O intestino apresenta a maior área do corpo exposta ao ambiente, recebendo constantemente antígenos provenientes da alimentação e de microrganismos. A fim de manter a homeostase, evitando respostas inflamatórias desnecessárias e ao mesmo tempo respondendo apropriadamente à possíveis ameaças ao tecido, as células intestinas tem que ser capazes de perceber e responder apropriadamente a uma diversa gama de perturbações vindas do ambiente. Além do seu vasto sistema imune o intestino também abriga o maior número de neurônios fora do sistema nervoso central, os quais compõe o Sistema Nervoso Entérico (SNE). O SNE é composto por aproximadamente 100 milhões de neurônios que são capazes de regular autonomamente diversas funções fisiológicas do intestino e também de receber e enviar sinais para os sistemas nervoso autônomo simpático e parassimpático. Diversas evidências clínicas correlacionam inflamações intestinais com alterações no SNE, demonstrando a importância de se entender melhor as relações neuroimunes presentes no intestino. Os macrófagos são células essências da imunidade inata que residem tanto na área do intestino conhecida como lâmina própria como também na área conhecida como muscularis. Essas células fagocíticas desempenham um importante papel nas respostas antibacterianas e também na manutenção da homeostase do tecido, sendo capazes de adaptar rapidamente sua fisiologia em resposta aos sinais ambientais. Neste trabalho avaliamos a existência de uma comunicação bidirecional entre macrófagos e neurônios intestinais. Caracterizamos as duas populações de macrófagos presentes no intestino em homeostase e após um estimulo com SpiB um mutante de Salmonella, avaliando assim como estas células respondem à sinais de infecção provenientes do lúmen intestinal. Utilizando abordagens in vivo e in vitro, observamos que os macrófagos presentes na região da muscularis respondem rapidamente a uma possível infecção presente no lúmen regulando positivamente genes de proteção tecidual e reparo de danos, como Arg1 e Chi3l3. Nossos resultados indicam ainda que são os neurônios através da liberação de norepinefrina capaz de ativar os receptores β2 adrenérgicos presentes nos macrófagos intestinais que induzem a expressão dos genes relacionados com a proteção tecidual e reparo de danos. Observamos ainda que esta via induzida através da ativação dos receptores β2 adrenérgicos parece conferir também aos macrófagos um papel neuro-protetor em caso de danos teciduais. Em conjunto nossos resultados indicam a presença de uma comunicação neuroimune bidirecional entre os neurônios e macrófagos intestinais capaz de modular a resposta dos macrófagos a uma infecção entérica e de proteger os neurônios em caso de danos teciduais / The intestine is the largest area of the body exposed to the environment, which receives food and microbe antigens. In order to maintain homeostasis, avoiding unnecessary inflammation, and at the same time responding properly to potential treats to the tissue, intestinal cells must be able to sense and respond properly to this diverse set of environmental perturbations. In addition to a vast immune system, the intestine also harbors the largest collection of neurons outside the central nervous system, which constitute the enteric nervous system (ENS). The ENS is composed of approximately 100 million neurons that are capable of regulating the physiological functions of the gut autonomously and also receive input and send signals to the sympathetic and parasympathetic nervous system. Numerous clinical findings correlate gut inflammation with abnormalities in the ENS, revealing the importance of a better understanding of the neuro-immune interactions at this site. Macrophages comprise an essential innate immune cell residing both in the intestinal lamina propria and muscularis regions. These phagocytic cells play important roles in anti-microbial responses but also in tissue homeostasis, being able to quickly adapt their physiology in response to environmental cues. We evaluated the crosstalk between intestinal macrophages and surrounding enteric neurons, characterizing how these cells respond to possible infection in the intestinal lumen. Using in vivo and in vitro approaches, we found that macrophages in the intestinal muscularis quickly respond to a possible distal luminal infection, up regulating tissue-protective and wound repair genes, like Arg1 and Chi3l3. Also, our results indicate that the neurons trough norepinephrine release and subsequent activation of the β2 adrenergic receptor present on the intestinal macrophages are the ones up regulating tissue-protective and wound repair genes. We also observed that this pathway, trough the β2 adrenergic receptor activation seems to induce a neuro-protective role to these macrophages under tissue damage scenarios. All together our results indicate that a neuro-immune crosstalk between neurons and macrophages modulates macrophages response towards enteric infections and confers neuro-protection in case of tissue damage

