Studies on cerebrospinal fluid kynurenic acid concentrations in epileptic children.

Kynurenic acid (KYA), the only known endogenous antagonist of the excitatory amino acids, is a metabolite of kynurenine. In the present study the levels of KYA were measured in the cerebrospinal fluid (CSF) of epileptic children and age-matched controls to investigate the relationship between various forms of epilepsy and KYA levels. CSF samples from four patients with West syndrome (WS), four patients with epilepsy with grand mal seizures on awakening (EGSA), and four patients with childhood epilepsy with occipital paroxysms (CEOP) were collected by lumbar puncture before treatment. The concentration of CSF KYA was analyzed by HPLC with electrochemical detection and compared with those of age-matched controls. The levels of CSF KYA were significantly lower (P < 0.05) in patients with WS compared with controls. The levels of CSF KYA in patients with EGSA and with CEOP did not differ significantly from control levels. These results suggest that the presence of seizures in WS is associated with altered kynurenine metabolism. The possibility that seizures in WS may be related to decreased production of KYA is discussed.