Acredita-se que quantidades elevadas de glutamato estejam relacionadas à neurobiologia da depressão e trabalhos recentes indicam que a quantidade de glutamato cortical está aumentada em pacientes depressivos quando comparada a indivíduos sadios. Dentre as estruturas corticais, o córtex pré-frontal medial ventral (CPFMv), dividido em infralímbico (IL) e pré-límbico (PL), tem sido mais frequentemente implicado no desenvolvimento de transtornos mentais, como a depressão. Considerando evidências de que o IL e o PL podem agir de forma diferente quanto ao controle emocional em resposta ao estresse, o presente trabalho visou avaliar a hipótese de participação da neurotransmissão glutamatérgica do CPFMv, IL e PL, no desenvolvimento das respostas comportamentais ao estresse de nado forçado, um modelo preditivo de efeitos antidepressivos. Para tal, investigamos os efeitos induzidos pela administração no IL ou no PL, de LY 235959, um antagonista dos receptores glutamatérgicos do tipo NMDA, em três momentos diferentes, em animais submetidos ao teste do nado forçado. A administração de LY 235959, no IL ou PL, produziu efeitos do tipo antidepressivo, sendo esse efeito sensível ao tempo de administração da droga em relação à exposição ao nado forçado. Sendo assim, foi observado efeito antidepressivo quando o bloqueio glutamatérgico no PL ocorreu imediatamente após o nado ou antes da re-exposição ao estresse; enquanto no IL, o tratamento promoveu efeito antidepressivo apenas quando administrado antes da re-exposição ao nado. Portanto, os resultados sugerem que a neurotransmissão glutamatérgica mediada por receptores NMDA no CPFMv contribui para o desenvolvimento de consequências comportamentais do estresse, de modo que o bloqueio desses receptores facilitaria a adaptação ao estresse e induziria efeitos do tipo-antidepressivo. Os resultados sugerem, ainda, que o PL e o IL participam de maneira semelhante na modulação desses processos. / It is believed that high amounts of glutamate are related to the neurobiology of depression. Recent studies indicate that the amount of cortical glutamate is increased in depressed patients compared to healthy subjects. Among the cortical structures, the ventral medial prefrontal cortex (CPFMv), divided into infralimbic (IL) and prelimbic (PL) has been most often implicated in the development of mental disorders, such as depression. Considering that IL and PL play different roles on the emotional control in response to stress, this study was aimed to evaluate the hypothesis that the activation of glutamate NMDA receptors within the CPFMv, IL and PL, would facilitate the development of forced swimming-induced behavioral responses, an animal model predictive of antidepressants effects. To this end, we investigated the effects induced by the administration in the PL or the IL of LY 235959, an antagonist of NMDA receptors, at three different times, in animals submitted to the forced swimming test. The administration of LY 235959, in the IL or PL, produced antidepressant-like effects, and this effect is sensitive to moment of drug administration in relation to exposure to forced swimming. Thus, the antidepressant-like effect was observed when blocking the NMDA blockade into the PL occurred immediately after swimming or before re-exposure to stress, whereas in the IL, such treatment promoted antidepressant-like effect only when administered before re-exposure to swimming. Therefore, the results suggest that the glutamatergic neurotransmission mediated by NMDA receptors in the CPFMv contributes to the development of behavioral consequences of stress, so that blocking these receptors would facilitate the adaptation to stress and induce antidepressant-like effects. The results also suggest that PL and IL may be similarly involved in modulating these processes.

