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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

From achiral to chiral analysis of citalopram

Carlsson, Björn January 2003 (has links)
Within the field of depression the “monoamine hypothesis” has been the leading theory to explain the biological basis of depression. This theory proposes that the biological basis of depression is due to a deficiency in one or more of three key neurotransmitter systems, namely noradrenaline, dopamine and serotonin which are thought to mediate the therapeutic actions of virtually every known antidepressant agent. Citalopram is a selective serotonin-reuptake inhibitor (SSRI) used for the treatment of depression and anxiety disorders. Citalopram is a racemic compound, in other words composed of a 50:50 mixture of two enantiomers (S-(+)-citalopram and R-(-)-citalopram) and with one of the enantiomers (S-(+)-citalopram) accounting for the inhibitory effect. At the time of introduction of citalopram the physician needed a therapeutic drug monitoring service to identify patients with interactions, compliance problems and for handling questions concerning polymorphic enzymes and drug metabolism. An achiral analytical separation method based on solid-phase extraction followed by high-performance liquid chromatography (HPLC) was developed for routine therapeutic drug monitoring (TDM) of citalopram and its two main demethylated metabolites. As the data available on citalopram were from achiral concentration determinations and to be able to further investigate citalopram enantiomers effects and distribution, a chiral method for separation of the enantiomers of citalopram and its demethylated metabolites was established. The advances within chiral separation techniques have made measurement of the concentrations of the individual enantiomers in biological fluids possible. The process behind enantioselective separation is however not fully understood and the mechanism behind the separation can be further scrutinized by the use of multivariate methods. A study of the optimization and characterization of the separation of the enantiomers of citalopram, desmethylcitalopram and didesmethylcitalopram on an acetylated ß-cyclodextrin column, by use of two different chemometric programs - response surface modelling and sequential optimization was performed. Sequential optimization can be a quicker mean of optimizing a chromatographic separation; response surface modelling, in addition to enabling optimization of the chromatographic process, also serves as a tool for learning more about the separation mechanism. Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent, despite the increasing use of citalopram in these age groups. A study was initiated to investigate adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites. The ratios between the S- and R-enantiomers of citalopram and didesmethylcitalopram were in agreement with studies involving older patients. The concentrations of the S-(+)- and R-(-) enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the polymorphic CYP2C19 enzyme. Even though the SSRIs are considered less toxic compared with older monoamine-active drugs like the tricyclic/tetracyclic antidepressants, the risk of developing serious side effects such as ECG abnormalities and convulsions has been seen for citalopram, when larger doses have been ingested. Furthermore, fatal overdoses have been reported where citalopram alone was the cause of death. Data on the toxicity of each of the enantiomers in humans have not been reported and no data on blood levels of the enantiomers in cases of intoxication have been presented. An investigation was initiated on forensic autopsy cases where citalopram had been found at the routine screening and these cases were further analysed with enantioselective analysis to determine the blood concentrations of the enantiomers of citalopram and metabolites. Furthermore the genotyping regarding the polymorphic enzymes CYP2D6 and CYP2C19 were performed. In 53 autopsy cases, we found increasing S/R ratios with increasing concentrations of citalopram. We found also that high citalopram S/R ratio were associated with high parent drug to metabolite ratio and may be an indicator of recent intake. Only 3.8 % were found to be poor metabolizers regarding CYP2D6 and for CYP2C19 no poor metabolizer was found. Enantioselective analysis of citalopram and its metabolites can provide valuable information about the time that has elapsed between intake and death. Genotyping can be of help in specific cases but the possibility of pharmacokinetic interactions is apparently a far greater problem than genetic enzyme deficiency. / On the day of the public defence the status of article IV was: Submitted.
122

The scanner as a stressor: Evidence from subjective and neuroendocrine stress parameters in the time course of a functional magnetic resonance imaging session

Mühlhan, Markus, Lüken, Ulrike, Wittchen, Hans-Ulrich, Kirschbaum, Clemens 13 August 2013 (has links) (PDF)
Subjects participating in magnetic resonance imaging (MRI) examinations regularly report anxiety and stress related reactions. This may result in impaired data quality and premature termination of scans. Moreover, cognitive functions and neural substrates can be altered by stress. While prior studies investigated pre–post scan differences in stress reactions only, the present study provides an in-depth analysis of mood changes and hormonal fluctuations during the time course of a typical fMRI session. Thirty-nine subjects participated in the study. Subjective mood, salivary alpha-amylase (sAA) and cortisol were assessed at six time points during the lab visit. Associations between hormonal data and neural correlates of a visual detection task were observed using a region of interest approach applied to the thalamic region. Mood and hormonal levels changed significantly during the experiment. Subjects were most nervous immediately after entering the scanner. SAA was significantly elevated after MRI preparation. A subgroup of n = 5 (12.8%) subjects showed pronounced cortisol responses exceeding 2.5 nmol/l. Preliminary fMRI data revealed an association between sAA levels and left thalamic activity during the first half of the experiment that disappeared during the second half. No significant correlation between cortisol and thalamic activity was observed. Results indicate that an fMRI experiment may elicit subjective and neuroendocrine stress reactions that can influence functional activation patterns.
123

