Effect of quinolinic acid administered during pregnancy on the brain of offspring

Elevated kynurenine pathway metabolism during neurodevelopment: Implications for brain and behavior

The kynurenine pathway (KP) of tryptophan degradation contains several neuroactive metabolites that may influence brain function in health and disease. Mounting focus has been dedicated to investigating the role of these metabolites during neurodevelopment and elucidating their involvement in the pathophysiology of psychiatric disorders with a developmental component, such as schizophrenia. In this review, we describe the changes in KP metabolism in the brain from gestation until adulthood and illustrate how environmental and genetic factors affect the KP during development. With a particular focus on kynurenic acid, the antagonist of α7 nicotinic acetylcholine (α7nACh) and N-methyl-d-aspartate (NMDA) receptors, both implicated in modulating brain development, we review animal models designed to ascertain the role of perinatal KP elevation on long-lasting biochemical, neuropathological, and behavioral deficits later in life. We present new data demonstrating that combining perinatal choline-supplementation, to potentially increase activation of α7nACh receptors during development, with embryonic kynurenine manipulation is effective in attenuating cognitive impairments in adult rat offspring. With these findings in mind, we conclude the review by discussing the advancement of therapeutic interventions that would target not only symptoms, but potentially the root cause of central nervous system diseases that manifest from a perinatal KP insult. This article is part of the Special Issue entitled 'The Kynurenine Pathway in Health and Disease'.

Kynurenines in the CNS: from endogenous obscurity to therapeutic importance

In just under 20 years the kynurenine family of compounds has developed from a group of obscure metabolites of the essential amino acid tryptophan into a source of intensive research, with postulated roles for quinolinic acid in neurodegenerative disorders, most especially the AIDS-dementia complex and Huntington's disease. One of the kynurenines, kynurenic acid, has become a standard tool for use in the identification of glutamate-releasing synapses, and has been used as the parent for several groups of compounds now being developed as drugs for the treatment of epilepsy and stroke. The kynurenines represent a major success in translating a basic discovery into a source of clinical understanding and therapeutic application, with around 3000 papers published on quinolinic acid or kynurenic acid since the discovery of their effects in 1981 and 1982. This review concentrates on some of the recent work most directly relevant to the understanding and applications of kynurenines in medicine.

Quinolinic acid: effect on the nucleus arcuatus of the hypothalamus in the rat (ultrastructural evidence)

Quinolinic acid was administered intraperitoneally to male Wistar rats in a dose of 60 mmol, once daily for 8 days. By electron microscopy, in quinolinic acid-treated rats, the neuronal cell bodies in the arcuate nucleus had features of increased cellular activity, but some damage of neuronal cell bodies was also evident.

The effect of quinolinic acid administered during pregnancy on the nigro-striatal complex of rat's offspring: ultrastructural investigation

The nigro-striatal complex of rat's offspring was ultrastructurally examined after quinolinic acid administration to mothers during the gestation period, in order to mimick the congenital metabolic disturbances, resulting from an excess of quinolinic acid within foetal tissues. Hence, quinolinic acid was administered to mothers intraperitoneally in a dose of 60 mmol, once daily, throughout the entire gestation period. Brain specimens were taken on day 5 after birth, from experimental and control animals. Within the nigro-striatal complex there can be distinguished the more characteristic neuronal cell body alterations, and the more toxic effect as the edema signs and the retardment of the neuronal cell body maturity. In the substantia nigra, both swollen and dark-degenerated neuronal cell bodies have been identified, while in the striatum the latter forms predominated. The maturation of neuronal cell bodies was retarded, mainly within the striatum.