Noradrenaline modulates the spontaneous firing activities of Purkinje cells via α2-adrenergic receptor in mouse cerebellar cortex / 生理学报

Cerebellar Purkinje cells (PCs) exhibit two types of discharge activities: simple spike (SS) and complex spike (CS). Previous studies found that noradrenaline (NA) can inhibit CS and bidirectionally regulate SS, but the enhancement of NA on SS is overwhelmed by the strong inhibition of excitatory molecular layer interneurons. However, the mechanism underlying the effect of NA on SS discharge frequency is not clear. Therefore, in the present study, we examined the mechanism underlying the increasing effect of NA on SS firing of PC in mouse cerebellar cortex in vivo and in cerebellar slice by cell-attached and whole-cell recording technique and pharmacological methods. GABAA receptor was blocked by 100 µmol/L picrotoxin in the whole process. In vivo results showed that NA significantly reduced the number of spikelets of spontaneous CS and enhanced the discharge frequency of SS, but did not affect the discharge frequency of CS. In vitro experiments showed that NA reduced the number of CS spikelets and after hyperpolarization potential (AHP) induced by electrical stimulation, and increased the discharge frequency of SS. NA also reduced the amplitude of excitatory postsynaptic current (EPSC) of parallel fiber (PF)-PC and significantly increased the paired-pulse ratio (PPR). Application of yohimbine, an antagonist of α2-adrenergic receptor (AR), completely eliminated the enhancing effect of NA on SS. The α2-AR agonist, UK14304, also increased the frequency of SS. The β-AR blocker, propranolol, did not affect the effects of NA on PC. These results suggest that in the absence of GABAA receptors, NA could attenuate the synaptic transmission of climbing fiber (CF)-PC via activating α2-AR, inhibit CS activity and reduce AHP, thus enhancing the SS discharge frequency of PC. This result suggests that NA neurons of locus coeruleus can finely regulate PC signal output by regulating CF-PC synaptic transmission.

Association between overweight and characteristics of young adult students: support for nursing care / Associação entre excesso de peso e características de adultos jovens escolares: subsídio ao cuidado de enfermagem / Asociación entre exceso de peso y características de adultos jóvenes escolares: contribución para el cuidado de enfermería

OBJECTIVE: to verify associations between overweight and the characteristics of young adult students to support nursing care. METHOD: case-control study conducted with young adults from public schools. The sample was composed of 441 participants (147 cases and 294 controls, with and without excess weight, respectively). Sociodemographic and clinical characteristics were collected together with exposure factors and anthropometrics. Multiple logistic regression was used. The study received Institutional Review Board approval. RESULTS: statistically significant association with overweight: non-Caucasian, having a partner; weight gain during adolescence, mother's excess weight, the use of obesogenic medication, augmented diastolic blood pressure, of abdominal circumference and waist/hip ratio. In addition to these, schooling and weight gain during childhood were also included in the multivariate analysis. After adjustment, the final model included: having a partner, weight gain during adolescence, augmented diastolic blood pressure and abdominal circumference. CONCLUSION: the analysis of predictor variables for excess weight among young adult students supports nurses in planning and developing educational practices aimed to prevent this clinical condition, which is a risk factor for other chronic comorbidities, such as cardiovascular diseases. .

OBJETIVO: verificar a associação entre excesso de peso e características de adultos jovens escolares, como subsídio ao cuidado de enfermagem. MÉTODO: estudo caso-controle, realizado com adultos jovens de escolas públicas. Amostra composta por 441 participantes (147 casos e 294 controles, com e sem excesso de peso, respectivamente). Coletaram-se informações sociodemográficas, clínicas, fatores de exposição e antropometria. Utilizou-se regressão logística múltipla. O estudo foi aprovado em comitê de ética. RESULTADOS: detectou-se associação estatística significativa com excesso de peso em: não brancos, ter companheiro(a), ganho ponderal na adolescência, excesso de peso materno, uso de fármacos obesogênicos, pressão arterial diastólica aumentada, circunferência abdominal e relação cintura quadril. Além destas, entraram na análise multivariada as variáveis escolaridade e ganho ponderal na infância. Após etapa de ajuste permaneceram no modelo final: estado civil com companheiro(a), ganho ponderal na adolescência, pressão arterial diastólica aumentada e circunferência abdominal aumentada. CONCLUSÃO: a análise das variáveis preditoras para o excesso de peso em adultos jovens escolares possibilita ao enfermeiro bases para elaboração e planejamento de práticas educativas que visem à prevenção desta condição clínica, visualizada como fator de risco para outras comorbidades de caráter crônico, como as doenças cardiovasculares. .

