Enhanced TrkA signaling impairs basal forebrain-dependent behavior.

Basal forebrain cholinergic neurons (BFCNs) modulate cognitive functions such as attention, learning and memory. The NGF/TrkA pathway plays an important role in the development and function of BFCNs, although two mouse models conditionally deleting TrkA expression in the central nervous system (CNS) have shown contradictory results. To shed light into this discrepancy, we used a mouse model with a gain-of-function in TrkA receptor signaling. Our results indicate that enhanced TrkA signaling did not alter hippocampal cholinergic innervation, general locomotion or anxiety-related behaviors, but it increases ChAT expression, the number of cholinergic neurons at early postnatal stages and, mutant mice showed impaired motor learning and memory functions. These data demonstrate that proper functioning of the cholinergic system in CNS requires a balanced NGF/TrkA signaling.

Mechanisms Controlling the Expression and Secretion of BDNF.

Brain-derived nerve factor (BDNF), through TrkB receptor activation, is an important modulator for many different physiological and pathological functions in the nervous system. Among them, BDNF plays a crucial role in the development and correct maintenance of brain circuits and synaptic plasticity as well as in neurodegenerative diseases. The proper functioning of the central nervous system depends on the available BDNF concentrations, which are tightly regulated at transcriptional and translational levels but also by its regulated secretion. In this review we summarize the new advances regarding the molecular players involved in BDNF release. In addition, we will address how changes of their levels or function in these proteins have a great impact in those functions modulated by BDNF under physiological and pathological conditions.

Human TrkAR649W mutation impairs nociception, sweating and cognitive abilities: a mouse model of HSAN IV.

A functional nerve growth factor NGF-Tropomyosin Receptor kinase A (TrkA) system is an essential requisite for the generation and maintenance of long-lasting thermal and mechanical hyperalgesia in adult mammals. Indeed, mutations in the gene encoding for TrkA are responsible for a rare condition, named Hereditary Sensory and Autonomic Neuropathy type IV (HSAN IV), characterized by the loss of response to noxious stimuli, anhidrosis and cognitive impairment. However, to date, there is no available mouse model to properly understand how the NGF-TrkA system can lead to pathological phenotypes that are distinctive of HSAN IV. Here, we report the generation of a knock-in mouse line carrying the HSAN IV TrkAR649W mutation. First, by in vitro biochemical and biophysical analyses, we show that the pathological R649W mutation leads to kinase-inactive TrkA also affecting its membrane dynamics and trafficking. In agreement with the HSAN IV human phenotype, TrkAR649W/m mice display a lower response to thermal and chemical noxious stimuli, correlating with reduced skin innervation, in addition to decreased sweating in comparison to TrkAh/m controls. Moreover, the R649W mutation decreases anxiety-like behavior and compromises cognitive abilities, by impairing spatial-working and social memory. Our results further uncover unexplored roles of TrkA in thermoregulation and sociability. In addition to accurately recapitulating the clinical manifestations of HSAN IV patients, our findings contribute to clarifying the involvement of the NGF-TrkA system in pain sensation.

Relación del consumo de VO2pico y el porcentaje de masa muscular en adultos que habitan sobre 2600 M. S. N. M / relationship of vo2 max consumption and muscle mass amiong adults living in altitudes over 2600 MAMSL

