bluuebunny/crossref_metadata_2025 huggingface dataset:
A IMIGRAÇÃO COMO UMA POLÍTICA DE DEFESA NACIONAL: É POSSÍVEL? O CASO DA IMIGRAÇÃO ESPANHOLA PARA A OCUPAÇÃO DA FRONTEIRA SUL DO BRASIL / Immigration as a National Defence Policy: is it Possible? The Case of the Spanish Immigration to the Occupation of Brazilian Southern Borderland
Authors: Georg Uebel Roberto Rodolfo , Paetzhold Pauli Rita Inês
Published: April 2018

O processo colonial do Brasil trouxe muitas questões sobre a ocupação do seu espaço territorial por colonos e imigrantes como uma forma de apropriação das territorialidades fronteiriças do país visando à conservação e defesa do jovem Estado. Todavia, o povoamento específico do estado do Rio Grande do Sul por imigrantes europeus observou um caráter não só econômico, mas também estratégico, de defesa das fronteiras. Nesse sentido, o presente trabalho aborda o caso da imigração espanhola para a fronteira sul do Brasil com o Uruguai e Argentina e também, por meio do Acordo de Migração entre Brasil e Espanha, as especificidades e pontualidades que essa distinta imigração trouxe à luz de uma possível e subjetiva política de defesa nacional, em prol do estabelecimento e consolidação das fronteiras brasileiras no território do Rio Grande do Sul. Este estudo é resultado de pesquisas documentais e in loco acerca da imigração espanhola e seus aportes econômicos, sociolaborais e territoriais no Rio Grande do Sul durante o século XX, que dentre suas potencialidades verificou a possibilidade político-militar de defesa nacional por meio de um acordo de migração, fato inédito até então na historiografia do país.ABSTRACTThe colonization process of Brazil brought many questions about the occupation of its territorial space by settlers and immigrants as a way of appropriation of the border territorialities of the country aiming at the conservation and protection of the young State. However, the specific settlement of the state of Rio Grande do Sul by European immigrants noticed not only an economic, but also a strategic, of borderlands defence features. In this sense, the present work deals with the case of Spanish immigration to the southern border of Brazil with Uruguay and Argentina and also, through the Migration Agreement between Brazil and Spain, the specificities of this distinct immigration that brought to light a possible and subjective policy of national defence, towards the establishment and consolidation of Brazilian borders on the territory of Rio Grande do Sul. This study is result of documentary and literature review researches about the Spanish immigration and its economic, socio-occupational and territorial contributions in Rio Grande do Sul during the twentieth century, which, among its potentialities verified the political and military possibility of national defence through an immigration agreement, an unprecedented fact until then in the country's historiography.Keywords: Immigration, Spaniards, Brazil, Border, Defence.
CARTOGRAFIA TÁTIL E A ELABORAÇÃO DE MATERIAL DIDÁTICO PARA ALUNOS CEGOS / Tactile Cartography and Elaboration Courseware for Blind Students
Authors: Ventorini Silvia Elena , Silva Patrícia Assis da , Rocha Gisa Fernanda Siega
Published: April 2018

Neste artigo apresenta-se a pesquisa na área da Cartografia Tátil desenvolvida por meio da parceria entre pesquisadores de três Instituições de Ensino Superior (IES). O objetivo do estudo é elaborar ações e material didático tátil que possam disseminar a Cartografia Tátil em municípios do Estado de Minas Gerais, contribuindo para o ensino e o aprendizado de alunos com deficiência visual e na Formação Continuada de Professores.  A área de estudo é o Instituto São Rafael, localizado no município de Belo Horizonte – MG. O procedimento teórico-metodológico tem como base a perspectiva histórico-cultural e a experiência do grupo de Cartografia Tátil da UNESP.    As ações desenvolvidas são: elaboração de mapas táteis e maquetes com e sem recursos sonoros; realização de workshops entre os pesquisadores das três IES; preparação e realização de cursos de extensão, criação de um Website e estudo sobre a organização espacial de alunos cegos.  A vivência no Instituto São Rafael tem direcionado o desenvolvimento das ações, tanto na produção de material didático como na divulgação da pesquisa. O resultado da experiência indica que há escassez de material didático e estudos coerentes com a realidade de ensino de Geografia para os alunos com deficiência visual que frequentam o Instituto.   ABSTRACTThe aim of this work is to report the study about Tactile Cartography that was developed by an association between researchers from three Institutions of Higher Education (IHE). The purpose of the project is to develop strategies and tactile teaching material to spread the Tactile Cartography around cities from Minas Gerais State in order to give both, blind students and teachers support during the learning process. The study takes place in Belo Horizonte City - MG, at São Rafael Institute. The methodological approach is based on the historic-cultural aspects and the previous experience of UNESP Tactile Cartography group. The procedures are: development of tactile maps and miniatures with and without sound resources; workshop involving researchers from the three IHE; promotion of extension course; website development. The experience gained at São Rafael Institute guides the development of procedures and teaching material, and influences the research dissemination. The result of the project proves that there is a lack of materials and resources concerning teaching Geography to visually impaired or blind students at the Institute.Keywords: Tactile Teaching Material, Blind Student, Teaching Geography
DESAFIOS PARA O PLANEJAMENTO E O DESENVOLVIMENTO TERRITORIAL NO ESTADO DO RIO GRANDE DO SUL / CHALLENGES FOR TERRITORIAL PLANNING AND DEVELOPMENT IN THE RIO GRANDE DO SUL STATE
Authors: Cargnin Antonio Paulo
Published: April 2018

