<p>Autoimmune polyendocrine syndrome type I (APS) is a monogenous, recessively inherited disease characterised by endocrine and non-endocrine autoimmune manifestations. One fifth of APS I patients suffer from periodic intestinal dysfunction with varying degrees of malabsorbtion, steatorrhea and constipation. Alopecia areata is found in one third of APS I patients. By immunoscreening human cDNA libraries derived from normal human duodenum and scalp with APS I sera, we identified tryptophan hydroxylase (TPH) as an intestinal autoantigen and tyrosine hydroxylase (TH) as a dermal autoantigen. Forty-eight percent (38/80) of the APS I patients had TPH antibodies (Ab) and 44% (41/94) showed TH immunoreactivity. No reactivity against TPH or TH was seen in healthy controls. TPH-Abs showed a statistically significant correlation with gastrointestinal dysfunction (p<0.0001) and TH-Abs were significantly correlated to alopecia (p=0.02). TPH-Ab positive APS I sera specifically immunostained TPH containing enterochromaffin cells in normal duodenal mucosa. In affected mucosa a depletion of the TPH containing EC cells was seen. In enzyme inhibition experiments TPH and TH activity <i>in vitro</i> was reduced by adding APS I sera. TPH and TH together with phenylalanine hydroxylase (PAH) constitute the group of pteridine dependent hydroxylases. These are highly homologous enzymes involved in the biosynthesis of neurotransmitters. Immunoprecipitation of PAH expressed <i>in vitro</i> showed that 27% (25/94) of APS I patients had antibodies reacting with PAH, but no associations with clinical manifestations was observed. An immunocompetition assay showed that the PAH reactivity reflects a cross-reactivity with TPH.</p><p>In conclusion, we have identified TPH and TH as intestinal and dermal autoantigens in APS I, coupled to gastrointestinal dysfunction and alopecia. We have also demonstrated immunoreactivity against PAH in APS I patient sera reflecting a cross-reactivity with TPH.</p>

Autoimmune polyendocrine syndrome type I (APS) is a monogenous, recessively inherited disease characterised by endocrine and non-endocrine autoimmune manifestations. One fifth of APS I patients suffer from periodic intestinal dysfunction with varying degrees of malabsorbtion, steatorrhea and constipation. Alopecia areata is found in one third of APS I patients. By immunoscreening human cDNA libraries derived from normal human duodenum and scalp with APS I sera, we identified tryptophan hydroxylase (TPH) as an intestinal autoantigen and tyrosine hydroxylase (TH) as a dermal autoantigen. Forty-eight percent (38/80) of the APS I patients had TPH antibodies (Ab) and 44% (41/94) showed TH immunoreactivity. No reactivity against TPH or TH was seen in healthy controls. TPH-Abs showed a statistically significant correlation with gastrointestinal dysfunction (p&lt;0.0001) and TH-Abs were significantly correlated to alopecia (p=0.02). TPH-Ab positive APS I sera specifically immunostained TPH containing enterochromaffin cells in normal duodenal mucosa. In affected mucosa a depletion of the TPH containing EC cells was seen. In enzyme inhibition experiments TPH and TH activity in vitro was reduced by adding APS I sera. TPH and TH together with phenylalanine hydroxylase (PAH) constitute the group of pteridine dependent hydroxylases. These are highly homologous enzymes involved in the biosynthesis of neurotransmitters. Immunoprecipitation of PAH expressed in vitro showed that 27% (25/94) of APS I patients had antibodies reacting with PAH, but no associations with clinical manifestations was observed. An immunocompetition assay showed that the PAH reactivity reflects a cross-reactivity with TPH. In conclusion, we have identified TPH and TH as intestinal and dermal autoantigens in APS I, coupled to gastrointestinal dysfunction and alopecia. We have also demonstrated immunoreactivity against PAH in APS I patient sera reflecting a cross-reactivity with TPH.

