Search

The nervous system has a highly complex organization, including many cell types with multiple functions, with an intricate anatomy and unique structural and functional characteristics. The study of its (dys)functionality following exposure to xenobiotics, neurotoxicology, constitutes an important issue in neurosciences. Despite the extensive use of in vivomodels to reveal the neurotoxicological phenomena, the existence of difficulties related to the increasing cost and time required for neurotoxicity studies with experimental animals, as well as the animal ethical concerns, have limited their use. Consequently, in vitroalternatives, providing an understanding of the mechanistic basis, at the molecular and cellular level, have earned a notable consideration in the field of neurotoxicological research. In this field, the selection of the most appropriate in vitroneuronal system relies on specific endpoints that are of particular relevance for the neurotoxicological phenomena that will be studied. Furthermore, application of specific endpoints to various neuronal cellular models should be done in a careful way to build reliable and feasible testing strategies. This review addresses the use of in vitromodels for neurotoxicity research, aiming to contribute to a better understanding and guidance of in vitroneurotoxicological studies. As such, subcellular systems, namely isolated mitochondria and synaptosomes, and cellular models, including immortalized cell lines, primary cultures, co-cultures, organotypic cultures, neural stem cells and blood–brain barrier models, as well as their inherent advantages and limitations, are discussed.

[Display omitted]

3,4-Methylenedioxymethamphetamine (MDMA or "Ecstasy") is a widely abused, psychoactive recreational drug. There is growing evidence that the MDMA neurotoxic profile may be highly dependent on both its hepatic metabolism and body temperature. Metabolism of MDMA involves N-demethylation to 3,4-methylenedioxyamphetamine (MDA), which is also a drug of abuse. MDMA and MDA are O-demethylenated to N-methyl-alpha-methyldopamine (N-Me-alpha-MeDA) and alpha-methyldopamine (alpha-MeDA), respectively, both of which are catechols that can undergo oxidation to the corresponding ortho-quinones. In the presence of glutathione (GSH), ortho-quinones may be conjugated with GSH to form glutathionyl adducts. In this study, we evaluated the neurotoxicity of MDMA and three of its metabolites obtained by synthesis, N-Me-alpha-MeDA, alpha-MeDA, and 5-(GSH)-alpha-MeDA [5-(glutathion-S-yl)-alpha-methyldopamine] in rat cortical neuronal serum-free cultures under normal (36.5 degrees C) and hyperthermic (40 degrees C) conditions. Cell viability was assessed, and the mechanism of cell death was also evaluated. Our study shows that these metabolites are more neurotoxic [5-(GSH)-alpha-MeDA being the most toxic] than the parent compound MDMA. The neurotoxicity of MDMA metabolites was partially prevented by the antioxidants N-acetylcystein and also, in a minor extent, by alpha-phenyl-N-tert-butyl nitrone. All the tested compounds induced apoptotic cell death in cortical neurons, and their neurotoxic effect was potentiated under hyperthermic conditions. These data suggest that MDMA metabolites, especially under hyperthermic conditions, contribute to MDMA-induced neurotoxicity.