5-HT denervation of the adult rat prefrontal cortex induces changes in the expression of α4 and α7 nicotinic acetylcholine receptor subtypes.

INTRODUCTION: Nicotinic acetylcholine receptors (nAChRs) are widely expressed throughout several brain regions. Formation of the α4ß2 and α7 subtypes in particular is involved in the organisation of different types of memory. Furthermore, due to their location, these receptors can control the release of various types of neurotransmitters and contribute to synaptic plasticity. METHODS: Rats were divided into three groups, an experimental group (E), a sham-operated group, (S) and an intact group (T). In group E, stereotactic guidance was used to induce a chemical lesion with 1 µ/µL of 5,7-dihydroxytryptamine (5,7-DHT) in the anteroventral part of the dorsal raphe nucleus (DRN). In the sham-operated group (S), animals underwent surgery including delivery of the same excipient solution to the same site. The intact group (T) received no treatment whatsoever. Twenty days after surgery, animals in all groups were euthanised by decapitation to evaluate the expression of α4 and α7 nAChRs by means of molecular biology techniques. RESULTS: 5-HT denervation of the rat PFC differentially modified the expression of α4 and α7 receptors: while α4 receptor expression increased, α7 expression decreased. CONCLUSION: Expression differences observed between the two subtypes may be due to their separate locations. The α4 subtype is found in postsynaptic locations and may be related to adaptive changes in postsynaptic cells, while the location of α7 is presynaptic. This explains why the lesion and the elimination of 5-HT fibres in the CPF would cause a decrease in α7 expression.

Actin-binding proteins and signalling pathways associated with the formation and maintenance of dendritic spines.

INTRODUCTION: Dendritic spines are the main sites of excitatory synaptic contacts. Moreover, they present plastic responses to different stimuli present in synaptic activity or damage, ranging from an increase or decrease in their total number, to redistribution of progenitor dendritic spines, to variations in their size or shape. However, the spines can remain stable for a long time. BACKGROUND: The use of experimental models has shown that different molecules of the F-actin binding and signalling pathways are closely related to the development, maintenance and plasticity of excitatory synapses, which could affect the number, size and shape of the dendritic spines; these mechanisms affect and depend on the reorganisation of the actin cytoskeleton. DEVELOPMENT: It is proposed that the filopodia are precursors of dendritic spines. Drebrin is an F-actin binding protein, and it is responsible for concentrating F-actin and PSD-95 in filopodia that will guide the formation of the new spines. CONCLUSION: The specific mechanisms of actin regulation are an integral part in the formation, maturing process and plasticity of dendritic spines in association with the various actin cytoskeleton-binding proteins The signalling pathways mediated by small GTPases and the equilibrium between G-actin and F-actin are also involved.

[Expression of NMDA receptor subunits in rat prefrontal cortex with CCL4-induced hepatic damage after a treatment with Rosmarinus officinalis L]. / Expresión de las subunidades del receptor NMDA en la corteza prefrontal de la rata con daño hepático inducido con CCL4 después del tratamiento con Rosmarinus officinalis L.

INTRODUCTION: In cirrhosis some toxic substances accumulate in brain and modify the expression of several neuronal receptors. Thus, the use of medicinal plants such as Rosmarinus officinalis L. has been proposed in several pathologies due to its hepatoprotective, antioxidant and neuroprotective activity. In this study we evaluated the expression of the subunits NR1, NR2A and NR2B of the glutamate receptor in rat prefrontal cortex in a model of hepatic damage induced with carbon tetrachloride after a treatment with Rosmarinus officinalis L. METHODS: We used a total of 24 male Wistar rats weighing 80-90 g. body weight. We formed three study groups: control group (C) without a treatment, carbon tetrachloride group (CC14), and CC14 group plus Rosmarinus officinalis L (CCl4+ROM; 1.5 g/kg of extract orally). RESULTS: The expression of the NR1, NR2A and NR2B subunits in cirrhotic animals increased compared to the control group, however treatment with Rosmarinus officinalis L. was able to reduce this expression to normal levels compared with CC14 and CCl4+ROM groups. These results could be due to an improvement in hepatic function. CONCLUSION: Treatment with extract of Rosmarinus officinalis L. in cirrhotic animals modifies the expression of subunits of the NMDA receptor due to an improvement in hepatocellular function in the presence of antioxidant compounds and flavonoids.

