Academic literature on the topic 'Glial cells. eng'

The diverse functions of glial cells prompt the question to which extent specific subtypes may be devoted to a specific function. We discuss this by reviewing one of the most recently discovered roles of glial cells, their function as neural stem cells (NSCs) and progenitor cells. First we give an overview of glial stem and progenitor cells during development; these are the radial glial cells that act as NSCs and other glial progenitors, highlighting the distinction between the lineage of cells in vivo and their potential when exposed to a different environment, e.g., in vitro. We then proceed to the adult stage and discuss the glial cells that continue to act as NSCs across vertebrates and others that are more lineage-restricted, such as the adult NG2-glia, the most frequent progenitor type in the adult mammalian brain, that remain within the oligodendrocyte lineage. Upon certain injury conditions, a distinct subset of quiescent astrocytes reactivates proliferation and a larger potential, clearly demonstrating the concept of heterogeneity with distinct subtypes of, e.g., astrocytes or NG2-glia performing rather different roles after brain injury. These new insights not only highlight the importance of glial cells for brain repair but also their great potential in various aspects of regeneration.

According to recent evidence, acupuncture at Tsusanli (ST 36) can regulate gastric activity. And this regulation mainly depends upon neural basis or structure and may probably relate to the central neurons in the dorsal vagal complex. However, whether the glias of the dorsal vagal complex participate in the regulation of gastric activity, when electro-acupuncture (EA) at Tsusanli, still remains to be interpreted. In this study, we observed the effect of EA at Tsusanli (ST 36) on regulation of gastric activity. Propentofylline (PPF), a glial metabolic inhibitor, was used to inhibit the function of glial cells. EA at Tsusanli showed that the expressions of glial fibrillary acidic protein (GFAP) and OX42 increased significantly compared to that of the control group, and gastric electric change was obvious, with significantly higher frequency and wave amplitude compared to the control group. The expressions of GFAP and OX42 were decreased markedly when pretreated with PPF group than without PPF pretreatment group. Compared to the Tsusanli group and the control group, the changes of electro gastric graph (EGG) were significantly decreased in PPF pretreatment group. On the other hand, we observed the changes of spontaneous electro-activity of the DVC (dorsal vagal complex) in our previous experiment. The results indicated that EA at Tsusanli could activate glial cells in the dorsal vagal complex and regulate gastric activity. PPF blocked the function of glia, thus the effect of EA at Tsusanli on gastric activity was weakened. Our study suggested that this electro-acupuncture regulation of gastric activity was possibly related with glia of the dorsal vagal complex.

In adult olfactory nerves of mammals and moths, a network of glial cells ensheathes small bundles of olfactory receptor axons. In the developing antennal nerve (AN) of the moth Manduca sexta, the axons of olfactory receptor neurons (ORNs) migrate from the olfactory sensory epithelium toward the antennal lobe. Here we explore developmental interactions between ORN axons and AN glial cells. During early stages in AN glial-cell migration, glial cells are highly dye coupled, dividing glia are readily found in the nerve and AN glial cells label strongly for glutamine synthetase. By the end of this period, dye-coupling is rare, glial proliferation has ceased, glutamine synthetase labeling is absent, and glial processes have begun to extend to enwrap bundles of axons, a process that continues throughout the remainder of metamorphic development. Whole-cell and perforated-patch recordings in vivo from AN glia at different stages of network formation revealed two potassium currents and an R-like calcium current. Chronic in vivo exposure to the R-type channel blocker SNX-482 halted or greatly reduced AN glial migration. Chronically blocking spontaneous Na-dependent activity by injection of tetrodotoxin reduced the glial calcium current implicating an activity-dependent interaction between ORNs and glial cells in the development of glial calcium currents.

