Dissection of striato-nigrostriatal circuits

• Autor(a) principal: Moreira, Sílvia Cristina Fernandes
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/30404
• topic: Addiction; Dopamine; Basal ganglia; Striato-nigrostriatal circuit; Cholera toxin b

Drug addiction is considered a neuropsychiatric disease, affecting about 5.5% of the global adult population. Drug use usually begins based on the achievement of a particular goal (motivated behavior) but eventually may become habitual behavior. This change of behavior occurs through a gradual shift of control from the ventral striatum (or nucleus accumbens; limbic region), to the dorsomedial striatum (associative region) and ending in the dorsolateral striatum (sensorimotor region), through the midbrain. The discovery of this information passing circuit was made by Haber and colleagues, when they analyzed studies performed in primates, and may therefore be called the Haber model. However, it is not yet well understood how this circuit works. In order to unravel this mystery, stereotaxic surgeries were performed in wild-type rats, with different neuroanatomic tracers, based on some experimental diagrams. Also, part of the methods used consisted in the labelling of dopaminergic cells by immunohistochemistry, visualization and obtaining of results by fluorescence microscopy, and data analysis using FIJI program. The results showed that the nigrostriatal projections for different functional striatal domains originate from distinct dopaminergic neuron populations and the striatonigral projections of different functional domains innervate segregated midbrain regions. In conclusion, we have seen from this work that there is an exchange of information between the three striatal regions mentioned, through distinct dopaminergic areas.