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Severe acute respiratory syndrome coronavirus (SARS-CoV-2) infections result in the temporary loss of smell and taste (anosmia and dysgeusia) in about one third of confirmed cases. Several investigators have reported that the viral spike protein receptor is present in olfactory neurons. However, no study has been published to date showing the presence of viral entry sites angiotensin-converting enzyme 2 (ACE2), neuropilin1 (NRP1), and TMPRSS2, the serine protease necessary for priming the viral proteins, in human nerves that are responsible for taste sensation (cranial nerves: VII, IX and X). We used immunocytochemistry to examine three postmortem donor samples of the IXth (glossopharyngeal) and Xth (vagal) cranial nerves where they leave/join the medulla from three donors to confirm the presence of ACE2, NRP1 and TMPRSS2. Two samples were paraffin embedded; one was a frozen sample. In addition to staining sections from the latter, we isolated RNA from it, made cDNA, and performed PCR to confirm the presence of the mRNAs that encode the proteins visualized. All three of the proteins required for SARS-CoV-2 infections appear to be present in the human IXth and Xth nerves near the medulla. Direct infection of these nerves by the COVID-19 virus is likely to cause the loss of taste experienced by many patients. In addition, potential viral spread through these nerves into the adjacent brainstem respiratory centers might also aggravate the respiratory problems patients are experiencing.
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OBJECTIVE: The ependymal cells, considered today as an active participant in neuroendocrine functions, were investigated by electron microscopy in the central canal of the lowest spinal cord, the filum terminale (FT), in adult rats. In this area of the spinal cord, the central canal is covered by a heterogeneous population of ependymal cells. The aim of the present work was to compare the regional features of the ependymal cells in two different parts of the FT with a special regard to their ultrastructure. METHODS: Two parts of the FT were selected for the ultrastructural observations: the rostral (rFT) and the caudal (cFT) ones. The rTF was removed at the level of the immediate continuation of the conus medullaris, while the cFT 30 mm further caudally. After formaldehyde fixation, the spinal cord was removed and cut into small blocks for electron microscopic processing. The material was embedded into durcupan, contrasted with uranyl acetate, lead citrate as well as osmium tetroxide, and investigated under JEOL 1200 EX electron microscope. RESULTS: In the rFT, the ependymal lining is pseudostratified and one-layered in the cFT, whereas the shape of the ependymal cells may vary from cuboidal to flatten in the rostro-caudal direction. The basal membrane of many ependymal cells possesses deep invaginations, so called "filum terminale labyrinths". Many neuronal processes occur in the pericanalicular neuropil. In contrast to the rFT, the cFT is less rich in the neuropil particles. Some of the ependymal cells concurrently reach both the intracanalicular and extracanalicular cerebrospinal fluid (CSF), thus they may represent a new variant of the ependymal cells designated as "bridge cells of the FT". CONCLUSIONS: The present data indicate that the FT ependymal cells exhibit clear differences in anatomy as well as ultrastructure that may reflect their distinct functional activity. Therefore, observations presented here may serve for the better understanding of the physiological role of the individual ependymal areas in this special portion of the rat spinal cord.
Assuntos
Cauda Equina/citologia , Epêndima/citologia , Sistemas Neurossecretores/citologia , Medula Espinal/citologia , Animais , Axônios/ultraestrutura , Cauda Equina/ultraestrutura , Dendritos/ultraestrutura , Epêndima/ultraestrutura , Masculino , Microscopia Eletrônica , Mitocôndrias/ultraestrutura , Neuroglia/ultraestrutura , Neurópilo/citologia , Neurópilo/ultraestrutura , Sistemas Neurossecretores/ultraestrutura , Ratos , Ratos Sprague-Dawley , Medula Espinal/ultraestruturaRESUMO
A high number of neurons express c-fos in response to unlimited food intake in fasted rats in the ventral subdivision of the hypothalamic dorsomedial nucleus (DMHv). We report here, that in same conditions, limited food consumption failed to induce Fos expression in DMHv neurons suggesting that satiation should be one of the important signals that activate these neurons. The possible origin of fibers conducting satiation signals to the DMHv could be in the lower brainstem, especially glucagon-like peptide-1 (GLP-1)-containing neurons in the nucleus of the solitary tract (NTS). We demonstrate that GLP-1-immunoreactive fibers and fiber terminals topographically overlap with activated Fos-positive neurons in the DMHv in refed rats. Using immunocytochemistry and in situ hybridization histochemistry, we demonstrated GLP-1 receptors in Fos-expressing neurons of the DMH. Unilateral transections of ascending GLP-1-containing fibers from the NTS inside the pons in refed rats (unlimited food consumption) resulted in a dramatic decrease in the density of GLP-1 fibers and in the number of Fos-immunoreactive neurons in the DMHv, but only on the side of the transection. Contralateral to the transection, neither the GLP-1 fiber density nor the number of Fos-positive cells changed significantly. Meanwhile, the density of GLP-1 immunoreactivity was markedly accumulated in transected nerve fibers caudal to the cuts, as a consequence of the interruption of the ascending GLP-1 transport route. These findings suggest that the solitary-hypothalamic projections may represent the neuronal route through GLP-1 neurons of the NTS activate DMHv neurons via GLP-1 receptors by conveying information on satiety.