Major depression is a serious mood disorder affecting more than 120 million people worldwide, irrespective of their race or socio-economic status. This psychiatric disorder is predicted to become the second leading cause of disability by the year 2020, second only to heart diseases in the global population, without distinguishing differences in the incidence within defined age groups. Depression is known to affect people across all age groups, including children, adolescents, adults and geriatrics, although older age is associated with an increased susceptibility to major depression and other psychiatric conditions. Until the 1970‘s depression during childhood and adolescence was thought to be uncommon or non-existent. Recent epidemiological studies have demonstrated that there is a persistent escalation in the prevalence of depression in children and adolescents. Accordingly, the number of prescriptions for drugs to treat this disorder in juveniles has escalated significantly. With our current limited understanding of the safety and long-term effects of treatment with antidepressants, the clinician is left making decisions without sound evidence of safety. In addition, psychotropic drugs may affect neurodevelopment during childhood and adolescence and may consequently modulate susceptibility to psychiatric disorders later in life. The objective of the current study was to investigate the effects of early-life (pre-natal and postnatal) chronic treatment with venlafaxine, a dual action serotonin-noradrenalin reuptake inhibitor, during the developmental phase of the serotonin and norepinephrine pathways in stress-sensitive rats on measures of cognition, anxiety-like and depressive-like behaviour later in life. The study also investigated which age shows optimal behavioural changes later in life, following the above mentioned administration of venlafaxine. In addition we also determined the effects that the administration of venlafaxine has on the levels of monoamines l-norepinephrine (l-NE) and serotonin (5-HT) in the prefrontal cortex and the hippocampus. A number of translational animal models of psychiatric disorders have been described and validated, and is suitable for such investigations. For the current study we used stress-sensitive Flinders Sensitive Line (FSL) rats and their controls, Flinders Resistant Line (FRL) rats. Pregnant dams were injected subcutaneously for 14 days with 10 mg/kg venlafaxine or saline from pre-natal day 15 (ND-15) to ND-01. New-born pups were then injected subcutaneously with 3 mg/kg venlafaxine or saline for 14 days from postnatal day 3 (ND+03) to ND+17. These doses were determined from previous studies reported in literature. Four rat treatment groups of both FSL and FRL rats received injections during pre-natal + postnatal ages as follows: saline + saline, venlafaxine + saline, saline + venlafaxine and venlafaxine + venlafaxine. Following the drug treatments, all rat groups were housed under normal conditions until the indicated time to be subjected to a battery of behavioural tests, including the novel object recognition test (nORT), locomotor activity test (Digiscan®), elevated plus maze (EPM) and forced-swim test (FST), scheduled on either ND+35, ND+60 or ND+90. Separate treatment groups were used for each age group. After the behavioural tests animals were decapitated, the brains removed and the prefrontal cortex and hippocampus dissected out. These were analysed at a later stage using an HPLC with electrochemical detection to determine the levels of the monoamines l-NE and 5-HT. All animal procedures were approved by the Ethics Committee of the North-West University (approval number: NWU-00045-10-S5), and are in accordance with the recommendations of the National Institutes of Health guide for the care and use of laboratory animals. The data from the current study suggest that in general FRL rats were not influenced by the early-life treatment with venlafaxine, as observed in the nORT, EPM or FST on ND+35, ND+60 or ND+90. There was minimal changes seen in the immobile behaviour in the FST of FRL rats that received prenatal venlafaxine. As expected, depressive-like behaviour in the FST was significantly enhanced in FSL rats relative to corresponding FRL rat groups as observed at ND+35 and ND+60, but not ND+90. Importantly, depressive-like behaviour was reversed following pre- and postnatal treatment with venlafaxine in FSL rats at ND+60, relative to the corresponding FRL rat groups. Reversal of depressive-like behaviour in FSL rats were not observed at ND+35 or ND+90, suggesting a delayed response that is reversed later in adulthood. The data from the nORT, Digiscan® or EPM did not reveal any significant differences between the various FSL treatment groups, including at ND+60. The current study therefore demonstrated that the treatment regimen employed had a transient effect on depressive-like behaviour later in life and suggested that genetic susceptibility plays an important role in the treatment of depression. This was suggested by the venlafaxine-induced decrease in immobile behaviour exhibited by FSL rats at ND+60 in the FST, and the subsequent increase in immobile behaviour at ND+90. In general, the most significant venlafaxine-induced effects were seen in FSL rats, suggesting genetic susceptibility plays an important role. / MSc (Pharmacology), North-West University, Potchefstroom Campus, 2014

