A habenula lateral (LHb) inibe neurônios dopaminérgicos no mesencéfalo através de um nodo GABAérgico no tegmento mesopontino, o núcleo tegmental rostromedial (RMTg). Ambos a LHb e o RMTg também projetam para o núcleo dorsal da rafe (DR). A organização das projeções da LHb e do RMTg para o DR foi investigada através de injeções de um traçador anterógrado na LHb ou no RMTg e confirmada com injeções de traçadores retrógrados. Para identificar o fenótipo neuroquímico das projeções RMTg-DR, combinamos a hibridização in situ para mRNA de GAD67 com a detecção imunoistoquímica de traçadores retrógrados injetados no DR. Caracterizamos as subdivisões-alvo das projeções RMTg-DR através de dupla-imunofluorescência para o traçador anterógrado injetado no RMTg e serotonina ou o transportador vesicular de glutamato do tipo 3. Detectamos uma projeção focal direta da divisão medial da LHb para a parte caudal do DR. Em contraste, projeções GABAérgicas robustas do RMTg foram direcionadas para uma subdivisão central do DR enriquecida em neurônios presumidamente glutamatérgicos. / The lateral habenula (LHb) inhibits mesencephalic dopamine neurons through a mesopontine GABAergic node, the rostromedial tegmental nucleus (RMTg). Both LHb and RMTg also project to the dorsal raphe nucleus (DR). The organization of LHb and RMTg projections to the DR was investigated using anterograde tracer injections into the LHb or RMTg and confirmed with retrograde tracer injections. To identify the neurochemical phenotype of RMTg-DR projections, we associated in situ hybridization for GAD67 mRNA with immunohistochemical detection of retrograde tracers deposited in the DR. DR target regions of RMTg projections were characterized using double-imunofluorescence techniques for the anterograde tracer deposited into the RMTg and either serotonin or the type 3 vesicular glutamate transporter. We detected a focal direct projection from the medial LHb division to the caudal DR. In contrast the RMTg emits robust GABAergic projections to a central DR subdivision rich in presumptive glutamatergic neurons.

Os comportamentos agonísticos sociais dispostos por animais dominantes e subordinados podem ser notados no paradigma residente intruso. No hipotálamo há o núcleo pré-mamilar ventral (PMv) ligado a um sistema sexualmente dimórfico e relacionado a reprodução e comportamentos agonísticos. A cópula é fundamental para a modulação do comportamento de dominância e aumenta os níveis de CART (Cocaine and Amphetamine Regulated Transcript) no PMv. Animais knockout de Sintase do Óxido Nítrico (NOS) apresentam agressão acentuada. Através da hibridização in situ estudamos a expressão de CART e de NOS nos animais com experiência sexual prévia ao encontro agonístico e sem experiência sexual (naive). No grupo que copulou foi visto aumento na expressão de CART e comportamento diferente do grupo naive visto que buscam a dominância e não apresentam posturas de submissão. Este aumento não foi observado nos níveis de NOS. Sugere-se que a experiência sexual esteja relacionada ao aumento de CART no PMv e possivelmente perda do comportamento subordinado e aumento da busca da dominância. / Aggressive behavior occurs when the interests of one or more individuals conflict. Territory is one of these interests, and the resident intruder paradigm is widely used to observe the expression of social agonistic behaviors. The dominance behavior has been studied under several views and it was shown that it can be raised by the presence of the female, its olfactory clues and by the sexual behavior. In the hypothalamus there is the premammillary ventralis nucleus (PMv) connected to a sexual dimorphic system and related to reproduction and agonistic behaviors. This nucleus was suggested as being involved in the modulation of aggressive behavior, and PMvs neuropeptides can have a direct relation with the expression of those agonistic behaviors. Males exposed to females olfactory clues show an increase in the expression of CART (C Cocaine and Amphetamine Regulated Transcript) in the PMv. Nitric oxide synthase (NOS) knockout animals show increased aggression. In the present investigation, using in situ hybridization we studied the expression of the mRNA of CART and NOS on intruders exposed to the resident-intruder paradigm. Two experimental groups were examined: one with sexual experience before the agonistic encounter and other naïve. It was observed increased expression of CART in the PMv in the sexual-experienced intruder. More, these animals behaved differently from naive intruders, and did not display submissive postures and start searching for dominance. Sexual experienced intruders presented increased expression of CART, but not NOS, mRNA. Thus, suggesting that the sexual experience is related to an increase in CART expression in the PMv and possibly with the lost of submissive behavior and increased search for dominance status.