The brain is a major target site in acute cyanide intoxication, as indicated by several symptoms and signs. Cyanide inhibits the enzyme cytochrome oxidase. This inhibition causes impaired oxygen utilization in all cells affected, severe metabolic acidosis and inhibited production of energy. In this thesis, some neurotoxic effects of cyanide, in particular, the effects on dopaminergic pathways were studied. In a previous study, decreased levels of striatal dopamine and HVA were found after severe cyanide intoxication (5-20 mg/kg i.p.). However, increased striatal dopamine were found in rats showing convulsions after infusion of low doses of cyanide (0.9 mg/kg i.v.), at the optimal dose rate (the dose rate that gives the treshold dose). Increased striatal dopamine synthesis was observed in rats after cyanide treatment and in vitro. Furthermore, in rat, as well as in pig striatal tissue, cyanide dose- dependently increased the oxidative deamination of 5-HT (MAO-A) and DA (MAO-A and -B) but not that of PEA (MAO-B). Thus cyanide affects both the synthesis and metabolism of dopamine. In rats, sodium cyanide (2.0 mg/kg, i.p.) decreased the striatal dopamine Dj- and D2-receptor binding 1 hour after injection. Increased extracellular levels of striatal dopamine and homovanillic acid were also shown after cyanide (2.0 mg/kg; i.p.). DOPAC and 5-HIAA were slightly decreased. This indicates an increased release or an extracellular leakage of dopamine due to neuronal damage caused by cyanide. Thus the effects of cyanide on dopamine Dj- and D2~receptors could in part be due to cyanide-induced release of dopamine. Because of reported changes in intracellular calcium in cyanide-treated animals, the effects of cyanide on inositol phospholipid breakdown was studied. Cyanide seemed not to affect the inositol phospholipid breakdown in vitro. The effects of cyanide on the synthesis and metabolism of brain GAB A were also examined. A decreased activity of both GAD and GAB A-T were found in the rat brain tissue. The reduced activity of GAB A-T, but not that of GAD returned to the control value after adding PLP in the incubation media. The cyanide-produced reduction of GABA levels will increase the susceptibility to convulsions, and could partly be due to GAD inhibition. In conclusion, cyanide affects the central nervous system in a complex manner. Some effects are probably direct. The main part, however, appears to be secondary, e.g. hypoxia, seizures, changes in calcium levels or transmitter release produced by cyanide. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 7 uppsatser</p> / digitalisering@umu

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Evidências crescentes mostram que os distúrbios de sono associados à doença de Parkinson (DP) são mais relacionados à doença per se, do que apenas fenômenos secundários. Dados apresentados pela literatura sugerem a hipótese de que o sistema dopaminérgico nigroestriatal esteja envolvido na regulação de padrões de sono. Demonstrou-se no presente trabalho que uma lesão de 50% dos neurônios dopaminérgicos residentes na substância negra pars compacta (SNpc) foi capaz de gerar um prejuízo em diversos parâmetros de sono em ratos. Essa redução neuronal provocou uma diminuição importante na porcentagem de sono paradoxal durante os três primeiros dias de registro de sono. Observou-se também uma forte correlação (r=0.91) entre o número de neurônios e a porcentagem de sono paradoxal. A partir disso, propomos que os neurônios dopaminérgicos presentes na SNpc possuem um papel fundamental para a regulação dos padrões de sono, particularmente na promoção de sono paradoxal. Em outro experimento, apresentamos evidências de que a proteína tirosina hidroxilase (TH) encontra-se com sua expressão reduzida no sistema dopaminérgico nigroestriatal após um período de 24 h de privação de sono paradoxal (PSP) em camundongos. De acordo com esses resultados, sugerese que a redução da expressão da TH, produzida pela (PSP), possa explicar em parte a existência da supersensibilidade dopaminérgica de receptores D2. As implicações dessas alterações podem reverberar diretamente sobre anormalidades motoras e de sono encontradas em pacientes portadores da DP. xiii Achados eletrofisiológicos demonstraram que o