Post-traumatic stress disorder (PTSD) is a severe anxiety disorder affecting cognitive function. 1 in 4 individuals exposed to a life-threatening event may develop PTSD, which is characterised by symptoms of hyperarousal, avoidance and intrusions. Although treatment is effective in most cases, the response is far from satisfactory. It is now clear that novel drug treatment and a better understanding of the neurobiology of PTSD are necessary if we are to realise a better response and treatment outcome in these patients. Glutamatergic pathways play an important role in cognition, while recent studies have emphasized a causal role for glutamate in PTSD, and of the potential value of glutamate receptor modulators in treating the disorder. Stress-related elevation in glutamate exerts detrimental effects on cognition, especially via activation of the N-methyl-D-aspartate (NMDA) receptor, and has been implicated in PTSD associated cognitive deficits. Recently, the cr-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptor has been found to exert a modulatory action on NMDA receptor function. Ampakines are positive allosteric modulators of the AMPA receptor, and have demonstrated beneficial effects in animal models of learning as well as antidepressant action, and to improve short-term memory in humans. The aims of this study were firstly to study the effects of the ampakine, Org 26576, on spatial memory performance in healthy male Sprague-Dawley rats. Secondly, since PTSD is associated with pronounced deficits in cognition, we studied the ability of Org 26576 to modify stress-evoked spatial memory deficits in rats subjected to single prolonged stress (SPS), a putative animal model of PTSD. In both cases, neuroreceptor studies were performed to determine any relationship between hippocampal and cortical NMDA receptor binding characteristics and effects on spatial memory performance. After exposure of the animals to either normal handling or SPS conditions, spatial memory performance was assessed using a 5 day memory acquisition and consolidation protocol in a modified version of the Morris water maze (MWM). Experimental and control groups both received either saline (1 ml/kg i.p.) or Org 26576 at incremental doses of 1, 3 or 10 mg/kg intraperitoneally twice daily for 12 days. Separate groups of animals were used for the neuroreceptor studies, except that behavioural testing was not performed. 24hrs after drug treatment discontinuation, the animals were sacrificed and frontal cortex and hippocampus removed for NMDA receptor binding analysis. In normal rats, Org 26576 3 mg/kg and 10 mg/kg exerted a short-lasting reduction in escape latency on day 1, but which lost prominence over the subsequent training days. Org 26576 1, 3 and 10 mg/kg, however, significantly improved spatial memory retrieval on day 5. No changes in frontal cortical or hippocampal NMDA receptors were observed. Contrary to expected, rats subjected to SPS failed to express noteworthy deficits in spatial memory as previously described. Treatment of SPS-exposed animals with Org 26576 did not significantly alter spatial learning evident in SPS animals on day 1 of acquisition training, as well as on subsequent training days. Org 26576 1 mg/kg increased spatial memory retrieval compared to the unstressed saline control, but not compared to the SPS group. Org 26576 only at a dose of 1 mg/kg decreased cortical, but not hippocampal NMDA receptor density (Bmax) in SPS animals versus unstressed but not saline treated SPS animals. No changes in receptor affinity (Kd) were noted. Org 26576 therefore improves early initial spatial learning in healthy rats, but exerts a lesser effect on memory consolidation over the remainder of the training period. However, Org 26576 significantly improves retrieval of spatial memory without simultaneous changes in frontal cortical and hippocampal NMDA receptor binding. Org 26576 thus may benefit both short-term and long-term memory processes in normal animals without effects on limbic NMDA receptor binding, and provides a rationale for testing in conditions that present with cognitive disturbances. However, the SPS model failed to engender marked deficits in spatial memory performance; this result ultimately complicated the interpretation of the combined stress-drug treatment studies. Studies in healthy animals therefore conclude that Org 26576 is an effective agent to enhance long-term memory processes and should be investigated further for its possible application in disorders of cognition. Although the value of Org 26576 in an animal model of PTSD were inconclusive, further studies in SPS and other PTSD models, as well as models of relevance for schizophrenia, Alzheimer's disease and depression, are encouraged. / Thesis (M.Sc. (Pharmacology))--North-West University, Potchefstroom Campus, 2009.