Assuntos
Núcleo Hipotalâmico Dorsomedial/citologia , Peptídeo 1 Semelhante ao Glucagon/fisiologia , Saciação , Núcleo Solitário/metabolismo , Animais , Tronco Encefálico/citologia , Tronco Encefálico/metabolismo , Privação de Alimentos , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1 , Masculino , Vias Neurais/metabolismo , Neurônios/metabolismo , Neurônios/fisiologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Wistar , Receptores de Glucagon/metabolismo , Núcleo Solitário/citologiaRESUMO
OBJECTIVE: To determine whether the anorexigenic peptide, nesfatin-1 affects energy expenditure, and to follow the time course of its effects. DESIGN: Food intake duration, core body temperature, locomotor activity and heart rate of rats were measured by telemetry for 48 h after a single intracerebroventricular injection of 25 or 100 pmol nesfatin-1 applied in the dark or the light phase of the day. Body weight, food and water intake changes were measured daily. Furthermore, cold-responsive nesfatin-1/NUCB2 neurons were mapped in the brain. RESULTS: Nesfatin-1 reduced duration of nocturnal food intake for 2 days independently of circadian time injected, and raised body temperature immediately, or with little delay depending on the dose and circadian time applied. The body temperature remained higher during the next light phases of the 48 h observation period, and the circadian curve of temperature flattened. After light phase application, the heart rate was elevated transiently. Locomotion did not change. Daily food and water intake, as well as body weight measurements point to a potential decrease in all parameters on the first day and some degree of compensation on the second day. Cold-activated (Fos positive) nesfatin-1/NUCB2 neurones have been revealed in several brain nuclei involved in cold adaptation. Nesfatin-1 co-localised with prepro-thyrotropin-releasing hormone in cold responsive neurones of the hypothalamic paraventricular nucleus, and in neurones of the nucleus raphe pallidus and obscurus that are premotor neurones regulating brown adipose tissue thermogenesis and skin blood flow. CONCLUSION: Nesfatin-1 has a remarkably prolonged effect on food intake and body temperature. Time course of nesfatin-1's effects may be varied depending on the time applied. Many of the nesfatin-1/NUCB2 neurones are cold sensitive, and are positioned in key centres of thermoregulation. Nesfatin-1 regulates energy expenditure a far more potent way than it was recognised before making it a preferable candidate anti-obesity drug.
Assuntos
Temperatura Corporal , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação a DNA/metabolismo , Ingestão de Alimentos , Frequência Cardíaca , Hipotálamo/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Resposta de Saciedade , Animais , Fármacos Antiobesidade/farmacologia , Mapeamento Encefálico , Proteínas de Ligação ao Cálcio/farmacologia , Proteínas de Ligação a DNA/farmacologia , Modelos Animais de Doenças , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Imuno-Histoquímica , Injeções Intraventriculares , Masculino , Proteínas do Tecido Nervoso/farmacologia , Nucleobindinas , Ratos , Ratos Wistar , Resposta de Saciedade/efeitos dos fármacos , Transdução de SinaisRESUMO
Interleukin (IL)-6 deficient mice develop mature-onset obesity. Furthermore, i.c.v. administration of IL-6 increases energy expenditure, suggesting that IL-6 centrally regulates energy homeostasis. To investigate whether it would be possible for IL-6 to directly influence the energy homeostasis via hypothalamic regulation in humans and rodents, we mapped the distribution of the ligand binding IL-6 receptor α (IL-6Rα) in this brain region. In the human hypothalamus, IL-6Rα-immunoreactivity was detected in perikarya and first-order dendrites of neurones. The IL-6Rα-immunoreactive (-IR) neurones were observed posterior to the level of the interventricular foramen. There, IL-6Rα-IR neurones were located in the lateral hypothalamic, perifornical, dorsal and posterior hypothalamic areas, the hypothalamic dorsomedial nucleus and in the zona incerta. In the caudal part of the hypothalamus, the density of the IL-6Rα-IR neurones gradually increased. Double-labelling immunofluorescent studies demonstrated that IL-6Rα immunoreactivity was localised in the same neurones as the orexigenic neuropeptide, melanin-concentrating hormone (MCH). By contrast, IL-6Rα-immunoreactivity was not observed in the orexin B-IR neurones. To determine whether the observed expression of IL-6Rα is evolutionary conserved, we studied the co-localisation of IL-6Rα with MCH and orexin in the mouse hypothalamus, where IL-6Rα-immunoreactivity was present in numerous MCH-IR and orexin-IR neurones. Our data demonstrate that the MCH neurones of the human hypothalamus, as well as the MCH and orexin neurones of the mouse hypothalamus, contain IL-6Rα. This opens up the possibility that IL-6 influences the energy balance through the MCH neurones in humans, and both MCH and orexin neurones in mice.
