Identification in immuno-electron microscopy of solitary multi-polar peripheral neurons of adult Opisthorchis viverrini by antibody against rat diacylglycerol kinase / Identificación por microscopía imuno-electrónica de las neuronas periféricas multipolares solitarias del Opisthorchis viverrini adulto mediante anticuerpo contra la diacilglicerol kinasa de ratas

By utilizing the antibody for rat DGKz a substantial number of immunopositive cells were found in the OV (Opisthorchis viverrini). The immunopositive cells appeared solitarily and they were distributed rather symmetrically to the longitudinal axis of the OV. Some of them were located in close proximity to internal organs such as uterus, ovary, testes, vitelline glands and guts. The immunostained cells extended tapering processes horizontally or obliquely to the OV longitudinal axis. In immuno-electron microscopy, the immunopositive cells were characterized by intensely immunostained mitochondria and weakly immunostained cytoplasm and immunonegative chromatin-poor nucleus. Vacuoles of various sizes without the immunoreactivity were also contained in the cells. Thin cellular processes without the immunoreactivity were found to enclose thinly the entire surfaces of the immunostained cells and processes, and they were in continuity with the interstitial partition-like processes which contained nuclei and aggregation of microfibrils at some distance from the cytoplasmic envelopes. The present finding suggests the possibility that the immunostained cells were peripheral neurons enveloped by peripheral glia and that the glia are of mesenchymal origin because of their cytoplasmic continuity to the interstitial partition-like processes. The motor or sensory nature of the neurons remains to be elucidated.

Mediante el uso del anticuerpos DGK para rata se determinó un número considerable de células inmunopositivas en el Opisthorchis viverrini (OV). Las células inmunopositivas aparecían solitarias y se distribuían simétricamente al eje longitudinal de la OV. Algunas estaban ubicadas en las proximidades de los órganos internos como el útero, ovarios, testículos, glándulas vitelinas e intestino. Las células inmunoteñidas extendían sus procesos horizontalmente u oblicuamente al eje longitudinal de la OV. Por microscopía inmunoelectrónica, las células inmunopositivas se caracterizaron por presentar mitocondrias intensamente teñidas, citoplasma con tinción débil e inmunonegatividad en núcleos pobres en cromatina. También se observó en las células, vacuolas de diversos tamaños sin inmunorreactividad. Se encontraron procesos celulares sin inmunorreactividad para cerrar finamente todas las superficies de las células y procesos, y se continuaron con los procesos de partición intersticiales que contenían núcleos y agregación de microfibrillas a cierta distancia de las envolturas citoplásmicas. El presente hallazgo sugiere la posibilidad de que las células inmunoteñidas son neuronas periféricas envueltas por glia periférica y que la glía presenta origen mesenquimal debido a su continuidad citoplasmática con los procesos de partición intersticiales. La naturaleza motora o sensorial de las neuronas aún no se ha dilucidado.

Infraestructura, ingreso y desnutrición infantil en México / Child malnutrition, infrastructure and income in Mexico

Objetivo. Explicar la variación de la desnutrición infantil (DI), entendida como baja talla para la edad (0 a 5 años) entre 1999 y 2006. Material y métodos. Se emplearon estimaciones estatales de DI y diversos indicadores que reflejan las probables causas subyacentes del fenómeno como la pobreza, el producto per cápita estatal, la educación de las mujeres y los accesos a infraestructura de salud y de drenaje. Para el análisis de datos se utilizaron los métodos de regresión con datos panel de efectos fijos y aleatorios. Resultados. Se encontró que la carencia de salud y drenaje, así como la pobreza, empeoran la DI, mientras que la educación de las mujeres la disminuye. Conclusiones. El estudio muestra que las variables de infraestructura explican en buena parte la variación reciente de la DI entre estados, y que el crecimiento económico no es una condición suficiente para reducir la DI.

Objective. Explain the variation in child malnutrition (CM), understood as low height for age (0 to 5 years old) for the period 1999-2006. Materials and methods. State estimations of child malnutrition and several indicators of subjacent probable causes of CM were employed, such as poverty indices, state product per capita, women scholar attainment and access to health and the sewage system. Panel data regression analysis with fixed and random effects were used to analyze the data. Results. The results indicate that the lack to access to health and sewage systems and poverty worsen CM, whereas women education helps to diminish CM. Conclusion. The study shows that infrastructure variables explain a significant part of the recent variation in DI across Mexican states, and that economic growth is not a sufficient condition to diminish DI.

