Hippocampal serotonin-2A receptor-immunoreactive neurons density increases after testosterone therapy in the gonadectomized male mice / 대한해부학회지

The change of steroid levels may also exert different modulatory effects on the number and class of serotonin receptors present in the plasma membrane. The effects of chronic treatment of testosterone for anxiety were examined and expression of 5-HT(2A) serotonergic receptor, neuron, astrocyte, and dark neuron density in the hippocampus of gonadectomized male mice was determined. Thirty-six adult male NMRI mice were randomly divided into six groups: intact-no testosterone treatment (No T), gonadectomy (GDX)-No T, GDX-Vehicle, GDX-6.25 mg/kg testosterone (T), GDX-12.5 mg/kg T, and GDX-25 mg/kg T. Anxiety-related behavior was evaluated using elevated plus maze apparatus. The animals were anesthetized after 48 hours after behavioral testing, and decapitated and micron slices were prepared for immunohistochemical as well as histopathological assessment. Subcutaneous injection of testosterone (25 mg/kg) may induce anxiogenic-like behavior in male mice. In addition, immunohistochemical data reveal reduced expression of 5-HT(2A) serotonergic receptor after gonadectomy in all areas of the hippocampus. However, treatment with testosterone could increase the mean number of dark neurons as well as immunoreactive neurons in CA1 and CA3 area, dose dependently. The density of 5-HT(2A) receptor-immunoreactive neurons may play a crucial role in the induction of anxiety like behavior. As reduction in such receptor expression have shown to significantly enhance anxiety behaviors. However, replacement of testosterone dose dependently enhances the number of 5-HT(2A) receptor-immunoreactive neurons and interestingly also reduced anxiety like behaviors.

Dopamine receptors gene expression in male rat hippocampus after administration of MDMA (ecstasy) / La expresión génica de receptores de dopamina en el hipocampo de ratas macho después de la administración de MDMA (éxtasis)

Ecstasy is one of the most popular amusing drugs among young people. Documents indicate some effects of Ecstasy on hippocampus and close relations between dopaminergic functions with reward learning. Therefore, the aim of this study was evaluation of the chronic effects of Ecstasy on memory in male Wistar rats and determination of dopamine receptors' gene expression in hippocampus. Forty adult male Wistar rats randomly distributed in five groups: Control, sham (received 1 ml/kg 0.9% saline) and three experimental groups were: Exp. 1 (2.5 mg/kg), Exp. 2 (5 mg/kg), and Exp. 3 (10 mg/kg) received MDMA intraperitoneally once every 7 days (3 times a day, 3 hours apart) for 4 weeks. Before the first injection animals trained in Shuttle Box memory and tested after the last injection. 24 hours after the final testing, brains of rats were dissected and hippocampus was removed and homogenized. After total RNA extraction and cDNA synthesis, expression of dopamine receptor genes in the hippocampus determined with Real-Time PCR. Our results showed that 2.5 and 5 mg/kg MDMA-treated groups had memory impairment. Also we found that MDMA increased the mRNA expression of dopamine receptors in hippocampus and the highest increase found in dopamine D1 receptors in the 5 mg/kg experimental group. We concluded that low doses of Ecstasy could increase Dopamine takers gene expression in hippocampus and disorder avoidance memory. But in high doses the increase in Dopamine takers gene expression was not as much as that in low doses and avoidance memory disorder was not observed.

El éxtasis es una de las drogas de diversión más populares entre los jóvenes. La investigación reporta algunos de los efectos del éxtasis sobre el hipocampo y la relación entre las funciones dopaminérgicas con la recompensa en el aprendizaje. El objetivo de este estudio fue la evaluación de los efectos crónicos del éxtasis en la memoria de ratas macho Wistar y la determinación de la expresión de genes receptores de dopamina en el hipocampo. Cuarenta ratas macho adultas fueron distribuidas al azar en cinco grupos: grupo control, simulado (a 1 ml/kg 0,9% de solución salina) y tres grupos experimentales: Grupo exp. 1 (2,5 mg/kg), Exp. 2 (5 mg/kg), y Exp. 3 (10 mg/kg) recibió MDMA vía intraperitoneal cada 7 días (3 veces al día, con 3 horas de diferencia) durante 4 semanas. Antes de la primera inyección los animales fueron entrenados en memoria Shuttle Box y examinados después de la última inyección. Veinticuatro horas después de la prueba final, los cerebros de las ratas fueron diseccionados, el hipocampo fue separado y homogeneizado. Después de la extracción total de ARN y síntesis de ADNc, la expresión de genes de los receptores de dopamina en el hipocampo fue determinado con PCR en tiempo real. Nuestros resultados mostraron que los grupos de 2,5 kg y 5 mg/MDMA tratados tenían deterioro de la memoria. Además, encontramos que la MDMA aumentó la expresión de ARNm de los receptores de dopamina en el hipocampo y el aumento mayor se observó en los receptores D1 de dopamina en el 5 mg/kg Grupo experimental. En conclusión, las dosis bajas de éxtasis podrían aumentar tomadores de expresión génica de la dopamina en el hipocampo y trastornos de la memoria. Sin embargo, en dosis altas el aumento de la expresión génica no mostró un aumento significativo, a diferencia de los resultados con dosis bajas, tampoco se observaron trastornos disociativos de memoria.