Assuntos
Hormônios Hipotalâmicos/metabolismo , Hipotálamo/metabolismo , Melaninas/metabolismo , Hormônios Hipofisários/metabolismo , Receptores de Interleucina-6/metabolismo , Adulto , Animais , Humanos , Hormônios Hipotalâmicos/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Melaninas/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Neuropeptídeos/metabolismo , Orexinas , Hormônios Hipofisários/fisiologiaRESUMO
The ectoenzyme tissue non-specific alkaline phosphatase (TNAP) is mostly known for its role in bone mineralization. However, in the severe form of hypophosphatasia, TNAP deficiency also results in epileptic seizures, suggesting a role of this enzyme in brain functions. Accordingly, TNAP activity was shown in the neuropil of the cerebral cortex in diverse mammalian species. However in spite of its clinical significance, the neuronal localization of TNAP has not been investigated in the human brain. By using enzyme histochemistry, we found an unprecedented pattern of TNAP activity appearing as an uninterrupted layer across diverse occipital-, frontal- and temporal lobe areas of the human cerebral cortex. This marked TNAP-active band was localized infragranulary in layer 5 as defined by quantitative comparisons on parallel sections stained by various techniques to reveal the laminar pattern. On the contrary, TNAP activity was localized in layer 4 of the primary visual and somatosensory cortices, which is consistent with earlier observations on other species. This result suggests that the expression of TNAP in the thalamo-recipient granular layer is an evolutionary conserved feature of the sensory cortex. The observations of the present study also suggest that diverse neurocognitive functions share a common cerebral cortical mechanism depending on TNAP activity in layer 5. In summary, the present data point on the distinctive role of layer 5 in cortical computation and neurological disorders caused by TNAP dysfunctions in the human brain.
Assuntos
Fosfatase Alcalina/metabolismo , Neocórtex/enzimologia , Adulto , Vias Aferentes/citologia , Vias Aferentes/enzimologia , Idoso , Fosfatase Alcalina/fisiologia , Feminino , Lobo Frontal/citologia , Lobo Frontal/enzimologia , Humanos , Masculino , Pessoa de Meia-Idade , Neocórtex/citologia , Neurônios/citologia , Neurônios/enzimologia , Lobo Occipital/citologia , Lobo Occipital/enzimologia , Córtex Somatossensorial/citologia , Córtex Somatossensorial/enzimologia , Lobo Temporal/citologia , Lobo Temporal/enzimologia , Tálamo/citologia , Tálamo/enzimologia , Córtex Visual/citologia , Córtex Visual/enzimologiaRESUMO
Tuberoinfundibular peptide of 39 residues (TIP39) is expressed by neurons in the subparafascicular area, the posterior intralaminar complex of the thalamus and the pontine medial paralemniscal nucleus. TIP39-positive fibers from these areas do not form individual bundles or fascicles, they join other pathways to reach their innervated brain areas. Fibers arise from TIP39 perikarya located in the subparafascicular area and the posterior intralaminar complex of the thalamus could be followed to the hypothalamus. After uni- and bilateral posterolateral surgical deafferentations of the hypothalamus, accumulation of TIP39 immunoreactivity was observed in the fibers caudal to the knife cut, while it disappeared completely rostral to the transection. In serial sections of the forebrain, we could follow TIP39-ir fibers coursing within the zona incerta and the supraoptic decussations. TIP39-positive fibers that join the incerto-hypothalamic pathway reach the medio-dorsal part of the hypothalamus and form moderate to high density networks in the dorsomedial and paraventricular nuclei. The other set of TIP39-positive axons from the subthalamic area join the fibers of the supraoptic decussations and run in an antero-medial direction through the most ventral portion of the hypothalamus up to the retrochiasmatic area, where they crossover. A certain portion of these TIP39-positive fibers terminates in the territories of the arcuate and the medial preoptic nuclei, as well as in the retrochiasmatic area.
Assuntos
Hipotálamo Anterior/metabolismo , Neuropeptídeos/metabolismo , Sistemas Neurossecretores/metabolismo , Animais , Imuno-Histoquímica , Masculino , Ratos , Ratos WistarRESUMO
Parathyroid hormone receptor 2 (PTH2R) and its ligand, tuberoinfundibular peptide of 39 residues (TIP39) constitute a neuromodulator system implicated in endocrine and nociceptive regulation. We now describe the presence and distribution of the PTH2R and TIP39 in the brain of primates using a range of tissues and ages from macaque and human brain. In situ hybridization histochemistry of TIP39 mRNA, studied in young macaque brain, due to its possible decline beyond late postnatal ages, was present only in the thalamic subparafascicular area and the pontine medial paralemniscal nucleus. In contrast, in situ hybridization histochemistry in macaque identified high levels of PTH2R expression in the central amygdaloid nucleus, medial preoptic area, hypothalamic paraventricular and periventricular nuclei, medial geniculate, and the pontine tegmentum. PTH2R mRNA was also detected in several human brain areas by RT-PCR. The distribution of PTH2R-immunoreactive fibers in human, determined by immunocytochemistry, was similar to that in rodents, including dense fiber networks in the medial preoptic area, hypothalamic paraventricular, periventricular and infundibular (arcuate) nuclei, lateral hypothalamic area, median eminence, thalamic paraventricular nucleus, periaqueductal gray, lateral parabrachial nucleus, nucleus of the solitary tract, sensory trigeminal nuclei, medullary dorsal reticular nucleus, and dorsal horn of the spinal cord. Co-localization suggested that PTH2R fibers are glutamatergic, and that TIP39 may directly influence hypophysiotropic somatostatin containing and indirectly influence corticotropin releasing-hormone containing neurons. The results demonstrate that TIP39 and the PTH2R are expressed in the brain of primates in locations that suggest involvement in regulation of fear, anxiety, reproductive behaviors, release of pituitary hormones, and nociception.