A exposição a estressores incontroláveis leva a alterações comportamentais e bioquímicas significativas que parecem envolver um mau funcionamento da via serotoninérgica Núcleo Mediano da Rafe (NMnR)-Hipocampo Dorsal, mediada por receptores de tipo 5-HT1A (5-HT1aR), sugerindo que as associações aprendidas, relacionadas à exposição ao estresse e suas conseqüências emocionais, não foram desconectadas. Estudos na literatura sugerem que processos de memória são tempo-dependentes e podem ser alterados pela administração de drogas no momento de sua formação ou evocação. Assim, o objetivo do trabalho foi investigar se a interferência na neurotransmissão serotoninérgica mediada por 5-HT1aR, no NMnR, em diferentes momentos com relação à exposição ao estresse de nado forçado pode prevenir ou atenuar os efeitos desse estressor. Ratos Wistar machos (n=5-13/grupo) receberam duas injeções intra-NMnR de Salina (Sal), 8-OH-DPAT (DPAT; 3nmoles/0,2µL; agonista 5-HT1aR) e/ou WAY100635 (WAY; 0,3nmoles/0,2µL; antagonista 5-HT1aR) compondo os grupos experimentais: Sal+Sal, Sal+DPAT, WAY+Sal, WAY+DPAT. As drogas foram administradas em três condições experimentais distintas: antes da pré-exposição ao nado forçado; antes do teste em animais submetidos à pré-exposição; ou antes do teste em animais não pré-expostos. O teste ocorreu 24 horas após a pré-exposição. O tempo de latência para o primeiro episódio de imobilidade (LAT) e o tempo total gasto imóvel (IMO) foram registrados. Somente animais com sítios de injeção confirmados foram usados na análise (ANOVA de uma via seguida por teste post hoc de Duncan). Nossos resultados sugerem que o tratamento com 8-OH-DPAT antes da pré-exposição ou do teste em animais estressados previne ou atenua, respectivamente, as consequências comportamentais da exposição prévia ao estresse de nado forçado. Além disso, nossos dados sugerem que tanto a interferência no processo de aquisição da memória aversiva quanto da evocação da mesma são em parte mediados por 5-HT1aR. / Exposure to uncontrollable stressors leads to significant behavioral and biochemical changes which has been associated to mal functioning of the Median Raphe Nucleus (NMnR) Dorsal Hippocampus serotonergic pathway, mediated by receptor type 5-HT1A (5-HT1aR), suggesting that learned associations related to exposure to stress and emotional consequences from such exposure were not disconnected. Published studies suggest that memory processes are time-dependent and can be changed by the administration of drugs at the time of its formation or retrieval. The objective of the present study was to investigate whether interference with serotonergic neurotransmission mediated by 5-HT1aR in NMnR at different times in relation to exposure to forced swim stress could prevent or reduce the effects of this stressor. Male Wistar rats (n = 5-13/grupo) received two intra-NMnR injections of Saline (Sal), 8-OH-DPAT (DPAT; 3nmoles / 0.2 mL; 5-HT1aR agonist) and / or WAY100635 (WAY; 0.3 nmol / 0.2 mL; 5-HT1aR antagonist) composing the experimental groups: Sal + Sal, Sal + DPAT, WAY + Sal, WAY + DPAT. The drugs were administered in three different experimental conditions: before preexposure to forced swim; before testing in animals subjected to preexposure; or before testing in animals not preexposed. The test occurred 24 hours after preexposure. The latency to the first episode of immobility (LAT) and the total time spent immobile e (IMO) were registered. Only animals who had their sites of injection confirmed were used in the analysis (one-way ANOVA followed by post hoc test Duncan). Our results suggest that treatment with 8-OH-DPAT before preexposure or testing in stressed animals prevents or attenuates, respectively, the behavioral consequences of prior exposure to forced swim stress. Furthermore, our data suggest that both the interference in the acquisition of aversive memory, and the retrieval of the same are partly mediated by 5-HT1aR.

A exposição a estressores incontroláveis leva a alterações comportamentais e bioquímicas significativas que parecem envolver um mau funcionamento da via serotoninérgica Núcleo Mediano da Rafe (NMnR)-Hipocampo Dorsal, mediada por receptores de tipo 5-HT1A (5-HT1aR), sugerindo que as associações aprendidas, relacionadas à exposição ao estresse e suas conseqüências emocionais, não foram desconectadas. Estudos na literatura sugerem que processos de memória são tempo-dependentes e podem ser alterados pela administração de drogas no momento de sua formação ou evocação. Assim, o objetivo do trabalho foi investigar se a interferência na neurotransmissão serotoninérgica mediada por 5-HT1aR, no NMnR, em diferentes momentos com relação à exposição ao estresse de nado forçado pode prevenir ou atenuar os efeitos desse estressor. Ratos Wistar machos (n=5-13/grupo) receberam duas injeções intra-NMnR de Salina (Sal), 8-OH-DPAT (DPAT; 3nmoles/0,2µL; agonista 5-HT1aR) e/ou WAY100635 (WAY; 0,3nmoles/0,2µL; antagonista 5-HT1aR) compondo os grupos experimentais: Sal+Sal, Sal+DPAT, WAY+Sal, WAY+DPAT. As drogas foram administradas em três condições experimentais distintas: antes da pré-exposição ao nado forçado; antes do teste em animais submetidos à pré-exposição; ou antes do teste em animais não pré-expostos. O teste ocorreu 24 horas após a pré-exposição. O tempo de latência para o primeiro episódio de imobilidade (LAT) e o tempo total gasto imóvel (IMO) foram registrados. Somente animais com sítios de injeção confirmados foram usados na análise (ANOVA de uma via seguida por teste post hoc de Duncan). Nossos resultados sugerem que o tratamento com 8-OH-DPAT antes da pré-exposição ou do teste em animais estressados previne ou atenua, respectivamente, as consequências comportamentais da exposição prévia ao estresse de nado forçado. Além disso, nossos dados sugerem que tanto a interferência no processo de aquisição da memória aversiva quanto da evocação da mesma são em parte mediados por 5-HT1aR. / Exposure to uncontrollable