Introducción: la reducción de la capacidad oxidativa del músculo con el envejecimiento parece jugar un papel importante en la vejez disminuyendo hasta 50%. En zonas elevadas sobre el nivel del mar se producen cambios en la dinámica del oxígeno arterial que se relacionan con el metabolismo del músculo y la sarcopenia. Objetivos: determinar si hay relación entre el VO2pico y el porcentaje de masa muscular, nivel de actividad física e IMC, en adultos que habitan en regiones superiores a 2600 metros sobre el nivel del mar. Metodología: estudio descriptivo de tipo transversal, se incluyeron participantes sin sarcopenia mayores de 50 años, con mínimo un año de residencia en Bogotá, Colombia. Se excluyeron participantes con terapia de reemplazo hormonal, tensión arterial elevada durante la prueba, enfermedad coronaria, valvular o trastornos de la conducción. Se determinó el nivel de actividad física aplicando la encuesta Ainsworthy col, la composición corporal con bioimpedanciometría y VO2pico mediante ergoespirometría. Resultados: la muestra fue de 21 participantes. La mitad de lapoblación mostró VO2pico de 23.7 ml/k/min, IMC de 27.2g/m2 y porcentaje de masa muscular de 35.5%; hay baja correlación entre VO2pico y el porcentaje de masa muscular. La mitad de la población saludable tiene un VO2pico de 28.9 ml/k/min, sedentaria saludable 23.7 ml/k/min y sedentaria riesgosa 21.6 ml/k/min. Conclusiones: el presente estudio mostró que hay baja correlación entre el porcentaje de masa muscular y el VO2pico, sin embargo estos resultados pudieron estar influenciados por el tamaño de la muestra y otros factores.

Introduction: the decrease of muscle oxidative capacity with aging appears to play an important role in old age and is observed to decline by 50%. Changes in arterial oxygen dynamics related to muscle metabolism and sarcopenia are evidenced in high altitudes. Objectives: to determine if there is a relationship between VO2max and muscle mass, physical activity and BMI, in adults living in altitudes over 2600 MAMSL. Methodology: descriptive cross-sectional study in older than 50 years subjects without sarcopenia, who had lived in Bogota, Colombia for at least one year. Subjects with hormone replacement therapy or high blood pressure during this test, coronary artery or valvular heart disease or conduction disorders, were excluded. Physical activity was determined applying the Ainsworthy et al. survey, body composition by bioelectrical impedance analysis and VO2max by ergospirometry. Results: sample size was 21 participants. Half of the population showed a VO2max of 23.7 ml/k/min, BMI of 27.2g/m2 and muscle mass of 35.5%. A low correlation between VO2max and muscle mass was evidenced. Half of the healthy population had a VO2max of 28.9 ml/k/min, healthy sedentary subjects 23.7 ml/k/min and sedentary subjects with risk factors 21.6 ml/k/min. Conclusions: this study showed a low correlation between muscle mass and VO2max. However, these results could have been influenced by the sample size and other factors.

TrkB deubiquitylation by USP8 regulates receptor levels and BDNF-dependent neuronal differentiation.

Ubiquitylation of receptor tyrosine kinases (RTKs) regulates both the levels and functions of these receptors. The neurotrophin receptor TrkB (also known as NTRK2), a RTK, is ubiquitylated upon activation by brain-derived neurotrophic factor (BDNF) binding. Although TrkB ubiquitylation has been demonstrated, there is a lack of knowledge regarding the precise repertoire of proteins that regulates TrkB ubiquitylation. Here, we provide mechanistic evidence indicating that ubiquitin carboxyl-terminal hydrolase 8 (USP8) modulates BDNF- and TrkB-dependent neuronal differentiation. USP8 binds to the C-terminus of TrkB using its microtubule-interacting domain (MIT). Immunopurified USP8 deubiquitylates TrkB in vitro, whereas knockdown of USP8 results in enhanced ubiquitylation of TrkB upon BDNF treatment in neurons. As a consequence of USP8 depletion, TrkB levels and its activation are reduced. Moreover, USP8 protein regulates the differentiation and correct BDNF-dependent dendritic formation of hippocampal neurons in vitro and in vivo We conclude that USP8 positively regulates the levels and activation of TrkB, modulating BDNF-dependent neuronal differentiation.This article has an associated First Person interview with the first author of the paper.

Early Downregulation of p75NTR by Genetic and Pharmacological Approaches Delays the Onset of Motor Deficits and Striatal Dysfunction in Huntington's Disease Mice.