Alpha-2 Adrenoceptors in the Paraventricular Thalamic Nucleus: Effects of Agonist Stimulation and Chronic Psychosocial Stress / Alpha-2 adrenerge Rezeptoren im Nucleus paraventricularis thalami: Effekte der Stimulation mit Agonisten und chronischem psychosozialen Stress

Heilbronner, Urs 26 October 2005 (has links)
No description available.
124

New genetic mouse models for neurodegenerative diseases: Contribution of noradrenaline to Alzheimer’s disease pathogenesis and creation of a new genetic model for Parkinson’s disease.

Martinez Hernandez, Ana C. 18 November 2011 (has links)
No description available.
125

THE HUMAN COSTS AND BENEFITS OF WORK: JOBLOAD, SELF-PERCEIVED PERFORMANCE, AND EMPLOYEE WELLBEING.

Miller, Peta, Peta.Miller@dewr.gov.au, petajohnmiller@bordernet.com.au January 2004 (has links)
The primary purpose of this project was to investigate some relationships between workload and employee wellbeing. The necessary first stage was to formulate a theoretical framework � the JobLoad Model � to support a comprehensive and detailed investigation of the main factors that contribute to a job's workload. Building on the ergonomics concept of �workload�, this Model incorporates task- and job-level factors that have been identified within the research literatures of physical and cognitive ergonomics as important; additional constructs were added to take account of additional factors shown to be relevant to employee wellbeing, drawing on evidence from occupational health and organizational psychology literatures. Using this framework, available questionnaire-based measurement instruments for assessing workload and employee wellbeing were reviewed, new items were developed as required, and the JobLoad Index (JLI) was developed. The JLI was used to collect data from public servants in two different workplaces, with participation rates of 63% and 73% respectively. Relationships were determined between major task, job and organisational environment factors, self-perceived performance adequacy, and various aspects of employee wellbeing including job satisfaction, physical discomfort and psychological fatigue, stress and arousal. For a sub-sample of participants in one of the two workplaces, levels of adrenaline, noradrenaline and cortisol were also measured from 24-hour urine collections. The factors measured by the JLI accounted for a very substantial proportion of variance in these various dimensions of work-related wellbeing. The results provide potentially very useful insights into the relative influences of a wide range of work- and job-related variables on people's perceived abilities to cope with their job demands, and on several aspects of their wellbeing. Further, the importance of measuring multiple dimensions of wellbeing, and differentiating their separate sets of work-related determinants, was well demonstrated. Finally, and perhaps most significantly, this study has identified the powerful role that self-perceived performance plays as an intervening variable between job demands and people's work-related wellbeing.
126

Função da neurotransmissão noradrenérgica do núcleo medial da amígdala na modulação do sistema cardiovascular em ratos / Noradrenergic neurotransmission function of the medial nucleus of the amygdala in the modulation of the cardiovascular system in rats.