Assuntos
Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Neuropeptídeos/metabolismo , Receptor Tipo 2 de Hormônio Paratireóideo/metabolismo , Idoso de 80 Anos ou mais , Envelhecimento/metabolismo , Animais , Animais Recém-Nascidos , Criança , Hormônio Liberador da Corticotropina/metabolismo , Feminino , Humanos , Macaca mulatta , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Somatostatina/metabolismo , Proteína Vesicular 2 de Transporte de Glutamato/metabolismoRESUMO
The effect of experimentally induced acute renal failure (ARF) on neuronal cell activation was investigated by immunohistochemistry for Fos and Fra-2 in the rat brain. ARF in rats was induced by bilateral nephrectomy (BNX), bilateral ureter ligature (BUL) and uranyl acetate injection with proper controls (sham-operation or saline injections, respectively). To follow the effect of the development of ARF, rats were killed 30 and 60 min, and 3, 12, 24 and 72 h after surgery, or 3 h to 12 days after uranyl acetate injections. In the BUL and BNX rats, urea and creatinine rose markedly in the plasma within 72 h, while in the uranyl acetate-injected rats the highest levels were observed on the 7th day, followed by a marked decline. At each time-point of the three different, experimentally induced ARF, the presence of Fos- and/or Fra-2-immunoreactive neurons was determined in 120 different brain areas and nuclei. In general, the 73 of 120 brain areas that showed time and intensity dependent activation in response to ARF can be classified into four groups: 1) biogenic amine (noradrenaline, adrenaline, histamine and 5-HT) expressing cell groups in the lower brainstem, 2) "stress-sensitive" forebrain areas, with regard to certain hypothalamic, limbic and cortical areas, 3) neuronal cell groups that participate in the central regulation of body and brain water and electrolyte homeostasis, including the circumventricular organs, and 4) central autonomic cell groups, especially visceral sensory cell groups in the brain, which are in primary, secondary or tertiary connections with renal afferents. Data presented here indicate that a wide variety of neurons in several regulatory mechanisms is affected by ARF-induced peripheral and central alterations.
Assuntos
Injúria Renal Aguda/classificação , Injúria Renal Aguda/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Neurônios/metabolismo , Injúria Renal Aguda/etiologia , Animais , Aminas Biogênicas/metabolismo , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Creatina/sangue , Modelos Animais de Doenças , Antígeno 2 Relacionado a Fos/metabolismo , Ligadura/efeitos adversos , Masculino , Nefrectomia/efeitos adversos , Proteínas Oncogênicas v-fos/metabolismo , Compostos Organometálicos/toxicidade , Ratos , Ratos Wistar , Fatores de Tempo , Ureia/sangueRESUMO
The preoptic area orchestrates thermoregulatory responses in homeotherm animals and humans. This thermoregulatory center receives thermal information about core body and skin temperatures, and in turn, it induces thermogenic responses. The physiology of effector mechanisms has been described in detail outlining the brain areas participating in the execution of thermal responses. Previous studies have presented evidence of peripheral thermosensation, existence of skin thermoreceptors, participation of spinal and brainstem sensory neurons in thermal stress, but only recently has been identified the first evidence of an ascending neuronal pathway transmitting thermal signal to the preoptic thermoregulatory center. Nevertheless, a few brainstem areas have not been linked to an afferent or efferent thermal pathway and the neuronal network of thermoafferent signals has only partially been identified. In the present study, we identified a distinct ascending neuronal projection that originates from the thermoreactive cells of the peritrigeminal nucleus in the medulla oblongata, and projects to the thermoreactive cells of the medial preoptic area in the hypothalamus of rats. First, we have demonstrated retrogradely labeled thermoreactive neurons in the parabrachial, pontine and peritrigeminal cells following the injection of pseudorabies virus, a retrograde multi-synaptic tract tracer, into the ventrolateral subdivision of the medial preoptic area. Confirming the existence of a direct neuronal connection, we detected biotinylated dextran amine (BDA) containing axonal fibers and boutons around thermoreactive cells of the ventrolateral subdivision of the medial preoptic area after BDA injection into the peritrigeminal nucleus that is known to respond the temperature changes. Our findings indicate the existence of a so far unrecognized ascending direct neuronal pathway that transmits thermal signal from the lower brainstem to the thermoregulatory preoptic center.