OBJETIVO: verificar la asociación entre exceso de peso y características de adultos jóvenes escolares como contribución para el cuidado de enfermería. MÉTODO: estudio de caso control realizado con adultos jóvenes de escuelas públicas. Muestra compuesta por 441 participantes (147 casos y 294 controles, con y sin exceso de peso, respectivamente). Se recolectaron características sociodemográficas, clínicas, factores de exposición y antropometría. Se utilizó la regresión logística múltiple. El estudio fue aprobado por comité de ética. RESULTADOS: se detectó asociación estadística significativa con exceso de peso: no blancos, tener compañero, aumento de peso en la adolescencia, exceso de peso materno, uso de medicamentos obesogénicos, presión arterial diastólica aumentada, circunferencia abdominal aumentada y relación cintura-cadera. Además de estas, entraron en el análisis multivariado las variables escolaridad y aumento de peso en la infancia. Después de la etapa de ajuste permanecieron en el modelo final: estado civil con compañero, aumento de peso en la adolescencia, presión arterial diastólica aumentada y circunferencia abdominal aumentada. CONCLUSIÓN: el análisis de las variables de predicción para el exceso de peso en adultos jóvenes escolares suministra al enfermero bases para la elaboración y planificación de prácticas educativas que objetiven la prevención de esta condición clínica, visualizada como factor de riesgo para otras enfermedades concomitantes de carácter crónico, como las enfermedades cardiovasculares. .

Inibição do receptor de glutamato do tipo NMDA em um modelo de hipóxia-isquemia prenatal: avaliação morfofuncional do cerebelo / Inhibition of glutamate NMDA receptor in a prenatal hipoxia-ischemia model: morphofunctional analises of cerebellum

Lesões sistêmicas peri e pré-natais alteram o desenvolvimento do SNC, levando a problemas cognitivos e motores em crianças que podem perdurar por toda a vida. Um tipo particular de lesão é a hipóxia-isquemia (HI), caracterizada pela interrupção momentânea ou permanente do fluxo sanguíneo. Um dos mecanismos propostos para as lesões decorrentes da HI é a excitotoxicidade glutamatérgica. O uso de inibidores da neurotransmissão glutamatérgica tem sido estudados em diversos modelos de HI. Neste trabalho, avaliamos os efeitos morfofuncionais da administração de um antagonista não-competitivo do receptor de glutamato NMDA sobre o desenvolvimento do cerebelo. Ratas no 18º dia de gestação foram anestesiadas, os cornos uterinos expostos e as 4 artérias uterinas obstruídas por 45 minutos (Grupo H). Animais controle tiveram os úteros expostos, sem a obstrução (Grupo S). Após a cirurgia a gestação prosseguiu. Somente animais nascidos a termo foram utilizados. Um dia após o nascimento, metade de cada ninhada foi designada para receber MK801, 0,3mg/kg/dia, (grupos SM e HM) e a outra metade recebeu solução salina (grupos SS e HS), por 5 dias. Após anestesia e perfusão-fixação com paraformaldeído 4% aos 9, 23, 30 e 60 dias pós-natais, cortes parassagitais do cerebelo foram obtidos em criótomo e submetidos à imunohistoquímica para calbindina, GFAP, GLAST, PDGFRα e MBP. A partir de 45 dias de vida, os animais foram testados em vários de testes comportamentais: labirinto em cruz elevado (LCE), campo vazado (CV), ROTAROD, teste de caminhada sobre barras (ladder test) e teste do comprimento da passada (stride length). Aos 9 dias, a espessura da árvore dendrítica era menor nos animais SM, HS/HM, demonstrando efeitos deletérios tanto do MK801 quanto da HI. Menor número de células PDGFRα+ foi observado nos animais HS/HM, sem efeitos da administração de MK801. Aos 23 dias, maior número de células PDGFRα+ foi observado nos animais HM comparado aos outros 3 grupos, indicando efeito ...