stressors leads to significant behavioral and biochemical changes which has been associated to mal functioning of the Median Raphe Nucleus (NMnR) Dorsal Hippocampus serotonergic pathway, mediated by receptor type 5-HT1A (5-HT1aR), suggesting that learned associations related to exposure to stress and emotional consequences from such exposure were not disconnected. Published studies suggest that memory processes are time-dependent and can be changed by the administration of drugs at the time of its formation or retrieval. The objective of the present study was to investigate whether interference with serotonergic neurotransmission mediated by 5-HT1aR in NMnR at different times in relation to exposure to forced swim stress could prevent or reduce the effects of this stressor. Male Wistar rats (n = 5-13/grupo) received two intra-NMnR injections of Saline (Sal), 8-OH-DPAT (DPAT; 3nmoles / 0.2 mL; 5-HT1aR agonist) and / or WAY100635 (WAY; 0.3 nmol / 0.2 mL; 5-HT1aR antagonist) composing the experimental groups: Sal + Sal, Sal + DPAT, WAY + Sal, WAY + DPAT. The drugs were administered in three different experimental conditions: before preexposure to forced swim; before testing in animals subjected to preexposure; or before testing in animals not preexposed. The test occurred 24 hours after preexposure. The latency to the first episode of immobility (LAT) and the total time spent immobile e (IMO) were registered. Only animals who had their sites of injection confirmed were used in the analysis (one-way ANOVA followed by post hoc test Duncan). Our results suggest that treatment with 8-OH-DPAT before preexposure or testing in stressed animals prevents or attenuates, respectively, the behavioral consequences of prior exposure to forced swim stress. Furthermore, our data suggest that both the interference in the acquisition of aversive memory, and the retrieval of the same are partly mediated by 5-HT1aR.

Major depression is a serious mood disorder affecting more than 120 million people worldwide, irrespective of their race or socio-economic status. This psychiatric disorder is predicted to become the second leading cause of disability by the year 2020, second only to heart diseases in the global population, without distinguishing differences in the incidence within defined age groups. Depression is known to affect people across all age groups, including children, adolescents, adults and geriatrics, although older age is associated with an increased susceptibility to major depression and other psychiatric conditions. Until the 1970‘s depression during childhood and adolescence was thought to be uncommon or non-existent. Recent epidemiological studies have demonstrated that there is a persistent escalation in the prevalence of depression in children and adolescents. Accordingly, the number of prescriptions for drugs to treat this disorder in juveniles has escalated significantly. With our current limited understanding of the safety and long-term effects of treatment with antidepressants, the clinician is left making decisions without sound evidence of safety. In addition, psychotropic drugs may affect neurodevelopment during childhood and adolescence and may consequently modulate susceptibility to psychiatric disorders later in life. The objective of the current study was to investigate the effects of early-life (pre-natal and postnatal) chronic treatment with venlafaxine, a dual action serotonin-noradrenalin reuptake inhibitor, during the developmental phase of the serotonin and norepinephrine pathways in stress-sensitive rats on measures of cognition, anxiety-like and depressive-like behaviour later in life. The study also investigated which age shows optimal behavioural changes later in life, following the above mentioned administration of venlafaxine. In addition we also determined the effects that the administration of venlafaxine has on the levels of monoamines l-norepinephrine (l-NE) and serotonin (5-HT) in the prefrontal cortex and the hippocampus. A number of translational animal models of psychiatric disorders have been described and validated, and is suitable for such investigations. For the current study we used stress-sensitive Flinders Sensitive Line (FSL) rats and their controls, Flinders Resistant Line (FRL) rats. Pregnant dams were injected subcutaneously for 14 days with 10 mg/kg venlafaxine or saline from pre-natal day 15 (ND-15) to ND-01. New-born pups were then injected subcutaneously with 3 mg/kg venlafaxine or saline for 14 days from postnatal day 3 (ND+03) to ND+17. These doses were determined from previous studies reported in literature. Four rat treatment groups of both FSL and FRL rats received injections during pre-natal + postnatal ages as follows: saline + saline, venlafaxine + saline, saline + venlafaxine and venlafaxine + venlafaxine. Following the drug treatments, all rat groups were housed under normal conditions until the indicated time to be subjected to a battery of behavioural tests, including the novel object recognition test (nORT), locomotor activity test (Digiscan®), elevated plus maze (EPM) and forced-swim test (FST), scheduled on either ND+35, ND+60 or ND+90. Separate treatment groups were used for each age group. After the behavioural tests animals were decapitated, the brains removed and the prefrontal cortex and hippocampus dissected out. These were analysed at a later stage using an HPLC with electrochemical detection to determine the levels of the monoamines l-NE and 5-HT. All animal procedures were approved by the Ethics Committee of the North-West University (approval number: NWU-00045-10-S5), and are in accordance with the recommendations of the National Institutes of Health