Post-traumatic stress disorder (PTSD) is a severe anxiety disorder affecting cognitive function. 1 in 4 individuals exposed to a life-threatening event may develop PTSD, which is characterised by symptoms of hyperarousal, avoidance and intrusions. Although treatment is effective in most cases, the response is far from satisfactory. It is now clear that novel drug treatment and a better understanding of the neurobiology of PTSD are necessary if we are to realise a better response and treatment outcome in these patients. Glutamatergic pathways play an important role in cognition, while recent studies have emphasized a causal role for glutamate in PTSD, and of the potential value of glutamate receptor modulators in treating the disorder. Stress-related elevation in glutamate exerts detrimental effects on cognition, especially via activation of the N-methyl-D-aspartate (NMDA) receptor, and has been implicated in PTSD associated cognitive deficits. Recently, the cr-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptor has been found to exert a modulatory action on NMDA receptor function. Ampakines are positive allosteric modulators of the AMPA receptor, and have demonstrated beneficial effects in animal models of learning as well as antidepressant action, and to improve short-term memory in humans. The aims of this study were firstly to study the effects of the ampakine, Org 26576, on spatial memory performance in healthy male Sprague-Dawley rats. Secondly, since PTSD is associated with pronounced deficits in cognition, we studied the ability of Org 26576 to modify stress-evoked spatial memory deficits in rats subjected to single prolonged stress (SPS), a putative animal model of PTSD. In both cases, neuroreceptor studies were performed to determine any relationship between hippocampal and cortical NMDA receptor binding characteristics and effects on spatial memory performance. After exposure of the animals to either normal handling or SPS conditions, spatial memory performance was assessed using a 5 day memory acquisition and consolidation protocol in a modified version of the Morris water maze (MWM). Experimental and control groups both received either saline (1 ml/kg i.p.) or Org 26576 at incremental doses of 1, 3 or 10 mg/kg intraperitoneally twice daily for 12 days. Separate groups of animals were used for the neuroreceptor studies, except that behavioural testing was not performed. 24hrs after drug treatment discontinuation, the animals were sacrificed and frontal cortex and hippocampus removed for NMDA receptor binding analysis. In normal rats, Org 26576 3 mg/kg and 10 mg/kg exerted a short-lasting reduction in escape latency on day 1, but which lost prominence over the subsequent training days. Org 26576 1, 3 and 10 mg/kg, however, significantly improved spatial memory retrieval on day 5. No changes in frontal cortical or hippocampal NMDA receptors were observed. Contrary to expected, rats subjected to SPS failed to express noteworthy deficits in spatial memory as previously described. Treatment of SPS-exposed animals with Org 26576 did not significantly alter spatial learning evident in SPS animals on day 1 of acquisition training, as well as on subsequent training days. Org 26576 1 mg/kg increased spatial memory retrieval compared to the unstressed saline control, but not compared to the SPS group. Org 26576 only at a dose of 1 mg/kg decreased cortical, but not hippocampal NMDA receptor density (Bmax) in SPS animals versus unstressed but not saline treated SPS animals. No changes in receptor affinity (Kd) were noted. Org 26576 therefore improves early initial spatial learning in healthy rats, but exerts a lesser effect on memory consolidation over the remainder of the training period. However, Org 26576 significantly improves retrieval of spatial memory without simultaneous changes in frontal cortical and hippocampal NMDA receptor binding. Org 26576 thus may benefit both short-term and long-term memory processes in normal animals without effects on limbic NMDA receptor binding, and provides a rationale for testing in conditions that present with cognitive disturbances. However, the SPS model failed to engender marked deficits in spatial memory performance; this result ultimately complicated the interpretation of the combined stress-drug treatment studies. Studies in healthy animals therefore conclude that Org 26576 is an effective agent to enhance long-term memory processes and should be investigated further for its possible application in disorders of cognition. Although the value of Org 26576 in an animal model of PTSD were inconclusive, further studies in SPS and other PTSD models, as well as models of relevance for schizophrenia, Alzheimer's disease and depression, are encouraged. / Thesis (M.Sc. (Pharmacology))--North-West University, Potchefstroom Campus, 2009.

Com o aumento da expectativa de vida, estima-se um aumento na incidência de doenças neurodegenerativas, como a Doença de Alzheimer (DA). Vários processos fisiopatológicos interligados estão envolvidos tanto no processo do envelhecimento, quanto na etiologia das desordens neurodegenerativas, como por exemplo, o estresse oxidativo e a neuroinflamação. Têm sido descrito que mecanismos epigenéticos podem estar relacionados com o processo de envelhecimento, ocasionando modificações na expressão gênica em diferentes regiões do cérebro, como por exemplo, a acetilação de histonas que é responsável em parte, pela transcrição gênica, sendo esse processo controlado por duas enzimas, a histona acetiltransferase (HAT) e a histona desacetilase (HDAC). A HAT é responsável por ocasionar um relaxamento da cromatina e com isso uma maior acessibilidade para o processo de transcrição gênica enquanto que a HDAC causa uma maior compactação da cromatina, resultando uma supressão na transcrição gênica. Considerando o papel da acetilação de histonas no processo de envelhecimento, em especial em doenças neurodegenerativas, tem sido sugerido o uso