Morphometrical analysis of the effect of nicotine administration on brain's prefrontal region in male rat / Análisis morfométrico del efecto de la administración de nicotina sobre la región prefrontal del cerebro en rata macho

Nicotine is the most important alkaloid compound in tobacco. One of the major effects of nicotine is stimulation of mesocorticolimbic system. Prefrontal cortex plays a pivotal role in personality and mental state. It is considered the main cause of addiction as it is located in mesocorticolimbic dopamine system. Twenty four male rats were divided into four groups based on nicotine administration dose (0, 0.5, 1 and 1.5 g/kg). After animals were anesthetized, their brains were fixed using transcardiac method. Tissue processing and Golgi staining were performed and the stained tissue sections were analyzed by optic microscope and Motic software. By increasing the dose, nicotine significantly decreased the number of neuronal processes. In the higher dose, nicotine caused a significant decrease and increase in the size of pericarions and dendritic spines, respectively (p<0.05). Nicotine administration can decrease the size of pericarion and number of dendritic spines in the prefrontal cortex.

La nicotina es el compuesto alcaloide más importante del tabaco. Uno de sus principales efectos es la estimulación del sistema mesocorticolímbico. La corteza prefrontal desempeña un papel fundamental en la personalidad y estado mental. Esta es considerada la principal causa de la adicción, ya que se encuentra en el sistema mesocorticolímbico dopaminérgico. Veinticuatro ratas macho fueron divididas en cuatro grupos basados en la dosis de administración de nicotina (0, 0,5, 1 y 1,5 g/kg). Luego fueron anestesiados y sus cerebros se fijaron mediante perfusión transcardíaca. Se realizó el procesamiento de tejidos y las secciones bajo tinción de Golgi fueron analizadas mediante microscopia óptica y el software Motic. Con el aumento de dosis, la nicotina redujo significativamente el número de procesos neuronales. En la dosis más alta, la nicotina causó una disminución y aumento significativo en el tamaño de pericarion y espinas dendríticas, respectivamente (p<0,05). La administración de nicotina puede disminuir el tamaño del pericarion y el número de espinas dendríticas en la corteza prefrontal.

Morphoquantitative study of the submucous plexus (of Meissner) of the jejunum-ileum of young and old guinea pigs / Estudo morfoquantitativo do plexo submucoso (de Meissner) do jejuno-íleo de cobaias jovens e velhas

OBJECTIVE: To study the aging of submucous plexus of the small intestine (jejunum-ileum) of the guinea pigs from the quantitative, structural and ultrastructural perspective. METHOD: Chemical preparations of membrane of the jejunum-ileum of old and young animals with the use of light and electronic microscope. RESULTS: The ganglia of young animals presented between 1 and 56 neurons and the old animals presented from 1 to 30 neurons. The mean density of the ganglia by cm² in the young jejunum-ileum was of 551±36.89 and in the old one 413±11.86. The density of the neurons was 5011±291.11 neurons/cm² average in young animals and 2918±120.70 neurons/cm² in the old ones. The size of the neurons varied in both age groups. The collagen fibers in the ganglia of old animals they were condensed. Degenerated mitochondrias in the interior of the cell were frequent in the old animals. CONCLUSION: In submucous plexus of the jejunum-ileum there is a loss of 38 percent of the neurons with aging.

OBJETIVO: Estudar o envelhecimento do plexo submucoso do intestino delgado (jejuno-íleo) das cobaias do ponto de vista quantitativo, estrutural e ultra-estrutural. MÉTODO: Preparados de membrana do jejuno-íleo de animais jovens e velhos com a utilização de microscopia de luz e eletrônica. RESULTADOS: Os gânglios de animais jovens apresentaram entre 1 e 56 neurônios e os animais velhos apresentaram de 1 a 30 neurônios. A densidade média dos gânglios por cm² no jejuno-íleo jovem foi de 551±36,89 e no velho foi de 413±11,86. A densidade dos neurônios foi de 5011±291,11 neurônios/cm² em média nos animais jovens e 2918±120,70 neurônios/cm² nos velhos. O tamanho dos neurônios variou em ambos os grupos etários. As fibras colágenas nos gânglios de animais velhos estavam mais condensadas. Mitocôndrias degeneradas no interior da célula foram freqüentes nos animais velhos. CONCLUSÃO: No plexo submucoso do jejuno-íleo há uma perda de 38 por cento dos neurônios com o envelhecimento.

