Iván Ruminot

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Synaptic activity is followed within seconds by a local surge in lactate concentration, a phenomenon that underlies functional magnetic resonance imaging and whose causal mechanisms are unclear, partly because of the limited spatiotemporal resolution of standard measurement techniques. Using a novel Förster resonance energy transfer-based method that allows(More)
In recent years, the use of fluorescent glucose analogs has allowed the study of rapid transport modulation in heterogeneous cell cultures and complex tissues. However, the kinetic behavior of these tracers is not conventional. For instance, the fluorescent glucose analog 6-NBDG permeates the cell 50-100 times slower than glucose but the uptake of 6-NBDG is(More)
Glucose is the most important energy substrate for the brain, and its cellular distribution is a subject of great current interest. We have employed fluorescent glucose probes, the 2-deoxy-D-glucose derivates 6- and 2-([N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose) (2-NBDG), to measure transport and metabolism of glucose in acute slices of(More)
Lactate is shuttled between and inside cells, playing metabolic and signaling roles in healthy tissues. Lactate is also a harbinger of altered metabolism and participates in the pathogenesis of inflammation, hypoxia/ischemia, neurodegeneration and cancer. Many tumor cells show high rates of lactate production in the presence of oxygen, a phenomenon known as(More)
Excitatory synaptic transmission stimulates brain tissue glycolysis. This phenomenon is the signal detected in FDG-PET imaging and, through enhanced lactate production, is also thought to contribute to the fMRI signal. Using a method based on Förster resonance energy transfer in mouse astrocytes, we have recently observed that a small rise in extracellular(More)
The glycolytic rate is sensitive to physiological activity, hormones, stress, aging, and malignant transformation. Standard techniques to measure the glycolytic rate are based on radioactive isotopes, are not able to resolve single cells and have poor temporal resolution, limitations that hamper the study of energy metabolism in the brain and other organs.(More)
Glutamate triggers an acute stimulation of the glucose transporter GLUT1 in cultured astrocytes, a phenomenon thought to facilitate energy delivery to active areas in the brain. Here we have explored the cell signaling mechanisms involved in this response. Half-stimulation of GLUT1 occurred at low micromolar glutamate, thus within the physiological range(More)
The synthetic compound N-cyanosulphonamide S0859 has been described as a selective inhibitor of sodium-bicarbonate cotransporters (NBC, SLC4) in mammalian heart (Ch'en et al., 2008). First, for comparison, the electrogenic human NBCe1 (SLC4A4) was heterologously expressed in Xenopus laevis oocytes, where its transport activity was inhibited by S0859 with an(More)
Excitatory synaptic transmission is accompanied by a local surge in interstitial lactate that occurs despite adequate oxygen availability, a puzzling phenomenon termed aerobic glycolysis. In addition to its role as an energy substrate, recent studies have shown that lactate modulates neuronal excitability acting through various targets, including NMDA(More)
We set out to identify molecular mechanisms underlying the onset of necrotic Ca2+ overload, triggered in two epithelial cell lines by oxidative stress or metabolic depletion. As reported earlier, the overload was inhibited by extracellular Ca2+ chelation and the cation channel blocker gadolinium. However, the surface permeability to Ca2+ was reduced by 60%,(More)