RESUMO
OBJECTIVE: Vitamin D deficiency may be a clinical problem in patients with addictions. The authors systematically searched for studies addressing vitamin D and addiction and develop a hypothesis which can direct future research of the possible mechanistic role of vitamin D in the process of addiction. METHODS: Systematic review of the literature found in PubMed and EMBASE followed by narrative review combined with clinical experiences leading to hypotheses for future research. RESULTS: Only five articles were identified about a role of vitamin D in the pathophysiology of addiction. Their results are in line with a possible influence of vitamin D in dopaminergic transmission. The cerebral vitamin D status depends on the functionality of genetic variants of vitamin D receptor and other involved genes. Routine serum calcidiol levels may not adequately reflect cerebral vitamin D status. Uncertainty exists regarding appropriate calcidiol blood levels and proper dosages for affecting the central nervous system (CNS). CONCLUSIONS: The putative pathophysiological role of vitamin D in substance abuse has been insufficiently studied which calls to more studies how to measure cerebral vitamin D status in clinical practice. Research is indicated whether vitamin D supplementation should use higher dosages and aim to reach higher calcidiol serum levels. Measuring dopaminergic functioning within the prefrontal cortex as reflected by neuropsychological tests selected as suitable could be a appropriate proxy for the cerebral vitamin D status when studying the pharmacogenomics of this functionality in patients.
Assuntos
Alcoolismo/fisiopatologia , Comportamento Aditivo/fisiopatologia , Sistema Nervoso Central/metabolismo , Deficiência de Vitamina D/complicações , Vitamina D/sangue , Adulto , Alcoolismo/genética , Alcoolismo/metabolismo , Animais , Comportamento Aditivo/genética , Comportamento Aditivo/metabolismo , Calcifediol/sangue , Sistema Nervoso Central/química , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Animais , Farmacogenética , Polimorfismo de Nucleotídeo Único/genética , Ratos , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismoRESUMO
Anthocyanins are plant pigments present in flowers, leaves or fruits with polyphenolic structure belonging to the group of flavonoids. From a nutritional approach, they are the most abundant flavonoids in dietary sources responsible for the antioxidant properties of those foods. In addition, the food and pharma industries have used anthocyanins as food additives or excipients due to its colorant properties. However, beyond its antioxidant effects, anthocyanins may also act as therapeutic agents due to neuroprotective, antidiabetic and cardioprotective properties. There is a growing body of evidence suggesting the role of these compounds in the Central Nervous System (CNS). Previous in vitro and animal studies have suggested neuroprotective benefits, but we here review human interventions made with anthocyanins in relation to cognition, insomnia, anxiety or depression. Due to the link between oxidative stress and neurodegenerative disorders, human studies conducted on healthy volunteers evaluating oxidative stress parameters have also been included. As reviewed here, very few human studies (only ten) have been performed in the area of CNS; however, considering the obtained outcomes in those trials together with human interventions in relation with oxidative stress as well as data showing neuroprotective effects from preclinical experiments, we suggest that anthocyanins may have potential benefits for the CNS.
Assuntos
Antocianinas , Ingredientes de Alimentos , Animais , Antocianinas/farmacologia , Antioxidantes/farmacologia , Sistema Nervoso Central/química , Sistema Nervoso Central/metabolismo , Ensaios Clínicos como Assunto , Frutas , Humanos , Estresse OxidativoRESUMO
Bacopa monnieri has been used in Ayurvedic medicine to improve memory and cognition. The active constituent responsible for its pharmacological effects is bacoside A, a mixture of dammarane-type triterpenoid saponins containing sugar chains linked to a steroid aglycone skeleton. Triterpenoid saponins have been reported to be transformed in vivo to metabolites that give better biological activity and pharmacokinetic characteristics. Thus, the activities of the parent compounds (bacosides), aglycones (jujubogenin and pseudojujubogenin) and their derivatives (ebelin lactone and bacogenin A1) were compared using a combination of in silico and in vitro screening methods. The compounds were docked into 5-HT1A, 5-HT2A, D1, D2, M1 receptors and acetylcholinesterase (AChE) using AutoDock and their central nervous system (CNS) drug-like properties were determined using Discovery Studio molecular properties and ADMET descriptors. The compounds were screened in vitro using radioligand receptor binding and AChE inhibition assays. In silico studies showed that the parent bacosides were not able to dock into the chosen CNS targets and had poor molecular properties as a CNS drug. In contrast, the aglycones and their derivatives showed better binding affinity and good CNS drug-like properties, were well absorbed through the intestines and had good blood brain barrier (BBB) penetration. Among the compounds tested in vitro, ebelin lactone showed binding affinity towards M1 (Ki = 0.45 µM) and 5-HT2A (4.21 µM) receptors. Bacoside A and bacopaside X (9.06 µM) showed binding affinity towards the D1 receptor. None of the compounds showed any inhibitory activity against AChE. Since the stimulation of M1 and 5-HT2A receptors has been implicated in memory and cognition and ebelin lactone was shown to have the strongest binding energy, highest BBB penetration and binding affinity towards M1 and 5-HT2A receptors, we suggest that B. monnieri constituents may be transformed in vivo to the active form before exerting their pharmacological activity.
