RESUMO
Using Surface Plasmon Resonance (SPR) we investigated the interaction of seven neuropeptides with different characteristics and beta-amyloid (Abeta42) peptide, with membranes containing gangliosides. A wide range of affinities characterized the bindings (K(D) = 10(-3)- 10(-7) M), following the scheme: for GM1, Abeta42 > DYN > SP = GAL = SOM = BRD > OXY = ENK; for GD1a, Abeta42 = DYN = GAL > SP = SOM = BRD = OXY > ENK and for GT1b, Abeta42 > DYN > SP = GAL > SOM = BRD = OXY > ENK. The ganglioside sugar moiety, specifically the sialic acid, had an important role in the interactions. In general the affinities were higher with polysialo, than with monosialo gangliosides. The sensorgrams describing the interactions of Abeta42 and SP with gangliosides differed from the interactions of the other studied peptides. Ca(2+) promoted changes in peptide-glycolipid interactions.
Assuntos
Glicolipídeos/química , Neuropeptídeos/química , Neuropeptídeos/metabolismo , Ressonância de Plasmônio de Superfície/métodos , Sequência de Aminoácidos , Cálcio/metabolismo , Cálcio/farmacologia , Cloreto de Cálcio/farmacologia , Sequência de Carboidratos , Gangliosídeo G(M1)/metabolismo , Gangliosídeos/química , Gangliosídeos/metabolismo , Cinética , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica , Fatores de TempoRESUMO
The patterns of major gangliosides in the rat hippocampi and olfactory bulbs was examined in vivo after microinjections of Ibotenic acid and L-BOAA (NMDA and AMPA receptor agonists, respectively) which were given under free-movement conditions. The excitotoxicity induced by injections of Ibotenic acid promoted transient ganglioside changes in olfactory bulbs and permanent changes in hippocampus. Four days after injections, the amount of gangliosides in the hippocampus increased significantly for GQ1b, GT1b and GD1b and decreased in the olfactory bulb for GQ1b, GT1b, GD1b, GD1a and GM1 compared to normal ganglioside levels. The alterations of gangliosides were minimal 1 day after injections. After 5 weeks, the amounts of GQ1b, GT1b and GD1b dramatically decreased in the hippocampus while in the olfactory bulbs gangliosides recovered to normal levels. The results obtained with L-BOAA 4 days after injections strengthen the results observed in the experiments using Ibotenic acid and corroborate our suggestion that gangliosides have an active role in the compensatory mechanism to maintain the number of glutamate receptors during the excitotoxicity.
Assuntos
Diamino Aminoácidos , Encéfalo/metabolismo , Gangliosídeos/metabolismo , Ácido Ibotênico/farmacologia , beta-Alanina/análogos & derivados , beta-Alanina/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Agonistas de Aminoácidos Excitatórios/farmacologia , Lateralidade Funcional , Gangliosídeos/isolamento & purificação , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Bulbo Olfatório/efeitos dos fármacos , Bulbo Olfatório/metabolismo , Ratos , Ratos Wistar , Receptores de AMPA/agonistas , Receptores de N-Metil-D-Aspartato/agonistas , Valores de Referência , Fatores de TempoRESUMO
A solid phase immunoradiometric assay (IRMA) for quantification of bovine albumin fraction V (Bov.Alb.FV) in antileptospirosical Cuban vaccine vaxSpiral is described in the present work. Anti-Bov.Alb.FV IgG raised against rabbit purified by affinity chromatography was used as first antibody. Anti-rabbit IgG labeled by Chloromine-T reaction was used as a tracer and the method has demonstrated to be sensitive with high intra- and inter-assay reproducibility. Eight lots of vaccinal antigens were evaluated and in all of the cases, the bovine albumin fraction V concentration was lower than 1 microgram/mL, as the World Health Organization (WHO) establishes. This IRMA is a simple and sensitive assay and could be used as control method for all human vaccines that use Bov.Alb.FV in their production process, even cellular vaccines.