Densidad neuronal en la corteza visual primaria (área 17), en dos especies de octodon / Neuronal density in primary visual cortex (17 visual area), in two species of octodon

Estudios experimentales demuestran que modificaciones medioambientales pueden producir alteraciones en el desarrollo normal de la corteza cerebral visual y sus conexiones. Por otra parte, es posible que en condiciones naturales, las especies animales hayan desarrollado adaptaciones genéticas a las distintas condiciones de luminosidad en que realizan su actividad. Recientemente, se han observado variaciones significativas en la densidad neuronal cortical del área 17 (área visual primaria), en roedores silvestres con diferentes períodos diarios de actividad y relación filogenética distante (Abrothrix olivaceus y Phyllotis darwini), pero aún no se ha determinado la naturaleza genética o plástica de dichas diferencias. En este trabajo se compararon especies con una mayor cercanía filogenética, para disminuir al máximo la variable taxonómica. Se estudió la corteza visual primaria (área 17), de roedores silvestres nativos, de las especies Octodon degus (n=5) y Octodon bridgesi (n=3), pertenecientes a la Familia Octodontidae, con el propósito de evidenciar cambios a través de la medición de la densidad neuronal, mediante la técnica del disector óptico, en cortes de 40 µm, incluidos en celoidina y teñidos con Nissl. Complementariamente, se realizó una cuantificación de la densidad neuronal de la corteza motora de las especies en estudio. O. degus, que presenta un período de actividad diurna, evidenció una densidad neuronal menor en la corteza visual (34,32 +/- 2,51 x 104 neuronas/mm3), que la observada en O. bridgesi (39,55 +/- 0,64 x 104 neuronas/mm3), especie de período de actividad nocturna; lo cual fue estadísticamente significativo (t=3,44; p<0,05). Las diferencias encontradas se podrían relacionar con el tipo de condiciones de luminosidad en que se desenvuelven dichas especies, aunque no se puede descartar la influencia de otros factores.

Studies show that environmental modifications can produce profound alterations in the normal development of the visual cortex and its connectivity. For the other hand it is possible that in natural conditions, animal species have developed genetic adaptations to the different conditions of luminance in which they normally behave. Recently have observed significant changes in cortical neuronal density of area 17 (primary visual area), in two sympatric Chilean rodents with different daily activity (Phyllotis darwini and Abrothrix olivaceus), but have not yet determined the genetic nature or plastic such differences. In this paper we compared species with a closer phylogenetic relation so as to minimize the taxonomic variable. We studied the primary visual cortex (area 17) of wild rodents native of the species Octodon degus (n=5) and Octodon bridgesi (n=3), belonging to the Octodontidae family, in order to show changes in the neuronal density, using celloidin-embedded, 40µm-thickness Nissl sections, with the aid of an optical dissector. In addition, we performed a quantification of the neuronal density of the motor cortex of the species under study. O. degus, bearing a crepuscular-diurnal activity pattern, showed a lower neuronal density in the visual cortex (34.32 +/- 2.51 x10(4) neuron/mm³) than that observed in O. bridgesi (39.55 +/- 0.64 x10(4) neuron/mm³), a species that exhibits a nocturnal phase preference, which was statistically significant (t=3.44; p<0.05). These differences might be related to differences in daily activity in two species, but we cannot discount the influence of other factors.

Ultrastructural changes of the olfactory bulb in manganese-treated mice

The effect of manganese toxicity on the ultrastructure of the olfactory bulb was evaluated. Male albino mice were injected intraperitoneally with MnCl2 (5 mg/Kg/day) five days per week during nine weeks. The control group received NaCl (0.9%). The olfactory bulbs of five mice from each group were processed for transmission electron microscopy after 2, 4, 6 and 9 weeks of manganese treatment. On week 2, some disorganization of the myelin sheaths was observed. After 4 weeks, degenerated neurons with dilated cisternae of rough endoplasmic reticulum and swollen mitochondria appeared. A certain degree of gliosis with a predominance of astrocytes with swollen mitochondria, disorganization of the endomembrane system, dilation of the perinuclear cisternae and irregularly shaped nuclei with abnormal chromatin distribution were observed after 6 weeks. Some glial cells showed disorganization of the Golgi apparatus. On week 9, an increase in the number of astrocytes, whose mitochondrial cristae were partially or totally erased, and a dilation of the rough endoplasmic reticulum were found. Neurons appear degenerated, with swollen mitochondria and a vacuolated, electron dense cytoplasm. These changes seem to indicate that the olfactory bulb is sensitive to the toxic effects of manganese.