bloqueio dos receptores D2 (por haloperidol) produziu uma redução de sono paradoxal durante o período de rebote, realizado após 96 h de PSP. Essa redução foi acompanhada por um incremento de sono de ondas lentas, o que possivelmente tenha ocorrido em decorrência de um observado aumento de eficiência de sono. Os resultados também indicaram que a administração de piribedil não pôde gerar um aumento adicional de sono paradoxal. Sugerimos a existência de uma ação particular da neurotransmissão dopaminérgica recaindo sobre a ativação dos receptores D2. As evidências demonstradas no presente trabalho e na literatura permitem sugerir que os neurônios dopaminérgicos presentes na SNpc e na aérea tegmental ventral podem ser considerados essenciais para a regulação de sono, em particular no disparo e manutenção do sono paradoxal, respectivamente. Propõe-se que o paradigma que envolve a dopamina como sendo responsável apenas pela vigília, não é totalmente acurado. A teoria proposta nessa tese alega que esse neurotransmissor pode apresentar uma importante participação em ambos os estados: vigília e sono, e que cada estado deva ser gerado por intermédio de diferentes graus de modulação dopaminérgica. A conclusão delineada a partir desses achados é que a dopamina apresenta implicações significantes na regulação de sono, e essa condição particular deve ser considerada em relação ao tratamento de pacientes com a DP. / Dopamine (DA) is critically involved in regulating neural processes responsible for complex movements and emotions. Alterations in central dopaminergic neurotransmission have been implicated in important neurological and psychiatric disorders such as Parkinson’s disease (PD) and schizophrenia. In addition, DA has recently been recognized as instrumental in the regulation of sleep-wake states. Herein, we present evidence that tyrosine hydroxylase (TH) is down-regulated in the nigrostriatal pathway after 24 h of sleep deprivation (SD) in mice. To identify the involvement of DA in SD and sleep rebound (R) we administered reserpine (1 mg/kg) associated to a-methyl-p-tyrosine (aMT) (250 mg/kg) to produce DA depletion, and rotenone (10 mg/kg) to increase striatal DA turnover. Behavioral tests (catalepsy, grasping and open-field) were conducted to evaluate muscular rigidity and motor alterations inflicted by the drugs immediately after SD and R. Western blot and immunohistochemistry demonstrated that SD alone produced important down-regulation on TH protein expression within the substantia nigra (SN), without affecting the number of dopaminergic neurons. Pharmacological depletion of DA or increase of its turnover affected the entire nigrostriatal pathway. We propose that downregulation of TH expression produced by SD greatly explains the existence of supersensitivity of dopaminergic D2 receptors, especially along the nigrostriatal pathway, and suggest a novel role of DA in the mediation of sleep-wake states as a consequence of the modulation of TH protein expression along that pathway. The implications of these alterations may directly reverberate in motor and sleep abnormalities found in patients with PD. / TEDE / BV UNIFESP: Teses e dissertações

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-13T17:36:44Z No. of bitstreams: 1 andersondutrademelo.pdf: 664118 bytes, checksum: 3695f89c95d5ed609cc3f5bd69a7f406 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-10-22T12:58:01Z (GMT) No. of bitstreams: 1 andersondutrademelo.pdf: 664118 bytes, checksum: 3695f89c95d5ed609cc3f5bd69a7f406 (MD5) / Made available in DSpace on 2016-10-22T12:58:01Z (GMT). No. of bitstreams: 1 andersondutrademelo.pdf: 664118 bytes, checksum: 3695f89c95d5ed609cc3f5bd69a7f406 (MD5) Previous issue date: 2008-02-22 / O diabetes reduz a secreção de catecolaminas em resposta a variações glicêmicas, acentuando o quadro de descontrole metabólico dos indivíduos doentes. Diversos estudos têm demonstrado que a hiperglicemia é a principal causa dos problemas decorrentes da instalação do diabetes. Desta forma, o objetivo deste trabalho foi analisar o efeito do diabetes sobre o processo de síntese e secreção de catecolaminas e se o tratamento com insulina reverte as modificações causadas pela doença. Métodos e Resultados: Foram usados ratos Wistar, machos, com 