Este artigo tem como objetivo analisar, a partir das principais dinâmicas territoriais vigentes no Estado do Rio Grande do Sul, as alternativas para o desenvolvimento regional e os desafios para o planejamento territorial. Com base na análise das características socioeconômicas dos 28 Conselhos Regionais de Desenvolvimento (COREDEs) e de suas potencialidades e restrições, são apresentados, por Região Funcional de Planejamento (RF), iniciativas promissoras e pontos que merecem atenção para o desenvolvimento de cada uma das regiões funcionais. Por fim, são delineados temas, considerados fundamentais para o planejamento territorial e para o desenvolvimento regional do Estado e são tecidas considerações finais.Abstract:This article aims at analyzing, based on the main territorial dynamics existing in Rio Grande do Sul State, alternatives for regional development and challenges for territorial planning. With basis on socioeconomic characteristics of the 28 Regional Councils of Development, as well as their strengths and limitations, promising initiatives and points that deserve attention for the development of each region are presented by Functional Regions of Planning. Finally, topics considered essential for territorial planning and regional development of the State are outlined and final considerations are presented.Keywords: Territorial planning; Regional development; Public policies; Rio Grande do Sul State.
DELIMITAÇÃO E CARACTERIZAÇÃO AMBIENTAL DO BANHADO DO PONTAL DA BARRA, PELOTAS, RS (PARTE I): PORÇÃO LESTE
Authors: Maurício Giovanni Nachtigall , Venzke Tiago Schuch Lemos
Published: April 2018

NÃO HÁ RESUMO
Higiene e segurança em Arqueologia: Conceitos e sugestões para uma prática segura em campo e laboratório.
Authors: Okumura Mercedes , Oliveira Rodrigo Elias
Published: April 2018

Resumo: Assim como em qualquer profissão, a Arqueologia também apresenta ao arqueólogo alguns riscos inerentes ao exercício de suas atividades. Nosso trabalho apresenta e discute as práticas de higiene e de segurança em Arqueologia, com ênfase nos trabalhos de campo e de laboratório. Pretendemos com este artigo aumentar a conscientização da comunidade arqueológica para os potenciais riscos que envolvem os trabalhos nessa área, seja na iniciativa privada seja no ambiente acadêmico, e discutir algumas ações que podem ajudar a aumentar a segurança de trabalhadores e pesquisadores nesses contextos.
 
Abstract:Like any other profession, archaeology also presents to the archaeologist and to the whole team some inherent risks in the practice of their activities and the environment in which such activity is inserted. Our work presents and discusses the practice of hygiene and safety in archaeology, with emphasis on fieldwork and laboratory activities. We intend to improve awareness of the archaeological community to the potential risks involved in the work in this knowledge area, whether in the private sector either in the academic field work or laboratory activities, and discuss actions that can help increase the security of workers and researchers in these contexts.
Procedimentos geoarqueológicos da área da Fonte Tambiá, Parque Arruda Câmara, João Pessoa, PB
Authors: Azevedo Netto Carlos Xavier de , Rosa Conrad Rodrigues
Published: April 2018

Resumo: O Parque Zoobotânico Arruda Câmara abriga animais e plantas, bem como uma parte da história de João Pessoa. Antiga fazenda de engenho, a área comporta uma fonte de água situada no fundo do vale. As escavações arqueológicas conduzidas pelo NDIHR/UFPB mostraram os vestígios existentes no subsolo da área próxima à fonte. A metodologia utilizada pelo NDIHR incluiu sondagens e aberturas de transectos, perfis de estratigrafia arqueológica e croquis. Como resultado, os dados mostraram que a área da fonte em pedra calcária foi construída segundo padrão estético da época, com função de regular o volume de água; vários dutos construídos em tijolos prensados canalizavam a água evitando que houvesse inundação, esses dutos variavam de alguns centímetros a 2,50m de profundidade. Outros dados importantes obtidos nas escavações foram testemunhas de aterros na área que circunscreve à fonte. As sondagens e escavações foram executadas até 0,70m, quando acrescidos de dados históricos, estes revelam que vários imóveis haviam sido demolidos nas proximidades do bairro de Tambiá e ali foram sendo depositados. Assim, o revelo foi modificado com processos sucessivos de entulhos, haja vista os vestígios conterem traços de tempo de meados de 1900 até 1970. Os dados coletados mostraram intenso processo de transformação. A pedra calcária que foi utilizada para a construção da fonte está enfraquecendo em contato direto com a água se torna frágil e tende a sumir.
 
Abstract:The Zoological Park Arruda Câmara shelters animals and plants, as well as part of João Pessoa history. Former mill farm, the area comprises a water source located in the bottom of the valley. The archaeological excavations conducted by the NDIHR / UFPB showed the remains in the subsoil of the area near the source. The methodology used by the NDIHR included surveys and openings of transects, profiles of archaeological stratigraphy and sketches. As a result, the data showed that the area of the limestone source was built according to the esthetic standard of the time, with the function of regulating the volume of water; Several ducts built in pressed bricks channeled the water avoiding floods, these ducts varied from a few centimeters to 2,50m of depth. Other important data obtained in the excavations were witnesses of landfills in the area that circumscribes the water source. Surveys and excavations were carried out up to 0.70m, when added with historical data, these reveal that several properties had been demolished near the Tambiá neighborhood and were being deposited there. Thus, the revelation was modified with successive processes of debris, since the traces contained traces of time from the middle of 1900 until 1970. The data collected showed an intense process of transformation. The limestone that was used for building the fountain is weakening and in direct contact with the Water becomes brittle and tends to disappear.
Simmel e a confiança
Authors: Mota Rodrigo
Published: April 2018