Deficits in striatal brain-derived neurotrophic factor (BDNF) delivery and/or BDNF/tropomyosin receptor kinase B (TrkB) signaling may contribute to neurotrophic support reduction and selective early degeneration of striatal medium spiny neurons in Huntington's disease (HD). Furthermore, we and others have demonstrated that TrkB/p75NTR imbalance in vitro increases the vulnerability of striatal neurons to excitotoxic insults and induces corticostriatal synaptic alterations. We have now expanded these studies by analyzing the consequences of BDNF/TrkB/p75NTR imbalance in the onset of motor behavior and striatal neuropathology in HD mice. Our findings demonstrate for the first time that the onset of motor coordination abnormalities, in a full-length knock-in HD mouse model (KI), correlates with the reduction of BDNF and TrkB levels, along with an increase in p75NTR expression. Genetic normalization of p75NTR expression in KI mutant mice delayed the onset of motor deficits and striatal neuropathology, as shown by restored levels of striatal-enriched proteins and dendritic spine density and reduced huntingtin aggregation. We found that the BDNF/TrkB/p75NTR imbalance led to abnormal BDNF signaling, manifested as a diminished activation of TrkB-phospholipase C-gamma pathway but upregulation of c-Jun kinase pathway. Moreover, we confirmed the contribution of the proper balance of BDNF/TrkB/p75NTR on HD pathology by a pharmacological approach using fingolimod. We observed that chronic infusion of fingolimod normalizes p75NTR levels, which is likely to improve motor coordination and striatal neuropathology in HD transgenic mice. We conclude that downregulation of p75NTR expression can delay disease progression suggesting that therapeutic approaches aimed to restore the balance between BDNF, TrkB, and p75NTR could be promising to prevent motor deficits in HD.

A Review on Ubiquitination of Neurotrophin Receptors: Facts and Perspectives.

Ubiquitination is a reversible post-translational modification involved in a plethora of different physiological functions. Among the substrates that are ubiquitinated, neurotrophin receptors (TrkA, TrkB, TrkC, and p75NTR) have been studied recently. TrkA is the most studied receptor in terms of its ubiquitination, and different E3 ubiquitin ligases and deubiquitinases have been implicated in its ubiquitination, whereas not much is known about the other neurotrophin receptors aside from their ubiquitination. Additional studies are needed that focus on the ubiquitination of TrkB, TrkC, and p75NTR in order to further understand the role of ubiquitination in their physiological and pathological functions. Here we review what is currently known regarding the ubiquitination of neurotrophin receptors and its physiological and pathological relevance.

Selective and differential interactions of BNN27, a novel C17-spiroepoxy steroid derivative, with TrkA receptors, regulating neuronal survival and differentiation.

Nerve growth factor (NGF) holds a pivotal role in brain development and maintenance, been also involved in the pathophysiology of neurodegenerative diseases. Here, we provide evidence that a novel C17-spiroepoxy steroid derivative, BNN27, specifically interacts with and activates the TrkA receptor of NGF, inducing phosphorylation of TrkA tyrosine residues and down-stream neuronal survival-related kinase signaling. Additionally, BNN27 potentiates the efficacy of low levels of NGF, by facilitating its binding to the TrkA receptors and differentially inducing fast return of internalized TrkA receptors into neuronal cell membranes. Furthermore, BNN27 synergizes with NGF in promoting axonal outgrowth, effectively rescues from apoptosis NGF-dependent and TrkA positive sympathetic and sensory neurons, in vitro, ex vivo and in vivo in NGF null mice. Interestingly, BNN27 does not possess the hyperalgesic properties of NGF. BNN27 represents a lead molecule for the development of neuroprotective TrkA receptor agonists, with potential therapeutic applications in neurodegenerative diseases and in brain trauma.

Role of morphine, miR-212/132 and mu opioid receptor in the regulation of Bdnf in zebrafish embryos.