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Regulação da Temperatura Corporal/fisiologia , Tronco Encefálico/citologia , Área Pré-Óptica/citologia , Células Receptoras Sensoriais/fisiologia , Vias Aferentes/fisiologia , Animais , Biotina/análogos & derivados , Biotina/metabolismo , Temperatura Baixa , Dextranos/metabolismo , Proteínas de Fluorescência Verde/biossíntese , Proteínas de Fluorescência Verde/genética , Herpesvirus Suídeo 1/fisiologia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Tissue levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) have been determined in 16 regions and nuclei from human brains, using liquid chromatography/in-line mass spectrometry. Measurements in brain samples stored at -80 degrees C for 2 months to 13 years indicated that endocannabinoids were stable under such conditions. In contrast, the postmortal delay had a strong effect on brain endocannabinoid levels, as documented in brain samples microdissected and frozen 1-6 h postmortem, and in neurosurgical samples 0, 5, 30, 60, 180 and 360 min after their removal from the brain. The tissue levels of AEA increased continuously and in a region-dependent manner from 1 h after death, increasing about sevenfold by 6 h postmortem. In contrast, concentrations of 2-AG, which were 10-100 times higher in human brain regions than those of AEA, rapidly declined: within the first hour, 2-AG levels dropped to 25-35% of the initial ('0 min') value, thereafter they remained relatively stable. As analyzed in samples removed 1-1.5 h postmortem, AEA levels ranged from a high of 96.3 fmol/mg tissue in the nucleus accumbens to a low of 25.0 fmol/mg in the cerebellum. 2-AG levels varied eightfold, from 8.6 pmol/mg in the lateral hypothalamus to 1.1 pmol/mg in the nucleus accumbens. Relative levels of AEA and 2-AG varied from region to region, with the 2-AG:AEA ratio being high in the sensory spinal trigeminal nucleus (140:1), the spinal dorsal horn (136:1) and the lateral hypothalamus (98:1) and low in the nucleus accumbens (16:1) and the striatum (31:1). The results highlight the pitfall of analyzing endocannabinoid content in brain samples of variable postmortal delay, and document differential distribution of the two main endocannabinoids in the human brain.
Assuntos
Ácidos Araquidônicos/metabolismo , Química Encefálica/fisiologia , Encéfalo/metabolismo , Glicerídeos/metabolismo , Alcamidas Poli-Insaturadas/metabolismo , Mudanças Depois da Morte , Encéfalo/anatomia & histologia , Cromatografia Líquida/métodos , Endocanabinoides , Feminino , Humanos , Masculino , Espectrometria de Massas/métodos , Microdissecção , Fatores de TempoRESUMO
In postmortem brains of patients with major depression, the expression of corticotrophin-releasing factor (CRF) is enhanced and that of brain-derived neurotrophic factor (BDNF) decreased. In mice over-expressing neuronal CRF (an animal model for depression) the expression of urocortin 1 (Ucn1) in the non-preganglionic Edinger-Westphal nucleus (npEW) is strongly down-regulated. Therefore, we hypothesized that an altered activity of Ucn1 neurons in the npEW would contribute to the pathogenesis of major depression. To test this hypothesis we measured Ucn1 mRNA and BDNF mRNA levels in the npEW of seven male and four female, drug-free suicide victims with major depression, and compared the data with those obtained from 10 male and seven female individuals without neurological and psychiatric disorders (controls). We show that compared with controls, the Ucn1-mRNA level in npEW neurons is about 9.12 times higher in male but unchanged in female suicide victims. Furthermore, BDNF mRNA expression in microdissections of npEW was 3.36 times lower in male suicide victims, but 5.27 times higher in female victims, compared with controls. Our data also show that male suicide victims had almost 11.47 times more Ucn1 and 4.26 times less BDNF mRNA in the npEW than female suicide victims. We discuss the significance of these data for npEW Ucn1 and BDNF, and propose that altered expressions of Ucn1 and BDNF in the npEW contribute to the pathogenesis of major depression and/or suicidality in a gender-specific manner.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Transtorno Depressivo Maior , Mesencéfalo/metabolismo , Caracteres Sexuais , Suicídio , Urocortinas/metabolismo , Adulto , Idoso , Análise de Variância , Fator Neurotrófico Derivado do Encéfalo/genética , Transtorno Depressivo Maior/metabolismo , Transtorno Depressivo Maior/patologia , Transtorno Depressivo Maior/psicologia , Feminino , Humanos , Masculino , Mesencéfalo/patologia , Pessoa de Meia-Idade , Neurônios/metabolismo , Mudanças Depois da Morte , RNA Mensageiro/metabolismo , Urocortinas/genéticaRESUMO
In response to a pain-related acute stress, the expression of c-fos protein (Fos), a marker of acute neuronal excitation, was investigated in the hypothalamus of rats. Few Fos-immunopositive cells were seen 15 min after a single subcutaneous injection of 4% formalin in the hypothalamus, but only in the paraventricular nucleus (PVN). Fifteen minutes later, a high number of parvocellular neurons of the PVN showed Fos expression. By 60 min after injection, strong immunoreactivity appeared in the arcuate nucleus, but the Fos-positive neurons distributed almost exclusively in the ventromedial subdivision of the nucleus. Neurons in this part of the arcuate nucleus express mainly neuropeptide Y (NPY) that projects to the medial parvocellular subdivision of the PVN. It has been demonstrated by previous studies that this part of the arcuate nucleus receives blood partly from the anterior pituitary through the subependymal plexus of the median eminence, and that it establishes, together with the median eminence, a blood-brain barrier-free area in the medial basal hypothalamus. Since the PVN-projecting NPY neurons in the arcuate neurons are sensitive to alterations in circulating corticosterone levels, the existence of a possible short feedback route in the stress-activated hypothalamo-pituitary-adrenocortical system is discussed.