Este artigo é uma breve exposição de uma das diversas manifestações do pioneirismo de Georg Simmel na sociologia: o estudo do conceito de confiança. Para isto, recorro aos pequenos trechos das obras nos quais o autor faz referência direta ao termo, inserindo-o no contexto das suas influências filosóficas e teoria social. Simmelpercebeu como a impessoalidade crescente na modernidade fez da confiança mais necessária que nunca, como um mecanismo que torna a interação social possível dentro de um mundo no qual pouco se sabe sobre as outras pessoas. Recorre-se à própria história pessoal, ao mínimo conhecimento que se pode extrair sobre o outro eao elemento que faz o tratamento simmeliano deste tema inovador: a suspensão, um ato de fé no próximo. Concluo reforçando a importância do estudo de Simmel sobre a confiança e de como a influência da Lebenssoziologiefoi fundamental para fornecer a singularidade da sua visão, ao ver a vida social humana além da racionalidade instrumental.
Análise comparativa entre radiação micro-ondas e aquecimento resistivo para sinterização do aço inox 316L reforçado com B4C
Authors: Das Neves Ederson Bitencourt , Osório Alice Gonçalves , Gonçalves Margarete Regina Freitas , Pollnow Edilson Nunes
Published: April 2018

O aço inoxidável 316L é utilizado em diversas áreas da engenharia devido suas características de alta resistência à corrosão e bom acabamento superficial. Porém, sua aplicação é limitada em função de sua baixa resistência ao desgaste decorrente de sua baixa dureza. Uma forma de aumentar sua dureza é pela inclusão de partículas de um material mais duro em sua matriz. Este trabalho avalia a sinterização do aço inoxidável 316L reforçando sua matriz pela inclusão de partículas de carbeto de boro -B4C. Foi realizada uma análise comparativa entre o forno micro-ondas e o forno resistivo do tipo tubular durante a sinterização deste material, quanto seu consumo de energia a fim de verificar qual processo é mais efetivo energeticamente. Para avaliação da qualidade do sinterizado, foi realizada uma caracterização microestrutural a partir de microscopia óptica e eletrônica de varredura, bem como por difração de raios-X e ensaio de microdureza Vickers. Concluiu-se que o consumo de energia com uso de forno tipo micro-ondas foi menor que o resistivo e também apresentou uma sinterização mais homogênea e uma dureza maior.
Adaptation to altered support and visual conditions during stance: patients with vestibular deficits
Authors: Nashner LM , Black FO , Wall C
Published: April 2018

Patients whose deficits were limited to clinically well qualified vestibular disorders have been exposed to a number of altered support surface and visual environments while standing unsupported. A six- degrees-of-freedom platform employing movable support surfaces for each foot and a movable visual surround deprived patients of normal inputs derived from a fixed level support surface and from an immobile surround. Various tests employing EMG, force, and body movement recording identified quantitative changes in the patients' strategy for the relative weighting of proprioceptive, vestibular, and visual inputs. The most dramatic performance deficit of patients was their inability to suppress the influence of visual and proprioceptive inputs appropriately whenever motions of external surface disturbed the orientation information provided by these inputs. Thus, the more mildly afflicted patients experienced instability not so much because of the loss of vestibular inputs directly to posture but because of their inappropriate responses to proprioceptive inputs and vision. Discussion is centered on the role of vestibular input as an internal reference system for orientation about which adaptive changes in proprioceptive and visual inputs are made.
Irreversible opiate agonists and antagonists: the 14- hydroxydihydromorphinone azines
Authors: Hahn EF , Carroll-Buatti M , Pasternak GW
Published: April 2018

Further investigations into the molecular actions of the 14- hydroxydihydromorphinone hydrazones (naloxazone, oxymorphazone, and naltrexazone) have suggested that their irreversible actions can be explained by the formation of their azines. These azines, naloxonazine, naltrexonazine, and oxymorphonazine, irreversibly block opiate binding in vitro 20- to 40-fold more potently than their corresponding hydrozones, naloxazone, naltrexazone, and oxymorphazone. The blockade of binding by naloxonazine shows the same selectivity for high affinity, or mu1, sites as naloxazone.
Prenatal development of retinocollicular projections in the cat: an anterograde tracer transport study
Authors: Williams RW , Chalupa LM
Published: April 2018

The retinal projection to the superior colliculus of the cat was examined at four gestational ages, embryonic days 38, 46, 56, and 61, using the antegrade transport of horseradish peroxidase and tritiated leucine. Gestation in the cat averages 65 days. By the 38th day of gestation (E38), the anlage of the entire superior colliculus, both ipsilateral and contralateral to an injection, was labeled intensely. The peroxidase label had an extremely coarse grained texture. As late as E46, the ipsilateral retinal projection extended to the presumed caudal border of the colliculus, while by E56, as in the mature cat, the ipsilateral terminal field was largely excluded from the rostral and caudal tectal poles. The contralateral terminal field at E56, as in younger fetal material, extended across the entire tectal mantle. By E61, clear gaps of label were observed in the contralateral stratum griseum superficiale. At this age, patches or bands of label were accentuated on the ipsilateral side. In double labeled tissue, it could be demonstrated that the ipsilateral patches corresponded quite closely to the gaps in the contralaterally derived label. Thus, a few days before birth, the retinal projection to the superior colliculus has a pattern which resembles that of the adult.
The phase and magnitude of hair cell receptor potentials and frequency tuning in the guinea pig cochlea
Authors: Kossl M , Russell IJ
Published: March 2018