O intestino apresenta a maior área do corpo exposta ao ambiente, recebendo constantemente antígenos provenientes da alimentação e de microrganismos. A fim de manter a homeostase, evitando respostas inflamatórias desnecessárias e ao mesmo tempo respondendo apropriadamente à possíveis ameaças ao tecido, as células intestinas tem que ser capazes de perceber e responder apropriadamente a uma diversa gama de perturbações vindas do ambiente. Além do seu vasto sistema imune o intestino também abriga o maior número de neurônios fora do sistema nervoso central, os quais compõe o Sistema Nervoso Entérico (SNE). O SNE é composto por aproximadamente 100 milhões de neurônios que são capazes de regular autonomamente diversas funções fisiológicas do intestino e também de receber e enviar sinais para os sistemas nervoso autônomo simpático e parassimpático. Diversas evidências clínicas correlacionam inflamações intestinais com alterações no SNE, demonstrando a importância de se entender melhor as relações neuroimunes presentes no intestino. Os macrófagos são células essências da imunidade inata que residem tanto na área do intestino conhecida como lâmina própria como também na área conhecida como muscularis. Essas células fagocíticas desempenham um importante papel nas respostas antibacterianas e também na manutenção da homeostase do tecido, sendo capazes de adaptar rapidamente sua fisiologia em resposta aos sinais ambientais. Neste trabalho avaliamos a existência de uma comunicação bidirecional entre macrófagos e neurônios intestinais. Caracterizamos as duas populações de macrófagos presentes no intestino em homeostase e após um estimulo com SpiB um mutante de Salmonella, avaliando assim como estas células respondem à sinais de infecção provenientes do lúmen intestinal. Utilizando abordagens in vivo e in vitro, observamos que os macrófagos presentes na região da muscularis respondem rapidamente a uma possível infecção presente no lúmen regulando positivamente genes de proteção tecidual e reparo de danos, como Arg1 e Chi3l3. Nossos resultados indicam ainda que são os neurônios através da liberação de norepinefrina capaz de ativar os receptores β2 adrenérgicos presentes nos macrófagos intestinais que induzem a expressão dos genes relacionados com a proteção tecidual e reparo de danos. Observamos ainda que esta via induzida através da ativação dos receptores β2 adrenérgicos parece conferir também aos macrófagos um papel neuro-protetor em caso de danos teciduais. Em conjunto nossos resultados indicam a presença de uma comunicação neuroimune bidirecional entre os neurônios e macrófagos intestinais capaz de modular a resposta dos macrófagos a uma infecção entérica e de proteger os neurônios em caso de danos teciduais / The intestine is the largest area of the body exposed to the environment, which receives food and microbe antigens. In order to maintain homeostasis, avoiding unnecessary inflammation, and at the same time responding properly to potential treats to the tissue, intestinal cells must be able to sense and respond properly to this diverse set of environmental perturbations. In addition to a vast immune system, the intestine also harbors the largest collection of neurons outside the central nervous system, which constitute the enteric nervous system (ENS). The ENS is composed of approximately 100 million neurons that are capable of regulating the physiological functions of the gut autonomously and also receive input and send signals to the sympathetic and parasympathetic nervous system. Numerous clinical findings correlate gut inflammation with abnormalities in the ENS, revealing the importance of a better understanding of the neuro-immune interactions at this site. Macrophages comprise an essential innate immune cell residing both in the intestinal lamina propria and muscularis regions. These phagocytic cells play important roles in anti-microbial responses but also in tissue homeostasis, being able to quickly adapt their physiology in response to environmental cues. We evaluated the crosstalk between intestinal macrophages and surrounding enteric neurons, characterizing how these cells respond to possible infection in the intestinal lumen. Using in vivo and in vitro approaches, we found that macrophages in the intestinal muscularis quickly respond to a possible distal luminal infection, up regulating tissue-protective and wound repair genes, like Arg1 and Chi3l3. Also, our results indicate that the neurons trough norepinephrine release and subsequent activation of the β2 adrenergic receptor present on the intestinal macrophages are the ones up regulating tissue-protective and wound repair genes. We also observed that this pathway, trough the β2 adrenergic receptor activation seems to induce a neuro-protective role to these macrophages under tissue damage scenarios. All together our results indicate that a neuro-immune crosstalk between neurons and macrophages modulates macrophages response towards enteric infections and confers neuro-protection in case of tissue damage

