Neuroscience
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Angiopoietin (Ang) is an angiogenic factor, but its neuroprotective and neurotrophic effects have recently come to light. Ang exerts neuroprotective effects by inhibiting neuronal apoptosis, protecting the blood-brain/blood-spinal cord barrier, reducing inflammation and promoting neovascularization. ⋯ In addition, Ang and vascular endothelial growth factor (VEGF) are known to interact in blood vessels in the nervous system and the combination of Ang and VEGF can mitigate the negative effects of VEGF, such as inflammation and local edema. These data indicated that Ang is a novel neuroprotective/neurotrophic factor, which may become a new tool for the treatment of nerve injury.
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We study the transition in the functional networks that characterize the human brains' conscious-state to an unconscious subliminal state of perception by using k-core percolation. We find that the most inner core (i.e., the most connected kernel) of the conscious-state functional network corresponds to areas which remain functionally active when the brain transitions from the conscious-state to the subliminal-state. ⋯ Thus, the inner core and most robust component of the conscious brain corresponds to the unconscious subliminal state. This finding imposes constraints to theoretical models of consciousness, in that the location of the core of the functional brain network is in the unconscious part of the brain rather than in the conscious state as previously thought.
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Parkinson disease (PD) is a leading neurodegenerative disease, with multifaceted interacting mechanisms. The Thy1-aSyn mouse model of PD exhibits many features of PD patients, including sensorimotor and olfactory dysfunction and protein aggregation. Here, we tested the hypothesis that the dipeptide carnosine, which has anti-aggregating and metal-chelating properties, would provide beneficial effects on the motor and olfactory deficits observed in Thy1-aSyn mice. ⋯ In contrast, intranasal carnosine prevented the normal decline in gait function seen in the challenging beam test in the Thy1-aSyn mice. Moreover, carnosine-treated Thy1-aSyn mice exhibited decreased aSyn immunostaining in the olfactory epithelium compared to vehicle-treated Thy1-aSyn mice, and the carnosine transporter Pept2 was immunolocalized to the apical surface of the olfactory epithelium. These findings demonstrate that intranasal carnosine shows promise in slowing the progression of motor deficits and aSyn deposition in PD.
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Insulin Modulates Excitatory Synaptic Transmission and Synaptic Plasticity in the Mouse Hippocampus.
The administration of exogenous insulin into the hippocampus has the potential to enhance cognitive function and exert other beneficial effects. Elucidating the neurobiological substrates of insulin action and its underlying physiological mechanisms may further improve treatment efficacy. Previous work has shown that insulin affects synaptic plasticity, however there are discrepancies and contradictory conclusions between studies. ⋯ Moreover, a broad spectrum protein kinase C blocker, cannabinoid receptor type 1 activator, or a high glucose concentration inhibited fEPSPs per se, and disturbed insulin's effect on fEPSP. Insulin also caused depotentiation during LTP expression and triggered depression during LTD recovery. Given the essential roles of dynamic synaptic transmission and plasticity in learning and memory, our data provide more evidence that insulin application may actively modulate hippocampal-dependent cognitive events.
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Repeated stress induces systemic elevations in glucocorticoid levels. Stress is also associated with alterations in central nervous system astrocytes and oligodendrocytes that involve connexins and myelin proteins. Corticosteroid elevation seems a major factor in stress-induced neuropathology. ⋯ Prolonged exposure to CORT or DEX induced dose-dependent reduction of the myelination index, and of immunostaining for MBP and Cx43 in SC and CC myelination cultures, which was prevented by mifepristone. In glial cultures single CORT or DEX exposure caused shrinkage and simplification of/' MBP- or CNPase-positive oligodendrocyte processes. The results support that concurrent effects of glucocorticoids on myelination and astrocyte Cx43 immunoreactivity are mediated by glucocorticoid receptors and may partially account for the involvement of CNS glia in the pathological effects of prolonged stress.