No description available.

Resveratrol and catechin have behavioral and neuroprotective effects that may be due to their interaction with neuronal ion channels. It was hypothesized that the grape compounds, resveratrol and catechin modulate GABAAA receptors. To address this hypothesis, the effects of resveratrol and catechin were investigated on human recombinant GABAA receptors expressed in HEK-293 cells using electrophysiological techniques.<.p> HEK-293 cells were cultured and transfected using eDNA encoding human GABAA receptors. GABA-evoked currents were recorded from HEK cells 24-48 hours following transfection. Cells were voltage clamped in the whole cell configuration at -60mV using the patch-clamp technique. Ligand-activated currents were recorded and stored, using Win WCP software, on a desktop computer. Resveratrol (1- 100μM) dose-dependently potentiated GABA-evoked currents recorded from α1β2< /sup>γ2 and α1β2 GABAA receptors. Resveratrol did not modulate a α1β2< /sup>γ2 and α1β2 GABAA receptors. Furthermore, resveratrol did not act through the benzodiazepine binding site. The low efficacy and subunit selectivity of resveratrol is a promising discovery for the development of a highly specific GABAergic modulator. Conversely, catechin (1-100αM) dose-dependently inhibited GABA-evoked currents recorded from α1β2 and α1β1 GABAA receptors. The degree of inhibition was the same for both receptor subtypes. Catechin did not modulate α1β2γ2 or α1β1γ2 GABAA receptors. The selectivity of catechin for receptors lacking the γ subunit is similar to the effects of zinc and did not involve the benzodiazephine site on GABAA receptors. This study has shown that catechin and resveratrol are subunit-selective modulators of human GABAA receptors. These compounds could lead to the development of novel agents to be used in treating neurological disorders. These data support the use and study of natural products for the development of agents that act selectively on the nervous system.

No description available.

No description available.

<p>Commensal intestinal microbiota number in the realm of 10¹⁴organisms per gram of colonic contents. This considerable bacterial load is acquired during birth and in the early postnatal days and has a defining, extensive impact on host physiology. We now have persuasive evidence that the intestinal microbiota influence the development of the nervous system. The following body of work describes alterations in the nervous system of germ free mice – mice bred and maintained with no exposure to bacteria of any kind. Here we examine diverse measures of neural activity, ranging from stress reactivity and stress-associated behaviours, to changes in neurochemistry of brain regions mutually involved in feeding and stress, to electrophysiological measures of sensory cells in the enteric nervous system. We see that in the absence of colonizing microbiota that neural activity is considerably altered both peripherally and centrally. Specifically, germ free mice exhibit a reduction in basal anxiety-like behaviour accompanied by consistent changes in mRNA gene expression of plasticity-related genes in brain tissue, lifelong reduction in circulating plasma leptin, increases in mRNA gene expression of hypothalamic leptin receptors and neuropeptide Y, and decreased excitability in sensory neurons in the myenteric plexus of the enteric nervous system. Furthermore, while it appears that central systems responsible for stress may have an early critical window for bacterial-induced change, it would seem that the peripheral enteric nervous system retains plasticity into adulthood. This novel work provides insight into the microbial-gut-brain axis and suggests potential avenues for therapies aimed at treating the frequently comorbid gastrointestinal and psychiatric illnesses.</p> / Doctor of Philosophy (Medical Science)