60 dias. O diabetes foi induzido pela injeção intravenosa de estreptozotocina na proporção de 50 mg/Kg de animal. O grupo controle recebeu injeção de solução tampão. Para determinar o protocolo de tratamento com insulina, estudamos o padrão de ingestão alimentar e de variações glicêmicas durante um dia, medindo estes dois parâmetros de hora em hora, durante 24h consecutivas. Foi estabelecido o tratamento com insulina NPH humana na dose de 5U diárias, 1 U às 13 h e 4 U às 19h. Após 15 dias da indução, os animais foram sacrificados e as glândulas adrenais foram retiradas. Com a intenção de caracterizar o efeito do diabetes sobre alguns parâmetros bioquímicos correntemente utilizados como marcadores da doença, foram medidos os níveis de frutosamina, triglicerídeos e colesterol e suas frações. Foi quantificado o conteúdo total de catecolaminas e a secreção basal e a estimulada por altas concentrações de potássio, carbamilcolina e cafeína. As catecolaminas foram dosadas por método fluorimétrico. A expressão de tirosina hidroxilase (TH), enzima reguladora da via de síntese de catecolaminas, foi avaliada por Western Blot. A glicemia foi de 82,82 ± 1,24 mg/dl, 405,74 ± 23,35 mg/dl e 103,72 ± 6,79 mg/dl nos animais controle, diabéticos e diabéticos tratados com insulina (DTI). A variação na massa corporal durante o período experimental foi negativa nos ratos diabéticos, ou seja, eles emagreceram 6,1 ± 3,84 g, enquanto que os animais controles e os diabéticos tratados, aumentaram seus pesos, em média, 36,34 ± 1,8 g e 43,32 ± 3,79 g, respectivamente. O diabetes modificou os níveis de colesterol total, LDL e VLDL, modificações que foram corrigidas pelo tratamento com insulina. Não houve diferença, entre controles e diabéticos, nos níveis de triglicérides, frutosamina e LDH. O tratamento com insulina reduziu significativamente os níveis de frutosamina. O conteúdo total de catecolaminas foi 21,14% menor nos diabéticos sem tratamento, quando comparado aos controles (p<0,05). O tratamento com insulina recuperou os estoques de catecolaminas dos ratos diabéticos. A expressão de TH foi similar em todos os grupos experimentais. A secreção basal e a estimulada por altas concentrações de K+ e por carbamilcolina foi reduzida pelo diabetes em 24,3%, 42,28% e 28,9%, respectivamente. Este efeito não foi corrigido pelo tratamento com insulina. A secreção estimulada pela mobilização de Ca2+ de pools intracelulares sensíveis à cafeína não é afetada pelo diabetes. Os nossos resultados nos permitem concluir que o diabetes afeta a secreção basal de catecolaminas e a estimulada via membrana plasmática e que isto não é determinado pela redução dos estoques de catecolaminas, nem é revertido pelo tratamento com insulina exógena. / The diabetes reduces the catecholamine secretion with hypoglycemic episodes, to turning worse the metabolic disorder of diabetic people. Several studies have shown that hyperglycemia has pivotal role in diabetic complication development. This work studied the effect of diabetes on catecholamine synthesis and secretion and the effects of insulin treatment. Methods and results: 60 days old, male Wistar rats were used. The diabetes was induced by a single intravenous injection of streptozotocin (50mg/Kg body weight). The control group received buffer injection. To establish the protocol of insulin treatment the food consumption and the blood glucose levels were measured during 24h from hour to hour. The insulintreated diabetic rats received human NPH insulin at 1pm (1U) and 7pm (4U). After 15 days of the streptozotocin injection, the rats were sacrificed and the adrenal glands withdrew. To evaluate the effect of diabetes and the insulin treatment, fructosamine, triglycerides, total cholesterol, HDL, LDL and VLDL were measured. The total catecholamine content of adrenal gland and the basal and stimulated catecholamine secretion was quantified. The experiments of stimulated catecholamine secretion were performed with high potassium, carbachol and caffeine. The catecholamines measurement was done by fluorimetric method. The expression of tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine synthesis, was analyzed by western blotting. The glicemia was 82.82 ± 1.24 mg/dl, 405.74 ± 23.35 mg/dl and 103.72 ± 6.79 mg/dl