Peri and prenatal systemic lesions alter CNS development leading to motor and cognitive problems in children that might persist throughout life. A particular kind of injury, the hypoxic ischemic (HI), is characterized by a permanent or temporary blockage of blood flow. One of the proposed mechanisms downstream from a HI event is called glutamatergic excitotoxicity. The administration of glutamate inhibitors has been studied in HI models for several years. In this work, we evaluated the effects of administration of a non-competitive antagonist of glutamate receptor, NMDA, on cerebellar development and behavioral tests of HI animals. Pregnant rats in the 18th gestational day were anesthetized, the uterine horns were exposed and the four uterine arteries were clamped for 45 minutes (group H). Sham controls had the uterine horns exposed, but no arteries were clamped (group S). Gestation proceeded after surgery. Only full term animals were used. One day after birth half the animals was assigned to receive either SALINE (groups SS and HS) or MK801 (groups SM and HM). Animals were anesthetized and perfused with 4% paraformaldehyde at 9, 23, 30 and 60 days of age. Parasagittal cerebellar sections were submitted to Calbindin, GFAP, GLAST, PDGFRα and MBP immunohistochemistry. Beginning at P45 animals were subjected to a battery of behavioral tests: elevated plus maze (EPM), hole board (HB), ROTAROD, ladder test and stride length. At P9 the dendritic tree of Purkinje cells were thinner in SM, HS/HM animals, indicating that both HI and MK801 are deleterious regarding this Purkinje cell differentiation. A lower number of PDGFRα+ cells was observed in HS/HM animals, with no effects of MK801 administration. At P23 a greater number of PDGFRα+ cells was found in HM animals when compared to the other 3 groups, demonstrating a neuroprotector effect of MK801. A lower number of myelinated fibers (MBP+) was observed in HS animals at P9, and MK801 administration reverse this ...

Correlative microscopy of Purkinje cells

The Purkinje cell and their synaptic contacts have been described using (1) light microsocopy, (2) transmission and scanning electron microscopy, and freeze etching technique, (3) conventional and field emission scanning electron microscopy and cryofracture methods, (4) confocal laser scanning microscopy using intravital stain FM64, and (5) immunocytochemical techniques for Synapsin-I, PSD9-5, GluR1 subunit of AMPA receptors, N-cadherin, and CamKII alpha. The outer surface and inner content of plasma membrane, cell organelles, cytoskeleton, nucleus, dendritic and axonal processes have been exposed and analyzed in a three-dimensional view. The intramembrane morphology, in bi- and three-dimensional views, and immunocytochemical labeling of synaptic contacts with parallel and climbing fibers, basket and stellate cell axons have been characterized. Freeze etching technique, field emission scanning microscopy and cryofracture methods, and GluR1 immunohistochemistry showed the morphology and localization of postsynaptic receptors. Purkinje cell shows N-cadherin and CamKII alpha immunoreactivity. The correlative microscopy approach provides a deeper understanding of structure and function of the Purkinje cell, a new three-dimensional outer and inner vision, a more detailed study of afferent and intrinsic synaptic junctions, and of intracortical circuits.

