Cholinergic system in CNS is involved in learning and memory. Scopolamine as muscarinic acetylcholine receptor antagonist is used for creation of memory impairment. The purpose of this study is evaluation of scopolamine-based amnesia on memory retention and the effect of this phenomenon on the number of neurons contains M1-receptors in the male Wistar rats hippocampal regions. Thirty-five male Wistar rats (200±20 g) were distributed randomly into five groups. Control group (intact samples) and 3 experimental groups with sham group (saline) were tested by the method of passive avoidance (shuttle box) in doses of 0.2, 0.5 and 1 mg/kg (intraperitoneally) as a single dose. After one week, memory test was taken from the rats. Finally, brains dissected from sacrificed rats, and then processed tissues were stained with antibody against M1 receptors (Immunohistochemistry technique) followed by counting of hippocampal CA1, CA3 and DG regions. Our results showed significant decrease in neurons contains M1-receptors in all area of hippocampus. We found that the less number of M1-neurons showed in 1 mg/kg dose of scopolamine. We concluded that scopolamine as muscarinic acetylcholine receptor antagonist can reduce dose-dependently the density of M1-neurons in all areas of hippocampus.

El sistema colinérgico en el SNC está implicado en el aprendizaje y la memoria. La escopolamina como receptor antagonista de acetilcolina muscarínico es utilizada para la creación del deterioro de la memoria. El propósito de este estudio es la evaluación de la amnesia basada en escopolamina sobre la retención de memoria y el efecto de este fenómeno en la cantidad de neuronas en receptores M1 en regiones del hipocampo en ratas macho Wistar. Se distribuyeron al azar, 35 ratas macho Wistar (200±20 g) en cinco grupos. El grupo de control (muestras intactas) y 3 grupos experimentales con grupo de tratamiento simulado (solución salina) analizadas por método de evasión pasiva (caja de transporte) en dosis de 0,2; 0,5 y 1 mg/kg (por vía intraperitoneal) como dosis única. Al término de una semana se realizó prueba de memoria de las ratas. Por último, los cerebros diseccionados de las ratas sacrificadas y los tejidos procesados fueron teñidos con anticuerpos contra los receptores M1 (técnica inmunohistoquímica), seguido por el recuento de regiones CA1, CA3 y DG del hipocampo. Nuestros resultados mostraron una disminución significativa en las neuronas con receptores M1 en toda el área del hipocampo. Se encontró que el número menor de neuronas M1, y fue demostrado en 1 mg/kg de dosis de escopolamina. Llegamos a la conclusión de que la escopolamina como antagonista del receptor de acetilcolina muscarínico puede, dependiendo de la dosis, reducir la densidad de neuronas M1 en todas las áreas del hipocampo.

Study of liquid behavior in an expanded bed adsorption (EBA) system is important for understanding, modeling and predicting nanobioproduct/biomolecule adsorption performance in such processes. In this work, in order to analyze the local axial dispersion parameters, simple custom NBG (Nano Biotechnology Group) expanded bed columns with 10 and 26 mm inner diameter were modified by insertion of sampling holes. Based on this configuration, the particles and liquid can be withdrawn directly from various axial positions of the columns. Streamline DEAE particles were used as solid phase in this work. The effects of factors such as liquid velocity, viscosity, settled bed height and column diameter on the hydrodynamic parameters were investigated. Local bed voidages in different axial bed positions were measured by a direct procedure within the column with 26 mm diameter. Increasing trend of voidage with velocity at a certain position of the bed and with bed height at a certain degree of expansion was observed. Residence time distribution (RTD) analysis at various bed points showed approximately uniform hydrodynamic behavior in the column with 10 mm diameter while a decreasing trend of mixing/dispersion along the bed height at a certain degree of expansion was seen in the column with 26 mm diameter. Also lower mixing/dispersion occured in the smaller diameter column. Finally, a combination of two empirical correlations proposed by Richardson-Zaki and Tong-Sun was successfully employed for identification of the bed voidage at various bed heights (RSSE=99.9%). Among the empirical correlations presented in the literatures for variation of the axial dispersion coefficient, the Yun correlation gave good agreement with our experimental data (RSSE=87%) in this column.

