Navegando por Assunto "Hidroxidopaminas"

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Acesso aberto (Open Access)
Análise comportamental e histológica de um modelo animal da doença de Parkinson em camundongos suíços
(Universidade Federal do Pará, 2011-12-29) GARCEZ, Daniela Rosa; YAMADA, Elizabeth Sumi; http://lattes.cnpq.br/7240314827308306
Parkinson’s disease (PD) is one of the most common aging-related neurodegenerative diseases, having a clinical presentation featuring classic motor symptoms related to the degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNpc) and dopamine decr ease in the striatum. Animal models of PD are important tools employed by researcher aiming a better understading of pathophysiologic disease mechanisms and for evaluation of potential therapeutic interventions. Such models must mimic some aspect of the disease as for instances, the degeneration of nigral dopaminergic neurons. In this context, the PD model induced by the injection of the neurotoxina 6-hydroxydopamine (6-OHDA) has been widely established in rats but a better characterization in diferent mice strain is lacking, concerning both behavioral changes and the lesion in nigrostriatal system. Such characterization is important so that this model can be reliably used for investigations of therapeutic interventions. The goal of the present study was to improve the characterization of the unilateral 6-OHDA PD model using Swiss mice, through the evaluation of behavioral changes and the effects on the SNpc dopaminergic neurons. In this investigation we have used a single unilateral intraestriatal injection of 6-OHDA, in two different toxin concentrations: 10 µg/2µl e 20 µg/2 µl. Our results have demonstrated that both 6-OHDA concentrations used provoked severe loss of nigral dopaminergic neurons, amounting to 74,5% e 89,5% respectively. This neuronal loss was highly correlated to the apomorphine-induced rotational behavior but not to the ambulation assessed in the open field test. Therefore, intraestriatal injection of 10 µg/2µl or 20 µg/2µl of 6-OHDA, using Swiss mice, reproduce an effective unilateral 6-OHDA PD model that can be reliably employed in experiments aiming to investigate neuroprotective, cellular and/or pharmacological therapies for PD.
Acesso aberto (Open Access)
Efeito do extrato aquoso de folhas de mogno (Swietenia macrophylla) em modelo in vivo de doença de Parkinson com lesão com 6-hidroxidopamina
(Universidade Federal do Pará, 2012-09-28) RAMOS, Luciana Fernandes Pastana; YAMADA, Elizabeth Sumi; http://lattes.cnpq.br/7240314827308306; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978
Parkinson's disease (PD) is characterized by a progressive degeneration of dopaminergic neurons in the substantia nigra and the presence of classical clinical signs bradykinesia, muscle rigidity, resting tremor and postural instability. The etiology is still unknown and the available treatment options only promote relief of symptoms. Experimental models of PD are fundamental for studies aiming to identify the molecular events involved in the disease and to discover new neuroprotective therapies. This study used a hemiparkinsonism model with lesion induced by 6-hydroxydopamine (6-OHDA), and investigated effects of an aqueous extract of leaves of mahogany (Swietenia macrophylla) on the dopaminergic neurons of the substantia nigra pars compacta (SNpc) and on behavioural parameters assessed in the open-field and apomorphine-induced rotacional tests. The results showed that the 6-OHDA lesioned animals exhibited contralateral rotation induced by apomorphine and significant reduction of dopaminergic neurons in SNpc. However, only 6-OHDA lesioned animals treated with mahogany extract showed significant decrease in relation to the group vehicle/vehicle. There was also a significant decrease in ambulation and rearing in the group 6-OHDA/mahogany. In conclusion, the mahogany extract under the conditions used in the present study potentiated the cytotoxic effect of 6-OHDA and yet promoted worsening of behavioral parameters of the animals.
Acesso aberto (Open Access)
Modelo de doença de parkinson em camundongos baseado na injeção unilateral 6-hidroxidopamina no estriado: caracterização do curso temporal das alterações comportamentais e da degeneração nigroestriatal
(Universidade Federal do Pará, 2008-07-03) CARDOSO, Váldina Solimar Lopes; YAMADA, Elizabeth Sumi; http://lattes.cnpq.br/7240314827308306
Parkinson‘s disease (PD) is a common neurodegenerative disease that affects mainly elderly people. It is characterized by the progressive cell death of dopaminergic neurons in the nigrostriatal system, which causes the development of the classic tetrad of symptoms: resting tremor, muscular rigidity, bradikynesia and postural instability. There is evidence that both genetic and environmental factors play a role in the development of the disease. In order to better understand the mechanisms undelying this disease, several animal models have been used to mimic some aspect of the dopaminergic degeneration. The intracerebral injection of 6-OHDA has been one of the most used PD model. This toxin is preferentially injected into the striatum or in the substantia nigra to provoke a selective degeneration of dopaminergic neurons from the nigrostriatal pathway. When a unilateral injection is used, the animals display a stereotypical rotational behavior after pharmacological induction, and such behavior has been largely used as a measure of the degree of nigroestriatal degeneration. This model is well characterized in rats and has been an useful tool to test neuroprotective therapies. Mice, as much as rats, are also largely used in studies of DP, but the 6-OHDA model has not been well described. The objective of the present work was to improve the characterization of the hemiparkinsonism model based on a single unilateral intraestriatal injection of 6-OHDA in C57BL6 mice, to provide a more detailed evaluation of the temporal course of the neuronal dopaminergic degeneration in the substantia nigra and to establish the degree of correlation between the degeneration and behavioral changes. Our results showed that a single injection of 10 μg of 6-OHDA into the striatum causes progressive degeneration of nigral dopaminergic neurons dependent of survival time, and that there is a high correlation between the rate of degeneration and the rotational behavior induced by apomorphine. Spontaneous motor behaviors such as ambulation and rearing had a lower correlation with the degeneration. Therefore, we suggest that the rotational behavior induced by apomorphine provides a good measure of the degree of asymmetry in the nigrostriatal pathway of mice with 6- OHDA-induced hemiparkinsonism and that it can indeed be an useful tool in experiments to test therapies with neuroprotective potential for Parkinson’s disease.
Acesso aberto (Open Access)
Sintomas não motores na doença de Parkinson: modelo de lesão intraestriatal por 6-OHDA em camundongos
(Universidade Federal do Pará, 2014-02-10) SAMPAIO, Gabriela Santos Alvarez; YAMADA, Elizabeth Sumi; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978
Parkinson's disease (PD) is the second most common neurodegenerative disease in the elderly, characterized by neurodegeneration of dopaminergic neurons of the substantia nigra (SN), with no clearly established etiology, though the causes may be associated with exposure to environmental toxins and genetic factors. The pathological processes involved in PD are mitochondrial dysfunction, oxidative stress, inflammation and excitotoxicity. The symptoms of PD are motor, cognitive and autonomic changes. However, few studies have analyzed the non-motor symptoms of PD, especially in animal models. In this context, the objective of this study was to assess non-motor symptoms of PD in animal models with lesions caused by the neurotoxin 6-hydroxydopamine with two different doses, injected bilaterally into the striatum. To achieve our goals we performed tests of open field, apomorphine, Morris water maze and olfactory discrimination tests, and histological analyzes. Our results showed motor abnormalities, learning and memory deficits associated with decreased dopaminergic cells in the SN, striatal neurons and neurons of the hippocampal CA1. Thus, this model for non-motor symptoms of PD can be used to understand the mechanisms involved in the disease, as well as to evaluate therapeutic strategies to slow or stop progression of PD.