Assuntos
Transtornos Cognitivos/tratamento farmacológico , Ayurveda , Saponinas/química , Triterpenos/química , Bacopa/química , Sistema Nervoso Central/química , Sistema Nervoso Central/efeitos dos fármacos , Cognição/efeitos dos fármacos , Cognição/fisiologia , Transtornos Cognitivos/patologia , Terapia Cognitivo-Comportamental , Simulação por Computador , Humanos , Simulação de Acoplamento Molecular , Receptor Muscarínico M1/química , Receptor 5-HT2A de Serotonina/química , Saponinas/farmacocinética , Saponinas/uso terapêutico , Triterpenos/farmacocinética , Triterpenos/uso terapêutico , DamaranosRESUMO
OBJECTIVE: To study the analgesia mechanism of needle-knife lysis in spinal cord and other parts of central nervous system by comparing the changes of Leu-Enkephalin (L-ENK) content in different parts of centrium of rats undergone needle-knife lysis and electro-acupuncture respectively. METHODS: Sixty healthy SD rats were randomly devided into normal control group, model group, needle-knife lysis (NKL) group and electro-acupuncture (EA) group. 4% papain solution mixed with 0.3 mol/L cysteine solutin in the ratio of 1:1, paused for 0.5 h,injected the mixture, 20 microl each time,into the left knee joint cavities of rats in model, NKL, EA groups at the 1st, 4th, 7th day. After 4 weeks in NKL group and EA group were treated with needle-knife lysis and electro-acupuncture, respectively. Three weeks after treatment, samples of spinal cord of the swollen part of rat waists and rat brains were taken from and the content of L-ENK of medulla oblongata, midbrain, pituitary gland, and hippocampus were measured. RESULTS: L-ENK content of model group increased higher than that of normal control group in spinal cord, hippocampus and midbrain (P < 0.01); there were no significant difference between normal control group and modle group on L-ENK in medulla oblongata and thalamus (P > 0.05). After intervening of NKL or EA, L-ENK content of NKL group increased higher in hippocampus than that of model group and EC group (P < 0.05); but L-ENK content of NKL group in midbrain was lower than that of model group (P < 0.05). CONCLUSION: Needle-knife lysis has characteristic of regulation for the L-ENK content in different parts of central nervous system of rats with knee osteoarthritis, and analgesic effect of needle-knife was possibly related with regulation of center L-ENK.
Assuntos
Terapia por Acupuntura/métodos , Sistema Nervoso Central/química , Encefalina Leucina/análise , Osteoartrite do Joelho/terapia , Animais , Eletroacupuntura , Feminino , Masculino , Osteoartrite do Joelho/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Grape polyphenols confer potential health benefits, including prevention of neurodegenerative diseases. To determine the absorption and tissue distribution of the complex grape polyphenol mixture, (14)C-labeled polyphenols were biosynthesized by grape cell suspension cultures, during co-incubation with radioisotopically labeled sucrose, and fractionated into polyphenolic subfractions. The pharmacokinetics and distribution of grape polyphenols into blood, brain, and peripheral interstitial fluid were determined by tracking the (14)C label. The blood peak (14)C concentration of the fractions ranged from 15 minutes to 4 hours. Absorption and tissue distribution varied greatly between fractions. Concentrations in interstitial fluid were lower than in blood. The amount of residual label in the brain at 24 hours ranged from 0.1% to 1.7% of the dose, depending on the fraction. (14)C label found in the brain tissue and brain microdialysate indicated that grape polyphenols or their metabolites are able to cross the blood-brain barrier. Using (14)C-labeled plant polyphenols it is possible to track the compounds or their metabolic products into any tissue and determine distribution patterns in spite of low concentrations. A central question regarding the potential role of dietary polyphenolics in neurodegenerative research is whether they are bioavailable in the brain. Our observations indicate that some grape-derived polyphenolics do reach the brain, which suggests their potential value for applications in neurodegenerative disorders.