Assuntos
Núcleo Arqueado do Hipotálamo/citologia , Barreira Hematoencefálica/fisiologia , Hormônio Liberador da Corticotropina/metabolismo , Hipotálamo , Neurônios/metabolismo , Estresse Fisiológico , Animais , Núcleo Arqueado do Hipotálamo/metabolismo , Hipotálamo/citologia , Hipotálamo/metabolismo , Neurônios/citologia , Neuropeptídeo Y/metabolismo , Medição da Dor , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Prolonged neurotoxicity of the recreational drug, MDMA (3,4-methylenedioxymethamphetamine) on serotoninergic axon terminals has been suggested. The effect of a single (15 mg/kg) dose of intraperitoneally administered MDMA on serotoninergic fibre density, defined by tryptophan hydroxylase (TpH) and serotonin transporter (5-HTT) immunoreactivity, has been evaluated in the spinal cord and brain areas in Dark Agouti rats, 7 and 180 days after MDMA applications. Immunostaining for amyloid precursor protein (APP) has been performed to examine possible defects of the fast axonal transport, and 5-HTT mRNA expressions were quantified in neurones of medullary raphe nuclei. Seven days after MDMA treatment, a substantial decrease in the density of TpH-immunoreactive fibres was detectable in the frontal cortex, the caudate-putamen, the CA1 region of the hippocampus, and marked decreases were found in the spinal cord. These changes in TpH density showed a high correlation with 5-HTT densities. In contrast, APP-immunoreactive axonal bulbs were not detected in any of the brain regions studied. Seven days after MDMA administrations, significantly elevated 5-HTT mRNA expressions were found in the raphe pallidus and obscurus. Our results suggest that a single dose of MDMA elicits widespread depletion of TpH and 5-HTT immunoreactivity in serotoninergic axons without morphological sign of the blockage of the fast anterograde axonal transport. Our results do not support the notion of MDMA-induced axotomy of serotoninergic neurones. The up-regulation of 5-HTT mRNA expressions 1 week after MDMA injections might indicate the potential recovery of the serotonin system.
Assuntos
Transporte Axonal/efeitos dos fármacos , Sistema Nervoso Central/efeitos dos fármacos , N-Metil-3,4-Metilenodioxianfetamina/toxicidade , Fibras Nervosas/efeitos dos fármacos , Serotoninérgicos/toxicidade , Animais , Transporte Axonal/fisiologia , Temperatura Corporal/efeitos dos fármacos , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/fisiologia , Imuno-Histoquímica , Masculino , Fibras Nervosas/metabolismo , Fibras Nervosas/patologia , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos , Serotonina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Triptofano Hidroxilase/metabolismoRESUMO
The development of new molecular and neurobiological methods, computer-assisted quantification techniques and neurobiological investigation methods which can be applied to the human brain, all have evoked an increased demand for post-mortem tissue in research. Psychiatric disorders are considered to be of neurobiological origin. Thus far, however, the etiology and pathophysiology of schizophrenia, depression and dementias are not well understood at the cellular and molecular level. The following will outline the consensus of the working group for neuropsychiatric brain banking organized in the Brainnet Europe II, on ethical guidelines for brain banking, clinical diagnostic criteria, the minimal clinical data set of retrospectively analyzed cases as well as neuropathological standard investigations to perform stageing for neurodegenerative disorders in brain tissue. We will list regions of interest for assessments in psychiatric disorder, propose a dissection scheme and describe preservation and storage conditions of tissue. These guidelines may be of value for future implementations of additional neuropsychiatric brain banks world-wide.
