Lateralization in hemi-parkinsonian rats is affected by deep brain stimulation or glutamatergic neurotransmission in the inferior colliculus.

After unilateral lesion of the medial forebrain bundle (MFB) by 6-OHDA rats exhibit lateralized deficits in spontaneous behavior or apomorphine-induced rotations. We investigated whether such lateralization is attenuated by either deep brain stimulation (DBS) or glutamatergic neurotransmission in the inferior colliculus (IC) of Wistar rats. Intracollicular DBS did not affect spontaneous lateralization but attenuated apomorphine-induced rotations. Spontaneous lateralization disappeared after both glutamatergic antagonist MK-801 or the agonist NMDA microinjected in the IC. Apomorphine-induced rotations were potentiated by MK-801 but were not affected by NMDA intracollicular microinjection. After injecting a bidirectional neural tract tracer into the IC, cell bodies and/or axonal fibers were found in the periaqueductal gray, superior colliculus, substantia nigra, cuneiform nucleus and pedunculo-pontine tegmental nucleus, suggesting the involvement of these structures in the motor improvement after IC manipulation. Importantly, the side of the IC microinjection regarding the lesion (ipsi- or contralateral) is particularly important and this effect may not involve the neostriatum directly.Significance StatementThe inferior colliculus, usually viewed as an auditory structure, when properly manipulated may counteract motor deficits in Parkinsonian rats. Indeed, the present study showed that 30 Hz deep brain stimulation or glutamatergic neural network in the inferior colliculus reduced body asymmetry induced by medial forebrain bundle unilateral 6-OHDA lesion in rats, an animal model of Parkinsonism. Understanding how glutamatergic mechanisms in the inferior colliculus influence motor control, classically attributed to the basal nuclei circuitry, could be useful in the development of new therapeutics to treat Parkinson's disease and other motor disorders.

Estresse juvenil de curta frequência e intensidade não afeta a substância branca cerebral de ratos / Juvenile stress of short frequency and intensity does not affect rats´ brain white matter

O objetivo deste estudo foi avaliar os efeitos duradouros de dois tipos de estresse sobre o corpo caloso (CC). Foram estudados 42 ratos Wistar machos divididos aleatoriamente em três grupos: Grupo Controle (GC), Estresse Físico (EF, imobilização) e Estresse Psicológico (EP, exposição ao predador). Os procedimentos de estresse ocorreram durante três dias consecutivos na idade juvenil (P25-P27) e foram analisados na idade adulta (P74). Os cérebros foram coletados, processados com a técnica de Klüver-Barrera, e secções foram analisadas por meio de morfometria. Os resultados demonstraram que não houve alterações em aspectos gerais como peso dos animais, e histológicos como espessura do CC e quantidade dos núcleos gliais nesta região. O estudo sugere que os efeitos duradouros de ambos os modelos de estresse juvenil de curta frequência (3 dias) e intensidade (90 minutos/EF e 20 minutos/EP) não foram nem prejudiciais e nem protetores, o que pode ser considerado uma adaptação positiva.

The current study evaluates the lasting effects of two types of stress on the corpus callosum (CC). Forty-two male Wistar rats were randomly divided into three groups: Control Group (CG), Physical Stress (FS, immobilization) and Psychological Stress (PS, exposure to predators). Stress procedures occurred for three consecutive days at the juvenile stage (P25-P27) and analyzed at the adult age (P74); brains were retrieved and processed by Klüver-Barrera technique and sections were analyzed by morphometry. Results showed that there were no changes in the general aspects such as animal weight, and in the histological aspects such as CC thickness and quantity of the region´s glia nuclei. Current research suggests that the lasting effects of both models of juvenile stress of short frequency (3 days) and intensity (90 minutes/FS and 20 minutes/PS) were neither detrimental nor protective, featuring a positive adaptation.

Short Juvenile Stress Has No Long-Lasting Effects on Anxiety-Like Behavior, Object Recognition Memory, or Gross Brain Morphology but Affects Dendritic Spines in the Hippocampus in Male Rats.