Chronic stress effects on NPY neuronal population during rat development / Efectos del stress crónico sobre la población neuronal NPY durante el desarrollo de ratas

The aim of this work was to determine the chronical stress effects on the encephalic NPY neurons population during the fetal Central nervous system development. Immunocytochemical techniques were used for this purpose: NPY neurons presented a similar morphology during the gestation days studied but their distribution varied in the anterior, medium and posterior brain. Statistical Highly significant differences in number of NPY positive neurons (p<0.01) among anterior, medium and posterior brain of stressed fetus (SF) were determined depending on the gestation period and the brain area. The NPY neurons were increased in ARC (Arcuate Hypothalamic Nucleus), PH (Posterior Hypothalamic Area) and DM (Dorsomedial Hypothalamic Nucleus) in stressed fetuses (SF) of 17 days, and in ARC of 19 days SF (p< 0.01) were detected in the different brain nucleus. The NPY population increased in PnO (Pontine Reticular Nu, Oral Part) and RITg (Reticulotegmental Nu of the Pons) of 17 days SF, while they were detected in posterior brain at Pyx (Pyramidal Decussation), Rob (Raphe Obscurus Nucleus) and RPA (Raphe Pallidus Nucleus) in SF of 19 days. They also increased in number (p<0.05) in DPGI (Dorsal Paragigantocellular Nu), CGPn (Central Gray of Pons) and PrH (Prepositus Hypoglossal Nucleus) of 17 days SF. Finally, any statistical differences were found among CF and SF in the following nuclei: anterior brain, AH (Anterior Hypothalamic Nucleus), DM (Dorsomedia L Hypothalamic Nucleus) of 17 days; ME (Median Eminence)., VMH (Ventromedial Hypothalamic Nucleus) of 19 days; medium brain in CG (Central Periaqueductal Gray), DR (Dorsal Raphe Nucleus) of 17 days and posterior brain in PnC (Pontine Reticular Nu, Caudal Part), PrH (Prepositus Hypoglossal Nucleus), RMgG (Raphe Magnus Nucleus), IO (Inferior Olive) of 17 days. The increase number of NPY neurons found in the stressed rat fetuses in all periods studied would indicate the participation of the NPY System in...

El propósito del presente estudio fue determinar los efectos del estrés crónico en la población de neuronas NPY encefálicas durante el desarrollo del S.N.C. fetal mediante técnicas inmunocitoquímicas. Se demostró que las neuronas NPY presentan un morfología similar en los días de gestación estudiados, pero su distribución varía en el cerebro anterior, medio y posterior. Se comprobaron diferencias altamente significativas entre el cerebro anterior, medio y posterior (p<0,01) de fetos estresados (FE), variando dicha significación dependiendo del día de la gestación y del área estudiada. En los diferentes núcleos cerebrales del cerebro anterior se detectaron aumentos en ARC (Arcuate Hypothalamic Nucleus), PH (Posterior Hypothalamic Area) de 17 días y DM (Dorsomedia L Hypothalamic Nucleus) y en ARC (Arcuate Hypothalamic Nucleus) de 19días (p<0,01) de F.E. En el cerebro medio se detectaron aumentos en DR (Dorsal Raphe Nucleus) (p<0,01) y PN (Pontine Nucleus) (p<0,05) de 19 F.E. En el cerebro posterior se detectaron aumentos en PnO (Pontine Reticular Nu, Oral Part) y RITg (Reticulotegmental Nu of the Pons) de 17 F. E. y Pyx, (Pyramidal Decussation), Rob (Raphe Obscurus Nucleus) y RPA (Raphe Pallidus Nucleus) de 19 F.E. Asimismo se comprobaron aumentos (p<0,05) en DPGI (Dorsal Paragigantocellular Nu.) de 17 F.E, CGPn (Central Gray of Pons) y PrH (Prepositus Hypoglossal Nucleus), de 19 F.E. Finalmente, no se comprobaron diferencias entre F. C. (fetos controles) y F. E. en los siguientes núcleos del cerebro anterior: AH (Anterior Hypothalamic Nucleus), DM (Dorsomedia L Hypothalamic Nucleus), de 17 días; y EM, (Median Eminence), VMH (Ventromedial Hypothalamic Nucleus) de 19 días. En el cerebro medio CG, (Central Periaqueductal Gray), DR (Dorsal Raphe Nucleus) de 17 días. En el cerebro posterior el PnC, (Pontine Reticular Nu, Caudal Part), PrH (Prepositus Hypoglossal Nucleus), RMgG (Raphe Magnus Nucleus), IO (Inferior Olive) de 17 días del cerebro posterior...

