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Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xxii, 260 p.; also includes graphics (some col.). Includes bibliographical references (p. 232-260). Available online via OhioLINK's ETD Center

The effect of chloroethylclonidine on nodrenaline-induced contractions of the rat aorta was studied. Chloroethylclonidine (1.5 × 10-5 M) shifted noradrenaline dose-response curve to the right approximately 5000-fold without depressing the maximum. The response to noradrenaline after chloroethylclonidine was not antagonized by phenoxybenzamine (10-7 M), prazosin (10-7 M), WB 4101 (10-7 M) nor yohimbine (10-5 M) and is therefore not mediated via α1-adrenoceptors. These results would suggest that there is a homogenous population of chloroethylclonidine-sensitive α1-adrenoceptors in the rat aorta and that chloroethylclonidine treatment reveals a non-α-adrenoceptor noradrenaline binding site in this tissue.

No / Earlier it has been shown that human proliferating/undifferentiated basal keratinocytes hold the full capacity for autocrine catecholamine synthesis/degradation and express b2-adrenoceptors (b2-AR). In this report, we show that human melanocytes also express all of the mRNA and enzymes for autocrine synthesis of norepinephrine but fail to produce epinephrine. So far, it was established that human melanocytes express b1-AR which are induced by norepinephrine yielding the inosine triphosphate diacylglycerol signal. The presence of catecholamine synthesis and the b2-AR signal escaped definition at that time. Using RT-PCR, immunofluorescence and radioligand binding with the b2-AR antagonist (-)-[3H]CGP 12177, we show here that human melanocytes express functional b2-AR (4230 receptors per cell) with a Bmax at 129.3 and a KD of 3.19 nM but lack b1-AR expression. 2-AR stimulation with epinephrine 10-6 M and salbutamol 10-6¿10-5 M yielded a strong cyclic adenosine monophospate (cAMP) response in association with upregulated melanin production. Taken together these results indicate that the biosynthesis and release of epinephrine (10-6 M) by surrounding keratinocytes can provide the cAMP response leading to melanogenesis in melanocytes via the b2-AR signal. Moreover, the discovery of this catecholaminergic cAMP response in melanocytes adds a new source for this important second messenger in melanogenesis.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / "May 2008" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Thesis (Ph. D. in Molecular Physiology and Biophysics)--Vanderbilt University, Aug. 2009. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D. in Neuroscience)--Vanderbilt University, Aug. 2009. / Title from title screen. Includes bibliographical references.