Acrylamide, 2,5-hexanedione, Tri-o-tolyl phosphate and leptophos belong to three fundamentally different chemical classes but all four chemicals cause central-peripheral distal axonopathy. Some of these compounds have been shown to alter brain steady state levels of neurotransmitters or to inhibit the activities of adenosine triphosphatases which are involved in the uptake and storage of biogenic amines. Tests were performed to determine alterations in steady state levels of rat brain norepinephrine and dopamine in response to doses of the above chemicals and of the central nervous system toxin, methyl mercuric chloride sufficient to cause ataxia. Catecholamine synthesis rate constant estimations were performed. Specific activities of tyrosine in brains of control and treatment groups following intravenous injection of labelled tyrosine were compared to determine if passage of tyrosine across the blood-brain barrier were affected by treatments. Levels of the dopamine metabolite, dihydroxyphenylacetic acid were assayed in all cases. Levels of the norepinephrine metabolite, 3-methoxy-4-hydroxymethylethyleneglycol sulfate, were assayed in response to acrylamide administration. Animal weights were recorded at the beginning and end of the treatment period. Rats treated with a cumulative dose of 250 mg/kg acrylamide had significantly lower norepinephrine levels than controls. 2,5-hexanedione administration significantly increased the dopamine synthesis rate constant at a cumulative dose of 210 mg/kg. Cumulative doses of 700 and 2100 mg/kg also appeared to elevate norepinephrine and dopamine synthesis rate constants, but values were not statistically significant. Leptophos caused a slight but significant increase in dopamine levels in rats administered a cumulative dose of 75 mg/kg. Methyl mercuric chloride caused variable effects to norephinephrine synthesis rate and lowered dopamine synthesis rate constant at cumulative doses of 5 to 50 mg/kg. No other alterations were seen in levels of catecholamines or of their metabolites, nor in synthesis rate constants of the catecholamines in response to administration of the five neurotoxic compounds. No evidence of altered blood-brain transport of tyrosine was observed at any level of neurotoxins administered. Rats given the highest cumulative doses of all neurotoxins except tri-o-tolyl phosphate gained significantly less weight than control animals. It was concluded that the four compounds which cause delayed distal neurotoxicity do not alter levels of turnover rates of brain catecholamines in a consistent manner.

Generalized anxiety disorder (GAD) is associated with painful physical symptoms (PPS). These post hoc analyses of previous trial data assessed PPS and their response to duloxetine treatment in GAD patients. Studies 1 and 2 (n = 840) were 9- to 10-week efficacy trials; study 3 (n = 887) was a relapse prevention trial comprising a 26-week open-label treatment phase and a 26-week double-blind, placebo-controlled treatment continuation phase. Mean baseline visual analog scale scores (VAS, 0–100; n = 1727) ranged from 26 to 37 for overall pain, headache, back pain, shoulder pain, interference with daily activities, and time in pain while awake. In studies 1 and 2, improvement on all VAS scores was greater in duloxetine-treated than in placebo-treated patients (p ≤ 0.01). In study 3, pain symptoms worsened in responders switched to placebo compared with those maintained on duloxetine (p ≤ 0.02). In conclusion, duloxetine was efficacious in the short- and long-term treatment of PPS, which are common in GAD patients.

