RESUMO
Minocycline produces antidepressant-like actions in male rats tested in the forced swimming test (FST) and synergizes with several glutamate receptor antagonists. However, the limbic regions implicated in the antidepressant-like actions of minocycline are unknown. The objective of the present study was to test the potential antidepressant activity of nucleus accumbens infusions of minocycline alone or combined with antidepressant drugs or with several glutamate receptor antagonists, using the time-sampling method in the FST. The results show that intra-NAcc infusions of minocycline reduced immobility (1.0 microg, P<0.05; 1.5 microg, P<0.05) by increasing climbing (1.0 microg, P<0.05; 1.5 microg, P<0.05) in the FST. Likewise, systemic injections of desipramine (P<0.05), fluoxetine (P<0.05) or several glutamate receptor antagonists: EMQMCM (P<0.05), MTEP (P<0.05) or dizocilpine (P<0.05) combined with intra-nucleus accumbens infusions of vehicle produced antidepressant-like actions. The subthreshold dose of intra-nucleus accumbens infusions of minocycline combined with systemic injections of subthreshold doses of desipramine (P<0.05) or EMQMCM (P<0.05) or MTEP (P<0.05) or dizocilpine (P<0.05) produced antidepressant-like actions. It is concluded that intra-NAcc infusions of minocycline alone or combined with systemic injections of desipramine or with systemic injections of several glutamate receptor antagonists produced antidepressant-like actions in the FST.
Assuntos
Antidepressivos/uso terapêutico , Depressão/tratamento farmacológico , Desipramina/uso terapêutico , Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Minociclina/uso terapêutico , Núcleo Accumbens/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Comportamento Exploratório/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Núcleo Accumbens/fisiologia , Ratos , Ratos Wistar , Estatísticas não Paramétricas , NataçãoRESUMO
Stenotrophomonas maltophilia is an emerging nosocomial bacterial pathogen associated with several infectious diseases and opportunistic infections, especially in immunocompromised patients. These bacteria adhere avidly to medical implants and catheters forming a biofilm that confers natural protection against host immune defences and different antimicrobial agents. The nature of the bacterial surface factors involved in biofilm formation on inert surfaces and in adherence of S. maltophilia to epithelial cells is largely unknown. In this study, we identified and characterized fimbrial structures produced by S. maltophilia grown at 37 degrees C. The S. maltophilia fimbriae 1 (SMF-1) are composed of a 17 kDa fimbrin subunit which shares significant similarities with the N-terminal amino acid sequences of several fimbrial adhesins (G, F17, K99 and 20K) found in Escherichia coli pathogenic strains and the CupA fimbriae of Pseudomonas aeruginosa. All of the clinical S. maltophilia isolates tested produced the 17 kDa fimbrin. Antibodies raised against SMF-1 fimbriae inhibited the agglutination of animal erythrocytes, adherence to HEp-2 cells and biofilm formation by S. maltophilia. High resolution electron microscopy provided evidence of the presence of fimbriae acting as bridges between bacteria adhering to inert surfaces or to cultured epithelial cells. This is the first characterization of fimbriae in this genus. We provide compelling data suggesting that the SMF-1 fimbriae are involved in haemagglutination, biofilm formation and adherence to cultured mammalian cells.
Assuntos
Aderência Bacteriana/fisiologia , Células Epiteliais/microbiologia , Fímbrias Bacterianas/metabolismo , Stenotrophomonas maltophilia/metabolismo , Sequência de Aminoácidos , Biofilmes , Linhagem Celular , Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/ultraestrutura , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Dados de Sequência Molecular , Alinhamento de Sequência , Stenotrophomonas maltophilia/ultraestrutura , TemperaturaRESUMO
Stenotrophomonas maltophilia is an emerging nosocomial bacterial pathogen associated with several infectious diseases and opportunistic infections, especially in immunocompromised patients. These bacteria adhere avidly to medical implants and catheters forming a biofilm that confers natural protection against host immune defences and different antimicrobial agents. The nature of the bacterial surface factors involved in biofilm formation on inert surfaces and in adherence of S. maltophilia to epithelial cells is largely unknown. In this study, we identified and characterized fimbrial structures produced by S. maltophilia. The S. maltophilia fimbriae 1(SMF-1) are composed of a 17 kDa fimbrin subunit which shares significant similarities with the Nterminal amino acid sequences of several fimbrial adhesins (G, F17, K99 and 20K) found in Escherichia coli pathogenic strains and the CupA fimbriae of Pseudomonas aeruginosa. All of the clinical S. maltophilia isolates tested produced the 17 kDa fimbrin. Antibodies raised against SMF-1 fimbriae inhibited the agglutination of animal erythrocytes, adherence to HEp-2 cells and biofilm formation by S. maltophilia.High resolution electron microscopy ovided evidence of the presence of fimbriae acting as bridges between bacteria adhering to inert surfaces or to cultured epithelial cells. This is the first characterization of fimbriae in this genus. We provide compelling data suggesting that the SMF-1 fimbriae are involved in haemagglutination, biofilm formation and adherence to cultured mammalian cells...