Glia play key roles in the regulation of neurotransmission in the nervous system. Fluoroacetate (FA) is a metabolic poison widely used to study glial functions by disrupting the tricarboxylic acid cycle enzyme aconitase. Despite the widespread use of FA, the effects of FA on essential glial functions such as calcium (Ca2+) signaling and hemichannel function remain unknown. Therefore, our goal was to assess specifically the impact of FA on essential glial cell functions that are involved with neurotransmission in the enteric nervous system. To this end, we generated a new optogenetic mouse model to study specifically the effects of FA on enteric glial Ca2+ signaling by crossing PC::G5-tdTomato mice with Sox10::creER T2 mice. FA did not change the peak glial Ca2+ response when averaged across all glia within a ganglion. However, FA decreased the percent of responding glia by 30% ( P < 0.05) and increased the peak Ca2+ response of the glial cells that still exhibited a response by 26% ( P < 0.01). Disruption of Ca2+ signaling with FA impaired the activity-dependent uptake of ethidium bromide through connexin-43 (Cx43) hemichannels ( P < 0.05) but did not affect baseline Cx43-dependent dye uptake. FA did not cause overt glial or neurodegeneration, but glial cells significantly increased glial fibrillary acid protein by 56% ( P < 0.05) following treatment with FA. Together, these data show that the acute impairment of glial metabolism with FA causes key changes in glial functions associated with their roles in neurotransmission and phenotypic changes indicative of reactive gliosis. NEW & NOTEWORTHY Our study shows that the acute impairment of enteric glial metabolism with fluoroacetate (FA) alters specific glial functions that are associated with the modification of neurotransmission in the gut. These include subtle changes to glial agonist-evoked calcium signaling, the subsequent disruption of connexin-43 hemichannels, and changes in protein expression that are consistent with a transition to reactive glia. These changes in glial function offer a mechanistic explanation for the effects of FA on peripheral neuronal networks.

AbstractManagement of chronic pain is a real challenge, and current treatments that focus on blocking neurotransmission in the pain pathway have resulted in limited success. Activation of glial cells has been widely implicated in neuroinflammation in the CNS, leading to neurodegeneration in conditions such as Alzheimer's disease and multiple sclerosis. The inflammatory mediators released by activated glial cells, such as tumor necrosis factor-α and interleukin-1β not only cause neurodegeneration in these disease conditions, but also cause abnormal pain by acting on spinal cord dorsal horn neurons in injury conditions. Pain can also be potentiated by growth factors such as brain-derived growth factor and basic fibroblast growth factor, which are produced by glia to protect neurons. Thus, glial cells can powerfully control pain when they are activated to produce various pain mediators. We review accumulating evidence that supports an important role for microglial cells in the spinal cord for pain control under injury conditions (e.g. nerve injury). We also discuss possible signaling mechanisms, in particular mitogen-activated protein kinase pathways that are crucial for glial-mediated control of pain. Investigating signaling mechanisms in microglia might lead to more effective management of devastating chronic pain.

Heme oxygenase (HO) catabolizes heme to produce HO metabolites, such as carbon monoxide (CO) and bilirubin (BR), which have gained recognition as biological signal transduction effectors. The neurovascular unit refers to a highly evolved network among endothelial cells, pericytes, astrocytes, microglia, neurons, and neural stem cells in the central nervous system (CNS). Proper communication and functional circuitry in these diverse cell types is essential for effective CNS homeostasis. Neuroinflammation is associated with the vascular pathogenesis of many CNS disorders. CNS injury elicits responses from activated glia (e.g., astrocytes, oligodendrocytes, and microglia) and from damaged perivascular cells (e.g., pericytes and endothelial cells). Most brain lesions cause extensive proliferation and growth of existing glial cells around the site of injury, leading to reactions causing glial scarring, which may act as a major barrier to neuronal regrowth in the CNS. In addition, damaged perivascular cells lead to the breakdown of the blood-neural barrier, and an increase in immune activation, activated glia, and neuroinflammation. The present review discusses the regenerative role of HO metabolites, such as CO and BR, in various vascular diseases of the CNS such as stroke, traumatic brain injury, diabetic retinopathy, and Alzheimer’s disease, and the role of several other signaling molecules.

Radial glia have been classically defined as those early glial cells that radially span their thin processes from the ventricular to the pial surfaces in the developing central nervous system. These radial glia constitute a transient cell population, disappearing, for the most part, by the end of the period of neuronal migration. Traditionally, it has been difficult to definitively identify these cells because the principal criteria available were morphologic only.Using immunofluorescence microscopy, we have previously defined a phenotype for radial glia in rat spinal cord based upon the sequential expression of vimentin, glial fibrillary acidic protein and an intermediate filament-associated protein, IFAP-70/280kD. We report here the application of another intermediate filament-associated protein, IFAP-300kD, originally identified in BHK-21 cells, to the immunofluorescence study of radial glia in the developing rat spinal cord.Results showed that IFAP-300kD appeared very early in rat spinal cord development. In fact by embryonic day 13, IFAP-300kD immunoreactivity was already at its peak and was observed in most of the radial glia which span the spinal cord from the ventricular to the subpial surfaces (Fig. 1). Interestingly, from this time, IFAP-300kD immunoreactivity diminished rapidly in a dorsal to ventral manner, so that by embryonic day 16 it was detectable only in the maturing macroglial cells in the marginal zone of the spinal cord and the dorsal median septum (Fig. 2). By birth, the spinal cord was essentially immuno-negative for this IFAP. Thus, IFAP-300kD appears to be another differentiation marker available for future studies of gliogenesis, especially for the early stages of radial glia differentiation.