Assuntos
Sistema Nervoso Central/metabolismo , Líquido Extracelular/metabolismo , Flavonoides/farmacocinética , Fenóis/farmacocinética , Extratos Vegetais/farmacocinética , Vitis/química , Administração Oral , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Animais , Radioisótopos de Carbono/análise , Radioisótopos de Carbono/farmacocinética , Sistema Nervoso Central/química , Sistema Nervoso Central/efeitos dos fármacos , Modelos Animais de Doenças , Líquido Extracelular/química , Líquido Extracelular/efeitos dos fármacos , Flavonoides/administração & dosagem , Flavonoides/química , Humanos , Masculino , Fenóis/administração & dosagem , Fenóis/química , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Polifenóis , Ratos , Ratos Sprague-Dawley , Distribuição TecidualRESUMO
The G protein-coupled receptor 30 (GPR 30) has been identified as the non-genomic estrogen receptor, and G-1, the specific ligand for GPR30. With the use of a polyclonal antiserum directed against the human C-terminus of GPR30, immunohistochemical studies revealed GPR30-immunoreactivity (irGPR30) in the brain of adult male and non-pregnant female rats. A high density of irGPR30 was noted in the Islands of Calleja and striatum. In the hypothalamus, irGPR30 was detected in the paraventricular nucleus and supraoptic nucleus. The anterior and posterior pituitary contained numerous irGPR30 cells and terminal-like endings. Cells in the hippocampal formation as well as the substantia nigra were irGPR30. In the brainstem, irGPR30 cells were noted in the area postrema, nucleus of the solitary tract, and dorsal motor nucleus of the vagus; a cluster of cells were prominently labeled in the nucleus ambiguus. Tissue sections processed with pre-immune serum showed no irGPR30, affirming the specificity of the antiserum. G-1 (100 nM) caused a large increase of intracellular calcium concentrations [Ca(2+) ](i) in dissociated and cultured rat hypothalamic neurons, as assessed by microfluorometric Fura-2 imaging. The calcium response to a second application of G-1 showed a marked homologous desensitization. Our result shows a high expression of irGPR30 in the hypothalamic-pituitary axis, hippocampal formation, and brainstem autonomic nuclei; and the activation of GPR30 by G-1 is associated with a mobilization of calcium in dissociated and cultured rat hypothalamic neurons.
Assuntos
Sistema Nervoso Central/química , Receptores Acoplados a Proteínas G/análise , Animais , Cálcio/análise , Cálcio/metabolismo , Células Cultivadas , Sistema Nervoso Central/metabolismo , Ciclopentanos/farmacologia , Citosol/química , Feminino , Hipocampo/química , Hipocampo/metabolismo , Hipotálamo/química , Hipotálamo/metabolismo , Soros Imunes/farmacologia , Imuno-Histoquímica , Ligantes , Masculino , Bulbo/química , Bulbo/metabolismo , Mesencéfalo/química , Mesencéfalo/metabolismo , Hipófise/química , Hipófise/metabolismo , Prosencéfalo/química , Prosencéfalo/metabolismo , Quinolinas/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/imunologia , Receptores Acoplados a Proteínas G/metabolismoRESUMO
A number of RFamide peptides have been characterized in invertebrate species and these peptides have been found to exert a broad spectrum of biological activities. In contrast, in vertebrates, our knowledge on RFamide peptides is far more limited and only a few members of the RFamide peptide family have been identified in various vertebrate classes during the last years. The present review focuses on two novel RFamide peptides, Rana RFamide (R-RFa) and 26RFa, that have been recently isolated from the amphibian brain. R-RFa shares the C-terminal LPLRFamide motif with other RFamide peptides previously identified in mammals, birds and fish. The distribution of R-RFa in the frog brain exhibits strong similarities with those of other LPLRFamide peptides, notably in the periventricular region of the hypothalamus. There is also evidence that the physiological functions of R-RFa and other LPLRFamide peptides have been conserved from fish to mammals; in particular, all these peptides appear to be involved in the control of pituitary hormone secretion. 26RFa does not exhibit any significant structural identity with other RFamide peptides and this peptide is the only member of the family that possesses an FRFamide motif at its C-terminus. The strong conservation of the primary structure of 26RFa from amphibians to mammals suggests that this RFamide peptide is involved in important biological functions in vertebrates. As for several other RFamide peptides, 26RFa-containing neurons are present in the hypothalamus, notably in two nuclei involved in the control of feeding behavior. Indeed, 26RFa is a potent stimulator of appetite in mammals. Concurrently, recent data suggest that 26RFa exerts various neuroendocrine regulatory activities at the pituitary and adrenal level.
Assuntos
Hipotálamo/química , Neuropeptídeos/química , Neuropeptídeos/fisiologia , Animais , Sistema Nervoso Central/química , Humanos , Oligopeptídeos/análise , Ranidae , Receptores de Neuropeptídeos/análiseRESUMO
The neuropeptide FF (NPFF) is an octapeptide of the RFamide-related peptides (FaRPs) that was primarily isolated from the bovine brain. Its distribution in the CNS has been reported in several mammalian species, as well as in some amphibians. Therefore, in order to gain insight in the evolution on the expression pattern of this neuropeptide in vertebrates, we carried out an immunohistochemical study in the sea lamprey, Petromyzon marinus. The distribution of NPFF-like-immunoreactive (NPFF-ir) structures in the lamprey brain is, in general, comparable to that previously described in other vertebrate species. In lamprey, most of the NPFF-ir cells were found in the hypothalamus, particularly in two large populations, the bed nucleus of the tract of the postoptic commissure and the tuberomammillary area. Numerous NPFF-ir cells were also observed in the rostral rhombencephalon, including a population in the dorsal isthmic gray and the reticular formation. Additional labeled neurons were found inside the preoptic region, the parapineal vesicle, the periventricular mesencephalic tegmentum, the descending trigeminal tract, the nucleus of the solitary tract, as well as in the gray matter of the spinal cord. The NPFF-ir fibers were widely distributed in the brain and the spinal cord, being, in general, more concentrated throughout the basal plate. The presence of NPFF-ir fibers in the lamprey neurohypophysis suggests that the involvement of NPFF-like substances in the hypothalamo-hypophyseal system had emerged early during evolution.