Voltage responses to tones were recorded intracellularly from inner (IHC) and outer (OHC) hair cells in the basal turn of the guinea pig cochlea. Tone-evoked voltage responses were also recorded extracellularly from fluid-filled spaces adjacent to the hair cells and from supporting cells. The AC component of the OHC voltage responses to tones at frequencies between 8 and 24 kHz and those recorded extracellularly were remarkably similar with respect to phase as a function of sound level, but the magnitude of the AC response was 2–10 times larger when recorded intracellularly from an OHC. At frequencies more than half an octave below the characteristic frequency (CF), the phase of OHC AC response was independent of level, and the slope of the magnitude/level functions was 1 dB/db. At levels exceeding about 70 dB SPL, the slopes became less steep and depolarizing IHC and OHC DC responses appeared. At frequencies one-half an octave below CF and at frequencies between one-third and one-half an octave above CF, notches were present in the AC/level function between 70–100 dB SPL that were accompanied by a sudden phase lag of -180 degrees. These frequency- and level-dependent characteristics were also present in relatively insensitive preparations and were attributed to a change in the phase of OHC excitation due to level-dependent changes in the relative stiffness of the mechanical components of the cochlear partition. At CF the detection thresholds of the OHC AC response and IHC DC response and slopes of the response/level functions were similar. At sound levels around 60 dB SPL, the AC signal began to phase lead, amounting to approximately 90 degrees at 70 dB SPL. Within the same range of levels, the OHC DC potentials first appeared and the IHC DC response began to saturate. At frequencies just above the CF, the phase of the AC component increased with level to a lead of about 180 degrees. OHC and IHC tuning curves are comparable in the tip region, but they differ in that the low- and high-frequency shoulders of the OHC AC tuning curves are more sensitive by 10–30 dB SPL. On the basis of the frequency- and level-dependent characteristics of the IHC and OHC responses, it is proposed that OHC AC potentials provide a measure of the phase and magnitude of the proposed electromechanical feedback of the cochlear partition that enhance frequency tuning in the cochlea.
Modulation of hair cell voltage responses to tones by low-frequency biasing of the basilar membrane in the guinea pig cochlea
Authors: Russell IJ , Kossl M
Published: March 2018

Inner (IHC) and outer (OHC) hair cell receptor potentials were recorded during stimulation with combinations of high-frequency (HF) tones and a 100 Hz tone burst of constant level (80 dB SPL). For frequencies at and below characteristic frequency (CF), OHC AC receptor potentials were suppressed by the 100 Hz tone at levels of the HF tone below about 70 dB SPL (the initial steep part of the AC/level function) and at levels that were frequency specific for frequencies above CF. Suppression was associated with a phase lead for frequencies at and close to the CF. For frequencies above CF, the OHC AC response was either suppressed or augmented at levels of the HF tone both below and above 70 dB SPL, depending on the frequency. The action of the 100 Hz tone on the AC response/level functions was to change nonmonotonic functions into monotonic functions or vice versa. IHC DC receptor potentials were suppressed maximally at the CF and at levels and frequencies where suppression of the OHC AC response and the appearance of the IHC DC response overlapped. For levels of the HF tone above 70 dB SPL, the amplitude of the responses of both IHCs and OHCs to the 100 Hz tone are suppressed and become more symmetrical through selective attenuation of the depolarizing phase of the IHC response and the hyperpolarizing phase of the OHC response. In IHCs from insensitive preparations, the response to the 100 Hz tone is augmented in the presence of the HF tone, which may indicate a shift in the operating point of transduction. At frequencies about one-half an octave below the CF, the phase of the 100 Hz voltage response of OHCs but not IHCs is inverted for levels of the HF tone above about 90 dB SPL. It is proposed that amplitude and phase changes in the response to the HF tone due to the presence of the 100 Hz tone are the result of changes in OHC feedback processes and in the mode of movement of the interface between OHC stereocilia and tectorial membrane. The interaction between the responses to HF and 100 Hz tones indicates that feedback contributes significantly to the voltage responses of OHCs throughout the frequency response range.
Activity of medial mesopontine units during cataplexy and sleep-waking states in the narcoleptic dog
Authors: Siegel JM , Nienhuis R , Fahringer HM , Chiu C , Dement WC , Mignot E , Lufkin R
Published: March 2018