Eduardo Albino Trindade Fortaleza 21 March 2013 (has links)
RESUMO FORTALEZA, E. A. T. Função da neurotransmissão noradrenérgica do núcleo medial da amígdala na modulação do sistema cardiovascular em ratos. 2013. 153p. Tese (Doutorado) Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, 2013. O núcleo medial da amígdala (NMA) está envolvido no controle de uma variedade de processos fisiológicos e comportamentais, dentre eles, a regulação do sistema cardiovascular durante situações aversivas. Além disso, existem evidências indicando a presença de receptores noradrenérgicos no NMA e que os níveis de noradrenalina (NA) no NMA aumentam quando animais são submetidos ao modelo de estresse por restrição (ER). Portanto, o presente estudo foi dividido em duas partes: 1) avaliamos os efeitos da microinjeção local de NA no NMA de ratos, bem como os receptores locais e os mecanismos periféricos envolvidos na sua mediação e 2) investigamos o papel desempenhado pela neurotransmissão noradrenérgica do NMA sobre as respostas cardiovasculares causadas pelo ER. A primeira parte dos nossos resultados indicou que doses crescentes de NA (3, 9, 27 ou 45nmol/100nL) microinjetadas no NMA causavam respostas pressoras e bradicardicas de maneira dose-dependente em ratos não anestesiados. Os efeitos da NA no NMA foram abolidos pelo pré-tratamento local com antagonista de receptores 2-adrenérgicos (RX821002, 10 nmol/100nL), porém não foram alterados pelo pré-tratamento com antagonista de receptores 1adrenérgicos (WB4101, 10 nmol/100nL). A magnitude da resposta pressora à NA no NMA foi aumentada pelo pré-tratamento intravenoso (i.v.) com o bloqueador ganglionar pentolínio (5mg/kg) e foi significativamente reduzida pelo pré-tratamento i.v. com antagonista dos receptores vasopressinérgicos do tipo V1 dTyr(CH2)5(Me)AVP (50 g/Kg) sugerindo que o mecanismo periférico envolvido nestas respostas cardiovasculares é a liberação de vasopressina na circulação sanguínea. Como estruturas finais participando das respostas cardiovasculares desencadeadas pela microinjeção de NA no NMA, foi observado o possível envolvimento dos núcleos paraventricular (NPV) e supra-óptico (NSO) do hipotálamo, que sintetizam vasopressina. O bloqueio de sinapses, tanto no NPV quanto no NSO, com cloreto de cobalto (CoCl2, 1mM/100nL), reduziu as respostas cardiovasculares desencadeadas pela microinjeção de NA no NMA, sugerindo que ambos os núcleos são responsáveis pela liberação de vasopressina em resposta à NA no NMA. Na segunda parte deste estudo, os resultados mostraram que a microinjeção bilateral de WB4101, antagonista seletivo dos receptores 1- adrenérgicos (10, 15 e 20nmol/100nL) no NMA 10 min antes do ER, reduziu a resposta taquicárdica evocada pelo ER, de maneira dose-dependente. Em contraste, a microinjeção bilateral de RX821002, antagonista seletivo dos receptores 2- adrenérgicos (10, 15 e 20nmol/100nL) no NMA 10 min antes do ER, aumentou a resposta taquicárdica evocada pelo ER de maneira dose-dependente. Ambos os tratamentos não causaram alterações na resposta pressora observada nos animais submetidos ao ER. Estes resultados sugerem que receptores 1- e 2-adrenérgicos no NMA desempenham papel facilitatório e inibitório, respectivamente, na resposta taquicárdica durante o ER. Além disso, a microinjeção bilateral de propranolol, antagonista não seletivo dos receptores -adrenérgicos (10, 15 e 20nmol/100nL), no MNA 10 min antes do ER, causou aumento na resposta taquicárdica apenas quando os animais foram pré-tratados com a dose de 15 nmol, sem efeito significativo sobre a resposta pressora observada durante o ER. Este resultado indica que receptores -adrenérgicos no NMA desempenham um papel inibitório sobre a frequência cardíaca durante o ER. Uma vez que foi observada a participação dos receptores - adrenérgicos, realizamos o pré-tratamento com os antagonistas seletivos dos receptores 1- e 2- adrenérgicos, CGP 20712 e ICI 118,551, respectivamente. A microinjeção bilateral de ICI 118,551 (10, 15 e 20nmol/100nL) no NMA aumentou as respostas taquicárdicas ao ER após a microinjeção das doses de 15 e 20 nmol. Esse efeito foi semelhante ao observado após o tratamento prévio com propranolol, na dose de 15 nmol, sem efeito significativo sobre a resposta da pressora durante o ER. Porém, o pré-tratamento com o CGP 20712 (10, 15 e 20 nmol/100 nL) causou um efeito oposto sobre a resposta taquicárdica evocada pelo ER, ocorrendo uma redução da resposta taquicárdica que foi observada apenas após a dose de 20 nmol no NMA, sem efeito significativo sobre a resposta pressora evocada pelo ER. Esses resultados sugerem que os receptores 2-adrenérgicos desempenham influência inibitória sobre a resposta taquicárdica, ao passo que, os receptores 1-adrenérgicos desempenham influência facilitatória na resposta taquicárdica evocada pelo ER. / ABSTRACT FORTALEZA, E. A. T. Noradrenergic neurotransmission function of the medial nucleus of the amygdala in the modulation of the cardiovascular system in rats. 2013. 