Computational psychiatry describes psychological phenomena as abnormalities in biological computations. Current available technologies span multiple organizational and temporal domains, but there remains a knowledge gap with respect to neuromodulator dynamics in humans. Recent efforts by members of the Montague Laboratory and collaborators adapted fast scan cyclic voltammetry (FSCV) from rodent experiments for use in human patients already receiving brain surgery. The process of modifying established FSCV methods for clinical application has led improved model building strategies, and a new "random burst" sensing protocol. The advent of random burst sensing raises questions about the capabilities of in-vivo electrochemistry techniques, while opening introducing possibilities for novel approaches. Through a series of in-vitro experiments, this study aims to explore and validate novel electrochemical sensing approaches. Initial expository experiments tested assumptions about waveform design to detect dopamine concentrations by reducing amplitude and duration of forcing functions, as well as distinguishing norepinephrine concentrations. Next, large data sets collected on mixtures of dopamine, serotonin and pH validated a newly proposed "low amplitude random burst sensing" protocol, for both within-probe and out-of-probe modeling. Data collected on the same set of solutions also attempted to establish an order-millisecond random burst sensing approach. Preliminary endeavors into using convolutional neural networks also provided an example of an alternative modeling strategy. The results of this work challenge existing assumptions of neurochemistry, while demonstrating the capabilities of new neurochemical sensing approaches. This study will also act as a springboard for emerging technological developments in human neurochemistry. / Doctor of Philosophy / Neuroscience characterizes nervous system functions from the cellular to the systems level. A gap in available technologies has prevented neuroscientist from studying how changes in the molecular dynamics in the brain relate to psychiatric conditions. Recent efforts by the Montague Laboratory have adapted neurochemistry techniques for use in human patients. Consequently, a new "random burst sensing" approach was developed that challenged existing assumptions about electrochemistry. In this study, in-vivo experiments were conducted to push the limits of electrochemical sensing by reducing the voltage amplitude range and increasing sensing temporal resolution of electrochemical sensing beyond previously established limits. The results of this study offer novel neurochemistry approaches and act as a jumping off point for future technological developments.

Dissertation (PhD)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Obsessive-compulsive disorder (OCD) is characterized by intrusive thoughts (obsessions) and repetiti ve mental acts or behaviours (compulsions) . For many years, it was considered a rather uncommon condition, caused by unconscious conflict, and somewhat resistant to treatment. In recent decades, however, it has emerged that OCD is a highly prevalent disorder, mediated by particular neuroanatomical circuits (e.g. striatal pathways) and neurochemical systems (e.g. the serotonin system), and responsive to treatment with serotonin reuptake inhibitors (SRIs) . Nevertheless, many questions remain; about the specificity of neuroanatomical findings to OCD, about the role of the multiple serotonin (5-HT) receptor subtypes (e.g. 5-HT10)' and about the appropriate pharmacotherapy for patients resistent to SRI treatment? In a series of studies, 1) the neuroanatomy of OCD was assessed by means of magnetic resonance imaging and neuropsychological testing, 2) the neurochemistry of OCD was assessed by means of functional brain imaging after administration of a 5-HT10 agonist, and 3) the pharmacotherapy of OCD was explored in a series of treatment-refractory OCD and OCD spectrum disorder patients using SRI augmentation with a dopamine blocker. Although no significant difference was found in the volume of the caudate in women with OCD and controls, there was a significant correlation between caudate volume and neuropsychological dysfunction in patients, consistent with evidence of striatal involvement in OCD. Functional imaging demonstrated behavioural heterogeneity, but brain-behaviour correlations were positive, consistent with preclinical evidence of a role for the 5-HTlD receptor in the mediation of OCD. Finally, preliminary treatment findings with dopamine blocker augmentation of a SRI were promising, consistent with preclinical understandings of the interactions between the dopamine and serotonin systems. Although oeD is a complex disorder, a number of future research avenues hold promise for providing a thorough delineation of its pathogenesis. / AFRIKAANSE OPSOMMING: Obsessief-kompulsiewe steuring (OKS) word gekenmerk deur indringende gedagtes (obsessies) en herhalende gedagtes of gedrag (kompulsies). Vir baie jare is dit beskou as 'n redelik seldsame toestand wat veroorsaak word deur onbewustelike konflik, en wat in 'n mate teen behandeling weerstandig is. Meer onlangs het dit egter na vore getree as 'n toestand wat baie dikwels voorkom, wat deur spesifieke neuroanatomiese siklusse (bv. striatale bane) en neurochemiese sisteme (bv. die serotonien-sisteem) teweeg gebring word, en wat op behandeling met serotonien heropname inhibeerders (SHIs) reageer. Nogtans is daar steeds baie vrae; oor die spesifisiteit van neuroanatomiese bevindinge vir OKS, oor die rol van die veelvuldige serotonien (5-HT) reseptor subtipes (bv. 5- HT1D), en oor die toepaslike farmakoterapie vir pasiënte wat weerstandig is vir SHI behandeling. In' n reeks van navorsingstudies, is 1.) die neuroanatomie van OKS deur middel van magnetiese resonans beelding en neurosielkundige toetse ondersoek, 2. ) die neurochemie van OKS deur middel van funksionele breinbeelding na toediening van 'n 5-HT1D agonis bepaal, en 3.) die farmakoterapie van OKS in 'n reeks van behandelingsweerstandige OKS en OKS-spektrum steuring pasiënte - waar gebruik gemaak is van SHI aanvulling met 'n dopamien-blokker - ondersoek. Alhoewel daar geen beduidende verskil in die volume van die caudata in vroue met OKS en kontroles gevind is nie, was daar 'n beduidende korrelasie tussen die caudata volume en neurosielkundige wanfunksionering in pasiënte, in ooreenstemming met striatale betrokkenheid in OKS. Funksionele beelding het positief, in demonstreer, maar ooreenstemming met brein-gedrag pre-kliniese heterogeneïteit korrelasies was in gedrag bewyse vir 'n rol vir die 5-HT1D reseptor in die bemiddeling van OKS. Ten laaste, voorlopige behandelingsbevindinge oor dopamienblokker aanvulling van 'n SHI is belowend, in ooreenstemming met v

