RESUMO
The diagnosis of irreversible pulpitis (IP) depends on clinical data, especially the chief complaint of the patient, visual inspection, response to the application of stimuli, and radiographic examination. The characterization of nerve fibers (NF) in IP may contribute to better interpret painful symptoms, but has been barely explored. This study sought to characterize the density and integrity of NF in 16 samples of IP and in five healthy pulps (HP) using S-100 and PGP 9.5 markers. Immunohistochemistry was performed to determine the density/mm2 of S-100+ and PGP 9.5+ in NF. The amount of degenerated NF was obtained by subtracting the total NF density from the amount of intact NF. Associations between NF density and integrity and symptomatology were calculated. All samples were positive for S-100 and PGP 9.5. Compared to HP samples (38.20/mm2), IP samples had a lower density of intact NF (6.24/mm2). A significantly higher density of degenerated NF was found in IP samples with spontaneous pain (39.59/mm2) compared to those with provoked pain (23.96/mm2) (p = 0.02). No association was observed between intensity of the inflammatory infiltrate and NF density and integrity (p > 0.05). The findings of this study suggest that pulpitis may involve different stages of degeneration and may be more advanced in cases with spontaneous pain. The symptoms reported by affected individuals do not appear to depend on the intensity of the inflammatory infiltrate, but rather on the integrity of NF.
Assuntos
Pulpite , Humanos , Polpa Dentária/diagnóstico por imagem , Fibras Nervosas/metabolismo , Imuno-Histoquímica , DorRESUMO
Entorhinal cortex lesions have been established as a model for hippocampal deafferentation and have provided valuable information about the mechanisms of synapse reorganization and plasticity. Although several molecules have been proposed to contribute to these processes, the role of Wnt signaling components has not been explored, despite the critical roles that Wnt molecules play in the formation and maintenance of neuronal and synaptic structure and function in the adult brain. In this work, we assessed the reorganization process of the dentate gyrus (DG) at 1, 3, 7, and 30 days after an excitotoxic lesion in layer II of the entorhinal cortex. We found that cholinergic fibers sprouted into the outer molecular layer of the DG and revealed an increase of the developmental regulated MAP2C isoform 7 days after lesion. These structural changes were accompanied by the differential regulation of the Wnt signaling components Wnt7a, Wnt5a, Dkk1, and Sfrp1 over time. The progressive increase in the downstream Wnt-regulated elements, active-ß-catenin, and cyclin D1 suggested the activation of the canonical Wnt pathway beginning on day 7 after lesion, which correlates with the structural adaptations observed in the DG. These findings suggest the important role of Wnt signaling in the reorganization processes after brain lesion and indicate the modulation of this pathway as an interesting target for neuronal tissue regeneration.
Assuntos
Córtex Entorrinal/patologia , Hipocampo/metabolismo , Via de Sinalização Wnt , Vias Aferentes/metabolismo , Animais , Colina/metabolismo , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Modelos Biológicos , Fibras Nervosas/metabolismo , Isoformas de Proteínas/metabolismo , Ratos Wistar , Proteínas Wnt/metabolismoRESUMO
Hypocretins (Hcrt) 1 and 2 are two neuropeptides synthesized from neurons that are located in the perifornical area of the lateral hypothalamus. These neurons project diffusely throughout the central nervous system, and have been implicated in the generation and maintenance of wakefulness, as well as in critical physiological processes that occur during this behavioral state, such as motivation. The hypocretinergic projections towards the feline midbrain have not been studied before. Therefore, the aim of the present study was to analyze their relationship to the midbrain neurons, that are critically involved in the control of sleep and wakefulness. With this purpose, we examined the distribution of Hcrt1-positive fibers in the midbrain and pontomesencephalic area of the domestic cat (Felis catus), and their relationship with catecholaminergic and cholinergic neurons by means of single and double immunohistochemistry. Hcrtergic axons with distinctive varicosities and buttons were heterogeneously distributed, exhibiting different densities in distinct regions of the midbrain. High Hcrtergic fiber densities were observed in the periaqueductal gray, interpeduncular nucleus, locus coeruleus and cholinergic mesopontine regions. In addition, we studied in detail the Hcrtergic projection towards the dopaminergic nuclei of the midbrain. While very few Hcrtâ¯+â¯fibers were observed in the substantia nigra pars compacta, the highest density of Hcrtergic fibers was found in the dopaminergic ventral periaqueductal gray area (also called A10dc area); appositions between Hcrtergic terminals and dopaminergic somata and dendrites were observed within this area. Because this dopaminergic area has been involved in the control of wakefulness, the present anatomical data provides relevant support about the role of the Hcrtergic system in the generation of this behavioral state.