Ultrastructural study of neuronal death in rat hippocampus after transient and permanent focal cerebral ischemia

Morphological changes of CA1 neurons in rat hippocampus after transient and permanent focal cerebral ischemia were studied to clarify the nature of postischemic cell death in the subfield. Male adult rats were divided into 3 groups: Control [Shamoperated], transient ischemic group [30 minutes of MCAO followed by 48 hours of reperfusion], and permanent ischemic group [48 hours of MCAO]. After the mentioned times, deep anesthesia was induced in the rats and their brains were removed and processed for transmission electron microscopy [TEM] and evaluation. Electron-microscopic examination on day 2 showed key morphological signs of apoptosis in the permanent ischemic group, while morphological signs of necrosis were observed in the transient ischemic group. These results suggest necrosis [as dominant mechanism of neuronal death after transient ischemia] and apoptosis [after permanent ischemia] to be involved in neuronal death

Inmunomarcación de neuronas dopaminérgicas en cortes flotantes de hipotálamo de rata: Preservación alternativa del tejido nervioso antes del corte / Immunohistochemical studies of dopaminergic neurons on free floating sections: Alternative cryopreservation method of nervous tissue before cutting

Se realizó un estudio inmunohistoquímico de la enzima tirosina hidroxilasa (marcador de neuronas dopaminérgicas) en el hipotálamo de ratas Wistar machos adultas en cortes flotantes de muestras fijadas por perfusión. Debido a que el número de cerebros que se procesaron fue superior al número que pueden ser cortados inmediatamente, el material debió almacenarse congelando los cerebrosenteros a -80ºC. Pero por un desperfecto técnico del equipo de refrigeración, las muestras debieron trasladarse a -20ºC resultando en el deterioro de las mismas. Ante este inconveniente, los sucesivos cerebros fueron almacenados en sacarosa al 30%p/v en buffer fosfato salino (PBS) con 0,01% de azida sódica y mantenidos a 4ºC durante tiempos variables (de semanas a meses) hasta ser congelados con gas clorofluorado y cortados. Estos cerebros no mostraron alteración en la estructura morfológica del tejido. Esta metodología de preservación aquí descrita sería una alternativa de elección válida para aquellos laboratorios que no cuenten con un equipo de refrigeración de -80ºC.

In central nervous system histological studies, free-floating sections of perfusion-fixed samples are frequently used. Samples storage may be performed freezing either the entire brain at -80ºC or sections at -20ºC. When studying hypothalamic tyrosine hydroxylase enzyme(dopaminergic neurons marker) by immunohistochemistry in adult male Wistar rats, entire brains were stored at -80ºC. Due to an abrupt freezer technical failure, samples should be thawed to -20ºC with the resulting samples damage. To avoid this situation, subsequent brains were stored in 30% sucrose in saline phosphate buffer (PBS) with 0.01% sodium azide and kept at 4ºC for different periods (weeks to months) until they were frozen with chlorofluorade gas and cut. These brains showed no morphological alterations of tissue structure. This preservation method appeared to be an alternative valid option to laboratories with no -80ºC freezing equipment.

Age and gender-related differences in mitral cells of olfactory bulb

To investigate the age and gender-related differences in mitral cells of the human cadaveric olfactory bulbs. A cross-sectional study. The study was conducted in the Department of Anatomy, University of Health Sciences, Lahore, from August 2005 to July 2007. Sixty olfactory bulbs, 30 each from male and female [age 20-76 years] human cadavers divided into six groups of age and gender-wise were collected from the mortuary of the King Edward Medical University, Lahore. Mitral cells were counted and their diameter was calculated from 10 m thick cresyl violet stained histological sections. Statistical analysis was done using ANOVA for age-related differences and independent t-test for gender-related differences. There was significant reduction in the number of mitral cells and diameter of their nuclei with age. There was significant decrease in the number of mitral cells in males, between groups I and II [p < 0.001]; II and III [p < 0.001]; and I and III [p < 0.001]; statistically significant decrease also occurred in females, between groups IV and V [p < 0.001]; V and VI [p < 0.001]; and IV and VI [p < 0.001]. In most cases, the distance between individual mitral cells was seen to be much greater than in younger group. In group VI, few mitral cells were observed in the cell layer. There was also significant decrease in the diameter of mitral cell nuclei in males, between groups I and III [p < 0.001]; and II and III [p < 0.010]; in females, between groups IV and VI [p < 0.001]; and V and VI [p < 0.001]. No gender-related differences were observed. The number of mitral cells and diameter of their nuclei decreased with advancing age