Effects of the fluoride on the central nervous system.

INTRODUCTION: Fluoride (F) is a toxic and reactive element, and exposure to it passes almost unnoticed, with the consumption of tea, fish, meat, fruits, etcetera and articles of common use such as: toothpaste additives; dental gels, non-stick pans and razor blades as Teflon. It has also been used with the intention of reducing the dental cares. DEVELOPMENT: Fluoride can accumulate in the body, and it has been shown that continuous exposure to it causes damaging effects on body tissues, particularly the nervous system directly without any previous physical malformations. BACKGROUND: Several clinical and experimental studies have reported that the F induces changes in cerebral morphology and biochemistry that affect the neurological development of individuals as well as cognitive processes, such as learning and memory. F can be toxic by ingesting one part per million (ppm), and the effects they are not immediate, as they can take 20 years or more to become evident. CONCLUSION: The prolonged ingestion of F may cause significant damage to health and particularly to the nervous system. Therefore, it is important to be aware of this serious problem and avoid the use of toothpaste and items that contain F, particularly in children as they are more susceptible to the toxic effects of F.

La denervación 5-HTérgica córtico-frontal induce cambios en la expresión de las subunidades alfa 4 y alfa 7 de los receptores de acetilcolina tipo nicotínico en la corteza prefrontal de la rata adulta / 5-HT denervation of the adult rat prefrontal cortex induces changes in the expression of ¦Á4 and ¦Á7 nicotinic acetylcholine receptor subtypes

Introducción: Los receptores de la acetilcolina de tipo nicotínico (R-Ach-n) son expresados ampliamente en diferentes regiones del cerebro. Particularmente, la conformación de los subtipos α4β2 y la α7 ha sido involucrada con la organización de diferentes tipos de memoria. Además, debido a su localización, estos pueden controlar la liberación de diferentes tipos de neurotransmisores, así como su participación en la plasticidad sináptica. Métodos: Se conformaron 3 grupos de trabajo, un grupo experimental (E), un grupo control (C) y un grupo testigo (T). Al grupo E se le realizó la lesión farmacológica por vía estereotáxica en la región anteroventral del núcleo del rafe dorsal (NRD) con 1μ/μl de 5,7-dihidroxitriptamina. Al grupo C, se le sometió a cirugía y se le aplicó la solución vehículo y finalmente el grupo T no recibió ningún tratamiento; 20 días después de la cirugía, los animales de los 3 grupos fueron sacrificados por decapitación para el análisis de la expresión de las subunidades, α4 y α7 de los R-Ach-n mediante la técnica de biología molecular. Resultados: La denervación 5-HTérgica a la CPF de la rata modifica la expresión de los receptores α4 y α7 de manera diferencial. La expresión de las subunidades α4 se incrementa, mientras que las subunidades α7 disminuyen. Conclusión: Las diferencias de expresión que tuvieron las 2 subunidades podrían deberse a la localización que presentan. La subunidad α4 se localiza en sitios post sinápticos y podría estar relacionada con cambios post sinápticos adaptativos, en tanto que la de la α7 se localiza en sitios presinápticos, por lo que la lesión y eliminación de fibras 5-HTérgicas en la CPF provoca su disminución (AU)

Introduction: Nicotinic acetylcholine receptors (nAChRs) are widely expressed throughout several brain regions. Formation of the α4β2 and α7 subtypes in particular is involved in the organisation of different types of memory. Furthermore, due to their location, these receptors can control the release of various types of neurotransmitters and contribute to synaptic plasticity. Methods: Rats were divided into three groups, an experimental group (E), a sham-operated group, (S) and an intact group (T). In group E, stereotactic guidance was used to induce a chemical lesion with 1 μ/μL of 5,7-dihydroxytryptamine (5,7-DHT) in the anteroventral part of the dorsal raphe nucleus (DRN). In the sham-operated group (S), animals underwent surgery including delivery of the same excipient solution to the same site. The intact group (T) received no treatment whatsoever. Twenty days after surgery, animals in all groups were euthanised by decapitation to evaluate the expression of α4 and α7 nAChRs by means of molecular biology techniques. Results: 5-HT denervation of the rat PFC differentially modified the expression of α4 and α7 receptors: while α4 receptor expression increased, α7 expression decreased. Conclusion: Expression differences observed between the two subtypes may be due to their separate locations. The α4 subtype is found in postsynaptic locations and may be related to adaptive changes in postsynaptic cells, while the location of α7 is presynaptic. This explains why the lesion and the elimination of 5-HT fibres in the CPF would cause a decrease in α7 expression (AU)