de estratégias que aumentem a acetilação com finalidade neuroprotetora como, por exemplo, o uso de inibidores de HDAC. Diversos estudos demonstram que os inibidores da HDAC são capazes de melhorar as funções cognitivas e a formação de memória. Nesse contexto, a curcumina, um composto polifenólico encontrado no açafrão (Curcuma longa) tem demonstrado ser capaz de atuar sobre os mecanismos epigenéticos, sendo sugerido como um potente inibidor da HDAC. Assim, o objetivo desse trabalho foi investigar o tratamento agudo com extrato etanólico de Curcuma longa sobre a atividade da enzima histona desacetilase em estruturas cerebrais, hipocampo e córtex frontal, de ratos Wistar. Ratos Wistar machos adultos (3 e 20 meses de idade) foram aleatoriamente distribuídos nos seguintes grupos: salina, veículo (DMSO), extrato etanólico de Curcuma longa 10mg/Kg e 50mg/Kg. A atividade da histona desacetilase (HDAC) foi mensurada após 2 e 18 horas da administração, utilizando kit de ELISA específico. A ANOVA de três vias indicou um efeito do tempo (F(1,71)=4.238,p=0.044) após a administração do extrato etanólico de Curcuma longa e um efeito da idade em hipocampos (F(1,71) =10.430, p=0.002), ou seja, animais com 20 meses apresentaram atividade maior da HDAC quando comparados com os animais de 3 meses de idade. Em córtex frontal, a ANOVA de três vias indicou um efeito da idade (F(1,75)=4.438,p=0.039) e uma interação entre idade e tempo (F(1,75)=1.765,p=0.001). Em ambas as estruturas analisadas, não houve efeito da administração com extrato de Curcuma longa. Nossos resultados demonstram que a atividade da histona desacetilase foi aumentada em ambas as estruturas testadas de ratos com 20 meses de idade, sugerindo que no processo de envelhecimento cerebral ocorra uma redução na acetilação de histonas, o que pode reduzir a transcrição gênica. Além disso, a atividade da HDAC parece ser influenciada pelo ritmo circadiano, uma vez que houve um efeito do tempo nos níveis da atividade da HDAC em ambas as estruturas analisadas. A atividade da HDAC foi maior no tempo de 18 horas (correspondendo ao período da manhã) quando comparado ao tempo de 2 horas, que corresponde ao turno da tarde, este dado pode estar relacionado à cronobiologia, onde a organização circadiana permite que o organismo mantenha a homeostase em resposta a variações diárias decorrentes do ambiente externo e do próprio organismo. Cabe descrever que os ratos Wistar são notívagos, onde o período da manhã é o início do período de sono; assim poderíamos sugerir uma redução da acetilação e consequentemente uma redução na expressão gênica nesse período. / With the increase of life expectancy, an increase in the incidence of neurodegenerative diseases, for example, the Alzheimer‟s disease (AD),is estimated. Several interconnected pathophysiological processes are involved both in the aging process and neurodegenerative diseases, oxidative stress and neuroinflammation. It has been described that epigenetic alterations may be related to the aging process, causing changes in gene expression in different regions of the brain, such as, histone acetylation (HAT), and histones deacetylases (HDAT). The HAT is responsible for causing a relaxation of chromatin and, thus, a better accessibility to the process of gene transcription, while HDAC causes further compactation of chromatin, resulting in gene transcription suppression. Considering the role of histone acetylation in the aging process, especially in neurodegenerative diseases, it has been suggested the use of strategies to increase the acetylation with neuroprotective purposes, such as, for example, the use of HDAC inhibitors. Several studies have shown that HDAC inhibitors are capable of improving the cognitive functions and memory formation. In this context, curcumin, a polyphenolic compound found in turmeric (Curcuma longa) has been shown to be capable of acting on epigenetic mechanisms, being suggested as potent inhibitor of HDAC. The aim of this work was to investigate the effect of acute treatment with ethanol extract of Curcuma longa on the activity of histone deacetylases enzymes in brain structures, hippocampus and frontal cortex of Wistar rats. Male Wistar rats (3 and 20 months old) were randomly distributed into four groups: saline, vehicle (DMSO), Curcuma longa ethanol extract (10mg/kg and 50mg/Kg.) The histone deacetylase (HDAC) activity was measured 2 and 18 hours after administration, using specific ELISA kit. The three-way ANOVA showed a time effect (F(1,71)=4.238,p=0.044) after the administration of Curcuma longa ethanol extract and an age effect in hippocampus (F(1,71)=10.430,p=0.002), that is, 20-months Wistar rats presented a higher HDAC activity when compared to 3-months Wistar rats. In frontal cortex, the three-way ANOVA showed an age effect (F(1,75)=4.438,p=0.039) and an interaction between age and time (F(1,75)=1.765,p=0.001). In both structures, there was no effect of Curcuma longa extract administration. Our results show that the activity of histone deacetylase was increased in both structures of 20-months Wistar rats, suggesting that in the brain aging process it occurs a reduction in histone acetylation, which can reduce gene transcription. Furthermore, as there was a time effect on the levels of HDAC activity in both analyzed structures, the HDAC activity may be influenced by the circadian rhythm. The HDAC activity was higher in 18 – hour period (corresponding to the morning period) as compared to 2 - hour period (corresponding to the afternoon period). This finding may be related to chronobiology, in which the circadian organization allows the body to maintain homeostasis in response to daily changes arising from the external environment and the body itself. It is important to highlight that Wistar rats are nocturnal creatures, having the morning as the beginning of the sleep period. So, they can present a reduction in acetylation and a consequent reduction in gene expression during this period.