guide for the care and use of laboratory animals. The data from the current study suggest that in general FRL rats were not influenced by the early-life treatment with venlafaxine, as observed in the nORT, EPM or FST on ND+35, ND+60 or ND+90. There was minimal changes seen in the immobile behaviour in the FST of FRL rats that received prenatal venlafaxine. As expected, depressive-like behaviour in the FST was significantly enhanced in FSL rats relative to corresponding FRL rat groups as observed at ND+35 and ND+60, but not ND+90. Importantly, depressive-like behaviour was reversed following pre- and postnatal treatment with venlafaxine in FSL rats at ND+60, relative to the corresponding FRL rat groups. Reversal of depressive-like behaviour in FSL rats were not observed at ND+35 or ND+90, suggesting a delayed response that is reversed later in adulthood. The data from the nORT, Digiscan® or EPM did not reveal any significant differences between the various FSL treatment groups, including at ND+60. The current study therefore demonstrated that the treatment regimen employed had a transient effect on depressive-like behaviour later in life and suggested that genetic susceptibility plays an important role in the treatment of depression. This was suggested by the venlafaxine-induced decrease in immobile behaviour exhibited by FSL rats at ND+60 in the FST, and the subsequent increase in immobile behaviour at ND+90. In general, the most significant venlafaxine-induced effects were seen in FSL rats, suggesting genetic susceptibility plays an important role. / MSc (Pharmacology), North-West University, Potchefstroom Campus, 2014

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Depression is a psychiatric disorder associated with a negative impact on quality of life. Monoaminergic system has been involved in this disease and in the action of antidepressants. This study aimed to investigate the potential antidepressant-like of 7-fluoro-1,3-diphenylisoquinoline-1-amine (FDPI) and the possible involvement of monoaminergic system. Results showed that FDPI (1, 10 and 20 mg/kg, intragastric (i.g.)) reduced the immobility time, increased swimming time, but did not alter climbing time of mice in the modified forced swimming test (FST). These effects were similar to those of paroxetine (8 mg/kg, intraperitoneally (i.p.)), a selective serotonin reuptake inhibitor, which was used as positive control. Pretreatments with p-chlorophenylalanine (pCPA, an inhibitor of serotonin (5-HT) synthesis, 100 mg/kg, i.p., once a day for 4 consecutive days), N-[1]-N-(2-pyridinyl) cyclohexanecarboxamide (WAY 100635, a 5-HT1A receptor antagonist, 0.1 mg/kg, subcutaneous injection (s.c.)) and ondansetron (a 5-HT3 receptor antagonist, 1 mg/kg, i.p.) reversed the antidepressant-like effect of FDPI at the dose 1 mg/kg in FST, this did not occurs with ritanserin (a 5-HT2A/2C receptor antagonist, 1 mg/kg, i.p.). Antagonist related with dopaminergic system, as haloperidol (a D2 receptor antagonist, 0.2 mg/kg, i.p.) and SCH23390 (a D1 receptor antagonist, 0.05 mg/kg, s.c.) were able to reverse the antidepressant-like effect of FDPI at the dose 1 mg/kg in FST, this did not occurs with sulpiride (a D2 and D3 receptors antagonist, 50 mg/kg, i.p.). FDPI, at doses of 10 and 20 mg/kg, inhibited monoamine oxidase-B activity in prefrontal cortex of mice. These results suggest that FDPI produced an antidepressant-like action in the FST in mice, possibly by an involvement of the monoaminergic system. Additional studies are necessary in order to propose FDPI as a drug for depression treatment. / A depressão é uma doença psiquiátrica associada com um impacto negativo na qualidade de vida. O sistema monoaminérgico parece estar envolvido nessa doença e na ação dos antidepressivos. Esse estudo teve como objetivo investigar o potencial do tipo antidepressivo do 7-flúor- 1,3 difenilisoquinolina-1-amino (FDPI) e o possível envolvimento do sistema monoaminérgico. Os resultados mostraram que o FDPI (1, 10 e 20 mg/kg, intragástrico (i.g.)) reduziu o tempo de imobilidade, aumentou o tempo de nado, mas não alterou o tempo de escalada dos camundongos durante o teste do nado forçado (TNF) modificado. Esses efeitos foram similares aos da paroxetina (8 mg/kg, intraperitoneal (i.p.)), um inibidor seletivo da recaptação de serotonina, o qual foi usado como controle positivo. Os pré-tratamentos com p-clorofenilalanina (pCPA, um inibidor da síntese de serotonina (5-HT), 100 mg/kg, i.p., uma vez por dia, por 4 dias consecutivos), N-{2-[4-(2-metoxifenil)-1-piperazinil]etil}-N-(2-piridinil) ciclohexanocarboxamida (WAY 100635, um antagonista dos receptores 5-HT1A, 0,1 mg/kg, subcutâneo (s.c.)) e ondansetrona (um antagonista dos receptores 5-HT3, 1 mg/kg, i.p.) conseguiram reverter o efeito do tipo antidepressivo do FDPI na dose de 1 mg/kg no TNF, o que não aconteceu com a ritanserina (um antagonista do receptores 5-HT2A/2C, 1 mg/kg, i.p.). Antagonistas relacionados com o sistema dopaminérgico, como haloperidol (um antagonista do receptor D2, 0,2 mg/kg, i.p.), e SCH23390 (um antagonista do receptor D1, 0,05 mg/kg, s.c.) foram capazes de reverter o efeito do tipo antidepressivo do FDPI na dose de 1 mg/kg no TNF, o que não aconteceu com o sulpiride (um antagonista dos receptores D2 e D3, 50mg/kg, i.p.). O composto FDPI nas doses de 10 e 20 mg/kg inibiu a atividade da monoamino oxidase B em córtex pré-frontal de camundongos. Estes resultados sugerem que o FDPI apresentou uma ação do tipo antidepressiva no TNF em camundongos, possivelmente por um envolvimento do sistema monoaminérgico. Mais estudos se fazem necessários antes que se possa propor o FDPI como uma droga para o tratamento da depressão.

