Long-Term Synaptic Changes Induced in the Cerebellar Cortex by Fear Conditioning

AbstractTo better understand learning mechanisms, one needs to study synaptic plasticity induced by behavioral training. Recently, it has been demonstrated that the cerebellum is involved in the consolidation of fear memory. Nevertheless, how the cerebellum contributes to emotional behavior is far from known. In cerebellar slices at 10 min and 24 hr following fear conditioning, we found a long-lasting potentiation of the synapse between parallel fibers and Purkinje cells in vermal lobules V-VI, but not in the climbing fiber synapses. The mechanism is postsynaptic, due to an increased AMPA response. In addition, in hotfoot mice with a primary deficiency of the parallel fiber to Purkinje cell synapse, cued (but not contextual) fear conditioning is affected. We propose that this synapse plays an important role in the learned fear and that its long-term potentiation may represent a contribution to the neural substrate of fear memory

Application of multielectrode array (MEA) chips for studying the neurotoxicity of mixtures

In vitro neuronal networks are a simplified and accessible model of the central nervous system. Moreover, they exhibit morphological and physiological properties and activity-dependent path-specific synaptic modification similar to the in vivo tissue. Cortical neurons grown on multi electrode array (MEA) chips have been shown to be a valuable tool to study fundamental properties of neuronal network activity, synaptic plasticity, learning in vitro, and functional pharmacological screening. The variation of spontaneous activity of in vitro neuronal networks coupled to MEAs has been studied using several binary mixtures (inhibitors with different mode of action: Verapamil and Muscimol, Fluoxetine and Muscimol; inhibitors with the same mode of action: Deltamethrin and Permethrin; and an excitatory and an inhibitory compound with different mode of action: Kainic acid and Muscimol) with the aim of characterize and assess their combined effects. Individual dose-response and binary mixtures curves have been generated. Concentration Addition (CA) and Independent Action (IA) frameworks have been used to compare calculated and experimental results. In addition, Nuclear Magnetic Resonance (NMR) spectroscopy has been employed to assess that no chemical reaction or complexation took place between mixtures components, as well as to monitor the presence of potential impurities and, in this case, to evaluate their relative amount in the tested samples. The results suggest that additivity: CA and IA are able to predict in most of the cases the total toxicity of the mixture. The variability of the results makes difficult to assess which of both approaches is the most accurate. The presence of both excitatory and inhibitory effects as in the case of Kainic acid may further complicate the analysis of the experimental datasets and biphasic concentration-dose response curves may be need to analyze the joint effect.JRC.I.6-Systems toxicolog

Genomic and Phenotypic Alterations of the Neuronal-Like Cells Derived from Human Embryonal Carcinoma Stem Cells (NT2) Caused by Exposure to Organophosphorus Compounds Paraoxon and Mipafox

Organophosphorus compounds (OPs) are pesticides of worldwide use due to the acute insecticidal effects mediated by the inhibition of esterases of the central nervous system (mainly acetylcholinesterase and neuropathy target esterase (NTE)). OPs need to inhibit acetylcholinesterase to be effective insecticides, but not NTE since its inhibition might cause progressive, irreversible delayed neuropathy in humans and other species. Additionally, other neurological and neurodevelopmental toxic effects with unknown targets have been reported in humans or animals chronically exposed to OPs. We used a mixed neuronal/glia culture derived from well-characterised human embryonal carcinoma stem cells (hNT2) to determine if neuropathic OP mipafox and non-neuropathic OP paraoxon are able to alter the neuronal differentiation process evaluated by gene expression studies, neuronal electrical activity measurements and neural cell morphology quantification. Exposure to paraoxon at non-cytotoxic concentrations altered the expression of different genes involved mainly in signalling pathways related to chromatin assembly and nucleosome integrity, generating cultures with a larger number of differentiated neurons-like cells and branching points than in the control. Moreover, these paraoxon-exposed neuronal-like cells displayed reduced electrical activity when compared with the control neurons as measured by Micro Electrode Array Chips. Similarly, exposure to mipafox, a known inhibitor of NTE activity, also reduced the electrical activity of hNT2 cultures differentiated into neurons-like cells, but no significant changes in cell morphology or gene expression were detected. Therefore, we conclude that paraoxon is able to strongly disturb in vitro neurodifferentiation, while the absence of morphological and transcriptional alterations did not allow us to conclude if the electrophysiological alterations detected in mipafox-exposed neurons are due to neurodevelopmental toxicity or to effects on mature neurons.JRC.I.2-Public Health Policy Suppor

Development of a pluripotent stem cell derived neuronal model to identify chemically induced pathway perturbations in relation to neurotoxicity: Effects of CREB pathway inhibition

JRC.I.5-Systems Toxicolog

Contributo di ricerca 274/2018. La telemedicina in Piemonte. Una ricognizione dei progetti di telemedicina in Piemonte all'inizio del 2017

Contributo di ricerca 274/2018- Indice #6- Capitolo 1. Obiettivi del lavoro e articolazioni dello studio #10- Capitolo 2. I risultati #12- Capitolo 3. Un'analisi del livello di maturità dei progetti di telemedicina #20- Capitolo 4. Considerazioni finali #2