RESUMO
The aetiology of idiopathic Parkinson's disease (PD) is poorly defined but environmental aggression may be relevant. Here, we report a new model of PD in mice, based on chronic inoculation with neurotoxins in the nasal cavity, which is a natural route of contact with the environment. C57BL/6 mice, submitted to daily intranasal inoculation with MPTP for 30 days, developed motor deficits that correlated with a progressive and severe depletion of striatal dopamine levels, and loss of tyrosine hydroxylase and dopamine transporter staining in substantia nigra and striatum. Moreover, mice intranasally inoculated with MPTP developed strong astrogliosis and microgliosis in substantia nigra and striatum. Consistent with these observations, a role for oxidant aggression was demonstrated by increased levels of Mn-superoxide dismutase. However, alpha-synuclein aggregation was not observed. This new animal model provides a new tool for studying PD symptoms that develop slowly over time, and it may be used to asses risk from environmental neurotoxins.
Assuntos
1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/administração & dosagem , Administração Intranasal , Modelos Animais de Doenças , Neurotoxinas/administração & dosagem , Doença de Parkinson , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/metabolismo , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Acetilcolinesterase/metabolismo , Animais , Comportamento Animal , Western Blotting/métodos , Encéfalo/metabolismo , Encéfalo/patologia , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Vias de Administração de Medicamentos , Imuno-Histoquímica/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurotoxinas/metabolismo , Doença de Parkinson/etiologia , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sinucleínas/genética , Sinucleínas/metabolismo , Fatores de Tempo , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Adenine phosphoribosyltransferase (APRT) has been 1200-fold purified from erythrocytes of a patient with partial hipoxanthine-guanine phosphoribosyltransferase (HGPRT) deficiency, Propositus, and in those of a controlHPRT+, with 20% efficiency in both proteins and specific activity of 550 and 243 nmol/h/mgprotein. The specific activity determined in the Propositus enzyme was, in all purification steps, higher than that of the controlHPRT+. Significant changes were found in their thermal stabilities. Half inactivation times at each temperature studied are greater for the Propositus enzyme in the temperature interval 60-80 degrees C. No significant difference has been observed in the affinity constants for adenine and PRPP substrates. Studies on inhibition by the reaction product suggest that AMP is a competitive inhibitor with respect to PRPP in both enzymes, with Ki values of 150 microM in Propositus and 220 microM in controlHPRT+.