Assuntos
Mesencéfalo/metabolismo , Neurônios/metabolismo , Orexinas/metabolismo , Vigília/fisiologia , Animais , Gatos , Imuno-Histoquímica , Masculino , Fibras Nervosas/metabolismo , Sono/fisiologiaRESUMO
Serotonergic neurons of the median raphe nucleus (MnR) and hypothalamic melanin-concentrating hormone (MCH)-containing neurons, have been involved in the control of REM sleep and mood. In the present study, we examined in rats and cats the anatomical relationship between MCH-containing fibers and MnR neurons, as well as the presence of MCHergic receptors in these neurons. In addition, by means of in vivo unit recording in urethane anesthetized rats, we determined the effects of MCH in MnR neuronal firing. Our results showed that MCH-containing fibers were present in the central and paracentral regions of the MnR. MCHergic fibers were in close apposition to serotonergic and non-serotonergic neurons. By means of an indirect approach, we also analyzed the presence of MCHergic receptors within the MnR. Accordingly, we microinjected MCH conjugated with the fluorophore rhodamine (R-MCH) into the lateral ventricle. R-MCH was internalized into serotonergic and non-serotonergic MnR neurons; some of these neurons were GABAergic. Furthermore, we determined that intracerebroventricular administration of MCH induced a significant decrease in the firing rate of 53 % of MnR neurons, while the juxtacellular administration of MCH reduced the frequency of discharge in 67 % of these neurons. Finally, the juxtacellular administration of the MCH-receptor antagonist ATC-0175 produced an increase in the firing rate in 78 % of MnR neurons. Hence, MCH produces a strong regulation of MnR neuronal activity. We hypothesize that MCHergic modulation of the MnR neuronal activity may be involved in the promotion of REM sleep and in the pathophysiology of depressive disorders.
Assuntos
Hormônios Hipotalâmicos/farmacologia , Hipotálamo/efeitos dos fármacos , Melaninas/farmacologia , Fibras Nervosas/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Hormônios Hipofisários/farmacologia , Núcleos da Rafe/efeitos dos fármacos , Receptores do Hormônio Hipofisário/metabolismo , Animais , Gatos , Hipotálamo/metabolismo , Hipotálamo/fisiologia , Fibras Nervosas/metabolismo , Fibras Nervosas/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Núcleos da Rafe/metabolismo , Núcleos da Rafe/fisiologia , Ratos , Ratos WistarRESUMO
Type-1 diabetes mellitus (T1DM) results in loss of innervation in some tissues including epidermis and retina; however, the effect on bone innervation is unknown. Likewise, T1DM results in pathological bone loss and increased risk of fracture. Thus, we quantified the density of calcitonin gene-related peptide (CGRP+) sensory and tyrosine hydroxylase (TH+) sympathetic nerve fibers and determined the association between the innervation density and microarchitecture of trabecular bone at the mouse femoral neck. Ten weeks-old female mice received 5 daily administrations of streptozocin (i.p. 50mg/kg) or citrate (control group). Twenty weeks later, femurs were analyzed by microCT and processed for immunohistochemistry. Confocal microscopy analysis revealed that mice with T1DM had a significant loss of both CGRP+ and TH+ nerve fibers in the bone marrow at the femoral neck. Likewise, microCT analysis revealed a significant decrease in the trabecular bone mineral density (tBMD), bone volume/total volume ratio (BV/TB), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) in mice with T1DM as compared to control mice. Analysis of correlation revealed a positive and significant association between density of CGRP+ or TH+ nerve fibers with tBMD, BV/TV, Tb.Th and Tb.Sp, but not with trabecular number (there was a positive association only for CGRP+) and degree of anisotropy (DA). This study suggests an interaction between sensory and sympathetic nervous system and T1DM-induced bone loss. Identification of the factors involved in the loss of CGRP+ sensory and TH+ sympathetic fibers and how they regulate bone loss may result in new avenues to treat T1DM-related osteoporosis.