The objective was to examine duloxetine 60–120mg/day treatment for relapse prevention in adults with generalized anxiety disorder (GAD). Adult patients (N=887; mean age=43.3 years; 61.0% female) with DSM-IV-TR-defined GAD diagnosis were treated with duloxetine for 26 weeks. Patients who completed open-label phase and were treatment responders (≥50% reduction in Hamilton Anxiety Rating Scale total score to ≤11 and “much”/“very much improved” ratings for the last 2 visits of open-label phase) were randomly assigned to receive duloxetine or placebo for a 26-week double-blind continuation phase. Relapse was defined as ≥2-point increase in illness severity ratings or by discontinuation due to lack of efficacy. During the double-blind phase, placebo-treated patients (N=201) relapsed more frequently (41.8%) than duloxetine-treated patients (13.7%, N=204, P≤0.001) and worsened on each outcome measure (P≤0.001, all comparisons). Duloxetine 60–120 mg/day treatment was efficacious and reduced risk of relapse in patients with GAD.

Previous investigators demonstrated that epididymal white adipose tissue (EWAT) lipectomy suppressed spermatogenesis and caused atrophy of the seminiferous tubules. EWAT lipectomy, however, may disrupt testicular innervation, which reportedly compromises testicular function. To resolve this confound and better clarify the role of EWAT in spermatogenesis, three experimental groups of hamsters were created in which: i.) the superior and inferior spermatic nerves were transected (SSNx) at the testicular level, ii.) EWAT was extirpated (EWATx), and iii.) testicular nerves and EWAT were left intact (SHAM controls). It was hypothesized that transection of the superior and inferior spermatic nerves would disrupt normal spermatogenesis. The findings indicate a significant reduction in spermatogenic activity and marked seminal tubule atrophy within the EWATx testis, as compared to the SSNx and controls testes, which did not differ significantly from each other. From these data, it is concluded that EWAT, and not testicular innervation, is central to normal spermatogenesis.

No description available.