Glial progenitor cells are widely distributed in brain parenchyma and represent a suitable target for future therapeutic interventions that generate new neurons via in situ reprogramming. Previous studies have shown successful reprogramming of mouse glia into neurons whereas the conversion of human glial cells remains challenging due to the limited accessibility of human brain tissue. Here, we have used a recently developed stem cell-based model of human glia progenitor cells (hGPCs) for direct neural reprogramming by overexpressing a set of transcription factors involved in GABAergic interneuron fate specification. GABAergic interneurons play a key role in balancing excitatory and inhibitory neural circuitry in the brain and loss or dysfunction of these have been implicated in several neurological disorders such as epilepsy, schizophrenia, and autism. Our results demonstrate that hGPCs successfully convert into functional induced neurons with postsynaptic activity within a month. The induced neurons have properties of GABAergic neurons, express subtype-specific interneuron markers (e.g. parvalbumin) and exhibit a complex neuronal morphology with extensive dendritic trees. The possibility of inducing GABAergic interneurons from a renewable in vitro hGPC system could provide a foundation for the development of therapies for interneuron pathologies.

The enteric nervous system (ENS) constitutes the largest part of the peripheral nervous system. In recent years, ENS development and its neurogenetic capacity in homeostasis and allostasishave gained increasing attention. Developmentally, the neural precursors of the ENS are mainly derived from vagal and sacral neural crest cell portions. Furthermore, Schwann cell precursors, as well as endodermal pancreatic progenitors, participate in ENS formation. Neural precursors enherite three subpopulations: a bipotent neuron-glia, a neuronal-fated and a glial-fated subpopulation. Typically, enteric neural precursors migrate along the entire bowel to the anal end, chemoattracted by glial cell-derived neurotrophic factor (GDNF) and endothelin 3 (EDN3) molecules. During migration, a fraction undergoes differentiation into neurons and glial cells. Differentiation is regulated by bone morphogenetic proteins (BMP), Hedgehog and Notch signalling. The fully formed adult ENS may react to injury and damage with neurogenesis and gliogenesis. Nevertheless, the origin of differentiating cells is currently under debate. Putative candidates are an embryonic-like enteric neural progenitor population, Schwann cell precursors and transdifferentiating glial cells. These cells can be isolated and propagated in culture as adult ENS progenitors and may be used for cell transplantation therapies for treating enteric aganglionosis in Chagas and Hirschsprung’s diseases.

The ability to automatically detect and classify populations of cells in tissue sections is paramount in a wide variety of applications ranging from developmental biology to pathology. Although deep learning algorithms are widely applied to microscopy data, they typically focus on segmentation which requires extensive training and labor-intensive annotation. Here, we utilized object detection networks (neural networks) to detect and classify targets in complex microscopy images, while simplifying data annotation. To this end, we used a RetinaNet model to classify genetically labeled neurons and glia in the brains of Mosaic Analysis with Double Markers (MADM) mice. Our initial RetinaNet-based model achieved an average precision of 0.90 across six classes of cells differentiated by MADM reporter expression and their phenotype (neuron or glia). However, we found that a single RetinaNet model often failed when encountering dense and saturated glial clusters, which show high variability in their shape and fluorophore densities compared to neurons. To overcome this, we introduced a second RetinaNet model dedicated to the detection of glia clusters. Merging the predictions of the two computational models significantly improved the automated cell counting of glial clusters. The proposed cell detection workflow will be instrumental in quantitative analysis of the spatial organization of cellular populations, which is applicable not only to preparations in neuroscience studies, but also to any tissue preparation containing labeled populations of cells.