PURPOSE: During the juvenile stage, such areas as the hippocampus and corpus callosum (CC) are still immature and sensitive to stress exposure. The present study investigated whether two different types of stressors in the juvenile stage of life have a long-lasting impact on behavior and biological outcomes in adult rats. METHODS: Male juvenile rats were exposed to restraint or predator stress on postnatal day 25 (P25) for 3 days. Thirty-two days later (P60-74), behavioral and biological analyses were conducted. The behavioral analysis included measures of anxiety-like behavior and recognition memory. The biological analysis investigated gross cerebral morphology, based on volume analysis of the CC and hippocampus, perirhinal cortex thickness, and dendritic spine density. RESULTS: Neither restraint stress nor predator stress affected anxiety-like behavior or object recognition memory in adulthood. Body weight and adrenal gland weight were unaffected by both types of stress. Overall, volumetric measures of the CC and hippocampus were not significant, with no changes in perirhinal cortex thickness. Spine density in the medial prefrontal cortex also was unaffected, but a decrease in dendritic spine density was found in the hippocampus in response to restraint stress and an increase to predator stress. CONCLUSION: Short-term and daily restraint and predator stress during the juvenile stage had no long-lasting effects on anxiety-like behavior, object memory, volume of the CC or hippocampus, or perirhinal cortex thickness, but a decrease in dendritic spine density was found in the hippocampus. These findings suggest that different types of stressors have different impacts on microstructures in the brain without affecting behavior or the gross morphology of stress-sensitive brain areas.

Short predictable stress promotes resistance to anxiety behavior and increases dendritic spines in prefrontal cortex and hippocampus.

PURPOSE: Some stress paradigms have shown protective effects of stress, suggesting increased resilience. Here we investigated whether a short predictable psychological stress, continuous or discontinuous, has a protective or negative long-lasting effect on behavior and cerebral morphology, and if there is difference when stress is experienced at different phases of neurodevelopment, namely in juvenile, adolescent, and adult rats. METHODS: Male and female rats were stressed on an elevated open platform at different ages (P23, P40, P75), and behavior was assessed later around 90 days of age. Behavioral analysis included measures of anxiety-like behavior, motor activity, and contextual memory. We also investigated the cerebral morphology by using dendritic spine analysis in pyramidal cells, in medial prefrontal cortex (Cg3), orbital prefrontal (AID) and hippocampal region CA1 as well as granule cells in the dentate gyrus (DG) of the hippocampus. RESULTS: Our results showed that short predictable psychological stress, continuous or discontinuous for 12 days, altered emotional behavior and neuronal morphology. Both behavioral and morphological results were sexually dimorphic and suggest a habituation and protective effect, as seen in the decrease of the anxiety-like behavior in the elevated plus maze (EPM), and an increase in excitatory synapse number, which is inferred from an increase of dendritic spines in the hippocampus and prefrontal cortex. CONCLUSION: We conclude that the response to short predictable psychological stress induces a protective/positive effect in both sexes and at different developmental ages.

Efeitos do estresse físico e psicológico juvenil sobre a glândula suprarrenal em ratos adultos / Effects of juvenile physical and psychological stress on the suprarenal gland in adult rats

Estresse é a resposta aos diferentes estímulos que o organismo sofre em busca de adaptação à homeostasia. Devido à sua alta incidência, diversos modelos experimentais estão sendo desenvolvidos para a melhor compreensão de sua inter-relação com outros órgãos. Neste contexto, o objetivo deste estudo foi avaliar os efeitos em longo prazo do estresse físico e psicológico juvenil agudo sobre as glândulas suprarrenais de ratos, no que se refere aos aspectos morfológicos, pois tais glândulas apresentam relação direta com situações de estresse. Para tanto, as glândulas suprarrenais destes animais foram processadas e análises morfológicas da medula e do córtex foram realizadas por meio de morfometria e quantificação por planimetria. Os resultados obtidos demonstraram que o estresse tanto físico quanto psicológico não provocaram alterações significativas em relação à área de superfície e espessura das suprarrenais, indicando adaptação dos animais aos fatores estressantes aqui estudados.

