Inhibiting peripheral serotonin (5-HT) synthesis has been shown to prevent the development of diet-induced obesity, glucose intolerance, insulin resistance and hepatic lipid deposition and to increase brown adipose tissue (BAT) thermogenic capacity. This thesis investigated 1) what effects 5-HT has on brown adipocytes (BAs), 2) if 5-HT and/or selective serotonin reuptake inhibitors (SSRIs) impair BAT function, 3) if 5-HT directly inhibits BA via a receptor-mediated mechanism, 4) which 5-HT receptor is predominantly expressed in BAT, 5) if 5-HT receptor antagonism improves BAT function and 6) if 5-HT receptor inhibition reduces SSRI induced weight gain. In murine BAs, 5-HT at concentrations ≥100 μM acutely reduced lipolysis, lipid accumulation and glycolytic flux but did not impair oxygen consumption; whereas 10 nM 5-HT reduced Ucp1 promoter activity via an extracellular receptor-mediated mechanism. Acute injection of 5-HT or the selective serotonin reuptake inhibitor (SSRI) Paroxetine decreased BA T thermogenic capacity and energy expenditure (EE), respectively. Mice lacking the serotonin transporter gene (Slc6a4-/- mice) had increased adiposity, decreased locomotor activity and increased food intake. However, male Slc6a4-/- mice had increased BAT thermogenic capacity, in contrast to the reduced EE expenditure following acute administration of Paroxetine. Using, RNA-Seq analysis and measurements of canonical 5-HT receptor second messengers (i.e. Ca2+ and cAMP transients), 5-HT2A was identified as the highest expressed 5-HT receptor in murine and human BAs and the only detected active 5-HT receptor in murine BAs. Genetic elimination of 5-HT2A prevented 5-HT induced increases in Ca2+ transient peaks and decreases in Ppargc1a mRNA expression in cultured BAs. In vivo ablation of 5-HT2A in adipose tissue increased BAT thermogenic capacity. Furthermore, in silico analyses predicted that pharmacological inhibition of 5- HT2A would induce a thermogenic program. In vitro, 5-HT2A receptor antagonists eliminated 5-HT induced Ca2+ transients and in vivo, a single injection of a peripherally-restricted 5-HT2A antagonist (Xylamidine) prevented 5-HT-induced impairments in BAT-mediated EE. Chronic administration of Xylamidine to chow- fed mice for 5-weeks improved BA T thermogenesis. Co-administration of Xylamidine with Paroxetine, however, did not attenuate Paroxetine-induced weight gain but did improve BAT functional capacity Therefore, 5-HT2A antagonism improves BAT thermogenic capacity but does not increase EE. This represents a novel therapeutic approach for increasing thermogenic capacity that may be used in conjunction with BAT activating strategies to increase EE and attenuate obesity. / Thesis / Doctor of Philosophy (PhD) / Obesity is a growing global pandemic caused by excessive energy intake over energy expenditure (EE). Some medications, such as certain selective serotonin (5-HT) reuptake inhibitor (SSRI) type antidepressants, also contribute to weight gain via reasons which are not fully understood. Currently available weight- loss medications decrease energy intake but do not affect EE. Recently, inhibiting the production of 5-HT outside the brain decreased weight gain in a model of obesity. Furthermore, this was associated with an improvement in the activity of a specialized type of adipose tissue, called brown adipose tissue (BAT). BAT is capable of expending energy in the form of thermogenesis and thus when active increases energy expenditure. We hypothesized that 5-HT impairs BAT activity and that blocking 5-HT activity may reduce weight gain in a model of antidepressant- induced weight gain. Herein, we investigated whether elevating 5-HT or increasing 5-HT downstream signaling modified BAT activity, which 5-HT receptor(s) is/are predominantly expressed in brown adipocytes (BAs), and what the effect on BAT would be if this/these receptors were eliminated. We found that in cell culture “supraphysiological” doses of 5-HT acutely impaired BA lipid mobilization and glucose metabolism; whereas, circulating concentrations of 5-HT impaired expression of select mitochondrial genes when serotonin transport was reduced. In mice, acute injections of high dose 5-HT attenuated BAT activity in response to an adrenergic stimulus. Acute treatment with an SSRI decreased EE and locomotor activity. Mice genetically lacking the serotonin transporter (the target of SSRIs) had increased weight gain (particularly fat mass), increased food intake and reduced locomotor activity, but improved BAT functional capacity. We subsequently identified that the predominantly expressed and active receptor in BAs was the 5- HT2A receptor. Genetically eliminating the 5-HT2A receptor in BAs prevented 5- HT’s reduction of a major mitochondrial gene expression regulator and improved BAT functional capacity in mice. Inhibiting 5-HT2A with a 5-HT2A brain impermeable antagonist, Xylamidine, increased BAT functional capacity in mice. Treating mice with Paroxetine (Paxil®), a SSRI known to increase weight gain, and Xylamidine did not attenuate Paroxetine-induced weight gain nor increase EE but did improve BAT functional capacity. In conclusion, we found that 1) chronic treatment with physiological levels of 5-HT impaired BAT functional capacity, 2) elimination/inhibition of adipocyte 5-HT2A improved BAT functional capacity in vivo and 3) inhibiting peripheral 5-HT2A alone did not attenuate Paroxetine- induced weight gain.