Orientadora: Márcia Rita Fernandes Machado
Banca: José Antonio Thomazini
Banca: Luiza da Silva Lopes
Banca: Áureo Evangelista Santana
Banca: Marcos Lania de Araujo
Resumo: Diversos estudos mostraram que a ingestão de dieta com níveis inadequados de ferro pode causar, no sistema nervoso central (SNC) de ratos, alterações morfológicas, bioquímicas e comportamentais no animal. Esses estudos têm ainda indicado que animais deficientes em ferro apresentam redução no número de lamelas de mielina e prejuízos na aprendizagem. A deficiência de ferro é uma das mais comuns desordens nutricionais em pacientes pediátricos e adultos e atinge cerca de 2,5 a 5 bilhões de pessoas em todo mundo. A consequência mais explícita da deficiência de ferro é a anemia. O ferro está relacionado ao desenvolvimento de fibras nervosas mielínicas, as quais constituem mais de 80% do nervo óptico. Objetivou-se, na presente investigação, avaliar com o auxílio de microscopia eletrônica de transmissão, os possíveis efeitos da anemia ferropriva na estrutura do nervo óptico de ratos Wistar durante os períodos de lactação e pós-lactação. Os animais foram divididos em 2 grupos: Controle e Anêmico. Os anêmicos receberam uma dieta com 4 mg de ferro/Kg, e os controle, uma dieta com 35 mg de ferro/Kg. Avaliações do peso corpóreo, hemoglobina e hematócrito foram feitas para checar os efeitos da deficiência de ferro. Os animais foram anestesiados com cloridrato de quetamina IM (22 mg/Kg) e então sacrificados por perfusão transcardíaca com PBS 0,05M, pH 7,4, seguido da mistura fixadora paraformaldeído 2% e glutaraldeído 1% diluída em tampão fosfato. Um segmento do nervo óptico foi retirado e pós-fixado em solução de tetróxido de ósmio a 1% por duas horas a 4ºC, desidratado em acetona e incluído em araldite. Cortes ultra-finos com 60 nanômetros de espessura foram montados em grades de cobre, contrastados com acetato de uranila e citrato de chumbo, observados e fotografados ao microscópio eletrônico de transmissão para detalhada análise ultraestrutural... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Several studies showed that ingestion of diets with inadequate iron levels can cause morphological, biochemical and behavioral changes in the central nervous system (CNS) of rats. These studies have also shown that iron-deficient animals have reduced number of myelin lamellae and prejudice on learning. Iron deficiency is one of the most common nutritional disorders in pediatric patients and adults and affects about 2.5-5 billion people around the world. The most explicit result of iron deficiency is anemia. The iron is related to the development of myelinated nerve fibers, which constitute more than 80% of the optic nerve. The aim of this research is to evaluate, with transmission electronic microscopy, the possible effects of iron deficiency anemia in Wistar rats optic nerve structure during lactation and pos-lactation period. The animals were divided into 2 groups: Control and Anemic. The anemic group received 4 mg iron/Kg, the control group received 35 mg iron/Kg. Evaluation of body weight, hemoglobin and hematocrit were made to check the iron deficiency effects. The animals were anesthetized with ketamine 22 mg/Kg and then sacrificed by transcardiac perfusion with PBS 0.05 M, pH 7.4, followed by paraformaldehyde fixative mixture 2% and 1% glutaraldehyde. An optic nerve segment was removed and post-fixed in a solution of osmium tetroxide for two hours at 4°C, dehydrated in acetone and embedded in Araldite. Ultrathin sections with 60 nanometers thick were mounted on copper grids, contrasted with uranyl acetate and lead citrate, observed and photographed by transmission electronic microscope for detailed ultrastructural analysis of nerve fibers, blood vessels and glial cells. Both hematological and body weight were smaller in the anemic group. The ultrastructural analysis showed damaged myelinated and unmyelinated fibers, and glial cells of the anemic animals when compared with... (Complete abstract click electronic access below)
Doutor

Alveolar macrophages reside in the healthy airspaces and are continuously exposed to environmental challenges. As such, mechanisms are in place to restrict their activity, including negative regulation by epithelial cells. Upon encountering a harmful pathogen, this inhibition is lost and pattern recognition receptors, such as toll-like receptors (TLRs), are activated. This stimulates the release of type I interferons, which exert anti-microbial actions on airway cells. The importance of neurotrophic factors in the immune response is becoming well established. However, research into their role in airway homeostasis and infectious disease is lacking. Therefore, in this thesis I aimed to determine which neurotrophic factors were highly expressed on airway macrophages and elucidate their potential role in homeostasis, as well as microbial clearance, of the airway. In this thesis, I have found that the glial cell line-derived neurotrophic factor (GDNF) family receptor, GFRα2, is highly expressed on mouse and human airway macrophages at steady state. However, the expression of the signalling partner for the GFRα receptors, the tyrosine kinase RET, is specifically induced in airway macrophages by type I interferons. Furthermore, TLR activation enhances the production and release of the GFRα2 ligand, neurturin, from airway epithelial cells. Therefore, I propose a novel role for the GDNF family in infectious disease, through modulation of airway macrophage anti-microbial activity.

