QUINOLINIC ACID is intriguing researchers as a possible cause and marker of neurological damage in human immunodeficiency virus (HIV) disease.
It is a neurotoxic convulsant metabolite of tryptophan that is activated by interferon gamma. It is elevated with any infection, from a common rhinovirus to the mysterious lentivirus linked to acquired immunodeficiency syndrome (AIDS).
But quinolinic acid remains elevated for extended periods with HIV and increases as much as a 1000-fold over controls in patients with AIDS dementia complex, says Melvyn Heyes, PhD, a visiting scientist in the analytical biochemistry section at the National Institute for Mental Health in suburban Washington, DC (Maryland).
It binds to and may down-regulate Nmethyl-D-aspartate receptors, which are involved in normal neurotransmission, neural regeneration, memory, and synaptic plasticity. It can also induce seizures and nerve cell death, says Heyes.
"There is a wide spectrum of possible consequences known to occur in AIDS and other infectious