BACKGROUND: Morphine is one of the first-line therapies for the treatment of pain despite its secondary effects. It modifies the expression of epigenetic factors like miRNAs. In the present study, we analyzed miR-212 and miR-132 and their implication in morphine effects in the zebrafish Central Nervous System (CNS) through the regulation of Bdnf expression. METHODS: We used control and knock-down zebrafish embryos to assess the effects of morphine in miRNAs 212/132 and mitotic or apoptotic cells by qPCR, immunohistochemistry and TUNEL assay, respectively. Bdnf and TrkB were studied by western blot and through a primary neuron culture. A luciferase assay was performed to confirm the binding of miRNAs 212/132 to mecp2. RESULTS: Morphine exposure decreases miR-212 but upregulates miR-132, as wells as Bdnf and TrkB, and changes the localization of proliferative cells. However, Bdnf expression was downregulated when miRNAs 212/132 and oprm1 were knocked-down. Furthermore, we proved that these miRNAs inhibit mecp2 expression by binding to its mRNA sequence. The described effects were corroborated in a primary neuron culture from zebrafish embryos. CONCLUSIONS: We propose a mechanism in which morphine alters the levels of miRNAs 212/132 increasing Bdnf expression through mecp2 inhibition. oprm1 is also directly involved in this regulation. The present work confirms a relationship between the opioid system and neurotrophins and shows a key role of miR-212 and miR-132 on morphine effects through the regulation of Bdnf pathway. GENERAL SIGNIFICANCE: miRNAs 212/132 are novel regulators of morphine effects on CNS. Oprm1 controls the normal expression of Bdnf.

Lifeguard Inhibits Fas Ligand-mediated Endoplasmic Reticulum-Calcium Release Mandatory for Apoptosis in Type II Apoptotic Cells.

Death receptors are members of the tumor necrosis factor receptor superfamily involved in the extrinsic apoptotic pathway. Lifeguard (LFG) is a death receptor antagonist mainly expressed in the nervous system that specifically blocks Fas ligand (FasL)-induced apoptosis. To investigate its mechanism of action, we studied its subcellular localization and its interaction with members of the Bcl-2 family proteins. We performed an analysis of LFG subcellular localization in murine cortical neurons and found that LFG localizes mainly to the ER and Golgi. We confirmed these results with subcellular fractionation experiments. Moreover, we show by co-immunoprecipitation experiments that LFG interacts with Bcl-XL and Bcl-2, but not with Bax or Bak, and this interaction likely occurs in the endoplasmic reticulum. We further investigated the relationship between LFG and Bcl-XL in the inhibition of apoptosis and found that LFG protects only type II apoptotic cells from FasL-induced death in a Bcl-XL dependent manner. The observation that LFG itself is not located in mitochondria raises the question as to whether LFG in the ER participates in FasL-induced death. Indeed, we investigated the degree of calcium mobilization after FasL stimulation and found that LFG inhibits calcium release from the ER, a process that correlates with LFG blockage of cytochrome c release to the cytosol and caspase activation. On the basis of our observations, we propose that there is a required step in the induction of type II apoptotic cell death that involves calcium mobilization from the ER and that this step is modulated by LFG.

Resultados del tratamiento médico con metotrexato en el embarazo ectópico no roto, en el Hospital Nacional de la Mujer, de enero a diciembre 2015 / Results of medical treatment with methotrexate in unruptured ectopic pregnancy, at the National Women's Hospital, from January to December 2015