Assuntos
Encéfalo/patologia , Transtornos Mentais/diagnóstico , Neurologia/normas , Patologia/normas , Psiquiatria/normas , Bancos de Tecidos/normas , Consenso , Dissecação/métodos , Dissecação/normas , Europa (Continente) , Humanos , Biologia Molecular/métodos , Biologia Molecular/normas , Doenças Neurodegenerativas/patologia , Neurologia/ética , Patologia/ética , Psiquiatria/ética , Sociedades Médicas , Bancos de Tecidos/ética , Bancos de Tecidos/organização & administração , Fixação de Tecidos/métodos , Fixação de Tecidos/normasRESUMO
The vasopressin 1b receptor (Avpr1b) is one of two principal receptors mediating the behavioral effects of vasopressin (Avp) in the brain. Avpr1b has recently been shown to strongly influence social forms of aggression in mice and hamsters. This receptor appears to play a role in social recognition and motivation as well as in regulating the hypothalamic-pituitary-adrenal axis. Most of these studies have been performed in knockout mice, a species in which the localization of the Avpr1b has not been described, thus precluding correlations with the behaviors. We performed in situ hybridization histochemistry (ISHH) with specific probes and found especially prominent expression within the CA2 pyramidal neurons of the hippocampus, with much lower expression in the hypothalamic paraventricular nucleus and amygdala. Reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed expression in those as well other areas in which the ISHH was not sensitive enough to detect labeled cells (e.g. piriform cortex, septum, caudate-putamen and lower brainstem areas). Mouse Avpr1b transcript levels were not altered in the CA2 field by restraint stress or adrenalectomy. Finally, ISHH and RT-PCR showed expression of the Avpr1b gene in the rat and human hippocampi as well. We suggest that the CA2 field may form or retrieve associations (memories) between olfactory cues and social encounters.
Assuntos
Corticosteroides/metabolismo , Hipocampo/anatomia & histologia , Hipocampo/metabolismo , Receptores de Vasopressinas/genética , Estresse Psicológico/metabolismo , Vasopressinas/metabolismo , Córtex Suprarrenal/metabolismo , Adrenalectomia , Adulto , Animais , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica/genética , Hipocampo/fisiopatologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Hipófise/metabolismo , Hipófise/fisiopatologia , RNA Mensageiro/metabolismo , Ratos , Restrição Física , Especificidade da Espécie , Estresse Psicológico/genética , Estresse Psicológico/fisiopatologiaRESUMO
Neurons containing tuberoinfundibular peptide of 39 residues (TIP39) constitute a rostro-caudally elongated group of cells in the posterior thalamus. These neurons are located in the rostral part of the subparafascicular nucleus and in the subparafascicular area, caudally. Projections of the caudally located TIP39 neurons have been previously identified by their disappearance following lesions. We have now mapped the projections of the rat rostral subparafascicular neurons using injections of the anterograde tracer biotinylated dextran amine and the retrograde tracer cholera toxin B subunit, and confirmed the projections from more caudal areas previously inferred from lesion studies. Neurons from both the rostral subparafascicular nucleus and the subparafascicular area project to the medial prefrontal, insular, ecto- and perirhinal cortex, nucleus of the diagonal band, septum, central and basomedial amygdaloid nuclei, fundus striati, basal forebrain, midline and intralaminar thalamic nuclei, hypothalamus, subthalamus and the periaqueductal gray. The subparafascicular area projects more densely to the amygdala and the hypothalamus. In contrast, only the rostral part of the subparafascicular nucleus projects significantly to the superficial layers of prefrontal, insular, ectorhinal and somatosensory cortical areas. Double labeling showed that anterogradely labeled fibers from the rostral part of the subparafascicular nucleus contain TIP39 in many forebrain areas, but do not in hypothalamic areas. Injections of the retrograde tracer cholera toxin B subunit into the lateral septum and the fundus striati confirmed that they were indeed target regions of both the rostral subparafascicular nucleus and the subparafascicular area. In contrast, TIP39 neurons did not project to the anterior hypothalamic nucleus. Our data provide an anatomical basis for the potential involvement of rostral subparafascicular neurons in limbic and autonomic regulation, with TIP39 cells being major subparafascicular output neurons projecting to forebrain regions.
Assuntos
Vias Neurais/metabolismo , Neurônios/metabolismo , Neuropeptídeos/metabolismo , Núcleos Posteriores do Tálamo/metabolismo , Prosencéfalo/metabolismo , Animais , Sistema Nervoso Autônomo/anatomia & histologia , Sistema Nervoso Autônomo/fisiologia , Biotina/análogos & derivados , Mapeamento Encefálico , Toxina da Cólera , Dextranos , Diencéfalo/anatomia & histologia , Diencéfalo/metabolismo , Sistema Límbico/anatomia & histologia , Sistema Límbico/fisiologia , Masculino , Vias Neurais/anatomia & histologia , Neurônios/citologia , Núcleos Posteriores do Tálamo/anatomia & histologia , Terminações Pré-Sinápticas/metabolismo , Terminações Pré-Sinápticas/ultraestrutura , Prosencéfalo/anatomia & histologia , Ratos , Ratos Sprague-Dawley , Telencéfalo/anatomia & histologia , Telencéfalo/metabolismoRESUMO
Previously we have shown that inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) are abundantly expressed in the atria of rat hearts. Since arrangement of atria is very heterogeneous, in this work we focused on the precise localization of IP3 receptors in the left atrium, where the gene expression of the type 1 IP3R was the highest. The mRNA levels of the IP3 type 1 receptors in the left atrium, left ventricle and myocytes were determined using real-time polymerase chain reaction and Taqman probe. For precise localization, immunohistochemistry with the antibody against type 1 IP3Rs was performed. The mRNA of type 1 IP3 receptor was more than three times higher in the left atrium than in the left ventricle, as determined by real-time PCR. Expression of the type 1 IP3 receptor mRNA was higher in the atria, especially in parts containing cardiac ganglion cells. The atrial auricles, which are particularly free of ganglion cells, and the ventricles (wall of the right and left ventricle and ventricular septum) contained four to five times less IP3 receptors than atrial samples with ganglia. IP3R type 1 immunoreactivity detected by a confocal microscope attributed the most condensed signal on ganglionic cells, although light immunoreactivity was also seen in cardiomyocytes. These results show that type 1IP3 receptors predominate in intrinsic neuronal ganglia of cardiac atria.
