Possible Interaction: Kynurenic Acid and Glutamate

“Pretreatments with the non-selective ionotropic glutamatergic-receptor antagonist kynurenic acid or the selective NMDA receptor antagonists AP-7 and LY235959 significantly reduced the hypotensive response to microinjection of L-glu in the LH.”

“ Aortic kynurenic acid production was diminished by modification of the ionic milieu, hypoxia and hypoglycemia, as well as by L-glutamate and L-aspartate, endogenous glutamate receptor agonists, and aminooxyacetic acid, a non-selective inhibitor of aminotransferases and mitochondrial respiration.”

“Aminooxyacetic acid, non-selective aminotransferase inhibitor, and L-glutamate , but neither N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-metyloisoxazolo-4-propionate (AMPA), nor kainate, diminished synthesis of KYNA.”

“Prior injection of kynurenic acid (0.1 micromol), a broad spectrum antagonist of ionotropic excitatory amino acid receptors, completely blocked the circulatory effects of L-proline, significantly reduced those of L-glutamate but had little effect on responses to L-arginine.”

“ KYN (500 and 100 microM) and 7-Cl KYN (10 microM) blocked evoked release of NE by L-GLU (1 mM).”

“The inhibitory effects of 100 microM KYN on evoked release of NE by L-GLU were reversed by 10 microM and 100 microM D-SER and, but not 10 or 100 microM GLY.”

“The spider toxin Argiotoxin636 (threshold 10(-11) M), 2-amino-4-phosphonobutyric acid (AP-4), glutamic acid diethyl ester (GDEE), gamma-D-glutamylaminomethyl-sulfonic acid (GAMS), and kynurenic acid decreased the resting activity and effectively blocked or reversed the effect of L-glutamate and its non-NMDA agonists.”

“The excitatory effect of L-glutamate on PGCL sympathoexcitatory neurons was blocked by iontophoretic applications of kynurenic acid , whereas identical amounts of 8-OH kynurenic acid were ineffective.”

“In addition, on a number of cells kynurenic acid reduced the depolarization evoked by L-glutamate by an equivalent amount and it is thus proposed that the synaptic transmitter is glutamate-like.”