MOLECULAR PHARMACOLOGY

Author: HERNANDEZ ARRIAGA ANA M..
Year: 2003.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: UNIVERSIDAD COMPLUTENSE MADRID.

Summary: This experimental work has focused on the characterization of the mechanism of transcriptional regulation mediated by repressor CopG in the promoter Pcr of plasmid pMV158.El research work has included the study of: 1) the complex DNA-proteína formed between RNA polymerase Escherichia coli and / or CopG, and the promoter Pcr through tests and trials delayed gel protection and 2) characterization of the DNA operator CopG through the construction of operators mutantes.Todos operators have been analyzed by testing of protection against a hydroxyl radical and methylation with DMS and 3) characterization of the union of CopG its operator DNA by estimating the affinity constant and the dissociation constant relative. The results have enabled us to demonstrate that the protein CopG regulates the promoter activity Pcr at two different points in the process of initiation of transcription: i) inhibits the binding of RNA polymerase, and ii) ejected from its binding site even when polimersa is sitting in the promotor.Además has characterized the role of the regions that are the operator CopG, and their influence on the binding of the protein to DNA.La protein binds with high affinity and cooperatividad its target DNA , binding characteristics essential to undertake its role in transcriptional repressor.

Author: TERENCIO ALEMANY JOSE VICENTE.
Year: 2004.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE BIOLOGÍA.
Place of preparation: CIDF DEL GRUPO FERRER.

Summary: At present affective disorders, and more importantly, major depression, is a major threat in public health, taking a major social and economic impact, due to its high incidence and the high failure resulting from it. At present, the most commonly used drugs for the treatment of depression and other emotional disorders are selective inhibitors of serotonin reuptake (SSRIs). These drugs work by enhancing the transmission of selectively serotoninérgica at the central level and has been a very important advantage, since its introduction into the market at the end of the decade of 80, compared to other drugs, mainly on their mechanism of action more selective, This has given a greater margin of safety. However, despite its mechanism of action more selective drugs belonging to this class pharmacology, Citalopram, Fluoxetina, Fluvoxamine, Paroxetina and Sertralina presented other pharmacological actions secondary that at high doses, and given the chronic use, might cause adverse effects in patients treated with them. The assumption that we are heading in this work was to have an SSRI with greater selectivity face interaction with other pharmacological targets would result in a compound with a better side effect profile, and therefore a greater margin of safety. This paper presents the basic purpose of preclinical characterization of a new selective inhibitor of serotonin reuptake, Omiloxetina, tackled from two points of view: On the one hand the study of the potential antidepressant activity related to their mechanism of action, and Furthermore, the study of the effects on other systems and vital functions, namely, the safety profile of the product. Finally, the relationship between dose antidepressant activity, and the dose with undesirable effects allow us to calculate the margin of safety of the product for future clinical use. All this study is conducted on a comparative to other drugs marketed from the same pharmacological class, SSRIs, with the ultimate goal of demonstrating that the drug have a more selective in their pharmacological actions, resulting in a compound with a larger margin security. The experimental approach was used in 3 large blocks, studies of activity, safety studies and pharmacokinetic studies. It also studied the effect of Omiloxetina on other mechanisms involved in antidepressant activity. Finally, we studied the effect of Omiloxetina in three animal models of depression. Two models acute, empowerment of lethality induced yohimbina in mice, and the test suspension by the tail in mice, and a subacute model, the paradigm of learned helplessness in the rat. In considering the safety profile of Omiloxetina, studies were conducted safety pharmacology, studied the effect of Omiloxetina at high doses on the central nervous system (CNS) through the test of Irwin, and more specifically on motor function, the potential convulsivante, on the cholinergic system, and on cardiovascular function. 8 Also e55 investigated the toxicological effects of Omiloxetina in acute toxicity studies in rats and mice, and subacute toxicity studies in rats and dogs. Lastly, pharmacokinetic studies were conducted at a single dose and repeated dose in rats administered doses similar to those used in pharmacological studies to prove exposure levels of the drug in the above studies. The results showed that Omiloxetina is a potent inhibitor of serotonin reuptake in the range nanomolar, with a power output similar to that shown by other SSRIs. Omiloxetina, as a result of its action on the serotonin transporter, elevated extracellular levels of serotonin in frontal cortex of rats, which is an area associated with affective disorders. The power displayed in vivo by Omiloxetina was slightly lower than Paroxetina, and the same rank as Fluoxetina. In addition, Omiloxetina no effect on the dopaminergic function, and showed greater selectivity in its action on the noradrenergic system that Fluoxetina and Paroxetina. Omiloxetina alone showed a moderate affinity on the sigma receptor, which has been postulated as a possible modulator of behavioral responses to stressful situations. In animal models of depression, Omiloxetina showed antidepressant effect, being the most powerful post in the subacute model in the studies of safety pharmacology, Omiloxetina showed no significant affinity compared with more than 75 targets studied, indicating a high selectivity of its shares in alive. Omiloxetina affect motor function to a lesser degree than other SSRIs, differing mainly Fluoxetina in this aspect. Omiloxetina changed to a lesser extent the threshold for excitability of the CNS, differing from Paroxetina. On the cholinergic function, Omiloxetina exerted a minor blockage cholinergic both in vitro and in vivo Regarding other SSRIs, clearly differentiating into this aspect of Paroxetina. Omiloxetina no effect on the cardiovascular function at high doses. The results of toxicological studies indicated a less acute toxicity of Omiloxetina regarding Fluoxetina and Paroxetina and reduced toxicity after repeated dosing, as reflected in a NOAEL (dose without adverse effects) high, at 40 mg / kg in rats . Since the doses that showed antidepressant activity in animal models, and showed that toxicological effects were calculated indices and therapeutic margin of safety, being clearly higher for Omiloxetina comparatively to Fluoxetina and Paroxetina. The cumulative results allow us to conclude that Omiloxetina is a new SSRI, with a wide selectivity in their pharmacological actions, which translates into improved safety profile compared to other drugs in its class drug. Therefore, Omiloxetina could be used for the treatment of emotional disorders associated with a deficit serotonin, which may have advantages over other SSRIs in the treatment of patient populations at greatest risk of overdose, polimedicados, etc., in which the margin safety of drug use is particularly important.