Narcolepsy has been hypothesized to be a disease of rapid eye movement (REM) sleep. According to this hypothesis, cataplexy is a result of the triggering during waking of the mechanism that normally serves to suppress muscle tone in REM sleep. REM sleep control mechanisms have been localized to the pons. Narcoleptic dogs have increased numbers of cholinergic receptors in the medial pons. These findings suggest that neurons mediating the triggering of cataplexy might be located in medial pontine regions. In the present study, this hypothesis has been investigated by recording the discharge of units in the medial mesopontine region of the narcoleptic dog. Unit activity was examined in the nucleus reticularis pontis oralis, caudalis, and central gray, with each cell being recorded during both cataplexy and sleep states. Maximal discharge rates were observed, in all of these regions, during active waking states (mean rate, 45.3/sec) and REM sleep (16.0/sec), with minimal discharge rates in non-REM sleep (8.3/sec). Unit discharge was reduced in cataplexy relative to precataplexy periods. Cataplexy discharge rates were 8.3/sec, 52% of the mean REM sleep rate. Cataplexy discharge rates were also significantly lower than those at REM sleep onset. Cataplexy discharge rates were comparable to rates in quiet waking and non-REM sleep. While medial mesopontine neurons discharge at high rates in REM sleep, they have little or no activity in cataplexy. We interpret the lack of activation of medial mesopontine units in cataplexy as indicating that the characteristic phasic motor activation of REM sleep does not occur in this state.(ABSTRACT TRUNCATED AT 250 WORDS)
Regional distribution and developmental expression of epidermal growth factor and transforming growth factor-alpha mRNA in mouse brain by a quantitative nuclease protection assay
Authors: Lazar LM , Blum M
Published: March 2018

A solution-hybridization ribonuclease-protection assay was used to identify epidermal growth factor (EGF) mRNA in mouse brain and to compare the regional and developmental levels of EGF gene expression in the CNS with those of its structural homolog, transforming growth factor-alpha (TGF-alpha). Adult brain regions examined included brainstem, cerebellum, cerebral cortex, hippocampus, basal hypothalamus, olfactory bulb, olfactory tubercle, striatum, and thalamus. While both EGF and TGF-alpha mRNAs were detected in all regions, TGF-alpha mRNA levels were 15–170 times higher, ranging from 0.39 (cerebellum and cerebral cortex) to 2.93 (striatum) pg TGF-alpha mRNA/micrograms total cytoplasmic RNA. In contrast, EGF mRNA levels ranged from 11 to 36 fg EGF mRNA/micrograms, with the highest regional concentrations observed in olfactory bulb, basal hypothalamus, and cerebellum. In our comparison between sexes, no significant male-female differences in EGF or TGF-alpha mRNA levels were observed for any region of adult brain. However, in the pituitary gland, consisting of both endocrine and neural elements, EGF and TGF-alpha mRNA levels were significantly higher in males (234 and 215 fg/micrograms, respectively) than in females (172 and 118 fg/micrograms, respectively). An examination of growth factor gene expression in the developing CNS revealed EGF and TGF-alpha mRNAs detectable as early as embryonic day 14 (earliest time point studied). While gene expression for both peptides continued into the postnatal period, EGF and TGF-alpha mRNA levels were nearly equal to adult concentrations by postnatal day 10. Taken together, our findings provide evidence for the synthesis of EGF in brain and suggest a role for both EGF and TGF-alpha in the development and support of the mammalian CNS.
Characterization of a cDNA clone encoding multiple copies of the neuropeptide APGWamide in the mollusk Lymnaea stagnalis
Authors: Smit AB , Jimenez CR , Dirks RW , Croll RP , Geraerts WP
Published: March 2018

Male mating behavior of the simultaneous hermaphrodite freshwater snail Lymnaea stagnalis is controlled by a neuronal network that consists of various types of peptidergic neurons, as well as serotonergic cells. In the present article, we describe the isolation and characterization of a cDNA clone that encodes a multipeptide preprohormone expressed in the anterior lobe of the right cerebral ganglion, in a group of neurons that principally innervate the penial complex. The preprohormone is 219 amino acids in length and contains 10 copies of the peptide Ala-Pro-Gly- Trp-Gly. Posttranslational processing of the prohormone may lead to the generation of the amidated neuropeptide Ala-Pro-Gly-Trp-amide (APGWamide), an amidated C-terminal anterior lobe peptide, and four connecting peptide sequences, C1-C4. We show by in situ and filter hybridizations that neurons of the right anterior lobe comprise the major site of expression of the APGWamide gene. Expression of the APGWamide gene is detected in the CNS of both adult animals and noncopulating juveniles. Peptides derived from the APGWamide prohormone are probably involved in the control of a part of the male mating behavior and have both central and peripheral targets.
Aluminum-induced neurofilamentous changes in cultured rat dorsal root ganglia explants
Authors: Gilbert MR , Harding BL , Hoffman PN , Griffin JW , Price DL , Troncoso JC
Published: March 2018

Intrathecal administration of aluminum (AI) salts to susceptible species causes prominent accumulations of neurofilaments (NFs) in neurons of the CNS. Involved nerve cells display abnormal phosphorylation of perikaryal NFs, impaired axonal transport of NFs, and reduced levels of mRNA for NF proteins. Further understanding of the pathogenesis of AI toxicity has been limited by difficulties inherent in the available in vivo systems. For this reason, we have developed a model to study the effects of AI on cultured sensory neurons. Explant cultures of rat dorsal root ganglia (DRG) were exposed to 1 mM aluminum lactate for 1 d, 3 d, or 7 d and then examined morphologically. Accumulations of NFs were noted as early as 1 d after exposure, and prominent masses of NFs were seen at 3 and 7 d. Northern analysis of mRNA extracted from the cultured ganglia showed that high, medium, and low molecular weight NF protein mRNA levels were markedly reduced compared to control values by 1 d of exposure. Class II beta- tubulin mRNA was also moderately decreased. Reversibility of toxicity was assessed by removing the aluminum lactate from the medium after a 3 d exposure and examining the cultures 1 week later. The perikaryal masses of NFs dispersed and the levels of mRNA coding for the NF proteins and class II beta-tubulin increased. The neurotoxic effects of AI on cultured DRG recapitulates the effects of intrathecal administration of AI on animals; this model produces similar changes in neuronal morphology with neurofilamentous masses and similar modifications of NF gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)
A critical period for experience-dependent synaptic plasticity in rat barrel cortex
Authors: Fox K
Published: March 2018