En el presente estudio se presentan 55 casos de embarazo ectópico no roto que fueron tratados con Metotrexato, desde enero de 2015 a diciembre de 2015 en el Hospital Nacional de La Mujer, teniendo como objetivos: Detallar el perfil epidemiológico de las pacientes que presentan embarazo ectópico, determinar qué tipo de embarazo ectópico fue el más frecuente en el Hospital Nacional de la Mujer, el número de casos de embarazo ectópico no rotos, así como evaluar los resultados del metotrexato como manejo conservador del embarazo ectópico. Enumerar el porcentaje de pacientes que presenta efectos secundarios con la aplicación de metotrexate y determinar el costo que el manejo médico del embarazo ectópico conlleva al Hospital Nacional de La Mujer. Estudio descriptivo, retrospectivo y transversal de los casos de embarazos ectópicos no complicados hospitalizados en la Unidad de alto riesgo en el periodo de enero a diciembre de 2015. Se identificó una incidencia de 9.2% por 1000 habitantes de embarazo ectópico, a las que se le aplico manejo medico una tasa de éxito de 48.91%, la cual es mucho menor a la internacionalmente descrita. Ninguna de las pacientes presento reacciones adversas importantes. En cuanto al tiempo de negativización de BHCG esta no pudo ser evaluado precisamente ya que no todas las pacientes tuvieron cita en consulta externa una fecha determinada

A selective role for ARMS/Kidins220 scaffold protein in spatial memory and trophic support of entorhinal and frontal cortical neurons.

Progressive cortical pathology is common to several neurodegenerative and psychiatric disorders. The entorhinal cortex (EC) and frontal cortex (FC) are particularly vulnerable, and neurotrophins have been implicated because they appear to be protective. A downstream signal transducer of neurotrophins, the ankyrin repeat-rich membrane spanning scaffold protein/Kidins 220 (ARMS) is expressed in the cortex, where it could play an important role in trophic support. To test this hypothesis, we evaluated mice with a heterozygous deletion of ARMS (ARMS(+/-) mice). Remarkably, the EC and FC were the regions that demonstrated the greatest defects. Many EC and FC neurons became pyknotic in ARMS(+/-) mice, so that large areas of the EC and FC were affected by 12 months of age. Areas with pyknosis in the EC and FC of ARMS(+/-) mice were also characterized by a loss of immunoreactivity to a neuronal antigen, NeuN, which has been reported after insult or injury to cortical neurons. Electron microscopy showed that there were defects in mitochondria, myelination, and multilamellar bodies in the EC and FC of ARMS(+/-) mice. Although primarily restricted to the EC and FC, pathology appeared to be sufficient to cause functional impairments, because ARMS(+/-) mice performed worse than wild-type on the Morris water maze. Comparisons of males and females showed that female mice were the affected sex in all comparisons. Taken together, the results suggest that the expression of a prominent neurotrophin receptor substrate normally protects the EC and FC, and that ARMS may be particularly important in females.

On the biomimetic design of agile-robot legs.

The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

The ankyrin repeat-rich membrane spanning (ARMS)/Kidins220 scaffold protein is regulated by activity-dependent calpain proteolysis and modulates synaptic plasticity.

The expression of forms of synaptic plasticity, such as the phenomenon of long-term potentiation, requires the activity-dependent regulation of synaptic proteins and synapse composition. Here we show that ARMS (ankyrin repeat-rich membrane spanning protein)/Kidins220, a transmembrane scaffold molecule and BDNF TrkB substrate, is significantly reduced in hippocampal neurons after potassium chloride depolarization. The activity-dependent proteolysis of ARMS/Kidins220 was found to occur through calpain, a calcium-activated protease. Moreover, hippocampal long-term potentiation in ARMS/Kidins220(+/-) mice was enhanced, and inhibition of calpain in these mice reversed these effects. These results provide an explanation for a role for the ARMS/Kidins220 protein in synaptic plasticity events and suggest that the levels of ARMS/Kidins220 can be regulated by neuronal activity and calpain action to influence synaptic function.

Ankyrin repeat-rich membrane spanning/Kidins220 protein interacts with mammalian Septin 5.