Stress is a response to different stimuli experienced by the organism for its adaption to homeostasis. Due to its high occurrence, several experimental models are being developed to understand better the interrelationships between these organs. Current paper evaluates long-term effects of juvenile physical and psychological stress on the suprarenal glands of rats with regard to morphological aspects. In fact, these glands have a direct relationship with stress conditions. Rats´ suprarenal glands were processed and their medulla and cortex were morphologically investigated through planimetry. Results show that physical and psychological stress failed to cause significant changes on the surface area and thickness of the glands. This fact showed adaptation of animals to the type of stress under analysis.

Postischemic fish oil treatment restores dendritic integrity and synaptic proteins levels after transient, global cerebral ischemia in rats.

We previously found that fish oil (FO) facilitated memory recovery in the absence of pyramidal neuron rescue after transient, global cerebral ischemia (TGCI). Fish oil preserved the expression of microtubule-associated protein 2 (MAP-2), suggesting a relationship between dendritic plasticity and memory recovery that is mediated by FO after TGCI. The present study examined whether postischemic treatment with FO prevents ischemia-induced loss of dendritic processes in remaining pyramidal neurons. The effects of FO on neuroplasticity-related proteins were also examined after TGCI. Rats were subjected to TGCI (15 min, four-vessel occlusion model) and then received vehicle or FO (300 mg/kg docosahexaenoic acid) once daily for 7 days. The first dose was administered 4 h postischemia. Golgi-Cox staining was used to evaluate dentrict morphology in the pyramidal neurons of hippocampus (CA1 and CA3 subfields) and prefrontal cortex (PFC). Neuronal nuclei protein (NeuN), brain-derived neurotrophic factor (BDNF), growth-associated protein 43 (GAP-43), synaptophysin (SYP), and postsynaptic density protein 95 (PSD-95) levels were measured by Western blot in both structures. Fifteen minutes of TGCI reduced consistently the length of dendrites, number of dendritic branches and dendritic spine density (average of 25%, 43%, 32%, respectively) 7, 14, and 21 days postischemia, indicating that they did not recover spontaneously. This outcome of TGCI was reversed by FO treatment, an effect that was sustained even after treatment cessation. The NeuN and BDNF protein levels were reduced in both the hippocampus and PFC, which were recovered by FO treatment. GAP-43 protein levels decreased after ischemia in the PFC only, and this effect was also mitigated by FO. Neither SYP nor PSD-95 levels were altered by ischemia, but PDS-95 levels almost doubled after FO treatment in the ischemic group. These data support our hypothesis that synaptic plasticity at the level of dendrites may at least partially underlie the memory-protective effect of FO after TGCI and strengthen the possibility that FO has therapeutic potential for treating the sequelae of brain ischemia/reperfusion injury.

O desafio para compreender a morfologia cerebral: da visualização à quantificação / Challenges in understanding brain morphology: from visualization to quantification

O objetivo deste trabalho é estudar a morfologia neuronal a partir de modelos animais, fornecer informações biológicas difíceis de serem obtidas em humanos, permitindo estudar condições neuropsiquiátricas como doença de Alzheimer, ansiedade, dentre outras. O presente trabalho descreveu metodologia de estudo para cérebro de roedores, duas técnicas neuroanatômicas, Klüver-Barrera e Golgi-Cox, e seus respectivos processos de quantificação. A técnica de Klüver-Barrera permitiu visualização da substância branca e cinzenta com destaque na bainha de mielina. A técnica de Golgi-Cox, adaptada para realidade de nosso laboratório, mostrou-se eficiente para visualização de neurônios e seus prolongamentos, como dendritos e espinhas dendríticas, permitindo assim a quantificação. A partir de imagens obtidas de microscópio descreveu-se os diferentes passos para quantificação, a determinação de volume de estruturas internas cerebrais (corpo caloso e camada celular do hipocampo) assim como a quantificação das espinhas dendríticas em neurônios piramidais. Os métodos descritos e detalhados poderão ser utilizados em vários campos da neurociência