Com o aumento da expectativa de vida, estima-se um aumento na incidência de doenças neurodegenerativas, como a Doença de Alzheimer (DA). Vários processos fisiopatológicos interligados estão envolvidos tanto no processo do envelhecimento, quanto na etiologia das desordens neurodegenerativas, como por exemplo, o estresse oxidativo e a neuroinflamação. Têm sido descrito que mecanismos epigenéticos podem estar relacionados com o processo de envelhecimento, ocasionando modificações na expressão gênica em diferentes regiões do cérebro, como por exemplo, a acetilação de histonas que é responsável em parte, pela transcrição gênica, sendo esse processo controlado por duas enzimas, a histona acetiltransferase (HAT) e a histona desacetilase (HDAC). A HAT é responsável por ocasionar um relaxamento da cromatina e com isso uma maior acessibilidade para o processo de transcrição gênica enquanto que a HDAC causa uma maior compactação da cromatina, resultando uma supressão na transcrição gênica. Considerando o papel da acetilação de histonas no processo de envelhecimento, em especial em doenças neurodegenerativas, tem sido sugerido o uso de estratégias que aumentem a acetilação com finalidade neuroprotetora como, por exemplo, o uso de inibidores de HDAC. Diversos estudos demonstram que os inibidores da HDAC são capazes de melhorar as funções cognitivas e a formação de memória. Nesse contexto, a curcumina, um composto polifenólico encontrado no açafrão (Curcuma longa) tem demonstrado ser capaz de atuar sobre os mecanismos epigenéticos, sendo sugerido como um potente inibidor da HDAC. Assim, o objetivo desse trabalho foi investigar o tratamento agudo com extrato etanólico de Curcuma longa sobre a atividade da enzima histona desacetilase em estruturas cerebrais, hipocampo e córtex frontal, de ratos Wistar. Ratos Wistar machos adultos (3 e 20 meses de idade) foram aleatoriamente distribuídos nos seguintes grupos: salina, veículo (DMSO), extrato etanólico de Curcuma longa 10mg/Kg e 50mg/Kg. A atividade da histona desacetilase (HDAC) foi mensurada após 2 e 18 horas da administração, utilizando kit de ELISA específico. A ANOVA de três vias indicou um efeito do tempo (F(1,71)=4.238,p=0.044) após a administração do extrato etanólico de Curcuma longa e um efeito da idade em hipocampos (F(1,71) =10.430, p=0.002), ou seja, animais com 20 meses apresentaram atividade maior da HDAC quando comparados com os animais de 3 meses de idade. Em córtex frontal, a ANOVA de três vias indicou um efeito da idade (F(1,75)=4.438,p=0.039) e uma interação entre idade e tempo (F(1,75)=1.765,p=0.001). Em ambas as estruturas analisadas, não houve efeito da administração com extrato de Curcuma longa. Nossos resultados demonstram que a atividade da histona desacetilase foi aumentada em ambas as estruturas testadas de ratos com 20 meses de idade, sugerindo que no processo de envelhecimento cerebral ocorra uma redução na acetilação de histonas, o que pode reduzir a transcrição gênica. Além disso, a atividade da HDAC parece ser influenciada pelo ritmo circadiano, uma vez que houve um efeito do tempo nos níveis da atividade da HDAC em ambas as estruturas analisadas. A atividade da HDAC foi maior no tempo de 18 horas (correspondendo ao período da manhã) quando comparado ao tempo de 2 horas, que corresponde ao turno da tarde, este dado pode estar relacionado à cronobiologia, onde a organização circadiana permite que o organismo mantenha a homeostase em resposta a variações diárias decorrentes do ambiente externo e do próprio organismo. Cabe descrever que os ratos Wistar são notívagos, onde o período da manhã é o início do período de sono; assim poderíamos sugerir uma redução da acetilação e consequentemente uma redução na expressão gênica nesse período. / With the increase of life expectancy, an increase in the incidence of neurodegenerative diseases, for example, the Alzheimer‟s disease (AD),is estimated. Several interconnected pathophysiological processes are involved both in the aging process and neurodegenerative diseases, oxidative stress and neuroinflammation. It has been described that epigenetic alterations may be related to the aging process, causing changes in gene expression in different regions of the brain, such as, histone acetylation (HAT), and histones deacetylases (HDAT). The HAT is responsible for causing a relaxation of chromatin and, thus, a better accessibility to the process of gene transcription, while HDAC causes further compactation of chromatin, resulting in gene transcription suppression. Considering the role of histone acetylation in the aging