Orientador: Dora Maria Grassi-Kassisse / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-13T16:45:10Z (GMT). No. of bitstreams: 1 Francesconi_ElainePatriciaMaltezSouza_D.pdf: 3201819 bytes, checksum: 12b57dbd9c491f94ccbc38e657b254fe (MD5) Previous issue date: 2008 / Resumo: O adipócito é a unidade funcional do tecido adiposo branco e o principal reservatório de energia, tendo um papel chave na investigação fisiológica dos mecanismos controladores da estocagem e mobilização de lipídeos e hoje sabe-se ser um importante sítio produtor de lactato. A obesidade e o diabetes tipo II estão associados, no homem, com um aumento na concentração de lactato sanguíneo e é mediado pelo adrenoceptor subtipo a1. Iniciamos este trabalho avaliando a relação das concentrações plasmáticas de glicose, insulina e lactato em indivíduos normais e indivíduos obesos mórbidos antes e durante a realização do clamp euglicêmico-hiperinsulinêmico. Apenas a insulinemia no jejum estava aumentada significativamente no grupo de homens obesos o que sugere fortemente que existe uma menor sensibilidade à insulina neste grupo experimental. O índice de HOMA neste estudo apontou para uma maior resistência insulinica no grupo de homens obesos, que foi significativamente maior principalmente ao final do clamp, sendo inclusive maior para homens obesos em relação a mulheres obesas. Verificamos uma inter-relação importante com a hiperinsulinemia, pois á medida que a insulina aumenta ao longo do clamp, a concentração de lactato decresce significativamente. As concentrações plasmáticas de lactato apresentaram-se bastante elevadas em indivíduos com IMC entre 40-55 Kg/m2, diminuindo â medida que o IMC estava próximo de 70 kg/m2. No tempo 180 de clamp do grupo obeso, a concentração de lactato caiu a ponto de alcançar numericamente os valores basais do seu respectivo grupo controle. Os adipócitos isolados de obesos mórbidos produziram mais glicerol em todas as concentrações utilizadas de noradrenalina em relação ao grupo de eutróficos, inclusive no basal. Quando foi adicionado o prazosin (mM), houve um aumento na produção de glicerol. Em nossos ensaios observamos que o tecido adiposo isolado de obesos apresenta uma produção basal de lactato significativamente elevada. Quando o estímulo utilizado foi a noradrenalina, a produção foi significativamente maior em adipócitos isolados de obesos quando comparados a eutróficos. A quantidade de lactato produzida pela noradrenalina em adipócitos isolados de obesos foi semelhante àquela produzida pela cirazolína, agonista seletivo de adrenoceptores a1. Nenhum antagonista utilizado, prazosin, WB4I04 ou BMY7378, produziu qualquer efeito sobre a produção de lactato, seja em eutróficos ou obesos. Quando a produção de lactato em adipócitos isolados foi induzida pela insulina, não houve diferença significativa na quantidade de lactato produzida por adipócitos de obesos quando comparados com eutróficos, exceto na concentração de 500 mU/ml. A estimulação máxima induzida pela insulina em eutróficos foi de 3 vezes e foi maior que aquela observada em adipócitos isolados de obesos que foi de 2,4 vezes. Estes resultados permitem inferir que não é a insulina o principal secretagogo de lactato responsável pela produção aumentada em adipócitos isolados de obesos. Por outro lado, quando co-íncubamos noradrenalina com crescentes concentrações de insulina pudemos observar uma produção de lactato significativamente mais elevada, em todos os pontos, proveniente de adipócitos isolados de obesos. Podemos concluir que os adipócitos de indivíduos obesos produzem lactato diferencial mente em relação ao gênero, e este lactato pode estar sendo usado em outras vias metabólicas auxiliando no desencadeamento das patologias relacionadas à obesidade / Abstract: The adipocyte is the functional unit of fat white and the main reservoir of energy, taking a key role in research physiological mechanisms of control of storage and mobilization of lipids and today it is known to be an important site producer of lactate. Obesity and type II diabetes are associated, in humans, with an increase lactate concentration in the blood. We started this work lactate and is mediated by adrenoceptor subtype evaluating the relationship plasma concentrations of glucose, insulin and lactate in normal and morbid obese subjects before and during the clamp euglicemico-hiperinsulinemico. Only in fasting insulin was increased significantly in the group of obese men which strongly suggests that there is less sensitivity to insulin in this group experimental. The HOMA index of this study pointed to a larger group of insulin resistance in obese men, which was significantly higher mainly the end of the clamp, and even higher for obese men regarding obesity women. We find an important inter-relationship with hyperinsulinemia, because that will measure the insulin increases over the clamp, the concentration of lactate decreases significantly. Plasma concentrations of lactate had to be quite high in individuals with BMI between 40-55 Kg/m2, decreasing as a BMI of 70 kg/m2 was next. At the time 180, clamp the obese group, the concentration of lactate fell about to reach numerically the baseline of their respective control group. The isolated adipocytes of obese morbid produced more glycerol concentrations used in all of norepinephrine in the group of eutrophic, including the basement. When the addition of prazosin (1 M) there was an increase in the production of glycerol. In our tests found m. that the fat isolated from obese presents a production base of lactate significantly high. When the stimulation was used to norepinephrine, the production was significantly higher in isolated adipocytes of obese compared to eutrophic. The amount of lactate produced by norepinephrine in isolated adipocytes of obese was similar to that produced by cirazolina, of selective I. None antagonist used, prazosin, WB4104 or BMY7378,a adrenoceptor agonist produced no effect on the production of lactate, in eutrophic or obese. When the production of lactate in isolated adipocytes was induced by insulin, there was no significant difference in the amount of lactate produced by adipocytes of mU / ml. The obese compared with eutrophic, except to the concentration of 500 maximum stimulation induced by insulin in eutrophic was 3 times and was higher than that observed in isolated adipocytes of obese which was 2.4 times. These results indicate that it is not the main insulin secretagogo of lactate responsible for increased production in isolated adipocytes of obese. On the other hand, when co-incubated with noradrenaline the concentrations of insulin have seen a lactate production significantly higher, at all points, from isolated adipocytes of obese. We can conclude that adipocytes of obese individuals produce lactate differentially in relation to gender, and this lactate may be being used in other metabolic pathways helping to trigger the diseases related to obesity / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

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