Neuronal morphology is analyzed in animal models to provide biological information difficult to obtain in humans. The above makes possible the study of neuro-psychiatric, such as Alzheimer´s disease, anxiety and others. Current study described methodology for rodents´ brains, two neuro-anatomic techniques, Klüver-Barrera and Golgi-Cox, and their respective quantification processes. Klüver-Barrera technique visualized the white and gray matter, particularly the myelin sheath. Golgi-Cox technique, adapted for current research, was efficient to visualize neurons and their prolongations, such as dendrites and dendritic spines, with quantification. Images by microscope described the different steps for the quantification, determination of volume of the brain´s internal structures (callous body and the hypocampus´s cell layer) coupled to the quantification of dendritic spines in pyramid neurons. Described and detailed methods will be useful in several fields of neuroscience

Neonatal Stress Has a Long-Lasting Sex-Dependent Effect on Anxiety-Like Behavior and Neuronal Morphology in the Prefrontal Cortex and Hippocampus.

The long-lasting effects of early stress on brain development have been well studied. Recent evidence indicates that males and females respond differently to the same stressor. We examined the chronic effects of daily maternal separation (MS) on behavior and cerebral morphology in both male and female rats. Cognitive and anxiety-like behaviors were evaluated, and neuroplastic changes in 2 subregions of the prefrontal cortex (dorsal agranular insular cortex [AID] and cingulate cortex [Cg3]) and hippocampus (CA1 and dentate gyrus) were measured in adult male and female rats. The animals were subjected to MS on postnatal day (P) 3-14 for 3 h per day. Cognitive and emotional behaviors were assessed in the object/context mismatch task, elevated plus maze, and locomotor activity test in early adulthood (P87-P95). Anatomical assessments were performed in the prefrontal cortex (i.e., cortical thickness and spine density) and hippocampus (i.e., spine density). Sex-dependent effects were observed. MS increased anxiety-related behavior only in males, whereas locomotor activity was higher in females, with no effects on cognition. MS decreased spine density in the AID and increased spine density in the CA1 area in males. Females exhibited an increase in spine density in the Cg3. Our findings confirm previous work that found that MS causes long-term behavioral and anatomical effects, and these effects were dependent on sex and the duration of MS stress.

Postischemic fish oil treatment restores long-term retrograde memory and dendritic density: An analysis of the time window of efficacy.

We reported that fish oil (FO) prevented the loss of spatial memory caused by transient, global cerebral ischemia (TGCI), provided the treatment covered the first days prior to and after ischemia. Continuing these studies, trained rats were subjected to TGCI, and FO was administered for 10days, with a time window of efficacy (TWE) of 4, 8 or 12h post-ischemia. Retrograde memory was assessed up to 43days after TGCI. In another experiment, ischemic rats received FO with a 4- or 12-h TWE, and dendritic density was assessed in the hippocampus and cerebral cortex. The brain lipid profile was evaluated in sham-operated and ischemic rats that were treated with FO or vehicle with a 4-h TWE. Ischemia-induced retrograde amnesia was prevented by FO administration that was initiated with either a 4- or 8-h TWE. Fish oil was ineffective after a 12-h TWE. Independent of the TWE, FO did not prevent ischemic neuronal death. In the hippocampus, but not cerebral cortex, TGCI-induced dendritic loss was prevented by FO with a 4-h TWE but not 12-h TWE. The level of docosahexaenoic acid almost doubled in the hippocampus in ischemic, FO-treated rats (4-h TWE). The data indicate that (i) the anti-amnesic effect of FO can be observed with a TWE of up to 8h, (ii) the stimulation of dendritic neuroplasticity may have contributed to this effect, and (iii) DHA in FO may be the main active constituent in FO that mediates the cognitive and neuroplasticity effects on TGCI.

Fish oil provides a sustained antiamnesic effect after acute, transient forebrain ischemia but not after chronic cerebral hypoperfusion in middle-aged rats.