process, especially in neurodegenerative diseases, it has been suggested the use of strategies to increase the acetylation with neuroprotective purposes, such as, for example, the use of HDAC inhibitors. Several studies have shown that HDAC inhibitors are capable of improving the cognitive functions and memory formation. In this context, curcumin, a polyphenolic compound found in turmeric (Curcuma longa) has been shown to be capable of acting on epigenetic mechanisms, being suggested as potent inhibitor of HDAC. The aim of this work was to investigate the effect of acute treatment with ethanol extract of Curcuma longa on the activity of histone deacetylases enzymes in brain structures, hippocampus and frontal cortex of Wistar rats. Male Wistar rats (3 and 20 months old) were randomly distributed into four groups: saline, vehicle (DMSO), Curcuma longa ethanol extract (10mg/kg and 50mg/Kg.) The histone deacetylase (HDAC) activity was measured 2 and 18 hours after administration, using specific ELISA kit. The three-way ANOVA showed a time effect (F(1,71)=4.238,p=0.044) after the administration of Curcuma longa ethanol extract and an age effect in hippocampus (F(1,71)=10.430,p=0.002), that is, 20-months Wistar rats presented a higher HDAC activity when compared to 3-months Wistar rats. In frontal cortex, the three-way ANOVA showed an age effect (F(1,75)=4.438,p=0.039) and an interaction between age and time (F(1,75)=1.765,p=0.001). In both structures, there was no effect of Curcuma longa extract administration. Our results show that the activity of histone deacetylase was increased in both structures of 20-months Wistar rats, suggesting that in the brain aging process it occurs a reduction in histone acetylation, which can reduce gene transcription. Furthermore, as there was a time effect on the levels of HDAC activity in both analyzed structures, the HDAC activity may be influenced by the circadian rhythm. The HDAC activity was higher in 18 – hour period (corresponding to the morning period) as compared to 2 - hour period (corresponding to the afternoon period). This finding may be related to chronobiology, in which the circadian organization allows the body to maintain homeostasis in response to daily changes arising from the external environment and the body itself. It is important to highlight that Wistar rats are nocturnal creatures, having the morning as the beginning of the sleep period. So, they can present a reduction in acetylation and a consequent reduction in gene expression during this period.

O estrógeno é importante para o desenvolvimento de redes neuronais. Assim, investigamos mecanismos celulares relacionados à neuroproteção, através da sinalização rápida mediada pelo GPER-1 em cultura mistas e enriquecida de neurônios submetidas ou não à privação de glicose/oxigênio (PGO). Mostramos que as células corticais em cultura expressam o receptor GPER-1 e esta marcação encontra-se dispersa tanto no citosol como no núcleo. Nossos resultados mostraram que a proteção, via sinalização estrogênica, foi dependente da composição celular. A ausência da sinalização via GPER-1 previamente à PGO aumentou a morte celular induzida pela PGO, sugerindo que o bloqueio desta sinalização via GPER-1 pode estar relacionado ao pior prognóstico de lesões isquêmicas, e a suplementação com G1 no meio de cultura durante a privação e reperfusão atenuaram estes efeitos. Além disso, nossos resultados apontam para a influência das células da glia como mediadores do papel neuroprotetor, via sinalização estrogênica não-nuclear, neste contexto de privação de glicose/oxigênio. / Estrogen is important to the development of neural networks. Thus, we investigated the cellular mechanisms related to neuroprotection through the rapid signaling mediated by GPER-1 in mixed culture and enriched neurons submitted or not to glucose/oxygen deprivation (OGD). We showed that cortical cell cultures express GPER-1 receptor and this are dispersed both in the cytosol and the nucleus. Our results showed that protection via estrogen signaling was dependent on the cellular composition. The lack of a signaling pathway GPER-1 before OGD increased cell death induced by OGD, suggesting that blocking of GPER-1 signaling pathway could be related to poor prognosis of ischemic lesions and G1 supplementation of culture media during deprivation and reperfusion attenuated these effects. In addition, our results point to the influence of glial cells as mediators of the neuroprotective role via non-nuclear estrogen signaling in this context of glucose/oxygen deprivation.