Dolor agudo postoperatorio: cómo el proceso quirúrgico induce neuroplasticidad / Accute postoperative pain: how the surgical process leads to neuroplasticity

El dolor agudo postoperatorio constituye un importante desafío para el anestesiólogo y un derecho para los pacientes. No obstante, en la actualidad éste continúa presente en un alto porcentaje de pacientes, a pesar de los esfuerzoz en la difusión de su evaluación y en el uso de diferentes terapias. una importante e interesante forma de cambiar estas cifras puede ser la investigación de la fisiopatología del dolor agudo postoperatorio y la difusión de los resultados. En los últimos años se ha profundizado en el conocimiento de la fisiopatología del dolor agudo postoperatorio, donde se ha determinado que existen cambios capaces de enfrentar la noxa quirúrgica, conocidos como neuroplasticidad, una de cuyas principales expresiones es el mecanismo de sensibilización. Se presenta a continuación una revisión de los principales mecanismos involucrados en el desarrollo y mantención de esta neuroplasticidad.

Accute postoperative pain is a great challenge for anesthesiologists and a right for patients. However, there is still an important percentage of patients with accute postoperative pain, despite all the efforts that have been made to divulge the existing evaluation methods and the use of different therapies. Research of physiopathology of accute postoperative pain might be a relevant and interesting way to change such percentage as well as the publication of the results from that research. In the last years, researchers have gained deeper knowledge in the field of physiopathology of accute postoperative pain and found there are some changes with the capacity to face the surgical noxa known as neuroplasticity, being one of the most important expressions the sensitizazation mechanism. A review of the most important mechanisms that play a part in the development and maintenance of this neuroplasticity is presented below.

Synaptic dimorphism in Onychophoran cephalic ganglia

The taxonomic location of the Onychophora has been controversial because of their phenotypic and genotypic characteristics, related to both annelids and arthropods. We analyzed the ultrastructure of the neurons and their synapses in the cephalic ganglion of a poorly known invertebrate, the velvet worm Peripatus sedgwicki, from the mountainous region of El Valle, Mérida, Venezuela. Cephalic ganglia were dissected, fixed and processed for transmission electron microscopy. The animal has a high degree of neurobiological development, as evidenced by the presence of asymmetric (excitatory) and symmetric (inhibitory) synapses, as well as the existence of glial cell processes in a wide neuropile zone. The postsynaptic terminals were seen to contain subsynaptic cisterns formed by membranes of smooth endoplasmic reticulum beneath the postsynaptic density, whereas the presynaptic terminal showed numerous electron transparent synaptic vesicles. From the neurophylogenetic perspectives, the ultrastructural characteristics of the central nervous tissue of the Onychophora show important evolutionary acquirements, such as the presence of both excitatory and inhibitory synapses, indicating functional synaptic transmission, and the appearance of mature glial cells.

Confocal laser scanning, conventional scanning and transmission electron microscopy of vertebrate cerebellar granule cells

Confocal laser scanning microscopy of hamster cerebellar granular layer showed in montages of z-series the presence of small, medium and large granule cells. A granule cell Golgi cell ratio of 50/4 was observed surrounding glomerular regions. Field emission high resolution scanning electron microscopy of mouse cerebellar granular and molecular layers showed SE-I images of the outer and inner surfaces of nuclear and cytoplasmic compartments of chromium coated granule cells and the axo-spinodendritic synapses of parallel fibers with Purkinje cell dendrites. Conventional scanning electron microscopy of teleost fish cerebellar cortex showed three dimensional morphology of granule cell soma and processes and the synaptic relationship with mossy and climbing fibers, Golgi cell axonal ramifications and dendrites of stellate neurons, by means of SE-II and SE-III signal image mode, in sagittally and transversally cryofractured cerebellar cortex. SE-II images of the non-synaptic segments and synaptic varicosities of parallel fiber outer surface were characterized in the molecular layer. Ultrathin sections of transmission electron microscopy (TEM) revealed somato-somatic, dendro-somatic and dendro-dendritic like-desmosomal and like-hemidesmosomal junctions in human cerebellar granule cells. Freeze-etching replicas of mouse cerebellar cortex displayed granule cell intramembrane morphology, cytoplasmic fractured face and the Bergman glial cell cytoplasm completely surrounding the parallel fibers in the molecular layer. The mossy fiber-granule cell dendrite synaptic relationship was observed in sagittally and transversally cryofractured cerebellar cortex and correlated with TEM images. SE-II images of the climbing fiber synaptic connections with granule cell dendrites were obtained in teleost fish cerebellar cortex. One to one axo-dendritic synaptic contacts between Golgi cell axonal ramifications and granule cell dendrites were also seen. The above findings provide new vistas for future studies dealing with intracortical circuits and information processing in the cerebellar cortex.