We reported that fish oil (FO) abolishes retrograde amnesia consistently following transient global cerebral ischemia (TGCI) in young rats, provided it covered the first days prior to and after ischemia. Here, we further evaluated whether FO given post-ischemia in older rats (15-18 months old) is equally effective in facilitating memory recovery. We also tested whether the antiamnesic effect of FO observed after TGCI can be reproduced after chronic cerebral hypoperfusion (CCH). FO (300 mg/kg docosahexaenoic acid [DHA]) was delivered orally 4h after TGCI and continued once per day for 9 days. In the CCH group, FO treatment began soon after the first stage of 4-VO/ICA and continued daily for 43 days. Two weeks after surgery, the animals were tested for retrograde memory performance across 5 weeks. Both TGCI and CCH caused persistent memory impairment and hippocampal and cortical neurodegeneration. TGCI-induced retrograde amnesia was reversed by FO, an effect that was sustained for at least 5 weeks after discontinuing treatment. In contrast, the memory deficit caused by CCH remained unchanged after FO treatment. Both hippocampal and cortical damage was not alleviated by FO. We conclude that the FO-mediated antiamnesic effect following TGCI can be extended to older rats, even when the treatment begins 4h postischemia. Such efficacy was not reproduced after CCH. Therefore, the present results support the notion that FO may have therapeutic utility in treating learning/memory dysfunction after acute/transient cerebral ischemia and suggest that such benefits may not apply when a state of chronic cerebrovascular insufficiency is present.

A base biológica da atenção / The biological bases of attention

As bases biológicas da função psíquica atenção despertam o interesse de muitos estudiosos. O neuropsicólogo Alexandre Luria é um dos pioneiros a descrever tal processo. Luria teorizou, em 1981, que as estruturas cerebrais envolvidas no processo de atenção seriam a formação reticular, a parte superior do tronco encefálico, o córtex límbico e a região frontal. O presente trabalho fez uma revisão das pesquisas desenvolvidas recentemente nesse campo da neurobiologia, e averiguou que elas confirmam e refinam as proposições feitas há quase três décadas por este autor.

The bases of the psychic function of attention have always been of great concern to such as Alexander Luria, one of the pioneer scientists to study such process. In 1981, Luria stated that the reticular formation, the upper section of the brain stem, the limbic cortex and the frontal region are the brain structures involved in the attention process. This research analyzes the results of contemporary theories in research on the biological basis of attention and verifies what they confirm the statements made almost 30 years ago.

Levantamento dos casos de Leishmaniose registrados no município de Jussara, Paraná, Brasil / A survey on cases of Leishmaniosis recorded at the municipal district of Jussara, Paraná, Brazil

As leishmanioses são doenças infecto-parasitárias que acometem o homem, causadas por protozoários do gênero Leishmania. Com o objetivo de avaliar os aspectos epidemiológicos da Leishmaniose Tegumentar Americana foi feito um levantamento de casos, entre 1998 a 2004 no município de Jussara, Paraná. Os dados foram coletados na 13ª Regional de Saúde de Cianorte-Pr, através de fichas epidemiológicas. Foram notificados 129 casos da doença, não sendo significativamente diferente quando comparados o ano de 2000 e 2001. O sexo masculino 84,5 por cento (p<0,001) foi o mais afetado. Representaram a maioria dos casos os indivíduos na faixa etária de 20 a 49 anos com 64,0 por cento (p<0,001). A forma clínica mais freqüente foi a cutânea com 96,1 por cento (p<0,001). Observou-se associação entre a doença e o local de moradia, sendo que os indivíduos da zona rural 56,6 por cento têm 10,6 vezes mais chances de contrair a infecção do que os da zona urbana. Conclui-se que a infecção é endêmica e tem infectado os indivíduos que desenvolvem algum tipo de atividade na zona rural, mas as alterações ambientais, a falta de conhecimento a respeito da doença, podem favorecer a infecção, sendo necessário medidas de controle e mais estudos para avaliar a hipótese de infecção domiciliar e peridomiciliar

Prevalência da neurocisticercose na região de Cianorte - PR no período de 1998 a 2003 / Prevalence of neurocysticercosis in the region of Cianorte - PR, from 1998 to 2003