Participación de las proteínas de unión a la actina y vías de señalización asociadas a la formación y mantenimiento de las espinas dendríticas / Actin-binding proteins and signalling pathways associated with the formation and maintenance of dendritic spines

Introducción: Las espinas dendríticas representan los principales sitios de contactos sinápticos de tipo excitador. Además, presentan respuestas plásticas a diferentes estímulos propios de la actividad sináptica o daño, que van de un aumento o disminución de su número total a una redistribución a lo largo de las dendritas progenitoras o variaciones en su tamaño o forma. Sin embargo, las espinas pueden permanecer estables durante tiempos largos. Fuentes: El uso de modelos experimentales ha reportado que distintas moléculas de unión a los F-actina y vías de señalización están estrechamente relacionadas con el desarrollo, el mantenimiento y la plasticidad de las sinapsis de tipo excitador, lo que podría influir en el número, tamaño y la forma de las espinas dendríticas; mecanismos que afectan y depende el reordenamiento del citoesqueleto de actina. Desarrollo: Se ha propuesto que los filopodios son los precursores de espinas dendríticas. Drebrina es una proteína de unión a los F-actina y es la responsable de concentrar los F-actina y PSD-95 en los filopodios que guiarán la formación de la nueva espina.Conclusiones: Los mecanismos específicos de regulación de la actina son parte integral en la formación, maduración y plasticidad de espinas dendríticas en correlación con diversas proteínas de unión al citoesqueleto de actina. Además, de las vías de señalización mediadas por pequeñas GTPasas, así como la relación entre la G-actina y F-actina (AU)

Introduction: Dendritic spines are the main sites of excitatory synaptic contacts. Moreover, they present plastic responses to different stimuli present in synaptic activity or damage, ranging from an increase or decrease in their total number, to redistribution of progenitor dendritic spines, to variations in their size or shape. However, the spines can remain stable for a long time. Background: The use of experimental models has shown that different molecules of the F-actin binding and signalling pathways are closely related to the development, maintenance and plasticity of excitatory synapses, which could affect the number, size and shape of the dendritic spines; these mechanisms affect and depend on the reorganisation of the actin cytoskeleton. Development: It is proposed that the filopodia are precursors of dendritic spines. Drebrin is an F-actin binding protein, and it is responsible for concentrating F-actin and PSD-95 in filopodia that will guide the formation of the new spines.Conclusion: The specific mechanisms of actin regulation are an integral part in the formation, maturing process and plasticity of dendritic spines in association with the various actin cytoskeleton-binding proteins The signalling pathways mediated by small GTPases and the equilibrium between G-actin and F-actin are also involved (AU)

Expresión de las subunidades del receptor NMDA en la corteza prefrontal de la rata con daño hepático inducido con CCL4 después del tratamiento con Rosmarinus officinalis L / Expression of NMDA receptor subunits in rat prefrontal cortex with CCL4-induced hepatic damage after a treatment with Rosmarinus officinalis L

Introduction: In cirrhosis some toxic substances accumulate in brain and modify the expression of several neuronal receptors. Thus, the use of medicinal plants such as Rosmarinus officinalis L. has been proposed in several pathologies due to its hepatoprotective, antioxidant and neuroprotective activity. In this study we evaluated the expression of the subunits NR1, NR2A and NR2B of the glutamate receptor in rat prefrontal cortex in a model of hepatic damage induced with carbon tetrachloride after a treatment with Rosmarinus officinalis L. Methods: We used a total of 24 male Wistar rats weighing 80-90g. body weight. We formed three study groups: control group (C) without a treatment, carbon tetrachloride group (CC14), and CC14 group plus Rosmarinus officinalis L (CCl4+ROM; 1.5g/kg of extract orally). Results:The expression of the NR1, NR2A and NR2B subunits in cirrhotic animals increased compared to the control group, however treatment with Rosmarinus officinalis L. was able to reduce this expression to normal levels compared with CC14 and CCl4+ROM groups. These results could be due to an improvement in hepatic function. Conclusion: Treatment with extract of Rosmarinus officinalis L. in cirrhotic animals modifies the expression of subunits of the NMDA receptor due to an improvement in hepatocellular function in the presence of antioxidant compounds and flavonoids (AU)