No description available.

Traumatic brain injury (TBI) has a dramatic impact on our society in terms of mortality, morbidity, and inherently high financial costs. Formidable research efforts are being addressed to the identification of neuroprotective agents capable of ameliorating the neurological outcome after TBI. Preclinical studies have recently demonstrated lithium to be a promising neuroprotective agent for both acute ischemic brain injury and chronic neurodegenerative disease. In light of these encouraging data, we designed a lateral fluid-percussion injury (FPI) study aimed at investigating the role of early post-traumatic administration of lithium as a strategy for reducing TBI-induced motor and cognitive deficits. The optimal dose of this agent and the time window for its administration have been determined on the basis of data derived from the assessment of motor and cognitive functioning in experimental animals, as well as from the stereological quantification of neuronal survival (PID 7) within the CA3 and hilar regions of the hippocampus ipsilateral to the FPI. In addition, we attempted to elucidate the mechanisms underlying the neuroprotective properties of this drug via western blot analysis of levels of the pro-apoptotic marker caspase-3 (PID 1, 7) and two neuroplasticity markers, growth associated protein-43 (GAP-43) and brain-derived neurotrophic factor (BDNF) (PID 1, 7, 21). Our findings indicate that low-dose lithium chloride (0.125 or 0.25 mmol/kg), given either 30 min or 8 hr after lateral FPI significantly ameliorates injury-induced cognitive and motor impairment. Specifically, cell survival in the CA3 region of the hippocampus of the injured lithium-treated animals (but not in the hilus) was significantly increased compared to injured vehicle-treated animals. Western blot analyses revealed a significant increase in GAP-43 levels on PID 7 in injured animals when treated with lithium, indicating a possible mechanism for lithium-induced neuroprotection. In contrast, BDNF levels were relatively unchanged until PID 21, and caspase-3 activation was not observed at all, suggesting that these proteins play less significant roles in the observed neuroprotective effects of lithium treatment after lateral FPI. Early administration of lithium, within 8 hours after TBI, holds promise as an effective therapy to ameliorate postinjury neurobehavioral deficits and warrants further investigation in clinical TBI studies.

O uso de répteis como modelos experimentais é limitado, principalmente devido às particularidades fisiológicas da classe, como as oscilações diárias e sazonais em seu comportamento. O objetivo deste estudo foi avaliar a atividade locomotora e nociceptiva de teiús (Salvator merianae) e iguanas-verdes (Iguana iguana) submetidos a testes comportamentais, ao longo do dia e do ano. Foram utilizados seis exemplares de cada espécie, mantidos em sala com temperatura ambiental (24 a 30°C) e fotoperíodo (12h:12h) controlados. Esses foram avaliados ao longo do dia (0:00h, 6:00h, 12:00h, 18:00h) e ao longo do ano (análise mensal). A análise locomotora foi realizada através do teste de campo aberto (teiús e iguanas), no qual o animal foi colocado no centro de uma arena circular por 15 minutos, e recebeu um ponto por cada ultrapassagem pelas subdivisões da mesma; e pelo teste de natação forçada (iguanas), no qual o tempo de atividade foi mensurado em piscina sem saída por 2 minutos. A resposta nociceptiva foi avaliada por meio de mensuração do período de latência do membro em resposta a estímulo nocivo térmico (25 segundos; 245 ± 7 mW/cm2) na superfície plantar do membro do animal. Não foram detectadas oscilações ao longo do ano no teste de campo aberto em nenhuma das espécies. Ao longo do dia, oscilações foram detectadas de Fevereiro a Dezembro em teiús; e em Abril, Maio, Junho e Outubro em iguanas. O tempo de atividade das iguanas foi menor em Janeiro e às 0:00h. Maiores latências de retirada do membro foram observadas nos meses de Maio e Agosto e às 6:00h em ambas espécies. Conclue-se que teiús e iguanas-verdes em ambiente controlado apresentam oscilações significativas em comportamento observado em teste de campo aberto, teste de natação forçada (somente iguanas) e teste plantar, que aparentemente não seguem padrões anuais claros, sendo provavelmente influenciado por fatores múltiplos ainda não compreendidos para as espécies. / The use of reptiles as experimental models is limited due to their physiological particularities, such as daily and annual fluctuations in behavior. The aim of this