Várias evidências têm caracterizado os efeitos benéficos do gangliosídeo GM1 no tratamento de lesões neurológicas. O GM1 também foi estudado para o tratamento de doenças neurodegenerativas, principalmente em relação ao seu papel na neuroplasticidade e neuroproteção. O objetivo deste estudo foi analisar os possíveis efeitos de GM1 em modelo de doença de Parkinson induzida pela injeção intraestriatal unilateral de 6-hidroxidopamina (6-OHDA) em ratos. O GM1 foi injetado em conjunto com 6-OHDA e sete dias após a cirurgia os cérebros foram coletados para análise. Os resultados bioquímicos mostraram que o tratamento com GM1 intraestrial atenua aspectos inflamatórios e reduz os indicadores de morte neuronal, tal como evidenciado pela manutenção dos níveis de GFAP, OX-42 e caspase-3 em níveis de controle. A melhoria no tratamento por GM1 foi também demonstrada com a preservação de um fator neurotrófico derivado do encéfalo (BDNF) e os níveis de tirosina hidroxilase após 6-OHDA. A análise comportamental corrobora os achados bioquímicos, demonstrando que o GM1 possui a capacidade de preservação dos movimentos, visto pelo teste de cilindro. Sugerimos que o GM1 exerce neuroproteção no modelo de 6-OHDA, quando administrado por uma via local. Isto poderia representar um meio viável para transpor as barreiras farmacocinéticos que afetam a entrega de uma concentração apropriada da droga para áreas do cérebro / Several evidences have characterized the beneficial effects of ganglioside GM1 in the treatment of neurological lesions. GM1 has also been studied for the treatment of neurodegenerative diseases, mainly in relation to its role in neuroplasticity and neuroprotection. The objective of this study was to analyze the possible effects of GM1 on a model of Parkinson\'s disease induced by unilateral intra-striatal injection of 6-hydroxydopamine (6-OHDA) in rats. The GM1 was injected together with 6-OHDA and seven days after surgery the brains were collected for analysis. Biochemical results showed that treatment with intra-striatal GM1 attenuates inflammatory aspects and reduces the indicators of neuronal death, as evidenced by maintaining levels of GFAP, OX-42 and caspase-3 at control levels. Improvement after GM1 treatment was also demonstrated by the preservation of a brain-derived neurotrophic factor (BDNF) and tyrosine hydroxylase levels after 6-OHDA. The behavioral analysis corroborates the biochemical findings, demonstrating that GM1 has the ability to preserve movements, as seen by the cylinder test. We suggest that GM1 exerts neuroprotection in the 6-OHDA model when administered by a local route. This could represent a viable means of overcoming the pharmacokinetic barriers affecting the delivery of an appropriate concentration of the drug to areas of the brain

This Thesis is a characterization study on substances having potency as drugs as well as on a lipid based drug-delivery matrix. The optical properties of newly synthesized molecules with proven pilicide properties have been characterized with several spectroscopic methods. These methods include optical absorption and fluorescence as well as time-resolved fluorescence. Upon covalently linking compounds with high quantum yields of fluorescence to specific parts of the pilicide, the biological impact was found to increase for some of the derivatives. Furthermore, by expanding the aromatic part of the pilicide molecule, a significant increase in the inherent fluorescence was obtained. The S0-S1 absorption band for these molecules was found to originate from an impure electronic transition, vibronically promoted by intensity borrowing from higher electronic states. Included in this Thesis is the measurement of how deeply some in this class of newly synthesized molecules become situated when placed inside ganglioside GM1 micelles, and how the molecules’ reorientation is affected. By means of radiation-less energy transfer, it was shown that the molecules place themselves close to the hydrophobic-hydrophilic interface inside the GM1 micelles. As a consequence they are exposed to a densely packed environment, which inhibits the free tumbling of the molecule. This restricted tumbling could be measured by means of time-resolved depolarization experiments. The release of drug-like fluorescent molecules is investigated from a lipid mixture, which upon equilibrium with water forms a mixture of inverted hexagonal and cubic phases. The lipid matrix displayed an extended release over the course of weeks, in vitro, for molecules having a large variation in hydrophobicity.

No description available.

No description available.

The homo and hetero dimerisation of two spectroscopically different chromophores were studied, namely: 4,4-difluoro-4-bora-3a,4a-diazas-indacene (g-BODIPY) and its 5-styryl-derivative (r-BODIPY). Various spectroscopic properties of the r-BODIPY in different common solvents were determined. It was shown that g- and r-BODIPY in the ground state can form homo- as well as hetero dimers. We demonstrate that the ganglioside GM1 in lipid bilayers of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) exhibits a non-uniform lateral distribution, which is an argument in favour of self-aggregation of GM1 being an intrinsic property of the GM1. This was concluded from energy transfer/migration studies of BODIPY-labelled gangliosides. An algorithm is presented that quantitatively accounts for donor–donor energy migration (DDEM) among fluorophore-labelled proteins forming regular non-covalent polymers. The DDEM algorithm is based on Monte Carlo (MC) and Brownian dynamics (BD) simulations and applies to the calculation of fluorescence depolarisation data, such as the fluorescence anisotropy. Thereby local orientations, as well as reorienting motions of the fluorescent groups are considered in the absence and presence of DDEM among them. A new method, in which a genetic algorithm (GA) was combined with BD and MC simulations, was developed to analyse fluorescence depolarisation data collected by the time-correlated single photon counting technique. It was applied to study g-BODIPY-labelled filamentous actin (F-actin). The technique registered the local order and reorienting motions of the fluorophores, which were covalently coupled to cysteine 374 (C374) in actin and interacted by means of electronic energy migration within the polymer. Analyses of F-actin samples composed of different fractions of labelled actin molecules revealed the known helical organiszation of F-actin, and demonstrated the usefulness of this technique for structure determination of complex protein polymers. The distance from the filament axis to the fluorophore was found to be considerably less than expected from the proposed position of C374 at a high filament radius. In addition, polymerisation experiments with BODIPY-actin suggest a 25-fold more efficient signal for filament formation than pyrene-actin.