Protective effects of Ginkgo biloba extract (EGB 761) on astrocytes of rat hippocampus after exposure with scopolamine / 대한해부학회지

The regular extract of Ginkgo biloba has been shown to possess neuroprotective properties in disorders like hypoxia, ischemia, seizure activity and peripheral nerve damage. Also, G. biloba has received attention as a potential cognitive enhancer for the treatment of Alzheimer's disease, but there is not any documentation about the effect of an extract of G. biloba on astrocytes. Therefore, the aim of this study was examined the effects of G. biloba extract on the rat's hippocampal astrocytes after scopolamine based amnesia. In this study, 36 adult male Wistar rats were used. Rats were randomly distributed into control, sham, protective and treatment groups. The rats in the sham group only received scopolamine hydrobromide (3 mg/kg) intraperitoneally. The rats in the protective and treatment groups received G. biloba extract (40, 80 mg/kg) for 7 days intraperitoneally before and after scopolamine injection. Forty eight hours after the last injection, the brains of the rats were withdrawn and fixed with paraformaldehide, and then after histological processing, the slices were stained with phosphotungstic acid-haematoxylin for astrocytes. Data were analyzed by the analysis of variance (ANOVA) post hoc Tukey test; P<0.05 was considered significant. Results showed that scopolamine can reduce the number of astrocytes in all areas of hippocampal formation compared with the control. However, G. biloba extract can compensate for the reduction in the number of astrocytes in the hippocampus before or after the encounter with scopolamine. We concluded that a pretreatment and treatment injection of G. biloba extract can have a protective effect for astrocytes in all areas of hippocampal formation.

Protective effects of Ginkgo biloba extract (EGB 761) on astrocytes of rat hippocampus after exposure with scopolamine / 대한해부학회지

The regular extract of Ginkgo biloba has been shown to possess neuroprotective properties in disorders like hypoxia, ischemia, seizure activity and peripheral nerve damage. Also, G. biloba has received attention as a potential cognitive enhancer for the treatment of Alzheimer's disease, but there is not any documentation about the effect of an extract of G. biloba on astrocytes. Therefore, the aim of this study was examined the effects of G. biloba extract on the rat's hippocampal astrocytes after scopolamine based amnesia. In this study, 36 adult male Wistar rats were used. Rats were randomly distributed into control, sham, protective and treatment groups. The rats in the sham group only received scopolamine hydrobromide (3 mg/kg) intraperitoneally. The rats in the protective and treatment groups received G. biloba extract (40, 80 mg/kg) for 7 days intraperitoneally before and after scopolamine injection. Forty eight hours after the last injection, the brains of the rats were withdrawn and fixed with paraformaldehide, and then after histological processing, the slices were stained with phosphotungstic acid-haematoxylin for astrocytes. Data were analyzed by the analysis of variance (ANOVA) post hoc Tukey test; P<0.05 was considered significant. Results showed that scopolamine can reduce the number of astrocytes in all areas of hippocampal formation compared with the control. However, G. biloba extract can compensate for the reduction in the number of astrocytes in the hippocampus before or after the encounter with scopolamine. We concluded that a pretreatment and treatment injection of G. biloba extract can have a protective effect for astrocytes in all areas of hippocampal formation.

effect of scopolamine on avoidance memory and hippocampal neurons in male wistar rats

Cholinergic systems are involved in learning and memory. Scopolamine, a muscarinic acetylcholine receptor antagonist, is used as a standard/ reference drug for inducing cognitive deficits in healthy humans and animals. The purpose of this study was to evaluate the effects of scopolamine on avoidance memory and number of neurons in rat's hippocampus. Thirty five male albino Wistar rats [200 +/- 20 g] were used in this study. The rats were divided randomly into five groups: control group [healthy samples], sham [saline] and 3 experimental groups 0.2, 0.5 and 1 mg/kg [intraperitoneally - single dose of Scopolamine]. Animals were tested by passive avoidance method [shuttle box]. After one week, a memory test was taken from rats. Finally, with dissection of the rats' brains and tissue operations, neurons were stained with cresyl violet. Photographs of the samples in hippocampal areas were prepared, and neurons were counted. Our results showed that the number of neurons in all experimental groups was lower than that in the control group. The highest decrease in number of neurons was shown in response to 1 mg/kg scopolamine compared to the control group in all regions of hippocampus. Also, we found that in comparison to the saline-treated animals, the injection of scopolamine to rats after training, caused memory destruction. We concluded that memory impairment-induced by scopolamine is probably associated with neuronal loss and this decrease was dose dependent

