| Autor: |
Monteiro T; UCIBIO-Applied Molecular Biosciences Unit, REQUIMTE-Rede de Química e Tecnologia, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Monte de Caparica, Portugal., Dias C; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.; Health Sciences Campus, Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal., Lourenço CF; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.; Health Sciences Campus, Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal., Ledo A; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.; Health Sciences Campus, Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal., Barbosa RM; Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.; Health Sciences Campus, Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal., Almeida MG; UCIBIO-Applied Molecular Biosciences Unit, REQUIMTE-Rede de Química e Tecnologia, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Monte de Caparica, Portugal.; Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Campus Universitário, Quinta da Granja, 2829-511 Monte de Caparica, Portugal. |
| Abstrakt: |
The impaired blood flow to the brain causes a decrease in the supply of oxygen that can result in cerebral ischemia; if the blood flow is not restored quickly, neuronal injury or death will occur. Under hypoxic conditions, the production of nitric oxide ( ● NO), via the classical L-arginine- ● NO synthase pathway, is reduced, which can compromise ● NO-dependent vasodilation. However, the alternative nitrite (NO 2 - ) reduction to ● NO, under neuronal hypoxia and ischemia conditions, has been viewed as an in vivo storage pool of ● NO, complementing its enzymatic synthesis. Brain research is thus demanding suitable tools to probe nitrite's temporal and spatial dynamics in vivo. In this work, we propose a new method for the real-time measurement of nitrite concentration in the brain extracellular space, using fast-scan cyclic voltammetry (FSCV) and carbon microfiber electrodes as sensing probes. In this way, nitrite was detected anodically and in vitro, in the 5-500 µM range, in the presence of increasing physiological concentrations of ascorbate (100-500 µM). These sensors were then tested for real-time and in vivo recordings in the anesthetized rat hippocampus; using fast electrochemical techniques, local and reproducible transients of nitrite oxidation signals were observed, upon pressure ejection of an exogenous nitrite solution into the brain tissue. Nitrite microsensors are thus a valuable tool for investigating the role of this inorganic anion in brain redox signaling. |