The 9-O-acetyl GD3 gangliosides are expressed by migrating chains of subventricular zone neurons in vitro

Neurons from the anterior subventricular zone (SVZ) of the cerebral cortex migrate tangentially to become interneurons in the olfactory bulb during development and in adult rodents. This migration was defined as neuronophilic, independent of a radial glial substrate. The cortical SVZ and the rostral migratory stream to the olfactory bulb were shown to be rich in 9-O-acetyl GD3 gangliosides (9-O-acGD3), which have been previously shown to be implicated in gliophilic migration in the rodent cerebral cortex and cerebellum. In the present study, we performed SVZ explant cultures using rats during their first postnatal week to analyze the expression of these gangliosides in chain migration of neuronal precursors. We characterized migrating chains of these neuroblasts through morphological analysis and immunocytochemistry for the neural cell adhesion molecule. By using the Jones monoclonal antibody which binds specifically to 9-O-acGD3 we showed that migrating chains from the SVZ explants express 9-O-acGD3 which is distributed in a punctate manner in individual cells. 9-O-acGD3 is also present in migrating chains that form in the absence of radial glia, typical of the neuronophilic chain migration of the SVZ. Our data indicate that 9-O-acetylated gangliosides may participate in neuronophilic as well as gliophilic migration

Correlative microscopy of cerebellar Golgi cells

The cerebellar Golgi cells of mouse, teleost fish, primate and human species have been studied by means of light and Golgi light microscopic techniques, confocal laser scanning microscopy, slicing technique, ethanol-cryofracturing and freeze-fracture methods for scanning electron microscopy and ultrathin sectioning and freeze-etching replicas for transmission electron microscopy. The Golgi cells appeared in the granular layer as polygonal, stellate, round or fusiform macroneurons surrounded by the granule cell groups. They exhibited ascending dendrites toward the molecular layer and horizontal dendrites and a short beaded axonal plexus confined to the granular layer. Scanning electron microscopy revealed their three-dimensional neuronal geometry and smooth outer surfaces. Freeze-fracture method for SEM showed the stereospatial cytoplasmic arrangement of endoplasmic reticulum, cell organelles and nuclear envelope. By means of transmission electron microscopy the asymmetric synaptic connections of Golgi cell horizontal dendrites--with mossy fiber rosettes at the cerebellar glomerulus--and of Golgi cell axons--with granule cell dendrites at the periphery of glomerular region--were identified. At the molecular layer, Golgi cell ascending dendrites exhibited short neckless spines establishing asymmetric contacts with granule cell axons or parallel fibers. Shaft asymmetric axodendritic and axospinodendritic contacts between Golgi cell dendrites and climbing fibers were also found in the molecular layer.

Studies on the intrinsic nervous system of the wild rodent Calomys callosus digestive tract. II. The submucous plexus

The submucous plexus of the normal small and large intestine of Calomys callosus was studied by NADH and AChE histochemical techniques and by transmission and scanning electron microscopy. The plexus contains (X + SD) 7,488 + 293 neurons/cm2 in the duodenum, 5,611 + 836 in the jejunum, 2,741 + 360 in the ileum, 3,067 + 179 in the cecum, and 3,817 + 256 in the proximal colon. No ganglia or nerve cell bodies were seen in the esophagus, stomach, distal colon or rectum. The neurons are pear-shaped with a round or oval nucleus and the neuronal cell profile areas were larger in the large intestine than in the small intestine. Most of the neurons display intense AChE activity in the cytoplasm. AChE-positive nerve fibers are present in a primary meshwork of large nerve bundles and in a secondary meshwork of finer nerve bundles. At the ultrastructural level, the ganglia are irregular in shape and covered with fibroblast-like cells. The nucleoplasm of the neurons is finely granular with a few condensations of chromatin attached to the nuclear envelope. In the neuropil numerous varicosities filled with vesicles of different size and electron densities are seen. The pre- and post-synaptic membrane thickenings are asymmetric. Characteristic glial cells with oval nuclei and few organelles are numerous. These data provide a detailed description of this submucosal meshwork.

