Determination of kynurenic acid levels in rat brain microdialysis samples and changes in kynurenic acid levels induced by N‐acetylaspartic acid

Abstract

The levels of kynurenic acid, an endogenous antagonist of alpha(7) nicotinic acetylcholine and N-methyl-D-aspartate receptors, were measured in microdialysis samples obtained from the prefrontal cortices of rats using column-switching high-performance liquid chromatography with fluorescence detection. When the perfusate was constantly infused at a rate of 1.0 mu/min, the in vitro recovery of kynurenic acid through the dialysis membrane was approximately 20.4%, and the precision was within 1.31%. Endogenous kynurenic acid in the microdialysis sample was clearly detected using column-switching high-performance liquid chromatography. As an application study, N-acetyl-L-aspartic acid, an endogenous metabolite and precursor of N-acetyl-L-aspartyl-L-glutamic acid, which is an agonist of metabotropic glutamate receptors, was infused for 120 min through the microdialysis probe. The kynurenic acid level significantly increased during the infusion of N-acetyl-L-aspartic acid, suggesting that kynurenic acid might have some association with N-acetyl-L-aspartic acid in vivo.

Changes in Extracellular Kynurenic Acid Concentrations in Rat Prefrontal Cortex After d-Kynurenine Infusion: An In vivo Microdialysis Study

“…Column-switching high-performance liquid chromatography (HPLC) [32][33][34] was performed for the fluorescence determination of KYNA levels in the microdialysis samples by using a previously reported technique [31]. The reported KYNA recovery through the probe, with this technique, is 20.4 ± 2.76% [31].…”

“…The reported KYNA recovery through the probe, with this technique, is 20.4 ± 2.76% [31]. The area under the curve (AUC) of the increments in the KYNA levels in the PFC was calculated using a trapezoidal method.…”

“…Surgery and microdialysis were carried out according to the methods described in our previous papers [30,31].…”

Comparative study on kynurenic acid production in the rat striatum by tryptophan enantiomers: An in vivo microdialysis study

“…Male Sprague‐Dawley rats weighing 350–450 g (age, 10–11 wk) were purchased from Charles River Japan (Kanagawa, Japan) and were housed in an environmentally controlled room for at least 1 wk before use. Surgery and MD were carried out according to the methods described in our previous articles 13, 16…”

Determinación de cis-/trans-Estilbenos (Resveratrol y Piceido), Triptófano y Metabolitos en productos apícolas por cromatografía de líquidos

“…El triptófano (TRP), que es uno de los diez aminoácidos esenciales para muchos organismos, juega un papel importante en la síntesis de proteínas, el KYNA es un metabolito del TRP formado a través de la vía de la kinurenina (KYN) que se considera ubicua en los sistemas vivos, por lo que su determinación es de gran interés por sus funciones biológicas y sus propiedades bioquímicas [67,68] . La mayoría de sus acciones parecen ser causadas por un antagonismo no competitivo que ejerce el ácido en un subtipo de los receptores de glutamato [69,70] , bloqueando la neurotoxicidad inducida por otros metabolitos del TRP tales como el ácido quinolínico [71][72][73] .…”