study was to evaluate locomotor and nociceptive activities of tegus (Salvator merianae) and green iguanas (Iguana iguana) throughout the day and the year, when undergoing behavioral tests. Six animals from each species, kept under controlled room temperature (24 to 30°C) and photoperiod (12h:12h), were used. They were evaluated throughout the day (0:00h, 6:00h, 12:00h and 18:00) and the year (monthly). Locomotor activity was measured by the open field test, in which the animal was placed in the center of a round arena for 15 minutes and the number of crossings through the subdivisions of the arena was counted, and by the forced swim test (iguanas), in which the activity period was timed after animals were placed in a pool with no scape for 2 minutes. Nociceptive activity was measured as the latency to limb withdrawal reflex in response to a noxious thermal stimulus (25 seconds, 245 ± 7 mW/cm2) in the plantar surface of the animal\'s limb. No differences were detected in locomotor activity in the open field test throughout the year in both species. Throughout the day, fluctuations were detected from February to December in tegus, and in April, May, June and October in iguanas. Activity period in iguanas were shorter in January and at 0:00h. Longer latencies to withdrawal reflex were detected in May and August and at 6:00h in both species. In conclusion, tegus and green iguanas kept in controlled environment have fluctuations in behavior presented in the open field test, the forced swim (only iguanas) test and the plantar test, which apparently do not follow a clear seasonal pattern and are probably influenced by multiple factors that are still unknown for both species.

PEREIRA, V.S. Participação da via NMDA-NO do córtex pré-frontal medial ventral na modulação das consequências comportamentais do estresse de nado forçado: mecanismos intracelulares. 2015. 191p. Tese (Doutorado) Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, 2014. A ativação dos receptores glutamatérgicos do tipo NMDA é capaz de desencadear a síntese de óxido nítrico (NO) no SNC. A administração de antagonistas NMDA (p.ex., ketamina) ou de inibidores da síntese de NO (p.ex., 7-NI) produz efeitos do tipo antidepressivo em animais e reforça o potencial dos sistemas glutamatérgico e nitrérgico como alvos terapêuticos para o tratamento da depressão. Trabalhos recentes sugerem o envolvimento de vias intracelulares no controle de mecanismos de plasticidade neural, como a via BDNF-TrkBmTOR, nos efeitos antidepressivos produzidos por antagonistas NMDA. Foi demonstrado, por exemplo, que os efeitos antidepressivos da ketamina dependem da síntese de BDNF e da ativação da mTOR no córtex pré-frontal medial (CPFMv) de ratos. O bloqueio farmacológico do CPFMv ou a administração de antagonista NMDA (LY235959) nessa estrutura também produz efeitos do tipo antidepressivo em animais. Porém, não se sabe se esses efeitos envolvem a via NMDA-NO do CPFMv, assim como não se sabe se o efeito antidepressivo induzido por inibidores da síntese de NO dependeria da via BDNF-TrkB-mTOR do CPFMv. Dessa forma, avaliamos a participação da neurotransmissão glutamatérgica e nitrérgica, bem como a participação da via BDNF-TrkB-mTOR, no CPFMv-pré límbico (PL), na modulação de respostas comportamentais de animais submetidos ao teste do nado forçado (TNF), um teste preditivo de efeito antidepressivo. Em um primeiro grupo de experimentos observou-se que a administração de inibidor da nNOS (NPA), da sGC (ODQ) ou de sequestrador de NO (c-PTIO) no PL de animais submetidos ao TNF promoveu efeito do tipo-antidepressivo, de forma similar ao que foi previamente descrito com a injeção local de LY235959. Posteriormente, os efeitos do LY235959, mas não os do NPA, foram bloqueados pelo tratamento prévio com antagonista dos receptores glutamatérgicos do tipo AMPA (NBQX), sugerindo que as vias NMDA e NO do PL estejam dissociadas na modulação das alterações comportamentais promovidas pelo TNF. A administração de BDNF no PL promoveu efeito tipoantidepressivo, o qual foi bloqueado pelo pré-tratamento com antagonista dos receptores TrkB (K252a) ou com inibidor da mTOR (rapamicina). Os efeitos tipo antidepressivo da administração de LY235959 ou NPA, no PL, não foram alterados na presença de K252a. No entanto, a administração prévia de rapamicina foi capaz de bloquear os efeitos do LY235959, mas não os do NPA, novamente sugerindo mecanismos distintos desencadeados por NMDA e NO no PL. Nossos dados indicam uma interação maior dos efeitos dos antagonistas NMDA com a via BDNF-TrkB-mTOR, enquanto os