153p. Thesis (Doctoral) School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 2013. The medial amygdaloid nucleus (MeA) regulates a variety of physiological and behavioral processes, as well as regulation of the cardiovascular system during aversive situations. Moreover, there is evidence indicating that noradrenergic receptors are present into the MeA and that the levels of noradrenaline (NA) in this nucleus increases when animals are submitted to acute restraint model. Therefore, this study was divided into two parts: 1) we tested the effects of local NA microinjection into the MeA on cardiovascular responses in unaesthetized rats. Moreover, we describe the type of adrenoceptors activated and the peripheral mechanisms involved in the cardiovascular responses and 2) we investigated the involvement of MeA adrenoceptors in the modulation of cardiovascular responses that are observed during acute restraint. The first part of our results indicated that increasing doses of NA (3, 9, 27 or 45 nmol/ 100nL) microinjected into the MeA of unanesthetized rats caused dose-related pressor and bradycardiac responses. The cardiovascular effects of NA were abolished by MeA local pretreatment with 10 nmol/ 100nL of the specific 2-adrenoceptor antagonist RX821002, but were not affected by local pretreatment with 10 nmol/100nL of the specific 1-adrenoceptor antagonist WB4101. The magnitude of pressor response evoked by NA microinjected into the MeA was potentiated by intravenous pretreatment with the ganglion blocker pentolinium (5 mg/kg, i.v.) and blocked by intravenous pretreatment with the selective V1 vasopressin antagonist dTyr (CH2)5(Me) AVP (50 g/Kg, i.v.). Our results suggest that microinjection of NA into the MeA of unanesthetized rats activates local 2- adrenoceptors, evoking pressor and bradycardiac responses, which are mediated by vasopressin release in the blood circulation. The vasopressin is synthesized by magnocellular cells of paraventricular (PVN) and supraoptic nucleus (SON) of the hypothalamus. Thus, it was investigated the role of these hypothalamic nucleus on the cardiovascular pathway activated by the microinjection of NA into the MeA. Pressor and bradycardiac responses to NA (27nmol/100nL) were blocked when cobalt chloride (CoCl2, 1mM/100nL) was microinjected into the PVN or SON, thus indicating that both hypothalamic nucleus are responsible for the mediation of the cardiovascular responses evoked by NA microinjection into the MeA. Our results suggest that pressor and bradycardic responses caused by NA microinjection into the MeA are mediated by magnocellular neurons in the PVN and SON. In the second part of this study Male Wistar rats received bilateral microinjections of the selective 1-adrenoceptor antagonist WB4101 (10, 15, and 20 nmoL/100nL) or the selective 2-adrenoceptor antagonist RX821002 (10, 15, and 20 nmoL/nL) into the MeA, 10 min before the exposure to acute restraint. The injection of WB4101 into the MeA reduced the restraint-evoked tachycardia. In contrast, the injection of RX821002 increased the tachycardia. Both drugs had no effect on the BP increase observed during the acute restraint. Our findings indicate that 1 and 2-adrenoceptors in the MeA play different roles in the modulation of the HR increase evoked by restraint stress in rats. Results suggest that 1-adrenoceptors and 2-adrenoceptors respectively mediate the MeA facilitatory and inhibitory influences on restraint-related HR responses. Moreover, we investigated the involvement of -adrenoceptors in the MeA in cardiovascular responses evoked in rats submitted to an acute restraint stress. We first pretreated Wistar rats with the nonselective -adrenoceptor antagonist propranolol, microinjected bilaterally into the MeA (10, 15, and 20 nmol/100nL) 10 min before exposure to acute restraint. The pretreatment with propranolol did not affect the BP increase evoked by restraint. However, it increased the tachycardiac response caused by acute restraint when animals were pretreated with a dose of 15 nmol, without a significant effect on the BP response. This result indicates that -adrenoceptors in the MeA have an inhibitory influence on restraintevoked HR changes. Pretreatment with the selective 2- adrenoceptor antagonist ICI 118,551 (10, 15, and 20 nmol/100 nL) significantly increased the restraint evoked tachycardiac response after the doses of 15 and 20 nmol, an effect that was similar to that observed after the pretreatment with propranolol at the dose of 15 nmol, without a significant effect on the BP response. Pretreatment of the MeA with the selective 1-adrenoceptor antagonist CGP 20712 (10, 15, and 20 nmol/100nL) caused an opposite effect on the HR response, and a significant decrease in the restraint-evoked tachycardia was observed only after the dose of 20nmol, without a significant effect on the BP response. Because propranolol is an equipotent antagonist of both 1 and 2-adrenoceptors, and opposite effects were observed after the treatment with the higher doses of the selective antagonists ICI 118,551 and CGP 20712, the narrow window in the dose-response to propranolol could be explained by a functional antagonism resulting from the simultaneous inhibition of 1 and 2-adrenoceptors by the treatment with propranolol.
127