Assuntos
Sistema Nervoso Central/química , Oligopeptídeos/análise , Receptores de Catecolaminas/análise , Animais , Feminino , Região Hipotalâmica Lateral/química , Hipotálamo/química , Imuno-Histoquímica , Lampreias , Masculino , Tirosina 3-Mono-Oxigenase/análiseRESUMO
The detection of central nervous system (CNS) tissue (i.e. brain and spinal cord) by the use of GC-MS and certain fatty acids (FAs) as their methyl esters (FAMEs) was previously shown to be a very promising approach towards identification of CNS tissue as a specified risk material (SRM) in meat products, contrasting available immunochemical methods. This GC-MS method promised to allow quantification of CNS material as low as 0.01%. Here, we show that the CNS-relevant FAMEs C22:6, C24:1omega9, C24:1omega7, C24:0 and C24-OH are present in pure muscle and adipose tissue samples in detectable amounts. Thus, limits of detection are not feasible as quality parameters in this analytical GC-MS approach. Instead, cut-off values have to be applied as calculated from the baseline content of the respective FAME in CNS-free samples and its variation for a given statistical security. Furthermore, the FAs used for quantification of the CNS showed distinct differences depending on species and age. This finding is in accordance with previous studies where it had been concluded that species and age differentiation of CNS might be possible with GC-MS. However, it was not taken into account that it also necessitates a strict analytical strategy for quantification of the CNS content: identification of the presence of CNS (step 1); identification of species and age (step 2); and quantification by use of a species- and age-specific CNS calibration (step 3). Differences between the FA content of the CNS used for calibrating and the CNS in the sample will cause up to fivefold deviation from the true CNS content. Our results show that the FA best suited for identification (step 1) and quantification (step 3) purposes is cerebronic acid C24-OH after silylation. Further in-depth studies are needed in order to elucidate variability of brain FA content and to determine analytical limits. However, the present GC-MS approach is already a highly promising supplement to existing immunochemical methods for the detection of traces of CNS material in meat products.
Assuntos
Sistema Nervoso Central/química , Análise de Alimentos/métodos , Produtos da Carne/análise , Fatores Etários , Animais , Química Encefálica , Ácidos Graxos/análise , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Cromatografia Gasosa-Espectrometria de Massas/métodos , Doenças Priônicas/prevenção & controle , Valores de Referência , Risco , Sensibilidade e Especificidade , Especificidade da EspécieRESUMO
Scrapie responsive gene one (Scrg1) is a novel transcript discovered through identification of the genes associated with or responsible for the neurodegenerative changes observed in transmissible spongiform encephalopathies. Scrg1 mRNA is distributed principally in the central nervous system and the cDNA sequence predicts a small cysteine-rich protein 98 amino acids in length, with a N-terminal signal peptide. In this study, we have generated antibodies against the predicted protein and revealed expression of a predominant immunoreactive protein of 10 kDa in mouse brain by Western blot analysis. We have established CAD neuronal cell lines stably expressing Scrg1 to determine its subcellular localization. Several lines of evidence show that the protein is targeted to dense-core vesicles in these cells. (i) Scrg1 is detected by immunocytochemistry as very punctate signals especially in the Golgi apparatus and tips of neurites, suggesting a vesicular localization for the protein. Moreover, Scrg1 exhibits a high degree of colocalization with secretogranin II, a dense-core vesicle marker and a very limited colocalization with markers for small synaptic vesicles. (ii) Scrg1 immunoreactivity is associated with large secretory granules/dense-core vesicles, as indicated by immuno-electron microscopy. (iii) Scrg1 is enriched in fractions of sucrose density gradient where synaptotagmin V, a dense-core vesicle-associated protein, is also enriched. The characteristic punctate immunostaining of Scrg1 is observed in N2A cells transfected with Scrg1 and for the endogenous protein in cultured primary neurons, attesting to the generality of the observations. Our findings strongly suggest that Scrg1 is associated with the secretory pathway of neuronal cells.