Neurotrophin receptors utilize specific adaptor proteins to activate signaling pathways involved in various neuronal functions, such as neurite outgrowth and cytoskeletal remodeling. The Ankyrin-Repeat Rich Membrane Spanning (ARMS)/kinase D-interacting substrate-220 kDa (Kidins220) serves as a unique downstream adaptor protein of Trk receptor tyrosine kinases. To gain insight into the role of ARMS/Kidins220, a yeast two-hybrid screen of a rat dorsal root ganglion library was performed using the C-terminal region of ARMS/Kidins220 as bait. The screen identified a mammalian septin, Septin 5 (Sept5), as an interacting protein. Co-immunoprecipitation using lysates from transiently transfected HEK-293 cells revealed the specific interaction between ARMS/Kidins220 and Sept5. Endogenous ARMS/Kidins220 and Sept5 proteins were colocalized in primary hippocampal neurons and were also predominantly expressed at the plasma membrane and in the tips of growing neurites in nerve growth factor-treated PC12 cells. Mapping of Sept5 domains important for ARMS/Kidins220 binding revealed a highly conserved N-terminal region of Sept5. The direct interaction between ARMS/Kidins220 and Sept5 suggests a possible role of ARMS/Kidins220 as a functional link between neurotrophin receptors and septins to mediate neurotrophin-induced intracellular signaling events, such as neurite outgrowth and cytoskeletal remodeling.

The ARMS/Kidins220 scaffold protein modulates synaptic transmission.

Activity-dependent changes of synaptic connections are facilitated by a variety of scaffold proteins, including PSD-95, Shank, SAP97 and GRIP, which serve to organize ion channels, receptors and enzymatic activities and to coordinate the actin cytoskeleton. The abundance of these scaffold proteins raises questions about the functional specificity of action of each protein. Here we report that basal synaptic transmission is regulated in an unexpected manner by the ankyrin repeat-rich membrane-spanning (ARMS/Kidins220) scaffold protein. In particular, decreases in the levels of ARMS/Kidins220 in vivo led to an increase in basal synaptic transmission in the hippocampus, without affecting paired pulse facilitation. One explanation to account for the effects of ARMS/Kidins220 is an interaction with the AMPA receptor subunit, GluA1, which could be observed after immunoprecipitation. Importantly, shRNA and cell surface biotinylation experiments indicate that ARMS/Kidins220 levels have an impact on GluA1 phosphorylation and localization. Moreover, ARMS/Kidins220 is a negative regulator of AMPAR function, which was confirmed by inward rectification assays. These results provide evidence that modulation of ARMS/Kidins220 levels can regulate basal synaptic strength in a specific manner in hippocampal neurons.

Role of transverse bands in maintaining paranodal structure and axolemmal domain organization in myelinated nerve fibers: effect on longevity in dysmyelinated mutant mice.

The consequences of dysmyelination are poorly understood and vary widely in severity. The shaking mouse, a quaking allele, is characterized by severe central nervous system (CNS) dysmyelination and demyelination, a conspicuous action tremor, and seizures in approximately 25% of animals, but with normal muscle strength and a normal lifespan. In this study we compare this mutant with other dysmyelinated mutants including the ceramide sulfotransferase deficient (CST-/-) mouse, which are more severely affected behaviorally, to determine what might underlie the differences between them with respect to behavior and longevity. Examination of the paranodal junctional region of CNS myelinated fibers shows that "transverse bands," a component of the junction, are present in nearly all shaking paranodes but in only a minority of CST-/- paranodes. The number of terminal loops that have transverse bands within a paranode and the number of transverse bands per unit length are only moderately reduced in the shaking mutant, compared with controls, but markedly reduced in CST-/- mice. Immunofluorescence studies also show that although the nodes of the shaking mutant are somewhat longer than normal, Na(+) and K(+) channels remain separated, distinguishing this mutant from CST-/- mice and others that lack transverse bands. We conclude that the essential difference between the shaking mutant and others more severely affected is the presence of transverse bands, which serve to stabilize paranodal structure over time as well as the organization of the axolemmal domains, and that differences in the prevalence of transverse bands underlie the marked differences in progressive neurological impairment and longevity among dysmyelinated mouse mutants.

