)(H,12,13) Key:HQPMJFFEXJELOQ-UHFFFAOYSA-N

Homoquinolinic acid (HQA) is a potent excitotoxin which is a conformationally-restricted analogue of N-methyl-D-aspartate (NMDA) and a partial agonist of the main/glutamate site of the NMDA receptor, with some selectivity for NR2B subunit-containing receptors. It is approximately equipotent to NMDA and about five times more potent than quinolinic acid as an agonist of the NMDA receptor. HQA has also been found to label a novel, yet uncharacterized binding site, which can be distinguished from the NMDA receptor with the use of 2-carboxy-3-carboxymethylquinoline (CCMQ), a selective ligand of the uncharacterized site.