There is increasing evidence that inflammatory processes play a pivotal role in the pathophysiology of ischaemic brain injury. Cerebrovascular endothelial cells that form the blood-brain barrier are critical for maintaining brain homeostasis, however, during cerebral ischaemia they contribute to the post-ischaemic inflammatory responses. It is not yet fully understood how different cerebral cells interact during this inflammatory response. This study aimed to test the hypothesis that oxygen-glucose deprivation (OGD) induces the inflammatory activation of the cerebrovascular endothelium and glial cells in vitro and that intercommunication between these cells regulate their responses to OGD. Primary murine brain endothelial cells (MBECs) monocultures, murine mixed-glial monocultures and MBEC-glial co-cultures were exposed to OGD for up to 24 hours (h), then reperfused cultures were returned to normoxia for a further 24 hours. MBECs and glia remained viable over a 24 h OGD exposure and during reperfusion. OGD induced a time-dependent increase in MBEC glucose transporter 1 (GLUT-1) expression but a time-dependent decline in expression and secretion of monocyte chemoattractant protein-1 (MCP-1). A significant increase in keratinocyte-derived chemokine (KC) secretion by MBEC monocultures was observed during reperfusion after prolonged exposure (18-24 h) to OGD whereas, KC secretion by co-cultured MBECs was increased during reperfusion after short exposure (4 h) to OGD. Co-cultured MBECs displayed a significant increase in intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression in response to a short or prolonged exposure to OGD with 24 h of reperfusion. Neither OGD nor reperfusion had any effect on permeability of the MBEC monolayer. OGD induced a time-dependent increase in nuclear stabilisation of hypoxia inducible factor-1 alpha (HIF-1α) in glial cells which correlated to vascular endothelial growth factor (VEGF) secretion during OGD and subsequent reperfusion. Nuclear stabilisation of the nuclear factor kappa B (NFκB)p65 subunit by glial cells was dependent upon the duration of OGD. Reperfusion induced a significant increase in KC secretion by co-cultured glial cells after short exposure to OGD. Inflammatory activation of co-cultured MBECs and glia after 4 or 24 h OGD caused a significant increase in neutrophil transendothelial migration which correlated with MBEC expression of ICAM-1 and VCAM-1. A combination of these cell adhesion molecules with neutrophil integrins and soluble glial-derived mediators contributed to neutrophil transendothelial migration. These studies provide evidence that combined hypoxia and glucose withdrawal induces the activation of MBECs and glial cells in vitro. Cross-talk between these two cell types may further regulate their activation. As a result of this inflammatory activation, soluble MBEC and glial-derived mediators may contribute to neutrophil transendothelial migration through the regulation of MBEC cell adhesion molecule expression.

Thesis (Ph.D.)--University of Florida, 2004.
Typescript. Title from title page of source document. Document formatted into pages; contains 87 pages. Includes Vita. Includes bibliographical references.

The enteric nervous system (ENS) continues its development after birth, with formation of ganglia and functional synapses; plasticity is also demonstrated in significant axon growth that occurs after experimental colitis in the adult colon. However, little is known about factors in the postnatal intestine that influence and regulate these processes. Therefore we tested the effects of known neurotrophins, NGF, NT-3, BDNF and GDNF on neonatal rat myenteric neurons. Cocultures were developed by isolating the myenteric plexus and surrounding muscular wall from neonatal rats, and effects of exogenous treatment of neurotrophins were analyzed using immunocytochemistry and image analysis. Western blotting and immunocytochemistry were performed to detect implicated neurotrophins and their receptors in the postnatal intestine. Functional aspects of effects of implicated neurotrophins were assessed by [3H]choline uptake and acetylcholine release in myenteric neurons. Last, TNBS-colitis was induced in adult rats to determine changes in GDNF secretion during the course of the disease. Application of 100ng/mL GDNF to a neonatal intestinal coculture containing neurons, glia and smooth muscle cells produced a 91.5% (p≤0.05) increase in axons. GDNF induced morphological changes in the structure and organization of neurons and axons; the incidence of neurons present in ganglia increased by 11.2% (p≤0.05), with a 32.9% (p≤0.05) increase in aggregated axons. Western blotting and immunocytochemistry confirmed intestinal smooth muscle as the major source of GDNF and demonstrated the presence of the GDNF receptor complex, GFRα1 and RET in the myenteric plexus. Choline uptake significantly increased at 50, 100 and 150ng/ml doses of GDNF, whereas stimulated ACh release increased only at 100 and 150ng/ml doses. In TNBS-colitis, a decrease in 35kD GDNF at days 1 and 6 post-induction of inflammation was observed, with a concomitant increase in 15kD GDNF. We conclude that GDNF, produced by intestinal smooth muscle, is a key factor influencing development of the postnatal myenteric neuron and may play a role in ENS-restructuring post-inflammation.
Thesis (Master, Physiology) -- Queen's University, 2008-09-03 13:27:23.042

