Neuroprotection achieved in the ischaemic rat cortex with l-kynurenine sulphate

l-Kynurenine is a metabolic precursor of kynurenic acid, which is one of the few known endogenous N-methyl-d-aspartate receptor inhibitors. In contrast with kynurenic acid, l-kynurenine is transported across the blood-brain barrier, and it may therefore come into consideration as a therapeutic agent in certain neurobiological disorders, e.g. ischaemia-induced events. The present study evaluated the effect of l-kynurenine administration (300 mg/kg i.p.) on the global ischaemic brain cortex both pre- and post-ischemic intervention. The statistical evaluation revealed that l-kynurenine administration beneficially decreased the number of neurones injured per mm2 in the cortex, not only in the pre-treated animals, but also in those which received l-kynurenine after the ischaemic insult. It is concluded that even the post-traumatic administration of l-kynurenine may be of substantial therapeutic benefit in the treatment of global brain ischaemia. This is the first histological proof of the neuroprotective effect achieved by the post-traumatic administration of l-kynurenine in the global ischaemic cortex.