As neuronastrocyte interactions play a crucial role in the adult brain, it is thought that astrocytes support learning and memory through specific mechanisms. In this study, the effect of scopolamine based amnesia on the number of astrocytes in rats' hippocampus was studied. Adult male albino Wistar rats were bilaterally cannulated into the CA1 region and animals received saline or different doses of scopolamine (0.5, 1 and 2 mg/ rat, intra - CA1), immediately after training. Then all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with PTAH. The area densities of the astrocytes in dentate gyrus were measured and compared in the all groups (p < 0.05). Data showed that post-training scopolamine (0.5, 1 and 2 µg/rat, intra-CA1) dose-dependently reduced the step-through latency in the inhibitory avoidance task, showing scopolamine-induced amnesia. Also we found different response of astrocytes in different subfields of hippocampal formation. In dentate gyrus the number of astrocytes was increased, but in other areas scopolamine can decreased the density of astrocytes. We concluded that scopolamine can cause amnesia and this phenomenon can have an effect on astrocyte numbers in the rats hippocampal formation.

Las interacciones neuronas-astrocitos desempeñan un papel crucial en el cerebro adulto, y se cree que los astrocitos apoyan el aprendizaje y la memoria a través de mecanismos específicos. Fue estudiado el efecto de amnesia inducida por escopolamina en el número de astrocitos del hipocampo de ratas. Ratas Wistar albinas macho adultas fueron canuladas bilateralmente en la región CA1 recibiendo solución salina o diferentes dosis de escopolamina (0,5, 1 y 2mg/rata, intra - CA1), inmediatamente después del entrenamiento. Luego, todas las ratas se sacrificaron y se tomaron secciones coronales de la formación del hipocampo dorsal del hemisferio cerebral derecho y se tiñeron con PTAH. Las densidades de área de los astrocitos en el giro dentado fueron medidas y comparadas en todos los grupos (p <0,05). Los datos mostraron que la escopolamina (0,5, 1 y 2 mg / rata, intra-CA1) dosis-dependiente post-entrenamiento redujo el paso de latencia de la tarea de evitación inhibitoria, mostrando amnesia inducida por escopolamina. También encontramos diferentes respuestas de los astrocitos en los distintos subcampos de la formación hipocampal. En el giro dentado, el número de astrocitos se incrementó, pero en otras áreas la escopolamina pudo disminuir la densidad de los astrocitos. Se concluye que la escopolamina puede causar amnesia y este fenómeno puede afectar el número astrocitos en la formación hipocampal de ratas.

Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells.

La terapia de radiación cerebral está asociada con muchas consecuencias, incluyendo los trastornos cognitivos. La patogénesis del trastorno cognitivo inducido por la radiación no está claro, pero la reducción de la neurogénesis en el hipocampo puede ser una razón subyacente. Fueron etudiadas 24 ratas macho adultas. La dosis de radiación absorbida en el mesencéfalo fue de 10 Gy, proveniente de una máquina de radioterapia de cobalto con una salida de 115,24 cGy/min. Las ratas fueron divididas en cuatro grupos de seis ratas cada uno, incluyendo un grupo control, fracción única de 10 Gy, fraccionada de 10 Gy y finalmente el grupo de anestesia simulado. El número de células nerviosas piramidales se contó en dos regiones de la formación del hipocampo (CA1 y CA3). La radiación podría reducir significativamente (p = 0,000) el número de células en dos regiones del hipocampo . Al parecer, la radiacioón fraccionada de 10 Gy es más eficiente que la fracción única, mientras que el rol de la anestesia debe ser cuidadosamente evaluado. Por otra parte la tasa de reducción de la neurogénesis fue observada en las mismas regiones del hipocampo es decir, con la misma radiosensibilidad de las células.

Liquid fluidized/expanded bed adsorption (LF/EBA) is a novel chromatography technique for capturing target biomolecules directly from crude feedstock in downstream processing. To widely extend the LF/EBA technology in biological industries, a better understanding of the expanded-bed behavior is necessary to maximize its efficient applications. In this study, streamline adsorbent was loaded into the column and the bed was subjected to physical and hydrodynamical experiments. Hydrodynamic characteristics of the bed (e.g., Daxl and Bo) with different settled bed height (SBH=5,6,7,8,9,10,11,12cm) along with a variety of column diameters (1,1.6,2.5 cm) have been investigated based on exact mathematical as well as approximate short-cut methods. It was found that the increasing column diameter promoted bed mixing, which was undesirable, and the optimal values for the bed expansion and SBH based on minimal liquid mixing were 80%-130% and 8-10 cm, respectively. However, exploiting the short-cut method for the bed hydrodynamic assessments also demonstrated results as good as the mathematical method. Hydrodynamic behavior of liquid fluidized bed adsorption and the generic application of the short-cut method and its potential as a simple method for study of hydrodynamic performance is discussed.