Efeitos da terapia estrogênica sobre a neuroquímica de fêmeas em modelo animal de perimenopausa (rata) induzida pelo 4-diepóxido de vinilciclohexano / Effects of estrogen therapy on neurochemistry in animal model of perimenopause (female rat)induced by 4-vinylcyclohexene diepoxide

Nayara Pestana de Oliveira 26 February 2018 (has links)
A perimenopausa representa a transição da vida reprodutiva para não reprodutiva. É geralmente caracterizada por alterações neuroendócrinas, metabólicas e comportamentais, um possível resultado da depleção folicular ovariana e consequente redução do número de folículos ovarianos. É o período em que as mulheres podem apresentar maior susceptibilidade a manifestar transtornos afetivos e de ansiedade. A exposição de roedores ao resíduo químico 4-diepóxido de vinilciclohexeno (VCD) é um modelo bem estabelecido para estudos sobre perimenopausa, pois o VCD acelera o processo natural de atresia folicular. Embora as concentrações plasmáticas de estradiol estejam normais ou elevadas durante a perimenopausa, a terapia com estradiol pode ser benéfica para mulheres sintomáticas na perimenopausa. Portanto, o objetivo do presente trabalho foi investigar se a depleção folicular gradativa acelerada pelo VCD resulta em alterações na neuroquímica de ratas fêmeas em núcleos cerebrais que controlam o humor, além de avaliar se o estradiol seria capaz de reverter as possíveis alterações. Ratas da linhagem Wistar (28 dias pós-natal) receberam diariamente, durante 15 dias consecutivos, injeções subcutâneas de VCD (160 mg / kg) ou óleo de milho (O). Aproximadamente 55 dias após a primeira injeção, cápsulas de silastic contendo 17?-estradiol (E) ou O foram inseridas subcutaneamente (Grupos O+O; VCD+O; VCD+E). Cerca de 21 dias após o implante das cápsulas, as ratas dos grupos O+O e VCD+O foram decapitadas na manhã do diestro, enquanto que as do grupo VCD+E foram decapitadas exatamente 21 dias após o implante das cápsulas contendo estradiol, entre 0900 h e 1100 h. O sangue foi colhido para avaliação das concentrações plasmáticas de estradiol e progesterona por radioimunoensaio (RIE). Os cérebros foram removidos para microdissecção do hipocampo, amígdala, Locus coeruleus (LC) e Núcleo Dorsal da Rafe (NDR), para posterior análise dos níveis de RNAm para os receptores de progesterona (PR) e estradiol do tipo beta (ER?) por meio de RT/PCR. Este experimento foi replicado para remoção do hipocampo e amígdala para dosagem dos conteúdos de noradrenalina (NA) e serotonina (5-HT) por meio de cromatografia líquida de alta performance, seguida de detecção eletroquímica (HPLC/ED). Outro conjunto de ratas submetidas às mesmas condições10 experimentais foi perfundido para imunohistoquímica para TPH no NDR e TH no LC. Como esperado, na periestropausa (grupo VCD+O) as concentrações plasmáticas de estradiol não foram diferentes daquelas das ratas controles (O+O). As concentrações plasmáticas de progesterona na periestropausa foram menores que as do grupo controle, o que foi revertido pelo estradiol. No LC, a expressão de PR na periestropausa foi igual à das ratas controles, enquanto a expressão do ER? foi menor; a terapia com estradiol não modificou a expressão de nenhum destes receptores. A densidade de neurônios noradrenérgicos (TH+) no LC não foi alterada nem pela depleção folicular nem pela terapia estrogênica. Na periestropausa, o conteúdo de NA foi menor na amígdala, mas não no hipocampo, e o estradiol não alterou este conteúdo em nenhuma das áreas. No NDR, a expressão de PR e de ER? nas ratas na periestropausa foi menor que nas ratas controles; o estradiol preveniu o declínio da expressão de ER?, mas não de PR. O NDR foi analisado separadamente por toda a extensão rostro-caudal em 3 níveis anatômicos: rostral, médio e caudal, cada um dividido em 3 sub-regiões: lateral, dorsal e ventral. O número de neurônios serotonérgicos (TPH+) no NDR foi menor na periestropausa, e o estradiol foi capaz de reverter esse efeito, atuando principalmente na região caudal. A expressão gênica de PR não foi alterada nem pela depleção folicular nem pela terapia estrogênica tanto na amígdala como no hipocampo. A expressão de ER? também não foi diferente na periestropausa, quando comparada ao grupo controle, mas o estradiol aumentou esta expressão no hipocampo. Tanto na amígdala como no hipocampo houve redução no conteúdo de 5-HT na periestropausa e estradiol foi capaz de reestabelecer os níveis deste neurotransmissor aos valores controles apenas no hipocampo. Estes dados elucidam, pelo menos em parte os mecanismos do efeito positivo da terapia estrogênica nos sintomas de mulheres normoestrogênicas na perimenopausa. Estes efeitos parecem não envolver de forma importante o sistema noradrenérgico central, mas resultar do aumento da biossíntese de