Assessing the impact of neuronal activityon the redox balance of neurons and glia

• Autor(a) principal: Silva, Jéssica José Abreu da
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10773/36361
• topic: Redox balance; Neuronal activity; Neuronal plasticity; Glial cells; Vitamin C

Maintaining physiological variables at a set point is crucial to the organization and function of the nervous system. Homeostatic synaptic plasticity, also known as synaptic scaling, is a form of neuronal plasticity which responds to disrupted activity in a neural circuit by using negative feedback, allowing individual neurons to modify their overall firing rate. Due to its importance in homeostasis, its investigation is of the utmost relevance. Until now, there was no evidence of the role of synaptic scaling in the redox balance of neurons and their neighboring glia. In this work, the retina of the chick embryo is used as the experimental model, and neuronal activity is modulated: neurons are upscaled (increase in the firing rate due to chronic inactivity) or downscaled (decrease in the firing rate due to chronic overactivity), to assess the impact of this modulation on the redox balance of neurons and glia. We demonstrated that upscaling or downscaling altered the redox balance of neurons. More specifically, both changed the redox balance towards a more reduced state of the cytosol. This change in cytosolic redox state was accompanied by an increase in the membrane expression of the Sodium Vitamin C co-transporter 2 (SVCT2) without affecting the content of intracellular ascorbate, the reduced form of vitamin C. Neuronal downscaling also led to redox alterations in the Müller glia, but not neuronal upscaling. Moreover, since mitochondria are the major ROS-producing organelle and previous studies have reported its alteration in neuronal activity, its oxidative damage level was assessed. Our model showed no alteration in the mitochondrial status upon synaptic scaling.