Recordings were made from neurons in layers II, III, and IV of rat barrel cortex. The animals were raised either from the day of birth (P0) or from P2, P4, or P7 with just the D1 vibrissa protruding on one side of the face and the contralateral side intact. Follicles were not ablated, but vibrissae were carefully removed by applying steady tension to the base of each vibrissa. Deprivation was continued until the day of recording (P30-P90), though in most cases vibrissae were allowed to regrow for 4–7 d prior to recording. The area of cortex driven by stimulating the spared D1 vibrissa was found to be enlarged in uni-vibrissae animals, but the characteristic anatomical map of the barrel field, defined by cytochrome oxidase staining, retained its normal form. In animals deprived from P0, layer IV cells outside the D1 barrel responded with short latencies (5–10 msec) to D1 stimulation, a condition never observed in normally reared animals. Short-latency responses to stimulation of regrown, deprived vibrissae were still present in layer IV despite the deprivation. Plasticity decreased rapidly in layer IV between P0 and P4 as judged by two measures: first, the percentage of cells in neighboring barrels that showed short- latency responses to D1 fell from 30% in P0 deprived animals to 18% in P2 and 13% in P4 deprived animals. Second, the percentage of cells in barrels surrounding D1 with larger responses to D1 stimulation than to stimulation of their anatomically related vibrissa also fell from 37% in P0 to 23% in P2 and 12% in P4 deprived animals. The percentage of “shifted cells” showed no further reduction in P7 deprived animals (14%). Plasticity in layers II and III showed little sign of decreasing between P2 and P7 after an initial drop between P0 and P2. Therefore, deprivation started at P4 and P7 had a far greater effect on layers II and III than on layer IV. In animals deprived from P4 onward, not only were responses to D1 stimulation greater in barrels neighboring D1 (in layers II/III), but responses were smaller to principal vibrissa stimulation. This suggests increased lateral transmission from the “experienced” barrel and a failure of vertical transmission within the “deprived” barrels. These results show that changes in the balance of experience acquired through vibrissae can affect development of connectivity in the barrel cortex. The main locus of plasticity is cortical when deprivations are started at P4 and beyond.(ABSTRACT TRUNCATED AT 400 WORDS)
Role of the hippocampal-entorhinal loop in temporal lobe epilepsy: extra- and intracellular study in the isolated guinea pig brain in vitro
Authors: Pare D , deCurtis M , Llinas R
Published: March 2018

This article introduces a new experimental paradigm for the study of temporal lobe epilepsy. This approach utilizes the isolated guinea pig brain in vitro preparation, which generates a pattern of hypersynchronous neuronal activity similar to the peculiar 8–30 Hz rhythm characterizing stereoelectroencephalographic hippocampal recordings in human temporal lobe epilepsy. The present report describes an attempt to identify the functional events underlying the epileptiform activities observed in this preparation. Rhythmic epileptiform discharges (EDs), here defined as population spikes (PSs) recorded from somata or dendritic layers, were induced in the hippocampal formation of the isolated guinea pig brain maintained in vitro by tetanic stimulation of the entorhinal cortex (EC). Two patterns of EDs were distinguished by performing simultaneous field potential recordings along the dentate gyrus (DG), EC, CA1, and CA3. During stage 1, the first self-sustained EDs were isolated PSs occurring at a frequency of 2–3 Hz at all levels of the entorhinal- hippocampal loop, the only exception being the DG, where no signs of synchronized neuronal discharge could be found. Over the next 30–50 sec, the temporal organization of these EDs changed dramatically. During stage 2, at all levels of the entorhinal-hippocampal loop, EDs occurred in 0.3–0.5 sec trains of 16–25 Hz population spikes interrupted by 0.7–1.3 sec silent periods. The transition between stages 1 and 2 coincided with the occurrence of population spikes in the DG. Laminar analyses and multiple simultaneous field potential recordings revealed that the trains of EDs observed in stage 2 resulted from the repetitive, sequential activation of the hippocampal- entorhinal loop. In the transverse axis, the earliest event usually occurred in the CA3 region. Thereafter, population spikes occurred sequentially in the CA1 region, EC, DG, and back to the CA3 region. Intracellular recordings confirmed that the EDs recorded extracellularly resulted from the synchronous activation of the cells in phase with the locally recorded field potentials. Dentate granule cells, layer II entorhinal cells, as well as CA1 pyramids displayed large-amplitude EPSPs crowned by an isolated action potential phase locked to the locally recorded field potential. In contrast, the activity of CA3 pyramids consisted of typical paroxysmal depolarization shifts on which bursts of action potentials of decreasing amplitude were observed. These results suggest that reentrant loop activity in the hippocampal-entorhinal circuit represents the central event in the functional organization of hippocampal epileptic discharges.
Glutamate-induced calcium transient triggers delayed calcium overload and neurotoxicity in rat hippocampal neurons
Authors: Randall RD , Thayer SA
Published: March 2018