Introducción: En la cirrosis, algunas sustancias tóxicas se acumulan en el cerebro y alteran la expresión de diversos receptores neuronales. En este sentido, se ha propuesto el uso de plantas medicinales como el Rosmarinus officinalis L. en diversas patologías debido su actividad hepatoprotectora, antioxidante y neuroprotectora. En el presente trabajo se evaluó la expresión de las subunidades NR1, NR2A y NR2B del receptor a Glutamato en la corteza prefrontal de la rata en un modelo de daño hepático inducido con tetracloruro de carbono después del tratamiento con Rosmarinus officinalis L. Métodos: Se utilizaron un total de 24 ratas macho Wistar de 80-90g. de peso corporal. Se formaron 3 grupos de trabajo: grupo testigo (T) sin ningún tratamiento, grupo tetracloruro de carbono (CCl4) y grupo CCl4 más Rosmarinus officinalis L (CCl4 +ROM; 1.5g/kg del extracto por vía oral). Resultados: La expresión de las subunidades NR1, NR2A y NR2B incrementaron en los animales cirróticos con respecto al grupo T, sin embargo el tratamiento con Rosmarinus officinalis L fue capaz de disminuir la expresión a niveles normales comparados con los grupos de CCl4 y T. Estos resultados podrían deberse a una mejora en la función hepática. Conclusión: El tratamiento con el extracto de Rosmarinus officinalis L en los animales cirróticos modifica la expresión de las subunidades del receptor NMDA debido a la mejora en la función hepatocelular dada la presencia de compuestos antioxidantes y flavonoides (AU)

Efectos del flúor sobre el sistema nervioso central / Effects of the fluoride on the central nervous system

Introducción: El flúor (F) es un elemento tóxico y reactivo; la exposición al mismo pasa casiinadvertida con el consumo de té, pescado de mar, carnes, frutas, etc., y el uso de artículoscomo aditivo en pastas de dientes, enjuagues bucales, antiadherentes sobre sartenes y hojas deafeitar como el teflón. Asimismo, ha sido utilizado con la intención de reducir la caries dental.Desarrollo: El F puede acumularse en el organismo y se ha demostrado que la exposicióncrónica al mismo produce efectos nocivos sobre distintos tejidos del organismo y de maneraparticular sobre el sistema nervioso, sin producir malformaciones físicas previas.Fuentes: Diversos trabajos, tanto clínicos como experimentales, han reportado que el Fprovoca alteraciones sobre la morfología y bioquímica cerebral, que afectan el desarrollo neurológicode los individuos y, por ende, de funciones relacionadas con procesos cognoscitivos,tales como el aprendizaje y la memoria.Las toxicidad del F se puede presentar a partir de la ingesta de 1 parte por millón (ppm) ylos efectos no son inmediatos ya que pueden tardar 20 a˜nos o más en manifestarse.Conclusión: La ingesta prolongada de F provoca da˜nos a la salud y de manera importante sobreel sistema nervioso central, por lo que es importante considerar y evitar el uso de artículos quecontengan flúor y de manera particular en individuos en desarrollo, debido a la susceptibilidadque presentan a los efectos tóxicos del F (AU)

Introduction: Fluoride (F) is a toxic and reactive element, and exposure to it passes almostunnoticed, with the consumption of tea, fish, meat, fruits, etcetera and articles of commonuse such as: toothpaste additives; dental gels, non-stick pans and razor blades as Teflon. It hasalso been used with the intention of reducing the dental cares.Development: Fluoride can accumulate in the body, and it has been shown that continuousexposure to it causes damaging effects on body tissues, particularly the nervous system directlywithout any previous physical malformations.Background: Several clinical and experimental studies have reported that the F induces changesin cerebral morphology and biochemistry that affect the neurological development ofindividuals as well as cognitive processes, such as learning and memory. F can be toxic byingesting one part per million (ppm), and the effects they are not immediate, as they can take20 years or more to become evident.Conclusion: The prolonged ingestion of F may cause significant damage to health and particularlyto the nervous system. Therefore, it is important to be aware of this serious problem andavoid the use of toothpaste and items that contain F, particularly in children as they are moresusceptible to the toxic effects of F (AU)