efeitos dos inibidores da via do NO parecem não modular essa via no PL. O tratamento sistêmico com ketamina (antagonista NMDA) ou 7-NI (inibidor preferencial da nNOS) foi capaz de produzir efeitos do tipo antidepressivo, sendo que esses tratamentos não alteraram a ativação ou expressão dos receptores TrkB e da mTOR, no CPFm de animais estressados ou não estressados. Assim, mais estudos são necessários para esclarecer a interação das neurotransmissões glutamatérgica e nitrérgica com a via BDNFTrkB-mTOR, no CPFMv-PL, no que diz respeito ao efeito antidepressivo em animais estressados, após administração sistêmica. Em conjunto, os dados do presente trabalho suportam o envolvimento da neurotransmissao glutamatérgica e nitrérgica do PL na neurobiologia das respostas comportamentais associadas a neurobiologia da depressão. Porém, a interação entre esses sistemas no PL e os mecanismos envolvidos se mostram consideravelmente complexos. / PEREIRA, V.S. Participation of NMDA-NO pathway from the medial préfrontal córtex on the behavioural consequences of forced swim stress: molecular mechanisms. 2015. 191p. Thesis (Doctoral) School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 2014. The activation of NMDA receptors is capable of increasing nitric oxide (NO) synthesis in the brain. The administration of NMDA antagonists (e.g., ketamine) or nitric oxide synthesis inhibitors (e.g., 7-NI) produce antidepressant-like effects in animals and highlights the potential of glutamatergic and nitrergic systems as therapeutic targets for the treatment of major depression. The involvement of intracellular mechanisms associated to neural plasticity, such as BDNF-TrkBmTOR pathway, has been implicated in the antidepressant-like effects induced by systemic administration of NMDA antagonists. For instance, the antidepressant effects of ketamine are associated with increased BDNF synthesis and mTOR in the medial prefrontal cortex (vMPFC). In addition, injection of an NMDA antagonist (LY235959) into the vMPFC-PL produces antidepressant-like effect in animals. However, it is not yet known if the aforementioned antidepressant-like effects involve the modulation of NO synthesis or the activation of the BDNF-TrkB-mTOR pathway in the vMPFC. Therefore, this work investigated the involvement of glutamatergic and nitrergic neurotransmission of the vMPFC, as well as the participation of local BDNF-TrkBmTOR pathway, in the modulation of behavioral responses of animals submitted to forced swimming test, an animal model predictive of antidepressant effects. The administration of nNOS inhibitor (NPA), sGC inhibitor (ODQ) or NO scavenger (c-PTIO) into the vMPFC-PL produced antidepressant-like effects, similarly to what has been previously described with the local injection of LY235959. The effects of LY235959 were blocked by pretreatment with an antagonist of AMPA receptors (NBQX), but not the NPA effects. Thus suggesting a possible dissociation between NMDA- and NO-induced mechanism in the PL. BDNF administration in the PL induced antidepressant-like effect, which was blocked by prior administration of the TrkB receptor antagonist (K252a) or the mTOR inhibitor (rapamycin). The antidepressant-like effects induced by intra-PL administration of LY235959 and NPA, into vMPFC-PL were not altered in the presence of K252a. However, the prior administration of rapamycin was able to block the effects of LY235959, but not NPA-induced effect. This result further supports the dissociation of the NMDA-NO system in the PL in the modulation of immobility in the FST. Systemic treatment with ketamine (NMDA antagonist) or 7-NI (nNOS inhibitor) produced antidepressant-like effects in the FST, although these treatments did not affect the activation or the expression of TrkB receptors or mTOR in the MPFC of stressed animals. These results further corroborate the involvement of the glutamatergic and nitrergic neurotransmission in the modulation of behavioral consequences of the forced swim stress and highlight that the interaction of these systems with mTOR and trkB in the PL is considerably complex. Altogether, our data supports the possible modulation of BDNF-TrkBmTOR pathway of the PL in the effects induced by NMDA antagonist injection.. However, the effects induced by inhibitors of the NO pathway semms dissociated from an interaction with the aforementioned pathway. Thus, further studies are necessary to clarify the interaction of glutamatergic and nitrergic neurotransmission with BDNF-TrkB-mTOR pathway into vMPFC-PL regarding the neurobiology of stress and depression.