The work discussed here is divided into two projects. The first project involves the interactions between antidepressants and the platinum based chemotherapeutics while the second project begins to investigate possible implications of a recently discovered uptake mechanism for positively charged platinum drugs. Gaining understanding of the interactions between antidepressants and platinum-based chemotherapeutics is important due to the frequency with which they are prescribed together. Although using a combination regimen of antineoplastics is beneficial to the patient, not all drug interactions are. For instance, many of the serotonin reuptake inhibitors have been shown to decrease the efficacy of tamoxifen. Desipramine, a tricyclic antidepressant used to treat neuropathic pain, has been shown to increase the cytotoxicity of cisplatin, oxaliplatin and carboplatin in the human colon carcinoma cell line, HCT116 wt. To study this interaction, the cell line specificity as well as the drug specificity with regard to both the platinum-based chemotherapeutic and the antidepressant were investigated. The data show that the effect is both cell line specific as well as drug specific with respect to both types of drugs. To elucidate the mechanism behind the alteration in cytotoxicity of the platinum drugs, the effect of p53 status was investigated. A reduction of the effect is observed in the absence of p53, suggesting that there is a p53 dependent mechanism as well as a p53 independent mechanism. The tricyclic antidepressants and fluoxetine are known to be calmodulin inhibitors. Calmodulin inhibition mirrored some of the effects seen with the antidepressants suggesting that calmodulin inhibition might also play a role in the mechanism. The second project is based on the discovery that heparan sulfate proteoglycans mediate the uptake of positively charged platinum complexes. Heparan sulfate proteoglycans are important in cell-cell as well as cell-extracellular matrix adhesion. In cancer, heparanase, the enzyme that cleaves heparan sulfate, is over expressed creating a pro-angiogenic and pro-metastatic state. This work demonstrates that the positively charged platinum complexes can inhibit heparanase activity by binding to the substrate (heparan sulfate proteoglycans). This suggests that this class of drugs may have the capacity to be anti-angiogenic and anti-metastatic as well as cytotoxic.

Through a series of original research articles, this thesis explores the characteristics of autonomic cardiac regulation and respiratory function during sleep in association with depression and antidepressant medication use and validates a novel diagnostic biomarker of depression. Cardiorespiratory dysfunction during sleep may contribute to the increased risk of developing cardiovascular disease amongst individuals with depression. Sleep represents a unique physiological state shielded from many external confounding factors and may be a more relevant window to observe the effects of depression on cardiorespiratory function. In a first study, we found that depression was associated with abnormal autonomic modulation of cardiac activity during sleep. Specifically, depression was associated with reduced heart rate variability compared to healthy controls, and this difference was most prominent during sleep as compared to wake, which may indicate impairments in the parasympathetic modulation of the cardiac sinoatrial node. Secondly, we validated a machine-learning algorithm that uses patterns of heart rate during sleep to identify depression. This algorithm was found to have 79.9% classification accuracy, based on the differences in autonomic modulation associated with distinct mental states. The algorithm was highly generalizable across different depression subgroups and thus may be useful as an adjunct diagnostic tool. Finally, we found that the use of antidepressants, particularly serotonergic agents, was associated with worse sleep-related respiratory disturbances compared to non-medicated individuals with depression and those using non-serotonergic antidepressants. We proposed that depression-related alterations in serotonin receptor expression and binding may shape the response of the respiratory system to the use of serotonergic agents. Considering the high comorbidity between depression and sleep-related breathing disturbances and their impact on cardiovascular health, this has great clinical implications for the management of depression. Taken together, these results show that depression is associated with several sleep-related abnormalities in terms of cardiorespiratory function, which may represent a valid biomarker of depression.