Com o aumento da expectativa de vida, estima-se um aumento na incidência de doenças neurodegenerativas, como a Doença de Alzheimer (DA). Vários processos fisiopatológicos interligados estão envolvidos tanto no processo do envelhecimento, quanto na etiologia das desordens neurodegenerativas, como por exemplo, o estresse oxidativo e a neuroinflamação. Têm sido descrito que mecanismos epigenéticos podem estar relacionados com o processo de envelhecimento, ocasionando modificações na expressão gênica em diferentes regiões do cérebro, como por exemplo, a acetilação de histonas que é responsável em parte, pela transcrição gênica, sendo esse processo controlado por duas enzimas, a histona acetiltransferase (HAT) e a histona desacetilase (HDAC). A HAT é responsável por ocasionar um relaxamento da cromatina e com isso uma maior acessibilidade para o processo de transcrição gênica enquanto que a HDAC causa uma maior compactação da cromatina, resultando uma supressão na transcrição gênica. Considerando o papel da acetilação de histonas no processo de envelhecimento, em especial em doenças neurodegenerativas, tem sido sugerido o uso de estratégias que aumentem a acetilação com finalidade neuroprotetora como, por exemplo, o uso de inibidores de HDAC. Diversos estudos demonstram que os inibidores da HDAC são capazes de melhorar as funções cognitivas e a formação de memória. Nesse contexto, a curcumina, um composto polifenólico encontrado no açafrão (Curcuma longa) tem demonstrado ser capaz de atuar sobre os mecanismos epigenéticos, sendo sugerido como um potente inibidor da HDAC. Assim, o objetivo desse trabalho foi investigar o tratamento agudo com extrato etanólico de Curcuma longa sobre a atividade da enzima histona desacetilase em estruturas cerebrais, hipocampo e córtex frontal, de ratos Wistar. Ratos Wistar machos adultos (3 e 20 meses de idade) foram aleatoriamente distribuídos nos seguintes grupos: salina, veículo (DMSO), extrato etanólico de Curcuma longa 10mg/Kg e 50mg/Kg. A atividade da histona desacetilase (HDAC) foi mensurada após 2 e 18 horas da administração, utilizando kit de ELISA específico. A ANOVA de três vias indicou um efeito do tempo (F(1,71)=4.238,p=0.044) após a administração do extrato etanólico de Curcuma longa e um efeito da idade em hipocampos (F(1,71) =10.430, p=0.002), ou seja, animais com 20 meses apresentaram atividade maior da HDAC quando comparados com os animais de 3 meses de idade. Em córtex frontal, a ANOVA de três vias indicou um efeito da idade (F(1,75)=4.438,p=0.039) e uma interação entre idade e tempo (F(1,75)=1.765,p=0.001). Em ambas as estruturas analisadas, não houve efeito da administração com extrato de Curcuma longa. Nossos resultados demonstram que a atividade da histona desacetilase foi aumentada em ambas as estruturas testadas de ratos com 20 meses de idade, sugerindo que no processo de envelhecimento cerebral ocorra uma redução na acetilação de histonas, o que pode reduzir a transcrição gênica. Além disso, a atividade da HDAC parece ser influenciada pelo ritmo circadiano, uma vez que houve um efeito do tempo nos níveis da atividade da HDAC em ambas as estruturas analisadas. A atividade da HDAC foi maior no tempo de 18 horas (correspondendo ao período da manhã) quando comparado ao tempo de 2 horas, que corresponde ao turno da tarde, este dado pode estar relacionado à cronobiologia, onde a organização circadiana permite que o organismo mantenha a homeostase em resposta a variações diárias decorrentes do ambiente externo e do próprio organismo. Cabe descrever que os ratos Wistar são notívagos, onde o período da manhã é o início do período de sono; assim poderíamos sugerir uma redução da acetilação e consequentemente uma redução na expressão gênica nesse período. / With the increase of life expectancy, an increase in the incidence of neurodegenerative diseases, for example, the Alzheimer‟s disease (AD),is estimated. Several interconnected pathophysiological processes are involved both in the aging process and neurodegenerative diseases, oxidative stress and neuroinflammation. It has been described that epigenetic alterations may be related to the aging process, causing changes in gene expression in different regions of the brain, such as, histone acetylation (HAT), and histones deacetylases (HDAT). The HAT is responsible for causing a relaxation of chromatin and, thus, a better accessibility to the process of gene transcription, while HDAC causes further compactation of chromatin, resulting in gene transcription suppression. Considering the role of histone acetylation in the aging process, especially in neurodegenerative diseases, it has been suggested the use of strategies to increase the acetylation with neuroprotective purposes, such as, for example, the use of HDAC inhibitors. Several studies have shown that HDAC inhibitors are capable of improving the cognitive functions and memory formation. In this context, curcumin, a polyphenolic compound found in turmeric (Curcuma longa) has been shown to be capable of acting on epigenetic mechanisms, being suggested as potent inhibitor of HDAC. The aim of this work was to investigate the effect of acute treatment with ethanol extract of Curcuma longa on the activity of histone deacetylases enzymes in brain structures, hippocampus and frontal cortex of Wistar rats. Male Wistar rats (3 and 20 months old) were randomly distributed into four groups: saline, vehicle (DMSO), Curcuma longa ethanol extract (10mg/kg and 50mg/Kg.) The histone deacetylase (HDAC) activity was measured 2 and 18 hours after administration, using specific ELISA kit. The three-way ANOVA showed a time effect (F(1,71)=4.238,p=0.044) after the administration of Curcuma longa ethanol extract and an age