Assuntos
Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 1/fisiopatologia , Colo do Fêmur/fisiopatologia , Fibras Nervosas/metabolismo , Sistema Nervoso Simpático/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Animais , Densidade Óssea , Diabetes Mellitus Tipo 1/complicações , Feminino , Colo do Fêmur/inervação , Colo do Fêmur/patologia , Camundongos Endogâmicos ICR , Fibras Nervosas/patologia , Estreptozocina , Sistema Nervoso Simpático/patologiaRESUMO
Melanin-concentrating hormone (MCH)-containing neurons are localized in the lateral hypothalamus and incerto-hypothalamic areas, and project to several brain regions including the dorsal raphe nucleus (DRN). The MCHergic system has been involved in the regulation of emotional states and we have demonstrated that MCH microinjections into the rat DRN promote a depressive-like state. To understand the MCHergic transmission into the DRN, in the present study we characterized the distribution and density of the MCHergic fibers along the rostro-caudal axis of the rat DRN and their anatomical relationship with the 5-HT- and GABA-containing neurons. Additionally, a functional in vivo microdialysis study was carried out in order to evaluate the MCH effects on the 5-HT extracellular levels. Immunolabeling studies showed that MCHergic fibers were widely distributed throughout the rostro-caudal DRN extent and a reduced density at the most caudal level was observed. Interestingly, MCHergic fibers appeared in close apposition to 5-HT and GABA-containing neurons. Microdialysis studies evidenced an opposite effect of two concentrations of MCH on 5-HT levels: the lower concentration (30 µM) produced a significant and long-lasting (up to 120 min) decrease while the higher (100 µM) induced a slight and brief (20 min) increase. Morphological and functional results strongly suggest that both 5-HT- and GABA-containing neurons of the DRN are modulated by MCH. A different sensitivity of these neurons to MCH may explain the dose-response effect on 5-HT release. The decrease in extracellular 5-HT levels may account for the depressive-like effect induced by MCH reported in our previous studies.
Assuntos
Núcleo Dorsal da Rafe/metabolismo , Neurônios GABAérgicos/metabolismo , Hormônios Hipotalâmicos/metabolismo , Melaninas/metabolismo , Hormônios Hipofisários/metabolismo , Neurônios Serotoninérgicos/metabolismo , Animais , Núcleo Dorsal da Rafe/efeitos dos fármacos , Imunofluorescência , Hormônios Hipotalâmicos/farmacologia , Masculino , Melaninas/farmacologia , Microdiálise , Fibras Nervosas/metabolismo , Hormônios Hipofisários/farmacologia , Ratos Wistar , Serotonina/metabolismo , Ácido gama-Aminobutírico/metabolismoRESUMO
Neuronal death in Parkinson's disease (PD) is often preceded by axodendritic tree retraction and loss of neuronal functionality. The presence of non-functional but live neurons opens therapeutic possibilities to recover functionality before clinical symptoms develop. Considering that iron accumulation and oxidative damage are conditions commonly found in PD, we tested the possible neuritogenic effects of iron chelators and antioxidant agents. We used three commercial chelators: DFO, deferiprone and 2.2'-dypyridyl, and three 8-hydroxyquinoline-based iron chelators: M30, 7MH and 7DH, and we evaluated their effects in vitro using a mesencephalic cell culture treated with the Parkinsonian toxin MPP+ and in vivo using the MPTP mouse model. All chelators tested promoted the emergence of new tyrosine hydroxylase (TH)-positive processes, increased axodendritic tree length and protected cells against lipoperoxidation. Chelator treatment resulted in the generation of processes containing the presynaptic marker synaptophysin. The antioxidants N-acetylcysteine and dymetylthiourea also enhanced axodendritic tree recovery in vitro, an indication that reducing oxidative tone fosters neuritogenesis in MPP+-damaged neurons. Oral administration to mice of the M30 chelator for 14 days after MPTP treatment resulted in increased TH- and GIRK2-positive nigra cells and nigrostriatal fibers. Our results support a role for oral iron chelators as good candidates for the early treatment of PD, at stages of the disease where there is axodendritic tree retraction without neuronal death.
Assuntos
Antioxidantes/farmacologia , Quelantes de Ferro/farmacologia , Intoxicação por MPTP/tratamento farmacológico , Fibras Nervosas/efeitos dos fármacos , Neuritos/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/antagonistas & inibidores , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacologia , 2,2'-Dipiridil/farmacologia , Animais , Deferiprona , Desferroxamina/farmacologia , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Feminino , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/agonistas , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/biossíntese , Hidroxiquinolinas/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Intoxicação por MPTP/metabolismo , Intoxicação por MPTP/patologia , Masculino , Mesencéfalo/efeitos dos fármacos , Mesencéfalo/metabolismo , Mesencéfalo/patologia , Camundongos , Camundongos Endogâmicos C57BL , Fibras Nervosas/metabolismo , Fibras Nervosas/patologia , Neuritos/metabolismo , Neuritos/patologia , Cultura Primária de Células , Piridonas/farmacologia , Ratos , Ratos Sprague-Dawley , Sinaptofisina/agonistas , Sinaptofisina/biossíntese , Tirosina 3-Mono-Oxigenase/biossínteseRESUMO
We examined the relationship between chronic hypoxia and erectile dysfunction in rat and its possible pathogenic mechanism. Forty-eight white male adult Sprague-Dawley rats were randomly divided into a test group and a control group. In accordance with the experimental time (2, 6, and 10 weeks), each group was divided into 3 subgroups, with 8 rats in each subgroup. Rats in the test group were fed in an airtight hypoxia cabin, while rats in the control group were maintained in a normal environment, with other conditions kept the same. At 2, 6, and 10 weeks, the rats in each group were observed for erectile function. Affinity purification was used to detect neural nitric oxide synthase (nNOS)-positive nerve fibers and endothelial nitric oxide synthase (eNOS) expression. After hypoxia, erectile frequency decreased significantly compared to before hypoxia (P < 0.001). Comparison of the test group and control group revealed a significant difference in the quantity of nNOS-positive nerve fiber and eNOS protein expression (P < 0.01). Hypoxia may influence erectile function and nNOS and eNOS expression in rats. The decrease in the quantity of nNOS nerve fibers and expression of eNOS may contribute to erectile dysfunction under hypoxic conditions in rats.