Dissertação de Mestrado em Bioquímica apresentada à Faculdade de Ciências e Tecnologia
A imunidade inata é a primeira linha de defesa efectiva de todos os organismos,englobando mecanismos moleculares e celulares com vista a uma acção imediata, reconhecendopadrões moleculares associados a patogénios de origem externa (PAMPs), bem como, padrõesmoleculares associados a uma ameaça de origem interna (DAMPs). Esse reconhecimento épossível através de diversos receptors de reconhecimento padrão (PRRs), orquestrando, assim, aactivação de respostas imunes. Um destes receptores é o receptor dos produtos de glicaçãoavançada (RAGE, também conhecido por AGER), que é um receptor, localizado à superfície dascélulas, pertencendo à superfamília de proteinas imunoglobulinas, tendo um papel central naresposta inflamatória, mediando acções na imunidade inata. Para além do mais, o receptor RAGEtem sido implicado na neurotoxicidade e activação das células da glia. É de salientar que esterecptor é expresso em muitos tipos de células incluíndo as células do sistema nervoso central(CNS) como os neurónios, microglia, astrócitos. De notar também que, sendo um receptor queinterage com multiplos ligandos, RAGE é capaz de reconhecer um largo espectro de diferentesfamílias de ligandos estruturalmente diversos, incluíndo o ligando S100β, pertencente à famíliade proteínas S100.Nos dias de hoje, o consumo inadequado e a adição de drogas de abuso, incluíndo a diçãodos estimulantes do tipo das anfetaminas (ATS), é um problema sério e verificado em todo omundo, com inegável impacto na saúde pública, direitos humanos e na segurança. A par destesaspectos, a rápida difusão e abuso de novas substâncias psicoactivas (new psychoactivesubstances, NPS), também conhecidas como “substâncias químicas de pesquisa” ou “drogasdesenhadas”, engloba a catinonas sintética, Methylenedioxypyrovalerone (MDPV), designadapor “sais de banho”, claramente parece piorar a actual situação, já que é usada como um substitutode estimulantes ilegais, como a cocaína. O acesso incrivelmente facilitado a estas catinonas, comoo MDPV, no mercado de drogas global, através das “smart shops”, internet (“darknet”), e oaspecto da “falsa legalidade” destas substâncias, assim como, o relativo baixo custo e a suaqualidade, comparativamente a outras drogas tradicionais, são factores que têm contribuído paraa sua crescente popularidade.Ultimamente, têm sido investigados novos aspectos dentro do tema das drogas de abuso.A título de exemplo, existem cada vez mais evidências no que diz respeito à methanphetamina naimunidade inata central e periférica. Contudo, os efeitos de catinonas (como o MDPV) naimunidade inata central ainda estão por investigar. Neste sentido, este trabalho tem como principalfoco, caraterizar, pela primeira vez o impacto do MDPV nas células da glia, no cortéx frontal enos intervenientes da imunidade inata, incluíndo o receptor dos productos de glicação avançada(RAGE) e o sei ligando S100 β, 24 houras após a um regime binge de MDPV.Para além disso, o perfil comportamental dos roedores após a administração do MDPVestá pouco documentado, em comparação com a METH. Assim sendo, o nosso objectivo comeste trabalho foi caraterizar, pela primeira vez, o impacto do MDPV no cortéx frontal,nomeadamente nas células da glia e nos intervenientes da imunidade inata, incluíndo o receptordos produtos de glicação avançada (RAGE) e o seu ligando S100β, nas 24 horas após um regimede “binging”. Em paralelo à administração de MDPV, também foi administrada uma dosagemigualmente aguda de METH, no sentido de aumentar os actuais conhecimentos sobre aneurotoxicidade da METH.Assim, em primeiro lugar, e no que diz respeito ao perfil comportamental, o nosso estudooferece a primeira evidência de que um episódio de administração aguda de MDPV não acarretouperturbações emocionais nem locomoras, aumentando, no entanto, e curiosamente, a actividadeexploratória nos ratinhos. Em segundo lugar, ficou demonstrado que nem o MDPV nem a METHinfluenciaram os parametros de neurotoxicidade relacionados com as células da microglia, célulasastrocíticas, fibras de mielina, bem como, com marcadores dopaminergicos. Tal foi comprovadopelos níveis inalterados de Iba-1, GFAP, S100β, MBP e TH, respectivamente. Para além do mais,concluímos que nenhuma droga influenciou marcadamente os níveis de expressão ou os níveis deproteína total correspondentes ao receptor RAGE.Finalmente, não podemos descartar a hipótese de esta janela temporal de 24 horascorresponder a uma fase prematura para observar quaisquer alterações moleculares e celularessignificativas, induzidas por ambos os psicoestimulantes, no cortéx frontal. Neste contexto,estudos posteriores serão necessários para caraterizar os efeitos, neuronais e ao nível das célulasda glia, do MDPV, que podem passar, quer pela adopção de outras janelas temporais, quer poroutros regimes de administração, ou ainda quer pela avaliação numa outra área cerebral.