Made available in DSpace on 2016-03-22T17:27:42Z (GMT). No. of bitstreams: 1 Carla 07.pdf: 347134 bytes, checksum: af93471bbac40314a413b4d9fbb565d5 (MD5) Previous issue date: 2006-10-30 / Objectives To estimate the prevalence and determinants of antidepressants among adults living in an urban area. Methods Transversal study in a representative sample of adults at the age of 40 years or older, living in the urban area of Pelotas, State of Rio Grande do Sul, Brazil. The data was collected through a pre-codified and standardized questionnaire. Was defined as an antidepressants user, the adult that had declared the use of antidepressant medication on the last fiftenn days. Variables were valued according to the social demographic and behavior of these individuals. The chi-squared test was used for comparisons between proportions. The non conditional logistic regression was used for multivariate analysis with robust adjustment for variances. Results Were interviewed 1327 adults, which 9,3 % had used antidepressants. The major use of antidepressants were associated significantly to the feminine gender, IC 95% 2,45 (1,50-4,02), to the upper social levels, IC 95% 2,07(0,68-1,95), and also associated to jobless subjects, 1,65(1,06-2,55). The most used antidepressants were of the Serotonin inhibiters group (ISRS), in a proportion of 60,2% of the interviewed subjects. Conclusions The prevalence of antidepressants use was superior to the ones found in other studies. These studied groups and a base to a better strategic therapy that can be elaborated to decrease the use of antidepressants in these groups Objectives To estimate the prevalence and determinants of antidepressants among adults living in an urban area. Methods Transversal study in a representative sample of adults at the age of 40 years or older, living in the urban area of Pelotas, State of Rio Grande do Sul, Brazil. The data was collected through a pre-codified and standardized questionnaire. Was defined as an antidepressants user, the adult that had declared the use of antidepressant medication on the last fiftenn days. Variables were valued according to the social demographic and behavior of these individuals. The chi-squared test was used for comparisons between proportions. The non conditional logistic regression was used for multivariate analysis with robust adjustment for variances. Results Were interviewed 1327 adults, which 9,3 % had used antidepressants. The major use of antidepressants were associated significantly to the feminine gender, IC 95% 2,45 (1,50-4,02), to the upper social levels, IC 95% 2,07(0,68-1,95), and also associated to jobless subjects, 1,65(1,06-2,55). The most used antidepressants were of the Serotonin inhibiters group (ISRS), in a proportion of 60,2% of the interviewed subjects. Conclusions The prevalence of antidepressants use was superior to the ones found in other studies. These studied groups and a base to a better strategic therapy that can be elaborated to decrease the use of antidepressants in these groups / Objetivo: Determinar a prevalência e fatores associados ao uso de antidepressivos em adultos residentes em uma área urbana. Métodos: Estudo transversal em uma amostra representativa de adultos com idade igual ou superior a 40 anos, moradores na zona urbana de Pelotas, Estado do Rio Grande do Sul. Os dados foram coletados por meio de um questionário padronizado e pré-codificado. Foi definido como usuário de antidepressivo o adulto que relatou ter usado medicação antidepressiva nos últimos quinze dias. Variáveis sóciodemográficas e comportamentais foram avaliadas. Para as comparações entre proporções, utilizou-se o teste de qui-quadrado e, para a análise multivariada, a regressão logística não condicional. Resultados: Foram entrevistados 1327 adultos, dos quais 9,3% tinham usado antidepressivos. O maior consumo de antidepressivos associou-se significativamente ao sexo feminino, IC 95% 2,45(1,50-4,02), ao nível sócioeconômico mais elevado (classes A e B), IC 95% 2,07(1,28 -3,34), e a não estar exercendo uma atividade de trabalho, IC 95% 1,65(1,06-2,55). Os antidepressivos do grupo dos Inibidores Seletivos da Recaptação da Serotonina (ISRS) foram os mais consumidos, 60,2%. Conclusões: A prevalência de uso de antidepressivos foi superior às encontradas em outros estudos. Os determinantes individuais de utilização, poderão servir de embasamento às estratégias para diminuir o consumo de antidepressivos nesses grupos