Assuntos
Proteínas de Ligação ao Cálcio , Proteínas do Tecido Nervoso/análise , Neurônios/química , Vesículas Sinápticas/química , Sequência de Aminoácidos , Animais , Anticorpos , Western Blotting , Linhagem Celular , Sistema Nervoso Central/química , Cromograninas , DNA Complementar , Imuno-Histoquímica , Glicoproteínas de Membrana/análise , Camundongos , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/imunologia , Proteínas/análise , Proteínas Recombinantes/análise , SinaptotagminasRESUMO
We reported that the common octopus, Octopus vulgaris, in common with vertebrates, possesses two members of the oxytocin/vasopressin superfamily: octopressin (OP) and cephalotocin (CT). This was the first observation of its kind in invertebrates. As OP and CT have different biological activities, the presence of specific receptors has been proposed. We cloned the cDNA of an orphan receptor from Octopus brain and found it to encode a polypeptide of 397 amino acids that displays sequences characteristic of G-protein coupled receptors. The orphan receptor showed high homology to receptors of the oxytocin/vasopressin superfamily and seemed to conserve the agonist-binding pocket common to the oxytocin and vasopressin receptors. Xenopus oocytes that express the orphan receptor responded to the application of CT by an induction of membrane Cl(-) currents coupled to the inositol phosphate/Ca(2+) pathway. OP and the other members of the oxytocin/vasopressin superfamily did not activate this receptor. HPLC fractionation of the Octopus brain extract combined with an oocyte assay yielded a single substance that was identical to CT. On the basis of these results, we conclude that the cloned receptor is the CT receptor (CTR). Expression of CTR mRNA in Octopus was detected in the central and the peripheral nervous systems, the pancreas, the oviduct and the ovary. This receptor may mediate physiological functions of CT in Octopus such as neurotransmission, reproduction and metabolism.
Assuntos
Encéfalo/metabolismo , Octopodiformes/metabolismo , Receptores de Vasopressinas/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Southern Blotting , Química Encefálica , Sistema Nervoso Central/química , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , DNA Complementar/genética , Feminino , Expressão Gênica , Humanos , Dados de Sequência Molecular , Venenos de Moluscos/análise , Venenos de Moluscos/metabolismo , Venenos de Moluscos/farmacologia , Oócitos/metabolismo , Ovário/química , Oviductos/química , Pâncreas/química , RNA Mensageiro/análise , Alinhamento de Sequência , XenopusRESUMO
Gamma-aminobutyric acid (GABA)ergic neurons in the central nervous system regulate the activity of other neurons and play a crucial role in information processing. To assist an advance in the research of GABAergic neurons, here we produced two lines of glutamic acid decarboxylase-green fluorescence protein (GAD67-GFP) knock-in mouse. The distribution pattern of GFP-positive somata was the same as that of the GAD67 in situ hybridization signal in the central nervous system. We encountered neither any apparent ectopic GFP expression in GAD67-negative cells nor any apparent lack of GFP expression in GAD67-positive neurons in the two GAD67-GFP knock-in mouse lines. The timing of GFP expression also paralleled that of GAD67 expression. Hence, we constructed a map of GFP distribution in the knock-in mouse brain. Moreover, we used the knock-in mice to investigate the colocalization of GFP with NeuN, calretinin (CR), parvalbumin (PV), and somatostatin (SS) in the frontal motor cortex. The proportion of GFP-positive cells among NeuN-positive cells (neocortical neurons) was approximately 19.5%. All the CR-, PV-, and SS-positive cells appeared positive for GFP. The CR-, PV, and SS-positive cells emitted GFP fluorescence at various intensities characteristics to them. The proportions of CR-, PV-, and SS-positive cells among GFP-positive cells were 13.9%, 40.1%, and 23.4%, respectively. Thus, the three subtypes of GABAergic neurons accounted for 77.4% of the GFP-positive cells. They accounted for 6.5% in layer I. In accord with unidentified GFP-positive cells, many medium-sized spherical somata emitting intense GFP fluorescence were observed in layer I.
Assuntos
Sistema Nervoso Central/química , Glutamato Descarboxilase/análise , Isoenzimas/análise , Proteínas Luminescentes/metabolismo , Parvalbuminas/análise , Proteína G de Ligação ao Cálcio S100/análise , Somatostatina/análise , Ácido gama-Aminobutírico , Animais , Western Blotting , Calbindina 2 , Expressão Gênica , Glutamato Descarboxilase/genética , Proteínas de Fluorescência Verde , Imuno-Histoquímica , Hibridização In Situ , Isoenzimas/genética , Proteínas Luminescentes/genética , Camundongos , Camundongos Mutantes Neurológicos , Córtex Motor/química , Neurônios/químicaRESUMO
In addition to its role as a potent vasodilator, adrenomedullin (ADM) affects an animal's physiological status through its effects in the brain. We have shown that circulating ADM activates neurons, including nitric oxide (NO)-producing neurons, in autonomic centers of the brain such as the hypothalamic paraventricular nucleus (PVN). Systemic ADM gains access to the brain through the area postrema (AP), a brainstem circumventricular organ, and the PVN is a major target of these ADM-sensitive AP neurons. Neurons expressing the preproADM (ppADM) gene are distributed throughout the brain, with high levels in autonomic centers. Lipopolysaccharide (LPS, immune stress), restraint (psychological stress), and 24 h dehydration all down-regulate ppADM gene expression in different subsets of autonomic centers. Receptor-activity-modifying protein (RAMP) 2 and RAMP3, ADM receptor subunits, are expressed in autonomic centers including the PVN and supraoptic nucleus. Intracerebroventricular injections of ADM increase arterial pressure, heart rate, tyrosine hydroxylase mRNA levels in the locus coeruleus, plasma levels of ACTH, and NO production in the hypothalamus. ADM excites putative GABAergic and cholinergic neurons in dissociated cells from a basal forebrain integrative center, the diagonal band of Broca. These results demonstrate that the signalling components necessary for ADM to influence physiological systems are present in the brain and that ADM is an important transmitter of brain autonomic pathways which are involved in regulating homeostatic balance.