Innate immunity is the first effective line of defense of all organisms, comprising cellularand molecular mechanisms for immediate action, recognizing exogenous pathogen associatedmolecular patterns (PAMPs), as well as, endogenous danger associated molecular patterns(DAMPs). Such detection is possible through diverse pattern recognition receptors (PRRs),thereby orchestrating the activation of innate responses. One of these receptors is the receptor foradvanced glycation end-products (RAGE, also known as AGER), which is a cell-surface receptorbelonging to the superfamily of immunoglobulin proteins, thus playing a central role in theinflammatory response mediating events of innate immunity. Moreover, RAGE has beenimplicated in the sustainment of glial activation and neurotoxicity. Noteworthy, RAGE receptorexhibits broad expression on many different cells including CNS cells, such as neurons, microgliaand astrocytes. Also, as a multiligand receptor, RAGE recognizes a broad repertoire ofstructurally different ligand families, including S100β, belonging to the S100 protein family.Nowadays, drug misuse, including amphetamine-type stimulants (ATS) addiction, is amajor worldwide issue with an undeniable impact on public health, human rights and security. Inparallel, the rapid emergence and abuse of new psychoactive substances (NPS), also termed as“research chemicals” or “design drugs”, including the synthetic cathinone,Methylenedioxypyrovalerone (MDPV), known as "bath salt", clearly seems to worsen thisscenario, as it acts as a substitute for illegal stimulant drugs such as cocaine. The incredibly easyaccess to these cathinones, including the newly synthesized MDPV, in the global drug market,through smart shops, internet (“darknet”), and the aspect of“fake legallyness” of such substances,as well as the relative affordability and better quality compared with traditional drugs, are on thebasis of some of the reasons underlying their increasing popularity.In the last decades, a great deal of attention has been drawn to the aspects underlyingmethamphetamine (METH; an ATS)-induced neurotoxicity, in many brain regions. Nevertheless,little is known regarding MDPV neurotoxicity, including in frontal cortex, which is known to beaffected by drugs of abuse. Additionally, the behavioral profile of rodents after drugadministration is poorly documented for MDPV, in comparison with METH.Additionally, novel avenues in drug addiction sciences are being explored. As anexample, there is a growing body of evidence regarding the impact of drugs of abuse includingMETH to both peripheral and central innate immunity. However, the effects of new cathinones(including MDPV) in the central innate immunity remain unknown. Therefore, this thesis aimedto characterize, for the first time, the impact of MDPV on frontal cortex glial cells and innateimmune players including receptor for advanced glycation end-products (RAGE) and its ligand S100β, within first 24 hours following a binge MDPV regimen. In addition, emotional behaviorwas assessed. A binge neurotoxic regimen of METH was also employed to deepen currentknowledge on METH neurotoxicity.Concerning the behavioral profile, we offer a first evidence that a single binge MDPVregimen did not come with any changes in both emotional and locomotor parameters, butcuriously enhanced exploratory activity in mice. Secondly, we concluded that neither drugimpose any changes in innate immunity as well as in neurotoxicity parameters includingmicroglial, astrocytic, myelin and dopaminergic markers, as seen by the unaltered levels ofRAGE, S100β, Iba-1, GFAP and, MBP and TH, respectively.One cannot exclude the hypothesis whereby this is a premature time-window to observesignificative molecular changes in frontal cortices following both stimulants. In this context,future studies are required to further characterize neuronal and glial effects of MDPV by usingother time-points, dosing regimens and brain regions.

