20^th World Conference on Environmental Toxicology and Pharmacology August 19-20, 2020 Tokyo, Japan

Paula Moyano received his JD degree at the University Complutense University of Madrid in 2013. She has a Masters in Pedagogical Sciences 2017. She specialized in neurotoxicology and legal sciences and received his PhD in Toxicology and legal medicine in 2016\r\n\r\n

Chlorpyrifos (CPF) is an organophosphate insecticide described to induce cognitive disorders, both after acute and repeated administration. However, the mechanisms through which it induces these effects are unknown. CPF has been reported to produce basal forebrain cholinergic neuronal cell death, involved on learning and memory regulation, which could be the cause of such cognitive disorders. Neuronal cell death was partially mediated by oxidative stress generation, P75NTR and α7-nAChRs gene expression alteration triggered through acetylcholinesterase (AChE) variants disruption, suggesting other mechanisms are involved. In this regard, CPF alters glutamatergic transmission, which have been related with basal forebrain cholinergic neuronal cell death and development of cognitive disorders. According to these data, we hypothesized that CPF induces basal forebrain cholinergic neuronal disruption of glutamatergic transmission. We evaluated this hypothesis in septal SN56 basal forebrain cholinergic neurons, after 24 h and 14 days CPF exposure. This study shows that CPF increases glutamate levels. CPF increases glutaminase activity and upregulates the VGLUT1 gene expression, which could mediate the disruption of glutamatergic transmission. Our present results provide new understanding of the mechanisms contributing to the harmful effects of CPF, and its possible relevance in the pathogenesis of neurodegenerative diseases.\r\n\r\n

Javier Del Pino received his PharmD degree at the University Complutense University of Madrid in 2004. He has two Masters in Sciences 2009 and 2010. He specialized in neurotoxicology and neurodevelopmental toxicology and received his PhD in Toxicology in 2009. In 2010 he worked in Institute of Health Carlos III in the National Center of Environmental Health. From 2010 to 2012 he was Associated Researcher at University of Massachusetts (UMASS) working in Sandra Petersen´s Lab in a National Institute of Health (NIH) project on developmental effects of TCDD endocrine disruptor on sexual differentiation. In 2016 he got a position as Associated Professor of Toxicology at the Complutense University of Madrid.\r\n\r\n

Paraquat (PQ) is a widely used non-selective contact herbicide shown to produce memory and learning deficits after acute and repeated exposure similar to those induced in Alzheimer’s disease (AD). However, the complete mechanisms through which it induces these effects are unknown. On the other hand, cholinergic system, mainly in the hippocampus, are involved on learning, memory and cell viability regulation. An alteration of hippocampal cholinergic transmission or neuronal cell loss may induce these effects. In this regard, it has been suggested that PQ may induce cell death and affect cholinergic transmission, which alteration could produce neuronal loss. According to these data, we hypothesized that PQ could induce hippocampal neuronal loss through cholinergic transmission alteration. To prove this hypothesis, we evaluated in hippocampal primary cell culture, the PQ toxic effects after 24 h and 14 consecutive days exposure on neuronal viability and the cholinergic mechanism related to it. This study shows that PQ impaired acetylcholine levels and induced AChE inhibition and increased CHT expression only after 14 days exposure, which suggests that acetylcholine levels alteration could be mediated by these actions. In addition, PQ induced, after 24 h and 14 days exposure, cell death on hippocampal neurons that was partially mediated by AChE variants alteration and cholinergic transmission disruption. Our present results provide new view of the mechanisms contributing to PQ neurotoxicity and may explain cognitive dysfunctions observed after PQ exposure.\r\n\r\n