Assuntos
Sistema Nervoso Autônomo/fisiologia , Encéfalo/fisiologia , Sistemas Neurossecretores/fisiologia , Peptídeos/farmacologia , Adrenomedulina , Peptídeos beta-Amiloides/fisiologia , Sistema Nervoso Autônomo/química , Sistema Nervoso Autônomo/efeitos dos fármacos , Encéfalo/citologia , Encéfalo/efeitos dos fármacos , Sistema Nervoso Central/química , Feixe Diagonal de Broca/química , Condutividade Elétrica , Homeostase , Humanos , Sistema Hipotálamo-Hipofisário/fisiologia , Hipotálamo/química , Potenciais da Membrana , Sistemas Neurossecretores/química , Sistemas Neurossecretores/efeitos dos fármacos , Óxido Nítrico/metabolismo , Núcleo Hipotalâmico Paraventricular/ultraestrutura , Técnicas de Patch-Clamp , Peptídeos/análise , Sistema Hipófise-Suprarrenal/fisiologia , Receptores de Adrenomedulina , Receptores de Peptídeos/análise , Núcleo Supraóptico/ultraestruturaRESUMO
Glutamine, the preferred precursor for neurotransmitter glutamate and GABA, is likely to be the principal substrate for the neuronal System A transporter SNAT1 in vivo. We explored the functional properties of SNAT1 (the product of the rat Slc38a1 gene) by measuring radiotracer uptake and currents associated with SNAT1 expression in Xenopus oocytes and determined the neuronal-phenotypic and cellular distribution of SNAT1 by confocal laser-scanning microscopy alongside other markers. We found that SNAT1 mediates transport of small, neutral, aliphatic amino acids including glutamine (K0.5 approximately 0.3 mm), alanine, and the System A-specific analogue 2-(methylamino)isobutyrate. Amino acid transport is driven by the Na+ electrochemical gradient. The voltage-dependent binding of Na+ precedes that of the amino acid in a simultaneous transport mechanism. Li+ (but not H+) can substitute for Na+ but results in reduced Vmax. In the absence of amino acid, SNAT1 mediates Na+-dependent presteady-state currents (Qmax approximately 9 nC) and a nonsaturable cation leak with selectivity Na+, Li+ >> H+, K+. Simultaneous flux and current measurements indicate coupling stoichiometry of 1 Na+ per 1 amino acid. SNAT1 protein was detected in somata and proximal dendrites but not nerve terminals of glutamatergic and GABAergic neurons throughout the adult CNS. We did not detect SNAT1 expression in astrocytes but detected its expression on the luminal membranes of the ependyma. The functional properties and cellular distribution of SNAT1 support a primary role for SNAT1 in glutamine transport serving the glutamate/GABA-glutamine cycle in central neurons. Localization of SNAT1 to certain dopaminergic neurons of the substantia nigra and cholinergic motoneurons suggests that SNAT1 may play additional specialized roles, providing metabolic fuel (via alpha-ketoglutarate) or precursors (cysteine, glycine) for glutathione synthesis.
Assuntos
Sistema A de Transporte de Aminoácidos/metabolismo , Sistema Nervoso Central/citologia , Neurônios/química , Sistema A de Transporte de Aminoácidos/fisiologia , Aminoácidos Neutros/metabolismo , Animais , Cátions Monovalentes , Sistema Nervoso Central/química , DNA Complementar , Glutamina/metabolismo , Cinética , Microinjeções , Microscopia de Fluorescência , Oócitos , Técnicas de Patch-Clamp , Ratos , Distribuição Tecidual , XenopusAssuntos
Acupuntura , Estimulação Elétrica/métodos , Neuropeptídeos/metabolismo , Neurotransmissores/metabolismo , Peptídeos Opioides/metabolismo , Analgesia , Animais , Sistema Nervoso Central/química , Eletroacupuntura/métodos , Humanos , Técnicas In Vitro , Neuropeptídeos/classificação , Peptídeos Opioides/classificaçãoRESUMO
To gain a greater insight into the relationship between hyperactivity of the corticotropin-releasing hormone (CRH) system and autonomic and physiological changes associated with chronic stress, we developed a transgenic mouse model of central CRH overproduction. The extent of central and peripheral CRH overexpression, and the amount of bioactive CRH in the hypothalamus were determined in two lines of CRH-overexpressing (CRH-OE) mice. Furthermore, 24 h patterns of body temperature, heart rate, and activity were assessed using radiotelemetry, as well as cumulative water and food consumption and body weight gain over a 7-day period. CRH-OE mice showed increased amounts of CRH peptide and mRNA only in the central nervous system. Despite the presence of the same CRH transgene in their genome, only in one of the two established lines of CRH-OE mice (line 2122, but not 2123) was overexpression of CRH associated with increased levels of bioactive CRH in the hypothalamus, increased body temperature and heart rate (predominantly during the light (inactive) phase of the diurnal cycle), decreased heart rate variability during the dark (active) phase, and increased food and water consumption, when compared with littermate wildtype mice. Because line 2122 of the CRH transgenic mice showed chronic stress-like neuroendocrine and autonomic changes, these mice appear to represent a valid animal model for chronic stress and might be valuable in the research on the consequences of CRH excess in situations of chronic stress.
