RESUMO
OBJECTIVE: Previous reports showed the reduction of dopamine transporter immunoreactivity in peripheral blood lymphocytes in Parkinson's disease. In this work, we sought to investigate the possible correlation between central and peripheral dopamine transporter immunoreactivity values in a group of 11 drug-naive patients with Parkinson's disease. METHODS: Densitometric measurements of dopamine transporter immunoreactivity in peripheral blood lymphocytes was accomplished as described recently, using a monoclonal antidopamine transporter antibody. Dopamine transporter binding in the caudate and putamen nuclei was measured by means of (123)I-fluopane single-photon emission computed tomography in the same patients. RESULTS: The results failed to show any significant correlation between dopamine transporter immunoreactivity in peripheral blood lymphocytes and the caudate or putamen dopamine transporter binding. Moreover, dopamine transporter immunoreactivity in peripheral blood lymphocytes was reduced also in the single patient with normal striatal dopamine transporter binding. DISCUSSION: These results indicate the lack of correlation between central and peripheral dopamine transporter reduction in Parkinson's disease, using the methodologies applied herein. They therefore suggest that the two phenomena are unlikely to share a common pathogenetic mechanism.
Assuntos
Núcleo Caudado/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Linfócitos/metabolismo , Doença de Parkinson/metabolismo , Putamen/metabolismo , Adulto , Idoso , Núcleo Caudado/diagnóstico por imagem , Feminino , Humanos , Radioisótopos do Iodo , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/sangue , Doença de Parkinson/patologia , Putamen/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , TropanosRESUMO
Previous studies showed the reduction of dopamine transporter immunoreactivity (DAT-IR) in peripheral blood lymphocytes (PBL) in Parkinson's disease. Here we report the reduction of DAT-IR in PBL in the extrapyramidal variant of multiple system atrophy. These results suggest the reduction of DAT-IR in PBL in a variety of neurodegenerative disorders, provided the presence of damage of the central dopaminergic systems. The reduction of DAT-IR in PBL in these disorders may represent a compensatory phenomenon aimed at reducing intracellular dopamine influx and, consequently, dopamine-mediated aggravation of oxidative stress in these cells.
Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/biossíntese , Linfócitos/metabolismo , Atrofia de Múltiplos Sistemas/sangue , Idoso , Dopaminérgicos/uso terapêutico , Feminino , Humanos , Imuno-Histoquímica , Levodopa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Atrofia de Múltiplos Sistemas/tratamento farmacológicoRESUMO
In this study we analyzed the interaction of prion protein PrP(C) with components of glycosphingolipid-enriched microdomains in lymphoblastoid T cells. PrP(C) was distributed in small clusters on the plasma membrane, as revealed by immunoelectron microscopy. PrP(C) is present in microdomains, since it coimmunoprecipitates with GM3 and the raft marker GM1. A strict association between PrP(C) and Fyn was revealed by scanning confocal microscopy and coimmunoprecipitation experiments. The phosphorylation protein ZAP-70 was immunoprecipitated by anti-PrP after T cell activation. These results demonstrate that PrP(C) interacts with ZAP-70, suggesting that PrP(C) is a component of the multimolecular signaling complex within microdomains involved in T cell activation.