As ações da atividade física na neuroquímica dos neurônios, com enfoque às proteínas ligantes de cálcio (Ca2+), e o estado de ativação de células gliais da medula espinal do rato foram investigadas em preparados imuno-histoquímicos através da análise morfométrica e microdensitométrica com auxílio do computador. Ratos machos adultos foram divididos em dois grupos: treinado, cujos animais foram expostos à roda de corrida onde realizava atividade física espontânea, por um período de 4 e 14 noites; e sedentário, onde os animais foram mantidos em caixas individualizadas, sem a roda de corrida. Após os períodos determinados, os animais sofreram eutanásia e suas medulas espinais foram processadas para imunohistoquímica. Os ligantes de Ca2+ neuronal e glial foram avaliados pela imunorreatividade das proteínas calbindina e parvalbumina e, ainda, pela imunorreatividade da proteína S100 astrocitária. A atividade física voluntária promoveu uma diminuição na imunorreatividade da proteína calbindina em nível torácico no corno posterior (lâminas I e II de Rexed), assim como no núcleo espinal lateral após 14 dias. No nível lombar, também se observou uma diminuição da imunorreatividade no corno posterior (lâminas I e II de Rexed). Contudo os animais submetidos à atividade física voluntária por 4 dias apresentaram um aumento na área imunorreativa da proteína parvalbumina em relação ao seu controle. Efeito semelhante ocorreu no núcleo dorsal nos grupos que treinaram por 4 e 14 dias. Entretanto, no fascículo cuneiforme ocorreu uma diminuição da imunorreatividade à parvalbumina. Já em relação à proteína S100, os animais treinados apresentaram um aumento na imunorreatividade (spMGV) no corno anterior. Assim, conclui-se que a atividade física voluntária modificou a imunorreatividade das proteínas ligantes de Ca2+ na medula espinal, o que pode estar associado aos mecanismos de ativação intracelular realizados pelo cálcio, bem como a liberação de neurotransmissores na fenda sináptica. / Actions of the physical activity in the neurochemistry focuzing calcium-bindin proteins and the activation of the glial cells in the spinal cord of the rat were investigated with imunohistochemistry over. Male wistar adult rats were divided in two groups: trained, which animals exercised in the wheel running for 4 and 14 nigths; and sedentary, which animals were maintained in private box without wheel running. After that period rats were sacrificed and their spinal cords were processed to imunohistochemistry. Calcium-bindin proteins neuronal (parvalbumin and calbindin) and glial (S100) were evaluted. The activity promoted a decrese in the imunoreativite of the calbindin protein in the torácic level of the posterior horn (lamina I and II of Rexed), and lateral spine nucle after 14 days. In the lombar level, decrese in the posterior horn was also found. Animals submited to physic activity for 4 days showed an increased in the imunoreatived area of parvalbumin. Similar effect was observed all of groups that were treineds for 4 e 14 days. However, in the cuneiforne fascicule, parvalbumin decreased. The S100 protein showed decresed in the anterior horn. In conclusion volunteer phisical activity changed the pattern of the calcium-bindin protein immunoreactivity in the spinal cord, effect than can be associated to neuroplasticity.