Assuntos
Sistema Nervoso Autônomo/fisiologia , Hormônio Liberador da Corticotropina/metabolismo , Hipotálamo/metabolismo , Animais , Temperatura Corporal/fisiologia , Sistema Nervoso Central/química , Sistema Nervoso Central/fisiologia , Hormônio Liberador da Corticotropina/análise , Frequência Cardíaca/fisiologia , Hipotálamo/química , Masculino , Camundongos , Camundongos Transgênicos/imunologia , Camundongos Transgênicos/fisiologia , Estresse Fisiológico , Regulação para Cima/fisiologiaRESUMO
Vesicular glutamate transporter 1 (VGluT1) is one of the best markers for glutamatergic neurons, because it accumulates transmitter glutamate into synaptic vesicles. Differentiation-associated Na(+)-dependent inorganic phosphate cotransporter (DNPI) shows 82% amino acid identity to VGluT1, and is another candidate for vesicular glutamate transporters. Here, we report the immunocytochemical localization of DNPI and compare it with that of VGluT1 in the adult rat brain. Both DNPI and VGluT1 immunoreactivities were found mostly in neuropil, presumably in axon terminals, throughout the brain. In the telencephalic regions, intense DNPI immunoreactivity was observed in the glomeruli of the olfactory bulb, layer IV of the neocortex, granular layer of the dentate gyrus, presubiculum, and postsubiculum. In contrast, VGluT1 immunoreactivity was intense in the olfactory tubercle, layers I-III of the neocortex, piriform cortex, entorhinal cortex, hippocampus, dentate gyrus, and subiculum. In the thalamic nuclei, DNPI-immunoreactive terminal-like profiles were much larger than VGluT1-immunoreactive ones, suggesting that DNPI immunoreactivity was subcortical in origin. DNPI immunoreactivity was much more intense than VGluT1 immunoreactivity in many brainstem and spinal cord regions, except the pontine nuclei, interpeduncular nucleus, cochlear nuclei, and external cuneate nucleus. In the molecular layer of the cerebellar cortex, climbing-like fibers showed intense DNPI immunoreactivity, whereas neuropil contained dense VGluT1-immnoreactive deposits. Both DNPI and VGluT1 immunoreactivities were observed as mossy fiber terminal-like profiles in the cerebellar granular layer. DNPI and VGluT1 immunoreactivities appeared associated with synaptic vesicles in the axon terminals forming asymmetric synapses in several regions examined electron microscopically. The present results indicate that DNPI and VGluT1 are used by different neural components in most, if not all, brain regions, suggesting the complementary functions of DNPI and VGluT1.
Assuntos
Química Encefálica/fisiologia , Proteínas de Transporte/análise , Proteínas de Membrana Transportadoras , Ratos Wistar/fisiologia , Proteínas de Transporte Vesicular , Animais , Proteínas de Transporte/imunologia , Sistema Nervoso Central/química , Ácido Glutâmico/fisiologia , Imuno-Histoquímica/normas , Masculino , Microscopia Imunoeletrônica , Neurópilo/química , Neurópilo/ultraestrutura , Proteínas de Transporte de Fosfato/análise , Proteínas de Transporte de Fosfato/imunologia , Ratos , Proteína Vesicular 1 de Transporte de Glutamato , Proteína Vesicular 2 de Transporte de GlutamatoRESUMO
Rats fed a semipurified diet supplemented with 3% (w/w) safflower oil [Saf, n-3 fatty acid deficient, high linoleic acid (18:2n-6)] through two generations exhibit decreased correct response ratios in a brightness-discrimination learning test compared with rats fed 3% perilla oil [Per, high alpha-linolenic acid (18:3n-3)]. This is associated with a decreased DHA (22:6n-3)-to-arachidonic acid (20:4n-6) ratio in brain lipids. In the first set of experiments, dietary oil was shifted from Saf to a mixture of 2.4% safflower oil plus 0.6% DHA after weaning (Saf-DHA), but all parameters measured in the learning test were essentially unchanged. Brain 22:6n-3 content of the Saf-DHA group reached that of the Per group but the levels of 20:4n-6 and docosatetraenoic acid (22:4n-6) did not decrease to those of the Per group at the start of the test. In the second set of experiments, dietary oil was shifted to a mixture of 0.6% safflower oil plus 1.2% oleic acid (OA) plus 1.2% DHA (Saf-OA-DHA group) with 18:2n-6 content comparable to that of the Per group. The Saf-OA-DHA group exhibited a learning performance similar to that of the Per group; brain 22:6n-3, 20:4n-6, and 22:4n-6 contents were also comparable to those of the Per group. These results indicate that the altered learning behavior associated with a long-term n-3 fatty acid deficiency is reversed by supplementing 22:6n-3 after weaning, when the levels of competing n-6 fatty acids in the diet and brain lipids are limited.