Assuntos
Disfunção Erétil/genética , Hipóxia/genética , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo I/genética , Oxigênio/farmacologia , Ereção Peniana/efeitos dos fármacos , Animais , Disfunção Erétil/metabolismo , Disfunção Erétil/fisiopatologia , Regulação da Expressão Gênica , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Masculino , Fibras Nervosas/efeitos dos fármacos , Fibras Nervosas/metabolismo , Fibras Nervosas/patologia , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Ereção Peniana/genética , Pênis/irrigação sanguínea , Pênis/efeitos dos fármacos , Pênis/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
The thalamic midline/intralaminar complex is part of the higher-order thalamus, which receives little sensory input, and instead forms extensive cortico-thalamo-cortical pathways. The midline thalamic nuclei connect with the medial prefrontal cortex and the medial temporal lobe. On the other hand, the intralaminar nuclei connect with the fronto-parietal cortex. Taking into account this connectivity pattern, it is not surprising that the midline/intralaminar complex has been implicated in a broad variety of cognitive functions, including memory process, attention and orientation, and also reward-based behavior. Serotonin (5-HT) is a neurotransmitter that exerts different post-synaptic roles. Serotonergic neurons are almost entirely restricted to the raphe nuclei and the 5-HT fibers are distributed widely throughout the brain, including the midline/intralaminar complex. The present study comprises a detailed description of the morphologic features and semiquantitative analysis of 5-HT fibers distribution in the midline/intralaminar complex in the rock cavy, a typical rodent of the Northeast region of Brazil, which has been used by our group as an anatomical model to expand the comprehension about phylogeny on the nervous system. The 5-HT fibers in the midline/intralaminar nuclei of the rock cavy were classified into three distinct categories: (1) beaded fibers, which are relatively fine and endowed with large varicosities; (2) fine fibers, with thin axons and small varicosities uniformly distributed in whole axon; and (3) stem axons, showing thick non-varicose axons. Moreover, the density of 5-HT fibers is variable among the analyzed nuclei. On the basis of this diversity of the morphological fibers and the differential profile of optical density among the midline/intralaminar nuclei of the rock cavy, we conclude that the serotonergic system uses a diverse morphologic apparatus to exert a large functional repertory in the midline/intralaminar thalamic nuclei.
Assuntos
Núcleos Intralaminares do Tálamo/anatomia & histologia , Núcleos da Linha Média do Tálamo/anatomia & histologia , Fibras Nervosas/metabolismo , Serotonina/metabolismo , Análise de Variância , Animais , CobaiasRESUMO
Food allergy accounts for a great number of reactions leading to diminished quality of life in western countries. There has been an abundance of reports of behavioral changes, as well as psychiatric conditions associated with food allergy over the past decades. Most of this field inspired little medical attention for its lack of a solid scientific ground. We review the literature on the association of food allergy and brain activity, leading to changes in emotion and behavior. Moreover, we describe an experimental paradigm employed to dissect the biological relevance of this association. Mice allergic to ovalbumin avoid a palatable sweet solution in order to escape contact with antigen. This choice is associated with increased levels of anxiety, compatible with a conflicting situation. These responses are associated with increased activity in brain areas associated with emotional and affective behavior, which are also important for anxiety and stress responses. Higher levels of corticosterone accompany these changes in behavior. These responses are mediated by specific antibodies and prevented by depletion or immunological tolerance. They are also partially mediated by C-sensitive afferents and mast cells. Far from anecdote, neural repercussions of food allergy should be considered when planning a therapeutic strategy in affected individuals.