Biomedical subjects

Gilles Bonvento

Publications and source records attributed to Gilles Bonvento.

3 recordsLinked to original sources

PubMed2003

Glial glutamate transporters mediate a functional metabolic crosstalk between neurons and astrocytes in the mouse developing cortex.

Neuron-glia interactions are essential for synaptic function, and glial glutamate (re)uptake plays a key role at glutamatergic synapses. In knockout mice, for either glial glutamate transporters, GLAST or GLT-1, a classical metabolic response to synaptic activation (i.e., enhancement of glucose utilization) is decreased at an early functional stage in the somatosensory barrel cortex following activation of whiskers. Investigation in vitro demonstrates that glial glutamate transport represents a critical step for triggering enhanced glucose utilization, but also lactate release from astrocytes through a mechanism involving changes in intracellular Na(+) concentration. These data suggest that a metabolic crosstalk takes place between neurons and astrocytes in the developing cortex, which would be regulated by synaptic activity and mediated by glial glutamate transporters.

Amino Acid Transport System X-AG↗

PubMed2003

Glial glutamate transporters and maturation of the mouse somatosensory cortex.

In the adult nervous system, glutamatergic neurotransmission is tightly controlled by neuron-glia interactions through glial glutamate reuptake by the specific transporters GLT-1 and GLAST. Here, we have explored the role of these transporters in the structural and functional maturation of the somatosensory cortex of the mouse. We provide evidence that GLT-1 and GLAST are early and selectively expressed in barrels from P5 to P10. Confocal and electron microscopy confirm that the expression is restricted to the astroglial membrane. By P12, and despite an increased global expression as observed by immunoblotting, the barrel pattern of GLAST and GLT-1 staining is no longer evident. In P10 GLT-1 -/- and GLAST -/- mice, the cytoarchitectural segregation of the barrels is preserved. However, at P9-10, the functional response to whisker stimulation, measured by deoxyglucose uptake, is markedly decreased in GLT-1 -/- and GLAST -/- mice. The role of GLAST is transient since the metabolic response is already restored at P11-12 in GLAST -/- mice and remains unchanged in adulthood. However, deletion of GLT-1 seems to impair the functional metabolic response until adulthood. Our data suggest that astrocyte-neuron interactions via the glial glutamate transporters are involved in the functional maturation of the whisker representation in the somatosensory cortex.

Amino Acid Transport System X-AG↗

PubMed2002

Does glutamate image your thoughts?

Functional imaging methods exploit the relationship between neuronal activity, energy demand and cerebral blood flow to functionally map the brain. Despite the increasing use of these imaging tools in basic and clinical neuroscience, the neurobiological processes underlying the imaging signals remain unclear. Recently, interest has been focused on uncovering the signals that trigger the metabolic and vascular changes accompanying variations in neuronal activity. Advances in this field have demonstrated that release of the major excitatory neurotransmitter glutamate initiates diverse signaling processes between neurons and astrocytes, and that this signaling could be crucial for the occurrence of brain imaging signals. In this article we review the hypothesis that glutamate represents a common trigger for both neurometabolic and neurovascular coupling.

Animals↗