Ankyrin Repeat-rich Membrane Spanning/Kidins220 protein regulates dendritic branching and spine stability in vivo.

The development of nervous system connectivity depends upon the arborization of dendritic fields and the stabilization of dendritic spine synapses. It is well established that neuronal activity and the neurotrophin BDNF modulate these correlated processes. However, the downstream mechanisms by which these extrinsic signals regulate dendritic development and spine stabilization are less well known. Here we report that a substrate of BDNF signaling, the Ankyrin Repeat-rich Membrane Spanning (ARMS) protein or Kidins220, plays a critical role in the branching of cortical and hippocampal dendrites and in the turnover of cortical spines. In the barrel somatosensory cortex and the dentate gyrus, regions where ARMS/Kidins220 is highly expressed, no difference in the complexity of dendritic arbors was observed in 1-month-old adolescent ARMS/Kidins220(+/-) mice compared to wild-type littermates. However, at 3 months of age, young adult ARMS/Kidins220(+/-) mice exhibited decreased dendritic complexity. This suggests that ARMS/Kidins220 does not play a significant role in the initial formation of dendrites but, rather, is involved in the refinement or stabilization of the arbors later in development. In addition, at 1 month of age, the rate of spine elimination was higher in ARMS/Kidins220(+/-) mice than in wild-type mice, suggesting that ARMS/Kidins220(+/-) levels regulate spine stability. Taken together, these data suggest that ARMS/Kidins220 is important for the growth of dendritic arbors and spine stability during an activity- and BDNF-dependent period of development.

Composición químico-nutricional y de factores antinutricionales en semillas de parota (enterolobium cyclocarpum) / Nutritional-chemical composition and antinutritional factors in seeds of Enterolobium cyclocarpum / Composição químico-nutricional e de fatores antinutricionais em sementes de guanacaste (enterolobium cyclocarpum)

Mediante el análisis químico proximal se determinaron proteínas (PC), grasas (GC), fibras (FC), cenizas, humedad y extracto libre de nitrógeno (ELN) de las semillas de Enterolobium cyclocarpum, y con espectrofotometría se determinaron sus factores antinutricionales. Por el contenido de minerales, carbohidratos y proteínas que posee esta leguminosa, tiene potencial industrial, medicinal y químico, siendo una limitante la presencia de factores antinutricionales tales como glucósidos cianogénicos e inhibidores de tripsina. Mediante hidrólisis enzimática (ß-glucosidasa) se analizó la inhibición de tripsina de un extracto acuoso (NaOH 0,1N) de la muestra y en una solución estándar de tripsina se midió la actividad proteolítica en un sustrato sintético (benzoil-arginina-p-nitroanilida). En las semillas completas se encontró PC 26,13%, GC 2,85%, FC 4,95%, cenizas 2,95% y ELN 63,1%. En las almendras desecadas los valores fueron PC 34,5%, GC 7,6%, ausencia de FC, cenizas 3,3% y ELN 54,6%. Se encontraron 4,82 unidades de inhibidores de tripsina/mg, ausencia de hemaglutininas y 0,76mg de ácido cianhídrico en 100g de semillas. Estos valores correspondientes a los factores antinutricionales descritos no constituyen un riesgo al consumir las semillas, ya que son termolábiles y se eliminan por cocción en agua.