Immunohistochemistry of GluR1 subunits of AMPA receptors of rat cerebellar nerve cells

The localization of GluR1 subunits of ionotropic glutamate receptors in the glial cells and inhibitory neurons of cerebellar cortex and their association with the climbing and parallel fibers, and basket cell axons were studied. Samples of P14 and P21 rat cerebellar cortex were exposed to a specific antibody against GluR1 subunit(s) ofAMPA receptors and were examined with confocal laser scanning microscopy. GluR1 strong immunoreactivity was confined to Purkinje cell and the molecular layer. Weak GluR1 immunoreactivity was observed surrounding some Golgi cells in the granule cell layer. Intense GluR1 immunoreactivity was localized around Purkinje, basket, and stellate cells. Purkinje cells expressed strong GluR1 immunoreactivity surrounding the cell body, primary dendritic trunk and secondary and tertiary spiny den dritic branches. Marked immunofluorescent staining was also detected in the Bergmann glial fibers at the level of middle and outer third molecular layer. Positive immunofluorescence staining was also observed surrounding basket and stellate cells, and in the capillary wall. These findings suggest the specific localization of GluR1 subunits ofAMPA receptors in Bergmann glial cells, inhibitory cerebellar neurons, and the associated excitatory glutamatergic circuits formed by climbing and parallel fibers, and by the inhibitory basket cell axons.

Immunohistochemistry of Voltage-Gated Calcium Channel alpha1B Subunit in Mouse Cerebellum

Secretion of neurotransmitters is initiated by voltagegated calcium influx through presynaptic, voltage- gated N-type calcium channels. However, little is known about their cellular distribution in the mouse cerebellum. In the cerebellum, alpha1B immunoreactivity is found mainly on the cell bodies of all Purkinje cells. In addition, the immunoreactivity was detected on a subset of Purkinje cell dendrites, clustered to form a parasagittal array of bands. In the anterior lobe vermis, immunoreactive Purkinje cell dendrites form narrow stripes separated by broad bands of unstained dendrites. Moving caudally through the vermis, these stripes become thicker as a larger fraction of the Purkinje cell dendrites become immunoreactive. This localization study of the alpha1B pore-forming subunits in mouse cerebellum may guide future investigations of the role of calcium channels in neurological pathways.

Deterioro cerebeloso inducido por aislamiento social temprano: estudio morfológico e inmunocitoquímico / Cerebellar impairment induced by early social isolation: a morphological and immunocytochemical study

En el presente trabajo se utiliza el modelo de aislamiento social en animales a objeto de estudiar el efecto que produce las experiencias tempranas adversas sobre el desarrollo morfofuncional de la corteza cerebelosa. Se utilizaron 103 ratas de la cepa Sprague-Dawley de 18 días de vida, las cuales fueron sepradas en dos grupos de estudio: (a) control (SC; 3- 4 ratas por jaula y (b) aislado (IC); estas últimas se colocaron en comportamientos individuales hasta los 32 días de edad (P32). En esta etapa, el 50 por ciento de los animales IC y SC fueron sacrificadas para su estudio neural; el resto de las ratas del grupo IC fue retirado de sus compartimientos individuales y reubicados en su entorno social normal hasta el día P62, realizándose el análisis neural respectivo. En ambas fases ontogenéticas (P32 y P62) se estudió el desarrollo dendrítico y la expresión de calbindina-D28k (CBD) en células de Purkinje vermianas. Los resultados obtenidos mostraron que la deprivación social y sensoriomotriz temprana altera el crecimiento dendríco en estrecha relación con una disminución del contenido intracelular de CBD. Además, la interacción social post-deprivación sólo logró recuperar la expresión de CBD, permaneciendo el deterioro estructural. Estos resultados indican que las experiencias postnatales adversas alteran el desarrollo morfológico y funcional de las neuronas de Purkinje vermianas cuando se emplea el modelo de aislamiento social

'Dark' cell formation under protein malnutrition: process of conversion and concept of 'semi-dark' type Purkinje cells.

This paper deals with some deleterious effects of protein malnourishment in rat cerebellum. Severe protein deprivation enhanced the formation of 'dark' cells in white rats. It is postulated that abnormal changes in the neuronal contents induced by nutritional stress play a vital role in the formation of the 'dark' cells through an intermediary stage, 'semi-dark' cells. Centrophenoxine a lipofuscinolytic agent, however, seems to interfere with the process of formation of 'dark' cells and/or helps reconversion of the 'dark' cells into the normal or 'light' type Purkinje cells.