Encontrados 35 documentos, a visualizar página 1 de 4
Differential Contribution of L-, N-, and P/Q-type Calcium Channels to [Ca2+]i C...
Santiago, Ana; Carvalho, Caetana; Carvalho, Arsélio; Ambrósio, AntónioAbstract We investigated the contribution of L-, N- and P/Q-type Ca2+ channels to the [Ca2+]i changes, evoked by kainate, in the cell bodies of hippocampal neurons, using a pharmacological approach and Ca2+ imaging. Selective Ca2+ channel blockers, namely nitrendipine, ?-Conotoxin GVIA (?-GVIA) and ?-Agatoxin IVA (?-AgaIVA) were used. The [Ca2+]i changes evoked by kainate presented a high variability, and were...
Trkb receptors modulation of glutamate release is limited to a subset of nerve ...
Pereira, Daniela B.; Rebola, Nelson; Rodrigues, Ricardo J.; Cunha, Rodrigo A.; Carvalho, Arsélio P.; Duarte, Carlos B.Brain-derived neurotrophic factor (BDNF) modulates glutamatergic excitatory transmission in hippocampal primary cultures by acting at a presynaptic locus. Although it has been suggested that BDNF also modulates adult hippocampus glutamatergic transmission, this remains a matter of controversy. To clarify a putative role for this neurotrophin in the modulation of glutamate release we applied exogenous BDNF to is...
Early calpain-mediated proteolysis following AMPA receptor activation compromis...
Araújo, Inês M.; Verdasca, Maria J.; Leal, Ermelindo C.; Bahr, Ben A.; Ambrósio, António F.; Carvalho, Arsélio P.; Carvalho, Caetana M.http://dx.doi.org/10.1111/j.1471-4159.2004.03043.x
Calpains are activated by photodynamic therapy but do not contribute to apoptot...
Almeida, Ramiro D.; Gomes, Edgar R.; Carvalho, Arsélio P.; Duarte, Carlos B.Photodynamic therapy (PDT) of cancer is a promising technique based on the formation of singlet oxygen following irradiation of a sensitizer with visible light. In the present work we investigated the role of calpains in PDT, using the human lymphoblastoid CCRF-CEM cells and bisulfonated aluminum phthalocyanine (AlPcS2) as a sensitizer. Photosensitization induced apoptotic cell death and a time-dependent activa...
Intracellular signaling mechanisms in photodynamic therapy
Almeida, Ramiro D.; Manadas, Bruno J.; Carvalho, Arsélio P.; Duarte, Carlos B.In photodynamic therapy (PDT) a sensitizer, light and oxygen are used to induce death of tumor cells and in the treatment of certain noncancerous conditions. Cell death in PDT may occur by apoptosis or by necrosis, depending on the sensitizer, on the PDT dose and on the cell genotype. Some sensitizers that have been used in PDT are accumulated in the mitochondria, and this may explain their efficiency in induci...
Neurotoxicity Induced by Antiepileptic Drugs in Cultured Hippocampal Neurons: A...
Araújo, Inês M.; Ambrósio, António Francisco; Leal, Ermelindo C.; Verdasca, Maria João; Malva, João Oliveira; Soares-da-Silva, PatrícioPurpose: Newly designed antiepileptic drugs (AEDs) are being evaluated for their efficacy in preventing seizures and for their toxic profiles. We investigated and compared the toxic effects of two dibenz[b,f]azepine derivatives with anticonvulsant activity, 10,11-dihydro-10-hydroxyimino-5H-dibenz[b,f]azepine-5-carboxamide (BIA2-024) and (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz[b,f] azepine-5-carboxamide (BIA2...
Contact sensitizer nickel sulfate activates the transcription factors NF-kB and...
Cruz, M. Teresa; Gonçalo, Margarida; Figueiredo, Américo; Carvalho, Arsélio P.; Duarte, Carlos B.; Lopes, M. CelesteNuclear factor kappa B (NF-kB) and activating protein-1 (AP-1) transcription factors are ubiquitously expressed signaling molecules known to regulate the transcription of a large number of genes involved in immune responses, namely the inducible isoform of nitric oxide synthase (iNOS). In this study, we demonstrate that a fetal skin-derived dendritic cell line (FSDC) produces nitric oxide (NO) in response to th...
Functional interaction between neuropeptide Y receptors and modulation of calci...
Silva, Ana P.; Carvalho, Arsélio P.; Carvalho, Caetana M.; Malva, João O.We investigated the functional interaction between neuropeptide Y (NPY) receptors using nerve terminals and cultured rat hippocampal neurons, and we evaluated the involvement of voltage-gated Ca2+ channels (VGCCs) in NPY receptors-induced inhibition of Ca2+ influx and glutamate release. The KCl-evoked release of glutamate from hippocampal synaptosomes was inhibited by 1 [mu]M NPY and this effect was insensitive...
Genistein inhibits Ca2+ influx and glutamate release from hippocampal synaptoso...
Pereira, Daniela B.; Carvalho, Arsélio P.; Duarte, Carlos B.The role of protein tyrosine kinases on glutamate release was investigated by determining the effect of broad range inhibitors of tyrosine kinases on the release of glutamate from rat hippocampal synaptosomes. We found that lavendustin A and herbimycin A did not inhibit glutamate release stimulated by 15 mM KCl, but genistein, also a broad range inhibitor of tyrosine kinases did inhibit the intracellular Ca2+ c...
Differential Expression of Syntaxin 1A and 1B by Noradrenergic and Adrenergic C...
Baltazar, Graça; Carvalho, Arsélio P.; Duarte, Emília P.The expression and localization of syntaxin isoforms 1A and 1B in adrenergic and noradrenergic chromaffin cells were examined by both immunoblot analysis and confocal immunofluorescence microscopy. Syntaxin 1A was found in higher levels in noradrenergic cells, whereas syntaxin 1B was similarly expressed in most noradrenergic and adrenergic cells. However, some heterogeneity was observed within each catecholamin...
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