Assuntos
Canais de Cálcio/genética , Gânglios Parassimpáticos/citologia , Gânglios Parassimpáticos/metabolismo , Coração/inervação , Receptores Citoplasmáticos e Nucleares/genética , Animais , Canais de Cálcio/análise , Gânglios Parassimpáticos/química , Expressão Gênica , Átrios do Coração/inervação , Imuno-Histoquímica , Receptores de Inositol 1,4,5-Trifosfato , Masculino , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Receptores Citoplasmáticos e Nucleares/análiseRESUMO
The subparafascicular nucleus and the subparafascicular area are the major sites of synthesis of the recently discovered neuropeptide, tuberoinfundibular peptide of 39 residues (TIP39). Better knowledge of the neuronal inputs to the subparafascicular area and nucleus will facilitate investigation of the functions of TIP39. Thus, we have injected the retrograde tracer cholera toxin B subunit into the rostral, middle, and caudal parts of the rat subparafascicular nucleus. We report that the afferent projections to the subparafascicular nucleus and area include the medial prefrontal, insular, and ectorhinal cortex, the subiculum, the lateral septum, the anterior amygdaloid area, the medial amygdaloid nucleus, the caudal paralaminar area of the thalamus, the lateral preoptic area, the anterior, ventromedial, and posterior hypothalamic nuclei, the dorsal premamillary nucleus, the zona incerta and Forel's fields, the periaqueductal gray, the deep layers of the superior colliculus, cortical layers of the inferior colliculus, the cuneiform nucleus, the medial paralemniscal nucleus, and the parabrachial nuclei. Most of these regions project to all parts of the subparafascicular nucleus. However, the magnocellular subparafascicular neurons, which occupy the middle part of the subparafascicular nucleus, may not receive projections from the medial prefrontal and insular cortex, the medial amygdaloid nucleus, the lateral preoptic area, and the parabrachial nuclei. In addition, double labeling of cholera toxin B subunit and TIP39 revealed a remarkable similarity between input regions of the subparafascicular area and the brain TIP39 system. Neurons within regions that contain TIP39 cell bodies as well as regions that contain TIP39 fibers project to the subparafascicular area. Overall, the afferent connections of the subparafascicular nucleus and area suggest its involvement in central reproductive, visceral, nociceptive, and auditory regulation.
Assuntos
Encéfalo/fisiologia , Neurônios Aferentes/fisiologia , Núcleos Posteriores do Tálamo/fisiologia , Vias Aferentes/fisiologia , Animais , Encéfalo/citologia , Toxina da Cólera , Imuno-Histoquímica , Masculino , Fibras Nervosas/fisiologia , Neuropeptídeos/metabolismo , Núcleos Posteriores do Tálamo/citologia , Ratos , Ratos Sprague-DawleyRESUMO
Subcutaneous (s.c.) injection of formalin into rats is frequently used as a painful stressor that produces a three-phase nociceptive response. We have shown previously that s.c. administered formalin (0.2 ml of 4% solution per 100 g body weight) unexpectedly attenuated the increase of plasma epinephrine levels in rats exposed to exteroceptive stressors (handling, immobilisation). To clarify the mechanism(s) responsible for this phenomenon, the effect of formalin applications on epinephrine plasma levels was investigated in various experimental conditions. Subcutaneous application of formalin combined with exposures of animals to an interoceptive stressor, insulin-induced hypoglycaemia, significantly attenuated the stress-induced increase in plasma epinephrine levels, whereas plasma norepinephrine levels remained highly elevated. Moreover, administration of formalin to unstressed animals also manifested signs of an attenuated epinephrine secretion. Interestingly, intraperitoneal administration of formalin did not reduce the elevated levels of plasma epinephrine. We suggest that formalin attenuates epinephrine secretion from the adrenal medulla most probably via irritation of s.c. somatosensory receptors. We hypothesise that the irritation of the primary sensory afferents fibres might reduce the activity of the sympathetic preganglionic neurones innervating adrenal medullary chromaffin cells. Further investigations are required to establish whether the observed reduction of epinephrine secretion from the adrenal medulla is controlled by either spinal or supraspinal neuronal circuits.