Introduction: Many medications have an unproven safety profile for use during pregnancy, leading to issues when chronic diseases, such as hypertension and depression, present during pregnancy. The focus of this research programme is to determine whether in utero exposure to antihypertensive and antidepressant medication is associated with increased risk of adverse events at birth, and up to 27 months of age in the child. Methods: Two systematic reviews were performed to identify current published literature and knowledge gaps. Following this, using Scottish healthcare data, a cohort of 268,711 children born 2010-2014 were identified. Following cleaning of the data, multiple imputation was used to account for missing values. Poisson, linear and multinomial regressions were performed to identify the relationship between in utero medication exposure and child outcomes. Results: In utero antihypertensive exposure was associated with preterm birth, low birth weight, small for gestational age, but not developmental issues. However, untreated hypertension was associated with low birth weight, preterm birth, and small for gestational age. In utero antidepressant exposure was associated with preterm birth, low birth weight, small for gestational age, preeclampsia, having a special needs indicator at 10 days and 6-8 weeks post-birth, developmental issues at 27 months Conclusions: This research programme identified several adverse outcomes following in utero exposure to antihypertensive and antidepressant medication.

The neurocognitive model of antidepressant treatment action states that antidepressants work by producing relatively immediate positive shifts in emotional processing, which translate into clinical improvement with time. Short-term or even acute doses of antidepressants can, for example, increase memory for positive self-referent words or decrease amygdala activation to fearful faces, and these early changes correlate with later clinical improvement. However, there are a number of ways in which the model needs further probing. The aim of this thesis was to test the neurocognitive model by: 1) investigating whether changes in emotional processing occur in an antidepressant with a novel mechanism of action, St John's wort, as the model predicts; and 2) examining whether there is a comparable pattern of neuropsychological changes to citalopram in a population of high neurotic volunteers, whose baseline emotional biases may make them a more ideal group in which to study drug effects. We found that seven days of St John's wort produced similar changes to other antidepressants, for example reducing recognition of disgusted faces and attention to fearful faces while increasing memory for positive words. The drug did not affect other aspects of cognition including working memory and reward learning. These findings support the theory that early psychological changes are a common feature of all antidepressants. On the other hand, four weeks of citalopram treatment produced apparently contradictory effects in high neurotics, increasing memory for positive words but also increasing recognition of negative facial expressions. Neuroimaging data showed that high neurotics had greater response to neutral faces in emotional processing areas compared to low neurotics, which was reduced with citalopram. High neurotics also showed increased resting state connectivity in default mode network areas and between amygdala and cortical areas, which was again reduced with citalopram. We suggest that in this group citalopram corrects general negative emotional processing biases, but also works to decrease a natural aversion to particularly threatening socially-relevant stimuli. Overall this thesis supports the idea that early changes in emotional processing are vital for antidepressant action, but also suggests that in certain groups such as high neurotics, some changes may be more nuanced than previously reported and warrant further scrutiny.

Post-traumatic stress disorder (PTSD) is a debilitating mental illness that results from exposure to intense, life-threatening trauma. Some of the symptoms of PTSD include intrusive flashback memories, persistent anxiety, hyperarousal and cognitive impairments. The finding of reduced basal glucocorticoid levels, as well as a greater suppression of glucocorticoid levels following dexamethasone administration, has also been commonly observed in people with PTSD. Our laboratory has developed an animal model of PTSD which utilizes chronic psychosocial stress, composed of unavoidable predator exposure and daily social instability, to produce changes in rat physiology and behavior that are comparable to the symptoms observed in PTSD patients. The present set of experiments was therefore designed to 1) test the hypothesis that our animal model of PTSD would produce abnormalities in glucocorticoid levels that are comparable to those observed in people with PTSD, 2) examine the ability of antidepressant and anxiolytic agents to ameliorate the PTSD-like physiological and behavioral symptoms induced by our paradigm and 3) ascertain how long the physiological and behavioral effects of our stress regimen could be maintained. The experimental findings revealed that our animal model of PTSD produces a reduction in basal glucocorticoid levels and increased negative feedback sensitivity to the synthetic glucocorticoid, dexamethasone. In addition, chronic prophylactic administration of amitriptyline (tricyclic antidepressant) and clonidine (α2-adrenergic receptor agonist) prevented a subset of the effects of chronic stress on rat physiology and behavior, but tianeptine (antidepressant) was the only drug to block the effects of chronic stress on all physiological and behavioral measures. The final experiment indicated that only a subset of the effects of chronic stress on rat physiology and behavior could be observed 4 months following the initiation of chronic stress, suggesting that some of the effects of our animal model diminish over time. Together, these findings further validate our animal model of PTSD and may provide insight into the mechanisms underlying trauma-induced changes in brain and behavior. They also provide guidance for pharmacotherapeutic approaches in the treatment of individuals suffering from PTSD.