Chemical analyses were performed to quantify the protein (CP), fat (CF), fiber (CF), ash, humidity, nitrogen free extract (NFE) and antinutritional factors in extracts from Enterolobium cyclocarpum seeds. E. cyclocarpum seeds have a great potential in pharmaceutical and chemical industries due to the high content of minerals, carbohydrates and proteins. However, the seeds also contain cyanogenic glycosides such as trypsin inhibitory factor and cyanhidric acid, resulting in antinutritional effects. Trough enzymatic hydrolysis (ß-glycosidase), trypsine inhibition on an aqueous extract of the sample (0.1 N NaOH). By using a standard trypsine solution, the proteolytic activity in a synthetic substrate (benzoyl-arginine-p-nitroanilide) was studied. Analyses of the complete seeds showed; CP 26.13%, CF 2.85%, CF 4.95%, Ash 2.95%, and NFE 63.1%. The dried almonds contained CP 34.5%, CF 7.6%, undetectable fiber, ash 3.3%, and NFE 54.6%. No hemaglutinins were detected, whereas 4.82 units/mg of trypsine inhibition and 0.76 mg/100g of HCN were found. The low concentrations of trypsine inhibitor and HCN will be reduced even more by the heat treatment previous consumption, which makes the seeds suitable for human beings or animals.

Mediante a análise química proximal se determinaram proteínas (PC), gorduras (GC), fibras (FC), cinzas, umidade e extrato livre de nitrogênio (ELN) das sementes de Enterolobium cyclocarpum, e com espectrofotometria se determinaram seus fatores antinutricionais. Pelo conteúdo de minerais, carboidratos e proteínas que possui, esta leguminosa têm potencial industrial, medicinal e químico, sendo uma limitante a presença de fatores antinutricionais tais como glicosídeos cianogênicos e inibidores de tripsina. Mediante hidrólise enzimática (ß-glucosidase) se analisou a inibição de tripsina de um extrato aquoso (NaOH 0,1N) da amostra e em uma solução padrão de tripsina se mediu a atividade proteolítica em um substrato sintético (benzoil-arginina-p-nitroanilida). Nas sementes completas se encontrou PC 26,13%, GC 2,85%, FC 4,95%, cinzas 2,95% e ELN 63,1%. Nas amêndoas dissecadas os valores foram PC 34,5%, GC 7,6%, ausência de FC, cinzas 3,3% e ELN 54.6%. Encontraram-se 4,82 unidades de inibidores de tripsina/mg, ausência de hemaglutininas e 0,76mg de ácido cianídrico em 100g de sementes. Estes valores correspondentes aos fatores antinutricionais descritos não constituem um risco ao consumir as sementes, já que são termolábeis e se eliminam por cozimento em água.

Developmental and activity-dependent regulation of ARMS/Kidins220 in cultured rat hippocampal neurons.

Neurotrophin activation of Trk receptors elicits diverse effects on neuronal survival, differentiation, and synaptic plasticity. One of the central questions is how specificity is encoded in neurotrophin receptor signaling and actions. A unique downstream protein is the Ankyrin-Repeat Rich Membrane Spanning (ARMS)/Kinase D-interacting substrate-220 kDa (Kidins220), a very abundant scaffold protein in the hippocampus. To determine the roles of ARMS/Kidins220 in hippocampal neurons, we have analyzed the effects of synaptic activity upon the regulation and distribution of ARMS/Kidins220. At early times in vitro (<7 DIV), synaptic activity was low and ARMS/Kidins220 levels were high. As synaptic activity and markers for synapse maturation, such as PSD-95, increased, ARMS/Kidins220 significantly decreased to a plateau by later times in vitro (>12 DIV). Immunocytochemistry showed ARMS/Kidins220 to be concentrated at the tips of growing processes in immature cultures, and more diffusely distributed in older cultures. To examine the apparent inverse relationship between activity and ARMS/Kidins220 levels, neuronal firing was manipulated pharmacologically. Chronic exposure to TTX increased ARMS/Kidins220 levels, whereas bicuculline caused the opposite effect. Moreover, using shRNA to decrease ARMS/Kidins220 levels produced a corresponding increase in synaptic activity. We find that ARMS/Kidins220 may function in neuronal development as an indicator and potentially as a homeostatic regulator of overall synaptic strength in hippocampal neurons.