Neuroscience
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Alzheimer's disease (AD) is the leading cause of dementia worldwide. This pathological condition is characterized not only by Aβ and tau accumulation in the central nervous system (CNS), but also by inflammation, processes that can lead to neurodegeneration. ⋯ Furthermore, cholesterol-associated genes are frequently associated with AD. Here, we extensively reviewed the literature and, based on the existing evidences, we suggest inflammation as an important link between dyslipidemias and AD.
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Mitochondria are key cellular organelles that play crucial roles in the energy production and regulation of cellular metabolism. Accumulating evidence suggests that mitochondrial activity can be modulated by nitric oxide (NO). As a key neurotransmitter in biologic systems, NO mediates the majority of its function through activation of the cyclic guanylyl cyclase (cGC) signaling pathway and S-nitrosylation of a variety of proteins involved in cellular functioning including those involved in mitochondrial biology. ⋯ In this review we highlight the possible mechanisms underlying the noxious effects of excess NO and RNS on mitochondrial function including (i) negative effects on electron transport chain (ETC); (ii) ONOO--mediated alteration in mitochondrial permeability transition; (iii) enhanced mitochondrial fragmentation and autophagy through S-nitrosylation of key proteins involved in this process such as dynamin-related protein 1 (DRP-1) and Parkin/PINK1 (protein phosphatase and tensin homolog-induced kinase 1) complex; (iv) alterations in the mitochondrial metabolic pathways including Krebs cycle, glycolysis, fatty acid metabolism, and urea cycle; and finally (v) mitochondrial ONOO--induced nuclear toxicity and subsequent release of apoptosis-inducing factor (AIF) from mitochondria, causing neuronal cell death. These proposed mechanisms highlight the multidimensional nature of NO and its signaling in the mitochondrial function. Understanding the mechanisms by which NO mediates mitochondrial (dys)function can provide new insights into the treatment of neurodegenerative diseases.
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The hippocampus plays a critical role in learning, memory, and spatial processing through coordinated network activity including theta and gamma oscillations. Recent evidence suggests that hippocampal subregions (e.g., CA1) can generate these oscillations at the network level, at least in part, through GABAergic interneurons. However, it is unclear whether specific GABAergic interneurons generate intrinsic theta and/or gamma oscillations at the single-cell level. ⋯ In contrast, CB1BCs, SCAs, neurogliaform cells, ivy cells, and the remaining PVBCs (17%) produced intrinsic theta, but not gamma, oscillations. These oscillations were prevented by blockers of persistent sodium current. These data demonstrate that the major types of hippocampal interneurons produce distinct frequency bands of intrinsic perithreshold membrane oscillations.
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Both calpain-2 (CALP2) and tumor necrosis factor-α (TNF-α) contribute to persistent bilateral hypersensitivity in animals subjected to L5 ventral root transection (L5-VRT), a model of selective motor fiber injury without sensory nerve damage. However, specific upstream mechanisms regulating TNF-α overexpression and possible relationships linking CALP2 and TNF-α have not yet been investigated in this model. We examined changes in CALP2 and TNF-α protein levels and alterations in bilateral mechanical threshold within 24 h following L5-VRT model injury. ⋯ CALP2 and TNF-α protein induction by L5-VRT were significantly inhibited by pretreatment using the calpain inhibitor MDL28170. Administration of CALP2 to rats without nerve injury further supported a role of CALP2 in the regulation of TNF-α expression. Although clinical trials of calpain inhibition therapy for alleviation of neuropathic pain induced by motor nerve injury have not yet shown success, our observations linking CALP2 and TNF-α provide a framework of a systems' approach based perspective for treating neuropathic pain.
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The amygdala plays a key role in the pathophysiology of depression, but the molecular mechanisms underlying amygdalar hyperactivity in depression remain unclear. In this study, we used a chronic mild stress (CMS) protocol to separate susceptible and insusceptible rat subgroups. Proteomes in the amygdalae were analyzed differentially across subgroups based on labeling with isobaric tags for relative and absolute quantitation (iTRAQ) combined with mass spectrometry. ⋯ This result suggested that CaMKIIβ functions upstream from PSD-95 and GluA1 to affect LTP-based postsynaptic functional plasticity in the amygdalae of susceptible rats. Therefore, amygdalar CaMKIIβ is a potential antidepressant target. Collectively, our findings contribute to a better understanding of amygdalar synaptic plasticity in depression.