in control, diabetic and insulin-treated diabetic groups, respectively. The body mass of diabetic rats was reduced in 6.1 ± 3.84g and increased on control and insulin-treated diabetic rats, in 36.34 ± 1.8g and 43.32 ± 3.79g, respectively. The diabetes changed total cholesterol, LDL and VLDL plasma levels, alteration reversed by insulin treatment. The triglycerides, fructosamine and LDH levels were not affected by diabetes. The insulin-treated rats showed significant reduction of fructosamine levels. The diabetic rats presented a significant reduction, 21.14% on the catecholamine content when compared to the control group, p<0.05. The insulin treatment recovered the catecholamine stores. The TH expression was similar in all three experimental groups. The diabetes reduced the basal and stimulated catecholamine secretion by 24.3%, 42.28% (high K+) e 28.9% (carbachol).The catecholamine secretion stimulated by mobilization of intracellular Ca2+ pools was not affected by diabetes or insulin treatment. Our results show that diabetes reduces the catecholamine secretion, and this is not consequence of reduction on cell catecholamine stores and it is not reversed by insulin therapy.

It has been postulated that alcoholism is associated with abnormalities in glutamatergic neurotransmission. This study examined the density of glutamate NMDA receptor subunits and its associated proteins in the noradrenergic locus coeruleus (LC) in deceased alcoholic subjects. Our previous research indicated that the NMDA receptor in the human LC is composed of obligatory NR1 and regulatory NR2C subunits. At synapses, NMDA receptors are stabilized through interactions with postsynaptic density protein (PSD-95). PSD-95 provides structural and functional coupling of the NMDA receptor with neuronal nitric oxide synthase (nNOS), an intracellular mediator of NMDA receptor activation. LC tissue was obtained from 10 alcohol-dependent subjects and eight psychiatrically healthy controls. Concentrations of NR1 and NR2C subunits, as well as PSD-95 and nNOS, were measured using Western blotting. In addition, we have examined tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of norepinephrine. The amount of NR1 was lower in the rostral (-30%) and middle (-41%) portions of the LC of alcoholics as compared to control subjects. No differences in the amounts of NR2C, PSD-95, nNOS and TH were detected comparing alcoholic to control subjects. Lower levels of NR1 subunit of the NMDA receptor in the LC implicates altered glutamate-norepinephrine interactions in alcoholism.

Dysfunction of the central noradrenergic and dopaminergic systems is the primary neurobiological characteristic of Parkinson’s disease (PD). Importantly, neuronal loss in the locus coeruleus (LC) that occurs in early stages of PD may accelerate progressive loss of dopaminergic neurons. Therefore, restoring the activity and function of the deficient noradrenergic system may be an important therapeutic strategy for early PD. In the present study, the lentiviral constructions of transcription factors Phox2a/2b, Hand2 and Gata3, either alone or in combination, were microinjected into the LC region of the PD model VMAT2 Lo mice at 12 and 18 month age. Biochemical analysis showed that microinjection of lentiviral expression cassettes into the LC significantly increased mRNA levels of Phox2a, and Phox2b, which were accompanied by parallel increases of mRNA and proteins of dopamine β-hydroxylase (DBH) and tyrosine hydroxylase (TH) in the LC. Furthermore, there was considerable enhancement of DBH protein levels in the frontal cortex and hippocampus, as well as enhanced TH protein levels in the striatum and substantia nigra. Moreover, these manipulations profoundly increased norepinephrine and dopamine concentrations in the striatum, which was followed by a remarkable improvement of the spatial memory and locomotor behavior. These results reveal that over-expression of these transcription factors in the LC improves noradrenergic and dopaminergic activities and functions in this rodent model of PD. It provides the necessary groundwork for the development of gene therapies of PD, and expands our understanding of the link between the LC-norepinephrine and dopamine systems during the progression of PD.

