Neuroscience
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Extracellular vesicles are lipid bilayer-enclosed extracellular structures. Although the term extracellular vesicles is quite inclusive, it generally refers to exosomes (<200 nm), and microvesicles (~100-1000 nm). Such vesicles are resistant to degradation and can contain proteins, lipids, and nucleic acids. ⋯ The influence that such extracellular vesicles might exert on peripheral nerve regeneration is just beginning to be investigated. In the current studies we show that muscle-derived extracellular vesicles significantly influence the anatomical accuracy of motor neuron regeneration in the rat femoral nerve. These findings suggest a basic cellular mechanism by which target end-organs could guide their own reinnervation following nerve injury.
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The damage of locus coeruleus (LC) noradrenergic neurons and associated with norepinephrine (NE) depletion are early events in Parkinson's disease (PD). Previous study showed that LC/NE neurodegeneration exacerbates dopaminergic neurotoxicity and motor deficits. However, whether the damage of LC/NE neurons contributes to non-motor symptoms in PD remain unclear. ⋯ DSP-4 treatment also exacerbated paraquat and maneb-induced decrease of glutathione peroxidase 4 (GPX4) and glutathione contents as well as increase of lipid peroxidation and expressions of gp91phox and p47phox, two subunits of NADPH oxidase, which are all involved in ferroptosis, in mice. Furthermore, exaggerated microglial activation and M1 polarization were observed in DSP-4 and paraquat and maneb co-treated mice compared with paraquat and maneb alone group. Altogether, our findings revealed a critical role of LC/NE neurodegeneration in mediating learning and memory dysfunction in a two pesticide-induced mouse PD model through ferroptosis and microglia-mediated neuroinflammation, proving novel insights into the pathogenesis of cognitive dysfunction in PD.
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Somatostatin is a neuropeptide thought to play a role in a variety of neuropsychiatric disorders, and is important for healthy aging and behavioral resiliency. Physiological conditions underlying somatostatin peptidergic release are not well-defined. Using a combination of optogenetic and biochemical approaches in transgenic mice, we demonstrate an assay for the induction and inhibition of somatostatin release in mouse acute brain slices.
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Synaptic vesicle protein 2A (SV2A), which plays an important role in the pathophysiology of epilepsy, is a unique vesicular protein recognized as a pharmacological target of anticonvulsant drugs. Furthermore, SV2A is a potential synaptic density marker, as it is ubiquitously expressed throughout the brain in all nerve terminals independently of their neurotransmitter content. Due to the growing interest in this protein, we thoroughly analyzed SV2A levels, expression patterns and colocalization in both excitatory and inhibitory synapses among different brain structures in healthy rats. ⋯ In addition, immunohistochemistry demonstrated slight but consistent asymmetrical SV2A levels in different laminated structures, and SV2A expression was increased by up to 40% in some specific layers compared to that in others. Finally, triple immunofluorescence revealed strong SV2A colocalization with GABAergic terminals, mainly around the principal cells, suggesting that SV2A primarily participates in this inhibitory system in different rat brain structures. Although the SV2A protein is considered a good candidate marker of synaptic density, our data show that changes in its expression in pathological processes must be viewed as not only increased or decreased synapse numbers but also in light of the type of neurotransmission being affected.
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The current evidence suggests that aerobic fitness is associated with inhibitory control of executive functioning in children and older adults. However, the relative contributions of different neurophysiological mechanisms to this relation remain unclear and have not yet been examined in young adults. The present study aimed to compare inhibitory control between high and low-fit young adult men, and to investigate a possible mediation of fitness effects by conflict monitoring (N450 component of event-related potentials) and lateralized oxygenation difference (LOD) in the DLPFC. ⋯ In contrast, LOD was inversely correlated with Stroop interference, but did not explain the relation of aerobic fitness with behavioral performance. The present findings indicate that greater inhibitory control in high- compared to low-fit young men can be explained by more effective conflict monitoring. Moreover, young adults with left-lateralizedDLPFC oxygenation also show higher inhibitory control, but this oxygenation pattern is not influenced by aerobic fitness.