Acute effects of sulphur mustard gas on the number of lymphocytes in the rat's spleen / Efectos agudos del gas mostaza sobre el número de linfocitos en el bazo de rata

Sulphur mustard (SM), commonly known as mustard gas is an alkylating agent that causes serious blisters upon contact with human skin. SM is frequently used as a chemical warfare agent. There is some evidence for sulfur mustard-induced lymph system effects in humans. Between 2000-2001, 42 male albino Wistar rats were used. After accommodation with environment, we divided rats to control, sham and experimental groups (2.5 mg/kg, 5 mg/kg, 10 mg/kg, 20 mg/kg and 40 mg/kg). Then we injected sulphur mustard oil in rat's intraperitoneal space. Then their spleens were removed for histological verification. Our results showed that significant difference in lymphocytes number in experimental groups after 24 hours. The number of lymphocytes in 5, 10, 20 and 40 mg/kg groups was increased and this increase in 40 mg/kg group was more than the other groups. We concluded that the number of lymphocytes increased due to exposure of mustard gas and there is a relationship between the increase of lymphocytes and dose of exposure.

El sulfuro de mostaza (SM), comúnmente conocido como gas mostaza, es un agente alquilante que causa graves ampollas en contacto con la piel humana. SM se utiliza con frecuencia como un agente de guerra química. Hay algunas evidencias que indican que el SM induce efectos en el sistema linfático en seres humanos. Entre los años 2000-2001, fueron utilizadas 42 ratas albinas Wistar macho. Después de la acomodación con el medio ambiente, las ratas se dividieron en grupos control, impostor y experimental (2,5 mg / kg, 5 mg / kg, 10 mg / kg, 20 mg / kg y 40 mg / kg). Luego se inyectó aceite de SM en el espacio intraperitoneal de las ratas. A continuación, sus bazos fueron removidos para la verificación histológica. Los resultados mostraron una diferencia significativa en el número de linfocitos en el grupo experimental después de 24 horas. El número de linfocitos en los grupos de 5, 10, 20 y 40 mg / kg fue mayor siendo este incremento en el grupo de 40 mg / kg más alto que en los otros grupos. Concluimos que el número de linfocitos aumenta debido a la exposición de gas mostaza existiendo una relación entre el aumento de linfocitos y la dosis de exposición.

[ effect of reference memory on the number of astrocytes in different subfield of rat's hippocampus]

In addition to pyramidal neurons and interneurons, the hippocampus contains Astrocytes that play important roles in regulating ion flux currents, energy production, neurotransmitter release and memory. Learning needs some instrument for information storage and information maintenances mechanisms resemble to memory. The aim of this study was determination of spatial memory effect on the number of astrocytes in rat's hippocampus. In this experimental study, with usage of Morris Water Maze and Reference memory technique, we used 10 male albino wistar rats. 5 rats were in control group and 5 rats in Reference memory group. After histological preparation, the slides were stained with PTAH staining for showing the Astrocytes. The findings of this study showed significant difference in astrocytes number in CA1, CA2 and CA3 area of hippocampus between control and reference memory group. The mean and SD of astrocytes in CA1, CA2 and CA3 of reference memory group were 118.57 +/- 25.29, 58.91 +/- 23.59 and 116.6 +/- 31.14, that they are more than control group with 49 +/- 17.29 in CA1, 48.8 +/- 25.21 in CA2 and 41.95 +/- 11.22 in CA3. We concluded that the number of astrocytes increased due to spatial learning [e.g. reference memory method]

[ effect of spatial learning on the number of astrocytes in the rat's dentate gyrus]

Dentate gyrus is a part of hippocampal formation that plays an important role in memory and learning. Astrocytes are one of the important glial cells in nervous tissue that play a more active role in neuronal activity, including regulating ion flux currents, energy production, neurotransmitter release, and synaptogenesis. The aim of this study was to determine the spatial memory effect on the number of astrocytes in Rat's dentate gyrus. This experimental study, was done on 18 male Wistar Rats with using Morris water maze and Reference and Working memory methods. After spatial learning the Rat's brains was carried out and histological preparation was carried out, the slices were with PTAH method. The data analyzed, using T-test and One-way ANOVA. The results showed significant difference in astrocytes number in dentate gyrus area between Reference memory [300.57 +/- 5.98] and control [73.73 +/- 22.61] groups [P<0.05]. The difference between working memory [375.77 +/- 4.11] and control groups was significant. Comparing two groups there was a significant difference of number of astrocytes cell between the working memory and Reference memory group [P<0.05]. This study showed that spatial learning such as Reference memory and Working memory increase the number of astrocytes in dentate gyrus and this increase can be due to duration of learning