Glutamate-induced changes in intracellular free Ca2+ concentration ([Ca2+]i) were recorded in single rat hippocampal neurons grown in primary culture by employing the Ca2+ indicator indo-1 and a dual- emission microfluorimeter. The [Ca2+]i was monitored in neurons exposed to 100 microM glutamate for 5 min and for an ensuing 3 hr period. Ninety-two percent (n = 64) of these neurons buffered the glutamate- induced Ca2+ load back to basal levels after removal of the agonist; thus, the majority of cells had not lost the ability to regulate [Ca2+]i at this time. However, following a variable delay, in 44% (n = 26) of the neurons that buffered glutamate-induced Ca2+ loads to basal levels, [Ca2+]i rose again to a sustained plateau and failed to recover. The changes in [Ca2+]i that occur during glutamate-induced delayed neuronal death can be divided into three phases: (1) a triggering phase during which the neuron is exposed to glutamate and the [Ca2+]i increases to micromolar levels, followed by (2) a latent phase during which the [Ca2+]i recovers to a basal level, and (3) a final phase that begins with a gradual rise in the [Ca2+]i that reaches a sustained plateau from which the neuron does not recover. This delayed Ca2+ overload phase correlated significantly with cell death. The same sequence of events was also observed in recordings from neuronal processes. The delayed Ca2+ increase and subsequent death were dependent upon the presence of extracellular Ca2+ during glutamate exposure. Calcium influx during the triggering phase resulted from the activation of both NMDA and non-NMDA receptors as indicated by studies using receptor antagonists and ion substitution. Treatment with TTX (1 microM) or removal of extracellular Ca2+ for a 30 min window following agonist exposure failed to prevent the delayed Ca2+ overload. The delayed [Ca2+]i increase could be reversed by removing extracellular Ca2+, indicating that it resulted from Ca2+ influx. The three phases defined by changes in the [Ca2+]i during glutamate-induced neuronal toxicity suggest three distinct targets to which neuroprotective agents may be directed.
SAG: a Schwann cell membrane glycoprotein
Authors: Dieperink ME , O'Neill A , Magnoni G , Wollmann RL , Heinrikson RL , Zucher-Neely HA , Stefansson K
Published: March 2018

We report on characterization of a 170,000 Da glycoprotein found exclusively in the PNS. We refer to this protein as the Schwann cell membrane glycoprotein (SAG). SAG contains the HNK-1 carbohydrate, which is considered by some to be a marker of adhesion molecules. Its N- terminal sequence is not similar to previously known polypeptide sequences. SAG is found exclusively in the PNS, is present in rat sciatic nerve prior to myelination, and is in both myelinating and nonmyelinating Schwann cells. Tumors of Schwann cell lineage express SAG where axons are present (neurofibromas) but do not in the absence of axons (schwannomas). Schwannoma cells in culture do not express SAG even when exposed to forskolin, an activator of adenylate cyclase. However, schwannoma cells grown in the presence of a neuronal cell line (PC12) express SAG.
Neuronal processes that underlie expression of kindled epileptiform events in the piriform cortex in vivo
Authors: Haberly LB , Sutula TP
Published: March 2018

Recent studies with kindling and convulsant drug models of epilepsy suggest that the piriform (primary olfactory) cortex may be particularly susceptible to generation of epileptiform activity. The present study has examined the generation of interictal epileptiform events in the piriform cortex of kindled rats in vivo, taking advantage of special features of this system that facilitate physiological analysis. The investigation included analysis of extracellular and intracellular potentials, and membrane currents computed by current source density (CSD) analysis. In pyramidal cells, epileptiform events consisted of an initial EPSP that occurred in all-or-none fashion and a long-lasting IPSP with Cl(-)- and K(+)-mediated components. Onset of the IPSP was sufficiently fast that firing evoked by the EPSP was consistently limited to single action potentials. CSD analysis revealed the presence of two distinctly different excitatory epileptiform currents: an initial inward current of unknown origin that is widely distributed over depth, and a second much larger inward current at the depths of proximal apical and basal dendrites of pyramidal cells. It was concluded that this second component is mediated by the associational projections of pyramidal cells excited by the first component. Since these heavy associational projections also extend to neighboring areas including the amygdala, entorhinal cortex, and insular and orbitofrontal areas of neocortex, this second component could be widely propagated within the basal forebrain. An important finding was that the EPSP generated by this associational pathway was completely blocked in cell bodies of pyramidal cells in piriform cortex by the IPSP during most events. This IPSP may therefore play a critical role in limiting seizure activity by preventing reverberating positive feedback in the pyramidal cell population. It can be speculated that compromise of this IPSP, as by repetitive activation by the shock trains used for kindling, leads to prolonged epileptic activity in the piriform cortex and the many limbic structures to which it projects.
Metabotropic glutamate receptors mediate excitatory transmission in the nucleus of the solitary tract
Authors: Glaum SR , Miller RJ
Published: March 2018

Following microinjection into the nucleus tractus solitarius (NTS), the effects of glutamate on the baroreceptor reflex are poorly antagonized by kynurenic acid and DL-2-amino-5-phosphonovaleric acid, suggesting the possible involvement of metabotropic glutamate receptors in this response. The metabotropic glutamate receptor agonist 1S,3R-1- aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) depolarized neurons located medial to the tractus solitarius (TS) at the level of the area postrema in coronal sections of the rat NTS. This effect was mimicked by glutamate and was not blocked by antagonists at alpha-amino- 3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA)/kainate or NMDA receptors. 1S,3R-ACPD also produced an inward current under voltage clamp that was not accompanied by a rise in [Ca2+]i, monitored with the Ca(2+)-sensitive dye fura-2. Conversely, the muscarinic agonist carbachol produced an outward current and a rise in [Ca2+]i. 1S,3R-ACPD reduced both the excitatory and the inhibitory postsynaptic current resulting from single electrical stimuli in the region of the TS. High- frequency stimulation of the TS produced an inward current in the presence of AMPA/kainate and NMDA receptor blockers. This current had similar properties to that produced by 1S,3R-ACPD. Thus, metabotropic glutamate receptors may mediate a component of excitatory transmission in the NTS.
Spatial and temporal expression of alpha- and beta-thyroid hormone receptor mRNAs, including the beta 2-subtype, in the developing mammalian nervous system
Authors: Bradley DJ , Towle HC , Young WS
Published: March 2018