Assuntos
Ácidos Graxos Ômega-3/farmacologia , Ácidos Graxos Insaturados/deficiência , Ácidos Graxos Insaturados/farmacologia , Aprendizagem/efeitos dos fármacos , Óleo de Cártamo/farmacologia , Envelhecimento/fisiologia , Animais , Sistema Nervoso Central/química , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/metabolismo , Gorduras Insaturadas na Dieta/administração & dosagem , Gorduras Insaturadas na Dieta/farmacologia , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/farmacologia , Ácidos Graxos Ômega-3/administração & dosagem , Ácidos Graxos Ômega-3/análise , Ácidos Graxos Ômega-6 , Ácidos Graxos Insaturados/administração & dosagem , Ácidos Graxos Insaturados/análise , Feminino , Luz , Testes Neuropsicológicos , Estimulação Luminosa , Óleos de Plantas , Ratos , Reforço Psicológico , Óleo de Cártamo/administração & dosagem , Percepção Visual/efeitos dos fármacos , Desmame , Ácido alfa-Linolênico/administração & dosagem , Ácido alfa-Linolênico/farmacologiaRESUMO
The molecular diversity of neuronal subpopulations was examined with a new monoclonal antibody, 8B3, that recognizes a condroitin sulfate proteoglycan expressed in anatomically discrete domains of central nervous system regions. In the neocortex, interneurons display 8B3 immunoreactivity in a rostrocaudal gradient, with a distinctive staining pattern that distinguishes known cytoarchitectonic and functional boundaries. The distribution pattern of 8B3 immunoreactivity in subcortical structures is very restricted. In the striatum, 8B3 stains spiny stellate neurons clearly defining a compartment that may correspond to the matrix. Gradients of immunoreactivity are detected in the putamen, globus pallidus, and deep cerebellar nuclei, where the most dense areas of 8B3 immunoreactivity corresponds to zones of polysynaptic projections to association prefrontal cortex. In contrast, the sensorimotor domains express lower levels of immunoreactivity. Only the projection neurons of the ventrolateral nucleus and the GABAergic neurons of the reticular nucleus express significant 8B3 immunoreactivity in the thalamus. In the spinal cord, 8B3 immunoreactivity is primarily associated with a subpopulation of motor neurons in the ventral horn and neurons in Clarke's nucleus. The complex distribution pattern reflects novel aspects of the functional organization of cortical and subcortical systems in the CNS of the primate brain and represents a potentially useful tool to assess subpopulations of neurons and brain areas as putative targets in human disease.
Assuntos
Sistema Nervoso Central/química , Sistema Nervoso Central/citologia , Proteoglicanas de Sulfatos de Condroitina/análise , Epitopos/análise , Imuno-Histoquímica/métodos , Macaca nemestrina/metabolismo , Neurônios/química , Animais , Anticorpos Monoclonais , Especificidade de Anticorpos , Tronco Encefálico/química , Tronco Encefálico/citologia , Núcleos Cerebelares/química , Núcleos Cerebelares/citologia , Córtex Cerebral/química , Córtex Cerebral/citologia , Corpo Estriado/química , Corpo Estriado/citologia , Macaca nemestrina/anatomia & histologia , Neurônios/citologia , Medula Espinal/química , Medula Espinal/citologia , Tálamo/química , Tálamo/citologiaRESUMO
Axoplasmic organelles obtained from the squid giant axon move on actin filaments at an average velocity of 1 microm/s [Nature 356 (1992) 722]. The unconventional myosins, in particular, the myosin-V class of motor proteins, represent the most likely candidates to have a role in this motility. Experiments were performed to determine whether a member of the myosin-V class of unconventional myosins is present in axoplasm and optic lobes. Western blots of axoplasm probed with an affinity purified antibody to chicken brain myosin-V (CBM-V) showed cross-reactivity with a protein of Mr 196 kD (p196) which was subsequently purified from squid optic lobes using a modification of a protocol for the purification of CBM-V [Methods Enzymol. 298 (1998) 3; Cell 75 (1993) 215]. Western blots of CBM-V probed with an alpha-p196 polyclonal IgG showed cross-reactivity with CBM-V. Purified p196 has been found to be a calmodulin (CaM) binding protein that possesses calcium-stimulated actin-activated ATPase activity. Equilibrium density fractionation of motile axoplasmic organelle preparations has revealed that p196 cosedimented with the peak organelle fraction into Percoll gradients in the presence of cytochalasin B and ATP. Based on this evidence, we conclude that the p196 present in axoplasm and purified from optic lobes is a squid homolog of CBM-V and functions as a motor for fast transport of membranous organelles on actin filaments in neurons.