effect in hippocampus (F(1,71)=10.430,p=0.002), that is, 20-months Wistar rats presented a higher HDAC activity when compared to 3-months Wistar rats. In frontal cortex, the three-way ANOVA showed an age effect (F(1,75)=4.438,p=0.039) and an interaction between age and time (F(1,75)=1.765,p=0.001). In both structures, there was no effect of Curcuma longa extract administration. Our results show that the activity of histone deacetylase was increased in both structures of 20-months Wistar rats, suggesting that in the brain aging process it occurs a reduction in histone acetylation, which can reduce gene transcription. Furthermore, as there was a time effect on the levels of HDAC activity in both analyzed structures, the HDAC activity may be influenced by the circadian rhythm. The HDAC activity was higher in 18 – hour period (corresponding to the morning period) as compared to 2 - hour period (corresponding to the afternoon period). This finding may be related to chronobiology, in which the circadian organization allows the body to maintain homeostasis in response to daily changes arising from the external environment and the body itself. It is important to highlight that Wistar rats are nocturnal creatures, having the morning as the beginning of the sleep period. So, they can present a reduction in acetylation and a consequent reduction in gene expression during this period.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho, estudos comportamentais, farmacolÃgicos e neuroquÃmicos em Ãreas cerebrais foram realizados em animais adultos (2 meses de idade) que apresentaram convulsÃo e estado epilÃptico (EP), atravÃs da administraÃÃo de pilocarpina 400mg/kg, s.c., P400, com a finalidade de investigar os mecanismos envolvidos durante a fase aguda (1 e 24h) do processo convulsivo. Os estudos comportamentais em animais mostraram que a administraÃÃo de P400 produziu sinais colinÃrgicos perifÃricos (SCP) e movimentos estereotipados (ME) em todos os animais em ambos os perÃodos de observaÃÃo. Os animais observados por 1h apresentaram parÃmetros comportamentais semelhantes ao grupo de 24h, somente o Ãndice de desenvolvimento de convulsÃes, EP, foi um pouco menor, e nÃo houve nenhuma morte. Os estudos farmacolÃgicos com antagonista colinÃrgico bloqueou todos os parÃmetros comportamentais observados. Das drogas gabaÃrgicas, os antagonistas dopaminÃrgico e glutamatÃrgico apresentaram melhor resultado, aumentado a latÃncia da primeira convulsÃo (LC), a latÃncia do EP (LEP) e reduzindo o nÃmero de mortes. Os antagonistas dopaminÃrgico D2, o opÃide, os antidepressivos e o agonista dopaminÃrgico reduziram a LC, LEP e aumentou o nÃmero de mortes, enquanto o antipsicÃtico testado aumentou a LC, a LEP e reduziu as mortes. O lÃtio potencializou os efietos da pilocarpina aumentado o nÃmero de mortes e reduzindo a LC e a LEP. Os estudos neuroquÃmicos revelaram que a atividade da acetilcolinesterase no hipocampo, cÃrtex frontal (CF) e corpo estriado dos animais sofreu uma reduÃÃo significativa apenas na primeira hora da fase aguda, enquanto que no perÃodo de 24h de observaÃÃo a atividade enzimÃtica praticamente se normalizou. O nÃvel de lipÃdio peroxidaÃÃo e o conteÃdo de nitrito e nitrato aumentaram, enquanto que, a concentraÃÃo de GSH diminui nos dois perÃodos do estudo nas Ãreas investigadas. A atividade da SOD aumentou durante 1h em todas a Ãreas. Por sua vez, no perÃodo de 24h aumentou apenas no CF. Na atividade da catalase em ambos os perÃodos e nas Ãreas estudadas verificou-se um aumento significativo. Estudos sobre a densidade mÃxima (Bmax) dos receptores colinÃrgicos muscarÃnicos (M1 e M2) e dopaminÃrgicos (D1 e D2) nas Ãreas analisadas durante 1 e 24h de observaÃÃo foram diminuÃdos e nÃo alterados, respectivamente. Em relaÃÃo aos receptores serotonÃrgicos (5-HT2) nÃo foi verificado alteraÃÃo no Bmax apÃs 1 e 24h de observaÃÃo, nas trÃs Ãreas estudadas. Nas trÃs Ãreas estudadas observou-se um aumento e uma diminuiÃÃo no Bmax dos receptores glutamatÃrgicos e GABAÃrgicos, respectivamente. O P400 alterou de forma diversificada a constante de dissociaÃÃo (Kd) dos receptores M1, M2, D1, D2, 5-HT2, GABAÃrgicos e glutamatÃrgicos nos animais que apresentaram convulsÃo, EP e que foram sacrificados 1 e 24 h depois do tratamento. Na determinaÃÃo de monoaminas e seus metabÃlitos com HPLC, o P400 alterou a concentraÃÃo de DA, DOPAC e HVA, bem como da NA e da 5-HT e seu metabÃlito o 5-HIAA nas diferentes regiÃes do cÃrebro apÃs 1 e 24 h de observaÃÃo. Nos experimentos de determinaÃÃo do conteÃdo dos aminoÃcidos com HPLC, o P400 alterou a concentraÃÃo de (glutamato) GLU estriatal, (glutamina) GLN hipocampal, (aspartato) ASP cortical e nÃo modificou o conteÃdo de tirosina com 1h nas trÃs Ãreas estudadas. JÃ com 24 horas de observaÃÃo nÃo houve alteraÃÃo em nenhuma das Ãreas nos aminoÃcidos GLU, GLN e ASP, mas o conteÃdo de tirosina aumentou de forma significativa nas Ãreas investigadas. / The present study was aimed at investigating behavioural and neurochemical alterations in brain areas of adults rat (2-month-old) which presented seizures and status epilepticus (SE) after treatment with a single dose of pilocarpine (400mg/kg, s.c., P400) in order to clarify the mechanisms of the acute phase in the convulsive process (1 and 24h). Behavioural studies have demonstrated that the P400 administration produced peripheral cholinergic signs and stereotyped movements in all of the animals in both periods of observation. The behavioural parameters assessed between 1 and 24 h were similar, but the seizure and SE development index was slightly lower in the 1h group and in the same group no case of fatality was observed. The pharmacological studies with antagonist cholinergic did not present