Thyroid hormone exerts profound effects on the developing mammalian brain, and its deficiency can lead to severe mental retardation and motor abnormalities. To identify specific anatomic targets of thyroid hormone action in the developing mammalian nervous system, we examined thyroid hormone receptor gene expression by hybridization histochemistry on serial adjacent sections from 12 stages of the developing rat nervous system. 35S-labeled cRNA probes were generated from divergent sequences of rat alpha 1-, alpha 2-, beta 1-, and beta 2- thyroid hormone receptor and related cDNAs. We found that alpha- and beta-thyroid hormone receptor genes have distinct patterns of spatiotemporal expression in the embryonic and postnatal rat nervous system. alpha 1- and alpha 2-mRNAs were widely expressed in similar patterns; highest levels were found in the fetal neocortical plate, site of cortical neuronal differentiation. In contrast, beta 1- transcripts were restricted in distribution, with prominent expression in zones of neuroblast proliferation such as the germinal trigone and the cortical ventricular layer. Surprisingly, the “pituitary-specific” beta 2-transcript was detected in the developing hippocampus and striatum. Our results suggest that alpha- and beta-thyroid hormone receptors may play distinct functional roles during development of the mammalian nervous system.
Disparity sensitivity of neurons in monkey extrastriate area MST
Authors: Roy JP , Komatsu H , Wurtz RH
Published: March 2018

We tested the disparity sensitivity of neurons from the medial superior temporal area (MST) in awake behaving monkeys. While the monkey looked at a fixation spot on a screen in front of it, random dot stimuli moved in the preferred direction of the cell under study, and the disparity of the dots made the stimuli appear to move in a frontoparallel plane in front of, on, or behind the screen. Over 90% of the 272 neurons studied were sensitive to the disparity of the visual stimulus. Of those disparity-sensitive cells, 95% were most responsive either to near stimuli (stimuli with crossed disparities appearing to move in front of the screen) or to far stimuli (stimuli with uncrossed disparities appearing to move behind the screen). In a smaller sample of the disparity-sensitive cells, we found cells whose preferred direction of stimulus motion reversed as the disparity of the stimulus reversed. For example, a cell that responded best to rightward motion for near stimuli responded best to leftward motion for far stimuli. We found that 40% of the disparity-sensitive cells had this disparity- dependent direction selectivity. This disparity-dependent direction selectivity was maintained over the entire range of speeds tested (6–56 degrees/sec). We tested whether the disparity sensitivity of the neurons indicated the distance of the stimulus from the screen where the monkey was fixating (relative depth) or the distance of the stimulus from the monkey (absolute depth) by having the monkey fixate at different depths in front of or behind the screen. For most MST neurons, the changes in vergence did not alter the disparity response, indicating that the disparity sensitivity of these neurons conveyed information on depth relative to the plane of fixation. We conclude that the disparity characteristics of cells in the dorsomedial MST are those expected of a system serving primarily coarse rather than fine stereopsis. The correlation between disparity selectivity and direction selectivity in these neurons, as well as their other properties, suggests a role in signaling the direction of self-motion of the observer through the environment.
A nonphotic stimulus causes instantaneous phase advances of the light- entrainable circadian oscillator of the Syrian hamster but does not induce the expression of c-fos in the suprachiasmatic nuclei
Authors: Mead S , Ebling FJ , Maywood ES , Humby T , Herbert J , Hastings MH
Published: March 2018

The study investigated whether nonphotic cues that alter the phase of overt circadian rhythms do so by causing instantaneous shifts in the underlying, light-sensitive clock. Wheel-running activity in Syrian hamsters was studied under free-running conditions of constant dim red light as an overt marker of circadian phase, the daily onset of activity being defined as circadian time 12 (CT 12). Exposure to a 15 min pulse of bright light at CT 12.20 caused a phase delay in activity onset, whereas pulses delivered at CT 11.20 had no effect upon the overt rhythm. Correlated with their effect on behavior, light pulses delivered at CT 12.20 induced expression of c-fos-like immunoreactivity in the retinorecipient regions of the suprachiasmatic nuclei of the hypothalamus (SCN), whereas pulses delivered at CT 11.20 had no effect upon the expression of c-fos. Expression of this immediate-early gene therefore provided a second marker of circadian phase, because its induction by light is closely correlated with the onset of subjective night (CT 12). To establish a suitable protocol for nonphotic shifts of the activity rhythm, animals were handled and received a subcutaneous injection of saline at different circadian phases. Injections at CT 8 or CT10 caused an immediate bout of wheel-running activity, and a consequent phase advance in the activity rhythm as assessed by the earlier onsets of activity in successive days. Handling and injections at other circadian phases were without effect. Despite shifting the overt rhythm, these procedures at CT 10 did not lead to the expression of c-fos in the SCN.(ABSTRACT TRUNCATED AT 250 WORDS)