Immunolocalization of estrogen receptor alpha in adult female rat hippocampus / Inmunolocalización del receptor de estrógeno alfa en el hipocampo de rata hembra adulta

The present study was planned to demonstrate the detailed immunoreactive (IR) distribution pattern of estrogen receptors (ER) in hippocampus of 15 female rats, adult, female Wistar rats in estrous phase. 30 µm thick setions of hippocampal region fixed (4 percent buffered paraformaldehyde) were obtained with cryostat. The sections were processed free- floating for immunolocalization of ER using, mouse monoclonal anti-ER-a antibody with PAP technique. The results showed presence of ER immunoreactive neurons in all the subfields of hippocampus with some variations. In cornua ammonis (CA) maximum ER positive (+ve) neurons were localized in CA3 region. Layer analysis showed maximum localization in the stratum oriens (SO) region. In other subfields and layers of CA the IR neurons were comparatively less in number. The morphological characters of all ER +ve neurons showed them to be interneurons both in CA as well as in Dentate gyrus (DG).

El estudio fue diseñado para demostrar el patrón de distribución inmunorreactivo (IR) detallado de los receptores estrogénicos (RE) en el hipocampo de 15 ratas Wistar, hembras, adultas, en fase de estro. Fueron obtenidas secciones 30 µm de grosor con un crióstato, de la región del hipocampo fijadas por perfusión (4 por ciento de paraformaldehído tamponado). Las secciones fueron procesadas, por libre flotación, para la inmunolocalización de RE utilizando anticuerpo monoclonal de ratón anti-ER-a con la técnica de PAP. Los resultados mostraron la presencia de neuronas inmunorreactivas ER en todos los subcampos del hipocampo con algunas variaciones. En el cuerno ventral (CA) la mayor zona RE positiva (+ ve) de las neuronas se localizaron en la región CA3. El análisis de las capas mostró la localización máxima en la región del estrato oriens (SO). En otros subcampos y capas de la CA las neuronas IR fueron comparativamente menores en número. Las características morfológicas de todas las neuronas RE + ve resultaron ser interneuronas tanto en el CA como en el giro dentado (DG).

Effects of tamoxifen on morphological and ultrastructural aspects of developing hippocampus of rat

Tamoxifen treatment induced cell death in the hippocampus formation of the prenatal and postnatal rat. The present study delineates the effect of tamoxifen on developing hippocampus in prenatal, postnatal and full term neonate rats received certain doses of the partial antagonist tamoxifen. After perfusion and fixation, the brains were removed and processed for light and electron microscopy. The morphology, ultrastructure and the density of the neurons in different ages [E22, P1, P7 and P21] and in different areas of developing hippocampus including cornu ammonis [CA1 and CA3], dentate gyrus and subiculum were studied. These findings showed that in tamoxifen-treated groups, the cell number of pyramidal neurons of CA1 and subiculum significantly decreased comparing to control groups in E22, P1 and P7 but not in third weeks. The mitochondria of the above mentioned groups also showed a dilated feature with less cristae than control group and most of them were greatly enlarged and swollen into spherical shapes rather than the normal ovoid or rod shape. The present study shows that prenatal exposure to tamoxifen alters neurogenesis in developing rat hippocampus. These results demonstrated the non-neuroprotective roles of tamoxifen

Effect of aspartame on the hippocampus of adult male albino rats histological and immunohistochemical study

Aspartame is an artificial sweetener used in more than 6,000 diet products, beverages, and pharmaceuticals. Aspartame had been the subject of controversy by many agencies regarding its safety and the circumstances of its approval. Was to evaluate the effect of aspartame on the hippocampus. Fifteen adult male albino rats were used. The rats were divided into 3 groups 5 animals each. Group I served as a control group. Group II was formed of the animals that received aspartame orally in a dose of 250 mg / kg / day for 2 months. Group III was formed of animals that received similar dose of the drug for 2 months and were left for recovery for 1 month. Specimens from hippocampus were processed for H and E, Golgi Cox, immunostaining for glial fibrillar acidic protein and electron microscopy. Sections obtained from animals of group II showed distortion and irregularity of some pyramidal cells of hippocampus. The nuclei appeared to be pyknotic. There was an increase in number of astrocytes showed by immunostain to glial fibrillar acidic protein. Electron microscopic study demonstrated cytoplasmic vacuoles and decreased number of ribosomes. Sections obtained from rats of group III showed slight improvement of the aspartame produced changes. Therefore it was concluded that consumption of aspartame had toxic effects on hippocampus of rats and one month of cessation was not sufficient to obtain a normal histological appearance of the hippocampus

Changes with age in the volume proportions of the hippocampal components

Stereological techniques were employed to examine changes with age in the volume proportions of different hippocampal components. The adult values were compared with those recorded in previous literatures. A significant decrease was observed in the volume proportions of the granular layer in the dorsal lip of dentate gyrus between two and five months of age. Comparing this results with the observed stability in the volume proportions of the granular layer in the whole dentate gyrus led to a conclusion that ventral lip of dentate gyrus showed a stage of increasing growth rate compared with the dorsal lip during this period of life. Stability of the volume proportions of dentate gyrus components was observed between five through to twenty-four months of age. An increase in the volume proportions of the pyramidal layer in the hippocampus between two and five months was attributed to an increase in the volume of the pyramidal neurons in this period. The dentate-to-Ammon's horn volume ratio showed a significant decrease between twelve and fourteen months which was suggested to reflect hippocampal functional change with ageing