Opposite effect of quinolinic acid on gastrointestinal motility in mice

Backgrounds: Quinolinic acid (QUIN) is an endogenous metabolite of L-tryptophan produced by kynurenine pathway. Elevated levels have been reported in (neuro)inflammatory diseases of the central nervous system and also in the gastrointestinal tract. Kynurenic acid, another metabolite of the kynurenine pathway, an antagonist of NMDA receptors is neuroprotective, and recent work revealed a modulatory effect on colonic motility in an experimental model of colitis. QUIN is an agonist at glutamate receptors and at high concentrations or after long exposure in moderate concentrations a neuronal excitotoxic effect has b…