Formation of endogenous glutamatergic receptors antagonist kynurenic acid - differences between cortical and spinal cord slices

Rat spinal cord slices produced kynurenic acid (KYNA) upon exposure to L-ky nurenine. Aminooxyacetic acid, non-selective aminotransferase inhibitor, an d L-glutamate, but neither N-methyl-D-aspartate (NMDA), alpha-amino-3-hydro xy-5-metyloisoxazolo-4-propionate (AMPA), nor kainate, diminished synthesis of KYNA. L-Glutamate action was less potent in spinal than in cortical sli ces. Metabotropic agonists, L-(+-)-2-amino-4-phosphonobutyrate (L-AP4) and ( +/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (t-ACPD), used in co ncentrations inhibiting cortical KYNA synthesis, were ineffective in spinal cord. Spinal KYNA production seems less susceptible to inhibitory modulati on. (C) 2000 Elsevier Science B.V. All rights reserved.