The pesticide/neurotoxin, rotenone, has been shown to cause systemic inhibition of mitochondrial complex I activity, with consequent degeneration of the nigrostriatal pathway, as observed in Parkinson’s disease. A novel intrastriatal rotenone model of Parkinson’s disease was used to examine the neuroprotective effects of valproic acid (VPA) and melatonin, both of which are known to induce neurotrophic gene expression in the central nervous system via mechanisms which may involve epigenetic modulation. In these studies, sham or lesioned rats were treated with either vehicle, VPA (4mg/mL), or melatonin (4µg/mL) in drinking water. Results from a forelimb asymmetry test indicated a significant decrease in use of the contralateral forelimb in rotenone-infused animals, in the third week post-surgery, which was abolished by VPA treatment. Apomorphine administration resulted in significantly higher ipsilateral rotation in rotenone-lesioned (12µg) animals, as compared to controls, which was attenuated by melatonin treatment. Subsequent immunohistochemical examination revealed a decrease in tyrosine hydroxylase immunoreactivity within the striatum and substantia nigra of rotenone-infused animals. VPA or melatonin treatment prevented this decrease in tyrosine hydroxylase in the striatum and substantia nigra. Stereological cell counting indicated a significant decrease in dopamine neurons within the substantia nigra of rotenone-treated animals. Importantly, this loss of dopamine neurons in rotenone-infused animals was blocked by chronic VPA or melatonin treatment. A third study explored whether rotenone infusion into the medial forebrain bundle and substantia nigra in mice could provide a model of Parkinson's disease. Densitometric analysis revealed a significant depletion of tyrosine hydroxylase immunofluorescence within the ipsilateral striatum and substantia nigra of lesioned animals, and a significant bilateral overexpression of α-synuclein in the substantia nigra, as compared to control animals. These novel findings support the use of intracranial rotenone as a Parkinsonian model, and provide a solid platform for future combinatorial therapeutic approaches with VPA and melatonin. / Dissertation / Doctor of Philosophy (PhD)

<p>The brain serotonergic and dopaminergic systems broadly influence our internal experience and the ways in which we interact with the outside environment, with crucial regulatory roles in mood, sleep, appetite and the control of voluntary movement. Serotonin and dopamine neurons are themselves influenced by a wide variety of internal and external factors, many of which remain poorly understood. The central aim of this thesis was to better characterize several of these modulatory influences via exploratory investigations involving pharmaceutical agents or environmental modification. Specifically, I examined the modulatory effects of selective serotonin reuptake inhibitors (SSRIs), atypical neuroleptics and environmental enrichment with exercise on the regulation of brain serotonin and dopamine neurons.</p> <p>This thesis documents, for the first time, that (1) inhibition of the serotonin transporter (SERT) by SSRIs induces a rapid and region-selective reduction of tryptophan hydroxylase (TPH)-immunoreactive neurons in serotonergic brainstem nuclei that persists over a prolonged treatment course; that (2) selective blockade of SERT by SSRIs can rapidly induce a reduction of tyrosine hydroxylase (TH)-positive dopaminergic neurons in the substantia nigra (SN) and the ventral tegmental area (VTA) that, again, persists over a lengthy treatment course; that (3) environmental enrichment with exercise can potentiate the effect of SERT inhibition on SN dopaminergic neurons, but not the dorsal raphe nucleus (DRN) serotonergic neurons; that (4) that SSRI fluoxetine triggers a significant upregulation of microglia in the SN; that (5) environmental enrichment with exercise can reduce TPH immunoreactivity in the DRN and TH immunoreactivity in the SN and VTA, even in the absence of any pharmacological intervention, and finally, that (6) the atypical neuroleptic risperidone significantly reduces TPH in the DRN of both young and aged animals and reduces DRN Nissl counts in aged animals. Taken together, the body of work included in this thesis suggests that SSRIs, atypical neuroleptics and environmental enrichment with exercise can have profound effects on brain serotonergic and dopaminergic neurons, possibly accounting for some of the side effects and therapeutic benefits associated with these interventions.</p> / Doctor of Philosophy (PhD)

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.