Part I: Racemic and asymmetric syntheses of a new substance with prospective antidepressant properties were achieved. In vitro assays with synthetic racemates (±)-25 and (±)-26 suggested that the former is a relatively selective inhibitor of serotonin transporter whereas the latter is a more balanced inhibitor of both serotonin and norepinephrine transporter. An initial approach to enantiomers of 25 and 26 via resolution of carboxylic acids 21 and 22 was unsuccessful but a de novo strategy which introduced asymmetry by means of Charette enantioselective cyclopropanation led to (+)-25, (-)-25, (+)-26 and (-)-26. In vitro assays with (+)-26, now known as synosutine synthesis/OSU), indicate that this substance is a highly effective dual inhibitor of serotonin and norepinephrine transporter. With IC₅₀ and K[subscript i] values in the 1-2 nM range, (+)-26 compares favorably with Eli Lilly's duloxetine (Cymbalta®) as a dual reuptake inhibitor of serotonin and norepinephrine and is thus a potential candidate for development as a drug for treatment of clinical depression. Synosutine was also assayed in vivo for its binding to human monoamine transporters. These studies indicate that synosutine, with a K[subscript i] of 1.2 nM for norepinephrine and 2.1 nM for serotonin, is a more balanced inhibitor than duloxetin. Part II: Synthetic studies towards the tetracyclic core structure of neomangicol A (129) led to advanced intermediate 245 which bears rings A and D of the neomangicol nucleus. This bicylic enone carries the correct stereochemical imprint for tetracycle 129 at C5, C6 and C14 and it contains all of carbon atoms needed to assemble the remaining two rings. Synthesis of bicyclic lactone 170, the precursor for ring A, was accomplished from the monoterpene (S)-(+)-carvone via radical cyclization and a series of Baeyer-Villiger oxidations as the key steps. Alkylation of 170 with alkyl iodide 217, obtained from the monoterpene (S)-(-)-citronellol furnished advanced intermediate 218 which was converted into diene 244. Ring closing metathesis of 244 with Grubbs-Hoveyda second generation catalyst afforded 245. Exploratory functionalization of 245 was carried out for the purpose of assembling rings B and C of the complete neomangicol skeleton. / Graduation date: 2012

The aim of this master thesis is to contribute to a deeper understanding of women’s experiences in regard to menstrually related suffering. These particular experiences are examined in relation to notions of normality and authenticity. The study designed for this purpose is based on the life world of women in order to explore these ideas. The visceral signs originating from within the body are generally understood to be undetectable when working properly. Such is not the case for many women who menstruate. The cyclical change in physical and mental states associated with the menstrual cycle provide an opportunity to study how going in and out of different ways of being in the world influence human experience. Thematic interviews were conducted asking ten women living in Sweden to share their experiences of suffering related to the menstrual cycle. A phenomenological approach with focus on the body was used to study how changing ways of being in the world contribute to the construction of illness and health. Beginning with discussions about their experiences of suffering revealed that women thought in terms of when they felt like themselves and when they did not. Organization of time was interrelated with how women understood their experiences. Emphasizing recurring negative experiences lead to contemplation about causes of suffering and comparison of different states of being. The lack of ‘one’s selfness’ due to what is commonly referred to as PMS represents the dilemma these women describe. The need to have control over the outward representation of one’s self is discussed in light of different medical technologies like SSRI antidepressant use and hormonal therapies which revealed that women saw the origins of their suffering to be a product of society but tightly connected to their identity as women and were not willing to be without a menstrual cycle. Phenomenological ideas about embodiment were used to understand how suffering was seen both as a sign of health and as a part of the self.

Thesis (Ph. D)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 65-78).