progesterona periférica em associação com a regulação positiva de ER? no NDR e hipocampo, que parece potencializar a via serotonérgica NDR/HPC. Portanto, o desenvolvimento de novas terapias que ativem os ER? pode ser uma alternativa para obter os efeitos positivos da ação do estradiol, eliminando os efeitos colaterais das terapias de estradiol que normalmente resultam da ativação do ER?. / Perimenopause represents the transition from reproductive to non-reproductive life. It is usually characterized by neuroendocrine, metabolic and behavioural changes, which result from a follicular depletion and reduced number of ovarian follicles. During this period, women are more likely to express mood disorders and anxiety. The exposure of animals to diepoxide 4-vinylcyclohexene (VCD) is a well-established experimental model for perimenopause studies, as VCD induces loss of ovarian small follicles (primary and primordial) in mice and rats by accelerating the natural process of atresia. Although estrogens levels are normal or even high during perimenopause, estrogen therapy can be beneficial for symptomatic perimenopausal women. The aim of this study was to investigate whether gradual follicular depletion induced by VCD results in changes in the neurochemistry of female rats in brain nuclei that control mood and the role of estradiol on these changes. Female rats (28 days) were daily injected with VCD or corn oil (O) for 15 days. Around 55 days after the first injection, pellets of 17?-estradiol (E) or O were inserted s.c (Groups O+O; VCD+O; VCD+E). Around 21 days after, rats O+O and VCD+O were decapitated between 0900 h and 1100 of diestrus while rats VCD+E were decapitated exactly 21 days after the onset of E therapy. Another set of rats followed the same experimental design and were perfused for TH and TPH immunohistochemistry in Locus coeruleus (LC) and Dorsal Raphe Nuclei (DRN), respectively. Blood was collected for estradiol and progesterone measurement by radioimmunoassay (RIA). The brains were removed from decapitated rats to punch out LC, DRN, hippocampus and amygdala to analyse the expression of mRNA for ER? and PR by RT/PCR. This experiment was replicated to punch out the hippocampus and amygdala for the determination of noradrenaline (NE) and serotonin (5-HT) contents by High Performance Liquid Chromatography, followed by Electrochemical Detection (HPLC/ED). As expected, plasma concentrations of estradiol were not different from those of control rats (O + O). Plasma concentrations of progesterone in the periestropause were lower than those in the control group, which was reversed by estradiol. In the LC, the PR expression in the periestropause was similar to that of the control rats, whereas the ER? expression was lower; estradiol therapy did not modify the expression of any of these receptors. The12 density of noradrenergic (TH +) neurons in LC was not altered by either follicular depletion or estrogen therapy. In periestropause, NA content was lower in the amygdala, but not in the hippocampus, and estradiol did not alter this content in any of the areas. In NDR, the expression of PR and ER? in periestropausal rats was lower than in controls; estradiol prevented the decrease of ER? expression, but not PR. The NDR was analyzed separately for the entire rostrocaudal axis in three anatomical levels: rostral, middle and caudal, each divided into three sub-regions: lateral, dorsal and ventral. The number of serotonergic neurons (TPH +) in NDR was lower in the periestropause, and estradiol was able to reverse this effect, acting mainly in the caudal region. PR gene expression was not altered by either follicular depletion or estrogen therapy in either the amygdala or the hippocampus. ER? expression was also no different in periestropause compared to the control group, but estradiol increased this expression in the hippocampus. Both in the amygdala and in the hippocampus there was a reduction in 5-HT content in the periestropause, and estradiol was able to reestablish the levels of this neurotransmitter at the control values only in the hippocampus. These data elucidate, at least in part, the mechanisms of the positive effect of estrogen therapy on the symptoms of normoestrogenic women in perimenopause. These effects do not appear to significantly involve the central noradrenergic system but result from increased peripheral progesterone biosynthesis in association with positive regulation of ER? in the NDR and hippocampus, which appears to potentiate the serotonergic NDR/HPC pathway. Therefore, the development of new therapies that activate ER? may be an alternative to obtain the positive effects of the estradiol action, eliminating the side effects of the estradiol therapies that normally result from the activation of ER?.
128