A história conta que o medo da cisticercose ocorria há 300 anos antes de Cristo, quando a lei dos judeus proibia, sob pena de prisão, a ingestão da carne de porco. O objetivo deste trabalho foi realizar uma pesquisa acerca do problema cisticercose e fazer um levantamento estatístico de casos notificados à 13ª Regional de Saúde de Cianorte. Foram notificados à 13ª Regional de Saúde de Cianorte 41 casos positivos para cisticercose, compreendendo os anos de 1998 a 2003, verificou-se que o município que mais apresentou incidência foi São Manoel do Paraná, o sexo com maior incidência foi o feminino, a faixa etária mais atingida foi a de 25 a 46 anos, que é a idade em que o indivíduo apresenta maior produtividade. Fazendo uma análise, no município de Cianorte, observou-se que 95 por cento dos pacientes residiam na zona urbana, e 5 por cento, na zona rural. Verificou-se somente a presença de neurocisticercose; com relação aos sintomas, houve maior incidência de cefaléia, seguida de distúrbios visuais e crises convulsivas. Pode-se concluir que, apesar da cisticercose ser uma velha doença, ela ainda acomete várias pessoas, principalmente as mulheres e em sua faixa etária de maior produtividade; é lamentável que, no século XXI, ainda exista uma parcela considerável de pessoas com cisticercose...

Características ultra-estruturais do nó sinoatrial de rato Wistar / Superstructural features of the wistar strain male rats' sinoatrial node (SAN)

As características ultra-estruturais do nó sinoatrial (NSA) de 5 ratos machos da variedade Wistar, com 3 meses de idade, foram estudadas por meio de microscopia eletrônica de transmissão (MET). Fragmento pequeno, contendo a região do NSA e área adjacente do átrio direito do coração, foi retirado e fixado em glutaraldeído 2,5 por cento e processado de acordo com técnica convencional para MET. A morfologia do nó sinoatrial de ratos é semelhante a de outros mamíferos. O NSA é uma estrutura anatômica independente do miocárdio atrial, constituído por células típicas (miócitos nodais, células de transição e, principalmente, células nodais) imersos em matriz extracelular, na qual predominam fibras colágenas, fibroblastos e nervos

Stereologic study of the sinoatrial node of rats -- age related changes.

Changes in the sinoatrial node represent the major mechanism of sudden death in humans, and because of the sparse knowledge about the effects of aging on this structure, light microscopic and quantitative studies of the sinoatrial node were undertaken. Twenty-one hearts were studied, seven rat hearts from each of the following age groups: three months of age, twelve months of age and eighteen months of age. In the stereologic study, the following parameters were studied: Vv([nc]) and Vv([interstitium]) % (the volume densities of the nodal cell and interstitium, determined by the point-counting method), and Nv([nc]) (1/mm(3)) (the numerical density of the nodal cell, determined by the disector method). The mean volume of the nodal cell (V([nc])) (microm(3)) was also determined. The comparisons showed that in the oldest animals, the volume density of the nodal cells decreased, while the volume density of the interstitium increased. Although numerical density of the nodal cell per volume of sinus node decreased, the nodal cells displayed increased mean volume with age. In conclusion, the aging process implies changes in the cell and fiber content of the sinoatrial node.

O nó sinoatrial de ratos (rattus norvegicus): estudo histológico / The sinoatrial node of rats (rattus norvegicus): histologic study

O presente estudo teve por objetivo contribuir com informações sobre os aspectos histológicos do nó sinoatrial de ratos. Foram utilizados sete ratos machos (Rattus norvegicus) da variedade Wistar. As regiões contendo o nó sinoatrial foram retiradas e fixadas em solução de Bouin alcoólico, submetidas à rotina histológica para observação em microscopia de luz e coradas pelos métodos de tricrômico de Masson, resorcina-fucsina de Weigert e picro-sirius. Verificou-se que o nó sinoatrial é constituído por células nodais, células de transição imersas em matriz extracelular, rica em fibras colágenas e fibroblastos. O envoltório fibro-elástico é mais rico em fibras colágenas. As células adiposas estão presentes, geralmente na periferia do nó sinoatrial

Os efeitos locais e sistêmicos da vasectomia / Local and systemic effects of vasectomy

A vasectomia é um método contraceptivo masculino cada dia mais comum sendo atualmente conceituado reversível. No entanto, a garantia de fertilidade após vasovasostonúa (cirurgia de ligaçäo dos ductos deferentes) assim como os efeitos da vasectomia a curto e longo prazo näo estäo bem definidos. Tais dúvidas motivaram-nos a realizar uma revisäo literária sobre os efeitos locais e sistêmicos da vasectomia em diferentes espécies