any of the behavioural alterations. The drugs gabaergic, the antagonist dopaminergic D1, antipsychotic used and glutamatergic antagonist presented increased in the latency to first seizure (LS), latency of the SE (LSE) and decreasing the number of the death. The antagonists dopaminergic D2, the opioide, the antidepressants, and the dopaminergic agonist decreased the LS and a LSE and increased the number of the death. The lithium increased the effects of the pilocapine as well as the number of the death and decreased the LS and LSE. Neurochemical assessments revealed that acetylcholinesterase activity in hippocampus, frontal cortex and striatum decreased significantly only the first hour of the acute phase, meanwhile after 24h, the enzymatic activity remained unaltered. Lipid peroxidation level and nitrite e nitrate content were augmented whereas the GSH concentration was decreased in the areas investigated in both periods of observation. The SOD activity was increased during the first hour in the three areas. In turn, in the 24h period it was augmented in the frontal cortex alone. The catalase activity was significantly increased in both periods and in all areas. Works concerning maximum density (Bmax) of muscarinc cholinergic (M1 e M2) and dopaminergic (D1 e D2) receptors in the areas studied during 1h and 24h of observation were decreased and unaltered, respectively. Regarding the serotonergic receptors (5-HT2) was not verified alteration in the Bmax after 1 and 24h of observation in the three areas studied. In the areas studied the Bmax from glutamatergic and GABAergic receptors were increased and decreased, respectively. P400 altered the M1, M2, D1, D2, 5-HT2, GABAergic e glutamatergic receptors dissociation constant values (Kd) in distinct ways after 1 e 24h from the treatment. In the monoamine and their metabolites with HPLC determination P400 changes the DA, DOPAC and HVA as well as NA and 5-HT and its metabolite 5-HIIAA concentrations in the different cerebral areas after 1 and 24h of observation. In the experimental determinations of the amino acids contents, the P400 altered the content of (glutamate) GLU striatal, (glutamine) GLN hippocampal and the (aspartate) ASP cortical and no modified the concentration od tyrosine in the areas observed. However the TYR contents after 24 h of observation increas in striatum, hippocampus and frontal cortex, but GLU, GLN e ASP reamained unaltered in this period of the observation .

This thesis describes the development of an optimized method for culturing dissociated, monolayer neuronal networks from murine frontal cortex and midbrain. It is presented as a guidebook for use by cell culture specialists and laboratory personnel who require updated and complete procedures for use with microelectrode array (MEA) recording technology. Specific cell culture protocols, contamination prevention and control, as well common problems encountered within the cell culture facility, are discussed. This volume offers value and utility to the rapidly expanding fields of MEA recording and neuronal cell culture. Due to increasing interest in determining the mechanisms underlying Parkinson's disease, the newly developed procedures for mesencephalon isolation and culture on MEAs are an important research contribution.

There is now considerable evidence that both schizophrenia and affective disorders have their origin at least in part in events that occur during early pre- and post-natal development. In the case of schizophrenia, many observations, for example, increased risk for schizophrenia in the offspring of mothers who had influenza A during their second trimester of pregnancy and evidence for abnormal neuronal migration in the cerebral cortex of post mortem tissue from schizophrenic patients, suggest that a second trimester insult may have occurred and that this insult may have increased the risk for the development of schizophrenia in late adolescence or early adulthood. Animal studies have found that rats that undergo excitotxic damage to the ventral hippocampus on postnatal day 7 develop exaggerated sensitivity to dopamine-stimulating drugs or to stressful stimuli that becomes apparent after sexual maturity but not before, providing a neurodevelopmental model of schizophrenia. Similarly, post-weaning social isolation leads to nehanced responses to dopaminergic drgus and to stress that emerges after sexual maturity. These animal models are proving to be valuable tools to study the neurobiological mechanisms mediating the influence of early insults to the nervous system on later behavioural functins. In the case of affective disorders, although the evidence is not as strong, a number of the same observations have been made suggesting that an insult during early ontogeny may lead to the development of affective disorders later in life. For example, retrospective studies of people with affective disorders showed that they were more likely to have attained motor milestones at a later age and to have had poorer academic performance as children. There is a wealth of evidence suggesting hyperfunctioning of the hypothalamic-pituitary-adrenal (HPA) axis in affective disorders. Animal studies have shown that early matenal deprivation can lead to lasting changes in the reactivity of the HPA axis to stressful stimuli, providing another link from early experience to adult psychopathology. Continued studies of the effects of pre- and early post-natal events on the development of the nervous system and the relationships of these events to schizophrenia or affective disorder will provide new insights into the mechanisms underlying these common neuropsychiatric illnesses.

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