Thermal, hormonal and cardiovascular responses to single and repeated nonhypothermic cold exposures in man

Korhonen, I. (Ilkka) 18 November 2008 (has links)
Abstract The purpose of this study was to find out and compare the physiological effects of different types of non-hypothermic cold exposure tests in man. In whole-body cold exposures lightly clothed subjects were exposed to 10°C for 2 hours (single exposure), as well as repeatidly for 2 h and 1 h on ten successive days in separate studies. For local cold exposures, cold pressor tests (immersion into ice-cold water) of both hands and both feet were used. In whole-body cold exposures, several hormonal and metabolic parameters as well as cold sensations were measured. In local cold exposures the measured parameters were blood pressure, heart rate and skin temperatures. The single 2-h whole-body cold air exposure decreased rectal and skin temperatures and body heat content, but increased the metabolic rate. At the same time the serum noradrenaline concentration increased indicating a general activation of the sympathetic nervous system. Serum free fatty acid concentration increased whereas cortisol, GH and prolactin concentrations fell. No significant changes were found in serum concentrations of adrenalin, TSH, T3, T4, testosterone or LH. Serum total proteins were enhanced apparently due to cold-induced hemoconcentration. After repeating the 2-h whole-body cold exposure for five days the increase in serum noradrenaline level was markedly lower in the cold. At the same time hemoconcentration, judged from serum protein concentrations, was attenuated and the subjects became habituated to the cold sensations. However, the results showed that the repeated 1-h cold exposure in 10°C was not sufficiently intensive to reduce the noradrenaline response. Comparison of the hand and foot cold pressor tests to whole-body cold exposure tests showed that all tests caused significant increases in systolic and diastolic blood pressures, but that heart rate increased significantly only in the cold pressor test of feet. During the 2-h cold air exposure the heart rate fell. This caused a reduction in rate pressure product (RPP, the product of heart rate and systolic blood pressure). In both cold pressor tests the rate pressure product increased, indicating the enhancement of the O2-need in the heart muscle. The results showed no significant correlation in systolic or diastolic blood pressures between whole-body and local cooling of hands or feet. The lack of the association between local and whole-body cold exposure tests may be due to differences in severity and site of the tests: whole-body cold exposure tests cause general cold discomfort while cold pressor tests cause local cold pain. / Tiivistelmä Tämän tutkimuksen tarkoituksena oli selvittää ja verrata eri tyyppisten lievien kylmäaltistustestien fysiologisia vaikutuksia ihmiseen. Yksittäisessä koko kehon kylmäaltistuksessa koehenkilöt olivat kevyesti vaatetettuina kahden tunnin ajan 10°C:n lämpötilassa. Toistetussa koko kehon kylmäaltistuksessa koehenkilöt oleskelivat myös 10°C:n lämpötilassa kahden tai yhden tunnin ajan kymmenenä perättäisenä päivänä. Paikallisessa kylmäaltistuksessa käytettiin kylmävesitestiä (ns. cold pressor koe). Testi tehtiin sekä käsille että jaloille. Koko kehon kylmäaltistuksessa mitattiin useita hormonaalisia, aineenvaihdunnan ja lämpötasapainon vasteita, sekä verenpainetta ja sydämen syketiheyttä. Paikallisissa kylmäaltistuksissa mitattiin verenpainetta, sydämen syketiheyttä ja iholämpötiloja. Yksittäinen koko kehon kahden tunnin kylmäaltistus laski syvälämpötilaa, iholämpötiloja ja kehon lämpösisältöä. Samanaikaisesti kehon lämmöntuotanto kasvoi. Seerumin noradrenaliinipitoisuus lisääntyi ilmentäen sympaattisen hermoston tehostunutta aktivoitumista. Seerumin vapaiden rasvahappojen pitoisuus kasvoi, samoin kokonaisproteiinipitoisuus, mutta kasvuhormonin, kortisolin ja prolaktiinin osalta todettiin pitoisuuksien vähenemistä. Merkitseviä muutoksia ei tapahtunut seerumin adrenaliinissa, TSH:ssa, T3:ssa, T4:ssä, testosteronissa tai LH:ssa. Toistetussa kahden tunnin pituisessa kylmäaltistuksessa seerumin noradrenaliinipitoisuudessa tapahtunut kasvu oli merkitsevästi vähäisempää viiden päivän jälkeen. Samanaikaisesti seerumin proteiinipitoisuus kylmässä väheni ja kylmätuntemukset muuttuivat lievemmiksi. Sen sijaan yhden tunnin toistettu altistus 10°C:ssa ei ollut riittävän voimakas vähentämään kylmän aiheuttamaa veren noradrenaliinipitoisuuden kasvua. Verenpaineen ja sydämen syketiheyden reaktioita verrattiin samoilla koehenkilöillä yksittäisessä kahden tunnin koko kehon kylmäaltistuksessa ja kylmävesitesteissä. Kaikki nämä testit kohottivat merkitsevästi systolista ja diastolista verenpainetta. Sydämen syketiheys laski koko kehon kylmäaltistuksessa. Jalkojen kylmävesitestissä sydämen syketiheys nousi merkitsevästi, mutta käsien testissä tämä nousu ei ollut merkitsevä. Verenpaineen nousu koko kehon kylmäaltistuksessa ei korreloinut merkitsevästi paikallisissa kylmäaltistuksissa mitattuihin verenpaineen nousuihin. Selittävänä tekijänä tähän lienee näiden kylmäaltistusmuotojen erilaisuus. Lievä koko kehon kylmäaltistus aiheuttaa yleistä epämiellyttävyyttä, kun taas äkilliseen, nopean iholämpötilan laskun aiheuttamaan paikalliseen kylmäaltistukseen liittyy usein kiputuntemuksia.
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Úloha vstupu vápenatých iontů a vápnikové senzitizace při kontrakci izolovaných artérií normotenzního a hypertenzního potkana / The role of calcium influx and calcium sensitization in contraction of isolated arteries of normotensive and hypertensive rat