Horizontal projections of area 17 in Cebus monkeys: metric features, and modular and laminar distribution

Metric features and modular and laminar distribution of intrinsic projections of area 17 were studied in Cebus apella. Anterogradely and retrogradely labeled cell appendages were obtained using both saturated pellets and iontophoretic injections of biocytin into the operculum. Laminar and modular distributions of the labeled processes were analyzed using Nissl counterstaining, and/or cytochrome oxidase and/or NADPH-diaphorase histochemistry. We distinguished three labeled cell types: pyramidal, star pyramidal and stellate cells located in supragranular cortical layers (principally in layers IIIa, IIIb alpha, IIIb beta and IIIc). Three distinct axon terminal morphologies were found i.e., Ia, Ib and II located in granular and supragranular layers. Both complete and partial segregation of group I axon terminals relative to the limits of the blobs of V 1 were found. The results are compatible with recente evidence of incomplete segreagation of visual information flow in V 1 of Old and New World primates.

Cambios en la excitibilidad neuronal y alteraciones en la densidad neuronal del hipocampo inducidos por isquemia focal / Changes in neuronal excitability and modifications in neural population of the hippocampus induce y focal ischemia

Despúes de un periodo de isquemia cerebral se observa aumento en la frecuencia de descarga neuronal de hipocampo y signos electroencefalográficos de actividad paroxística espontánea. Es probable que estos cambios en la excitabilidad se deban a mecanismos de excitotoxicidad que inducen muerte neuronal. En el presente estudio se evaluaron los cambios en la inhibición recurrente así como en la densidad neuronal del hipocampo de ratas sometidas a 5 y 20 min de isquemia focal con un periodo de recuperación de 7 días. El grado de inhibición recurrente se cuantificó mediante el índice de máxima inibición (IMI). La cuantificación neuronal se realizó a través de un sistema de procesamiento digital de imágenes (Imagenia 2000). Se observó aumento en la amplitud del segundo componente del segundo potencial provocado. Al calcular el IMI resultó mayor que 1. La mayor pérdida neuronal se observó en CA1 y CA2, mientras que la mayor vulnerabilidad se observó en el GD, CA3 y CA4. En conclusión, la isquemia focal con recuperación de 7 días provocó disminución en la densidad neuronal así como la aparición de un mecanismo de desinhibición, que condiciona cambios en la excitabilidad neuronal del hipocampo probablemente debido a lesión de interneuronas

Unilateral enucleation induces an increase of 160 kd neurofilament in lateral geniculate nuclei synapses

Ultrastructural synaptic changes of retinal origin in the pars dorsalis lateral geniculate nuclei (dLGN) after enucleation have been studied in this laboratory, showing a filamentous hypertrophy with maximal expression at 4-6 days post-lesion in monkeys (Pecci Saavedra et al., 1970, 1971). The aim of this work was to elucidate the nature of the newly formed filament in dLGN in post-enucleated rats. Male Wistar rats were fixed with 4 paraformaldehyde plus 0.25 glutaraldehyde in 0.1M phosphate buffer, through the abdominal aorta after 3, 5, and 7 days postenucleation. Sections obtained were incubated with antibodies to the phosphorylated portion of the 160 Kd neurofilaments (1:3000) and anti-GFAP (1:25000). There was an increase in 160 Kd neurofilament staining in axons and degenerating nerve endings in dLGN, as well as a typical astroglial immunostained reaction. Our results show that the newly formed neurofilaments after deafferentation are of the 160 Kd type, commonly present in normal axons.

Preliminary investigation about the effects of streptozotocin-induced chronic diabetes on the nerve cell number and size of myenteric ganglia in rat colon

Estudiamos el efecto de la diabetes mellitus crónica, inducida por estreptozotocina, en cuanto a los aspectos cuantitativos de las neuronas del plexo mientérico del colon proximal de ratas. Utilizamos cuatro grupos de animales: dos grupos de animales diabéticos (D2 y D8). En dos grupos D2 y D8, sacrificamos animales de dos y ocho meses, respectivamente, después de la inducción de diabetes; y los otros dos grupos C2 y C8, fueron mantenidos como control de los grupos anteriores. Retiramos el colon de las ratas y lo sometimos a cortes histológicos que fueron teñidos con Hematoxilina-Eosina. Se obtuvieron preparados de membrana teñidos con el método Giemsa y NADH-diaphorasa. Constatamos que la mayoría de las neuronas, tanto de animales diabéticos como no diabéticos, poseen núcleo excéntrico y que, por lo tanto, este hallazgo no es indicativo de proceso degenerativo. Verificamos que animales sacrificados dos meses después de la inducción de diabetes, no sufrieron reducción significativa en el número de neuronas por área, mientras que en animales sacrificados ocho meses después de la inducción de diabetes, presentaron reducción significativa en el número de neuronas por área, comparados con el grupo control