Author: QUINTERO ORTÍZ MARISOL.
Year: 2005.
University: VALENCIA [www.uv.es].
Place of defense: FACULTAD DE MEDICINA Y ODONTOLOGIA.
Place of preparation: FACULTAD DE MEDICINA Y ODONTOLOGÍA.

Summary: Since the beginning of research into the biology of nitric oxide (NO) a point that has aroused great interest is the versatility of its shares pathophysiological, not only in the cardiovascular system but also in the nervous system, central and peripheral, and the immune responses and inflammatory. A common feature in many of these systems is that low concentrations of NO (nanomolar) play a role in the homeostasis of various biological processes. However, in certain circumstances NO becomes a pathogen, possibly as a result of reaction with superoxide leading to the formation of peroxynitrite. The work in this thesis describes various cellular signaling systems that depend on the interaction of NO with cytochrome c oxidase (CcO), the terminal enzyme of oxidative phosphorylation in mitochondria. Our studies suggest that the signaling pathways that result from the interaction of NO with the mitochondria are important for understanding not only physiological actions of NO but also as NO can become a pathogen.

Author: BONZON KULICHENKO ELENA.
Year: 2006.
University: CASTILLA-LA MANCHA [www.uclm.es].
Place of defense: FACULTAD DE QUIMICA.
Place of preparation: FACULTAD DE QUIMICA.

Summary: The hormone leptin, acting both through central and peripheral pathways, reduces food intake, adiposity and increases the whole-body insulin sensitivity. Dysregulations of leptin action results in o 8 besity, dab insulin resistance and Type 2 diabetes. Thus, in order to get insight into the molecular mechanisms underlying these metabolic disorders and identify potential therapeutic targets, an increased understanding of leptin action is needed. Work presented in this thesis sought to explore the molecular mechanisms responsible for the lipostatic and insulin-sensitizing effects of leptin acting only through the brain. Central leptin infusion, independently of its anorexigenic actions, elicits tissue-specific effects on liver and epididymal white adipose tissue (eWAT), that reduce triacylglycerol (TAG) and total fatty acids (free and acyl-CoA) in both tissues and the content of TAG in plasma. Thus, by increasing the mRNA levels of the transcription factors involved in lipid oxidation, PPARa and PGC-1a, central leptin promotes b-oxidation of fatty acids eWAT. Additionally, leptin increases the ATGL-mediated lipolysis in this tissue. The released free fatty acids are taken up and oxidized mainly by the liver. Additionally, central leptin infusion down-regulates the expression of lipogenic enzymes in the liver by reducing the mRNA levels of the lipogenic transcription factor SREBP-1c. In eWAT leptin also reduces the expression of lipogenic and glyceroneogenic enzymes, but controlling SREBP-1c post-transcriptionally, inhibiting the proteolytic maturation of this transcription factor. Also, in eWAT leptin reduces lipogenesis by promoting insulin resistance from the early steps of the insulin signaling pathway (IR, IRS-1 and Akt2), which results in decreased glucose up-take by this tissue upon insulin stimulation. Additionally, by inhibiting de novo ceramide synthesis in eWAT, central leptin appears to protect this tissue from lipotoxicity, thereby improving its lipid buffering capacity. As a result of all these effects, central leptin treatment reduces plasmatic insulin levels and enhances the in vivo insulin actions that promote the reduction of plasmatic free fatty acids. On the other hand, the condition of central leptin resistance (aged rats) is linked to increased contents of lipids in liver, eWAT and plasma. The increased lipogenesis in the liver, but not in eWAT, is the one responsible for the augmented adiposity of the aged rats, and explains their hypertriglyceridemia and hypercholesterolemia. Also, we suggest that from the peripheral tissues, the liver could be the primary site for the leptin resistance build-up that precedes the development of insulin resistance in eWAT and skeletal muscle. Finally, the decrease in lipolysis, the increase in esterification and the maintenance of eWAT ceramide contents within normal levels, probably thanks to the hyperleptinemia that accompanies aging, contribute to eWAT hyperplasia. This may be regarded as a survival advantage that prevents the aged rats from becoming diabetic.