Bencze, Michal January 2017 (has links)
Vascular resistance is mainly determined by the contraction of vascular smooth muscle (VSM), which is regulated by the phosphorylation of myosin light chain (MLC). VSM contraction is initiated by calcium influx into the VSM cells, which is mediated by transient receptor potential (TRP) channels and L-type voltage- dependent calcium channels (L-VDCC). On the other hand, calcium sensitization is a mechanism enhancing vascular contractile response at a given level of intracellular calcium by RhoA/Rho kinase pathway-mediated inhibition of myosin light chain phosphatase. In this thesis I present the data about i) the role of TRP channels in the mechanisms of vascular smooth muscle contraction, ii) enhanced contractility of arteries from spontaneously hypertensive rats (SHR), and iii) the differences in contraction of arteries from normotensive and hypertensive rats related to the role of RhoA/Rho kinase pathway in three types of experimental hypertension (SHR, Ren-2 transgenic rats and salt-sensitive Dahl rats). In the study concerning TRP channels, I compared the effects of three commonly used non-selective TRP channels inhibitors (2-APB, SKF-96365, FFA) on isolated arteries. Among them 2-APB was the most interesting because the observed inhibitory effects of 2-APB were dependent on the type of...
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Adrenaline releases level on skin-to skin touches

George, Maryan January 2020 (has links)
Human pleasant touches promote feelings of security, supportiveness, and wellbeing. Conversely, human unpleasant touches promote the body for either “fight or flight” or “short term acute stress” during emergencies, feeling of stress or danger. The promoted stress response is released from the hypothalamus by the sympathetic nerve system further to the spinal cord to reach the signals to the adrenal medulla, where stress hormones adrenaline is released. Adrenaline, which is characterized by a mimic sympathetic nerve system, interacts with α and β receptors on different organs. The aim for this study was to investigate whether the stroker (partner/stranger) touch effects on adrenaline hormone releases. The null hypothesis for this study entails a significant adrenaline reduction in partners’ touches compared with strangers’ touches. Indirect competitive ELISA method was used, and concentration data of a total of sixteen participants was obtained. Whitney-U test was carried out to compare group differences within stroker (stranger/partner) touches and adrenaline releasing level. In addition, correlation in adrenaline with noradrenaline and oxytocin hormones was obtained using Spearman’s correlation test. The significant p-value 0.05 was conducted. The result of this study showed no differences between stroker (partner/stranger) associated with adrenaline hormone release. Correlation between partner maximum (max) concentration data for both oxytocin and adrenaline had significant differences. However, max variables for adrenaline and noradrenaline within stroker did not show significant differences. The conclusion of this study is that the gentle touch stimulus used in this study was not enough to detect stress hormone in adrenaline.

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