The purpose of this chapter is to familiarize the reader with the basic electrical patterns of the electroencephalogram (EEG). Brain cells (mainly neurons and glia) are organized in multiple levels of intricate networks. The cellular membranes are semipermeable media between extracellular and intracellular solutions, populated by ions and other electrically charged molecules. This represents the basis of electrical currents flowing across cellular membranes, further generating electromagnetic fields that radiate to the scalp electrodes, which record changes in the activity of brain cells. This chapter presents these concepts together with the mechanisms of building up the EEG signal. The chapter discusses the various behavioral conditions and neurophysiological mechanisms that modulate the activity of cells leading to the most common EEG patterns, such as the cellular interactions for alpha, beta, gamma, slow, delta, and theta oscillations, DC shifts, and some particular waveforms such as sleep spindles and K-complexes and nu-complexes.

Physiological pain is evoked by intense (noxious) stimuli acting on healthy tissue functioning as a warning signal to avoid damage of the tissue. In contrast, pathophysiological pain is present in the course of disease, and it is often elicited by low-intensity stimulation or occurs even as resting pain. Causes of pathophysiological pain are either inflammation or injury causing pathophysiological nociceptive pain or damage to nerve cells evoking neuropathic pain. The major peripheral neuronal mechanism of pathophysiological nociceptive pain is the sensitization of peripheral nociceptors for mechanical, thermal and chemical stimuli; the major peripheral mechanism of neuropathic pain is the generation of ectopic discharges in injured nerve fibres. These phenomena are created by changes of ion channels in the neurons, e.g. by the influence of inflammatory mediators or growth factors. Both peripheral sensitization and ectopic discharges can evoke the development of hyperexcitability of central nociceptive pathways, called central sensitization, which amplifies the nociceptive processing. Central sensitization is caused by changes of the synaptic processing, in which glial cell activation also plays an important role. Endogenous inhibitory neuronal systems may reduce pain but some types of pain are characterized by the loss of inhibitory neural function. In addition to their role in pain generation, nociceptive afferents and the spinal cord can further enhance the inflammatory process by the release of neuropeptides into the innervated tissue and by activation of sympathetic efferent fibres. However, in inflamed tissue the innervation is remodelled by repellent factors, in particular with a loss of sympathetic nerve fibres.

This chapter assesses the linked processes of brain growth and development. Each human life begins with the union of a sperm and an egg. Embryogenesis is the process by which the fertilized egg divides repeatedly to produce the 37 trillion cells that make up a person. But embryo development is about far more than just this dramatic increase in cell number. It also involves the formation of all the specialised cell types of the body, and their organization into tissues and organs. Initially, the embryo is just a ball of cells called a blastocyst. But then a dramatic transformation takes place called gastrulation, which is a key event in the formation of a human being. While these are the gross structural changes underlying brain development, equally important are the cellular changes. The development of the human brain occurs at such a rapid rate that a newborn baby’s brain has almost the same number of neurons as that of an adult. However, brain growth continues after birth due to the creation of new glial cells and connections between neurons.

Physiological pain is evoked by intense (noxious) stimuli acting on healthy tissue functioning as a warning signal to avoid damage of the tissue. In contrast, pathophysiological pain is present in the course of disease, and it is often elicited by low-intensity stimulation or occurs even as resting pain. Causes of pathophysiological pain are either inflammation or injury causing pathophysiological nociceptive pain or damage to nerve cells evoking neuropathic pain. The major peripheral neuronal mechanism of pathophysiological nociceptive pain is the sensitization of peripheral nociceptors for mechanical, thermal and chemical stimuli; the major peripheral mechanism of neuropathic pain is the generation of ectopic discharges in injured nerve fibres. These phenomena are created by changes of ion channels in the neurons, e.g. by the influence of inflammatory mediators or growth factors. Both peripheral sensitization and ectopic discharges can evoke the development of hyperexcitability of central nociceptive pathways, called central sensitization, which amplifies the nociceptive processing. Central sensitization is caused by changes of the synaptic processing, in which glial cell activation also plays an important role. Endogenous inhibitory neuronal systems may reduce pain but some types of pain are characterized by the loss of inhibitory neural function. In addition to their role in pain generation, nociceptive afferents and the spinal cord can further enhance the inflammatory process by the release of neuropeptides into the innervated tissue and by activation of sympathetic efferent fibres. However, in inflamed tissue the innervation is remodelled by repellent factors, in particular with a loss of sympathetic nerve fibres.