La dépression est une pathologie grave qui, malgré de multiples stratégies thérapeutiques, demeure résistante chez un tiers des patients. Les techniques de stimulation cérébrale sont devenues une alternative intéressante pour les patients résistants à diverses pharmacothérapies. La stimulation du nerf vague (SNV) a ainsi fait preuve de son efficacité en clinique et a récemment été approuvée comme traitement additif pour la dépression résistante. Cependant, les mécanismes d’action de la SNV en rapport avec la dépression n’ont été que peu étudiés. Cette thèse a donc eu comme premier objectif de caractériser l’impact de la SNV sur les différents systèmes monoaminergiques impliqués dans la pathophysiologie de la dépression, à savoir la sérotonine (5-HT), la noradrénaline (NA) et la dopamine (DA), grâce à l’utilisation de techniques électrophysiologiques et de la microdialyse in vivo chez le rat. Des études précliniques avaient déjà révélé qu’une heure de SNV augmente le taux de décharge des neurones NA du locus coeruleus, et que 14 jours de stimulation sont nécessaires pour observer un effet comparable sur les neurones 5-HT. Notre travail a démontré que la SNV modifie aussi le mode de décharge des neurones NA qui présente davantage de bouffées, influençant ainsi la libération terminale de NA, qui est significativement augmentée dans le cortex préfrontal et l’hippocampe après 14 jours. L’augmentation de la neurotransmission NA s’est également manifestée par une élévation de l’activation tonique des récepteurs postsynaptiques α2-adrénergiques de l’hippocampe. Après lésion des neurones NA, nous avons montré que l’effet de la SNV sur les neurones 5-HT était indirect, et médié par le système NA, via l’activation des récepteurs α1-adrénergiques présents sur les neurones du raphé. Aussi, tel que les antidépresseurs classiques, la SNV augmente l’activation tonique des hétérorécepteurs pyramidaux 5-HT1A, dont on connait le rôle clé dans la réponse thérapeutique aux antidépresseurs. Par ailleurs, nous avons constaté que malgré une diminution de l’activité électrique des neurones DA de l’aire tegmentale ventrale, la SNV induit une augmentation de la DA extracellulaire dans le cortex préfrontal et particulièrement dans le noyau accumbens, lequel joue un rôle important dans les comportements de récompense et l’hédonie. Un deuxième objectif a été de caractériser les paramètres optimaux de SNV agissant sur la dépression, en utilisant comme indicateur le taux de décharge des neurones 5-HT. Des modalités de stimulation moins intenses se sont avérées aussi efficaces que les stimulations standards pour augmenter l’activité électrique des neurones 5-HT. Ces nouveaux paramètres de stimulation pourraient s’avérer bénéfiques en clinique, chez des patients ayant déjà répondu à la SNV. Ils pourraient minimiser les effets secondaires reliés aux périodes de stimulation et améliorer ainsi la qualité de vie des patients. Ainsi, ces travaux de thèse ont caractérisé l’influence de la SNV sur les trois systèmes monoaminergiques, laquelle s’avère en partie distincte de celle des antidépresseurs classiques tout en contribuant à son efficacité en clinique. D’autre part, les modalités de stimulation que nous avons définies seraient intéressantes à tester chez des patients recevant la SNV, car elles devraient contribuer à l’amélioration des bénéfices cliniques de cette thérapie. / Depression is a severe psychiatric disorder, in which a third of patients do not achieve remission, despite the wide variety of therapeutic strategies that are currently available. Brain stimulation has emerged as a promising alternative therapy in cases of treatment resistance. Vagus nerve stimulation (VNS) has shown promise in treating resistant-depressed patients, and it has been approved as an adjunctive treatment for resistant depression. However, the mechanism of action by which VNS exerts its antidepressant effects has remained elusive. The first goal of this thesis was therefore to characterize the impact of VNS on monoaminergic systems known to be implicated in the pathophysiology of depression such as serotonin (5-HT), norepinephrine (NE) and dopamine (DA), by means of electrophysiologic techniques and microdialysis in the rat brain. Previous research has indicated that one hour of VNS increased the basal firing activity of locus coeruleus NE neurons and, secondarily, that of 5-HT neurons, but only after 14 days of stimulation. Our work demonstrated that VNS also modified the firing pattern of NE neurons towards a bursting mode of discharge. This mode of firing was shown to lead to enhanced NE release in the prefrontal cortex and hippocampus after 14 days. Increased NE neurotransmission was also evidenced by enhanced tonic activation of postsynaptic α2-adrenoceptors in the hippocampus. Selective lesioning of NE neurons was then used to demonstrate that the effects of VNS on the 5-HT system were indirect, and mediated by the activation of α1-adrenoceptors located on the dorsal raphe 5-HT neurons. Similar to classical antidepressants, VNS also enhanced the tonic activation of pyramidal 5-HT1A heteroreceptors, which are known to play a key role in the antidepressant response. We also found that in spite of a diminished firing activity of ventral tegmental area DA neurons after VNS, extracellular DA levels were significantly elevated in the prefrontal cortex, and particularly in the nucleus accumbens which plays an important role in reward behavior and hedonia. A second objective was to characterize the optimal VNS parameters to treat depression using the firing activity of 5-HT neurons as an indicator. It was found that less stimulation was as effective as the standard levels to increase 5-HT neurons firing rate. These novel parameters could be helpful for clinical application in VNS responsive patients, to potentially minimize and/or even prevent stimulation-related side effects, thus improving their quality of life. In brief, these studies reveal an influence of VNS on all three central monoamine systems, which differs in part from that of classical antidepressants while contributing to the clinical efficacy of this approach. It will also be interesting to determine whether the proposed lower stimulation parameters are as effective in providing antidepressant response in patients receiving VNS, which should contribute to improve the clinical benefits of that therapy.

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

Dissertation (Ph.D.)--University of South Florida, 2007. / Includes vita. Includes bibliographical references (leaves 109-141). Also available online.