کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1931147 | 1050542 | 2011 | 6 صفحه PDF | دانلود رایگان |

Astrocytes which lie between brain capillaries and neuronal terminals are the primary site of glucose uptake and have a key role in coupling synaptic activity to glucose utilization in the central nervous system (CNS). We used a fluorescence resonance energy transfer (FRET) based approach to monitor cytosolic glucose in astrocytes. We determined the effect of increasing extracellular glucose concentrations on FRET ratio as a measure of increased cytosolic glucose in astrocytes. By briefly raising extracellular glucose concentration, astrocytes responded promptly by increased cytosolic glucose levels, which was manifested by decreased time-dependent FRET ratio. The FRET ratio fall-time recorded at low extracellular d-glucose concentration change (from 0 to 0.5 mM) was 53 s, whereas 17 s was recorded by raising extracellular concentration of d-glucose from 0 to 10 mM, which is likely due to facilitated d-glucose entry along the increased d-glucose gradient across the plasmalemma. The relationship between the extracellular glucose concentration and the FRET ratio change is limited to the maximal ratio change, where the d-glucose plasma membrane permeability is balanced by the cytosolic utilization. We measured the effect of extracellular ATP, an important extracellular messenger for astrocyte-to-astrocyte communication, on intracellular glucose concentration. The results show that stimulation of astrocytes with ATP (1 mM) decreases cytosolic glucose concentration with a time constant of ∼145 s. The mechanism of this change is discussed.
Research highlights
► The extracellular glucose concentration affects cytosolic glucose in astrocytes.
► Raising extracellular glucose to 10 mM increased cytosolic glucose levels in 17 s.
► The stimulation of astrocytes with ATP decreases cytosolic glucose concentration.
► The time constant of ATP induced glucose decrease was 145 s.
Journal: Biochemical and Biophysical Research Communications - Volume 405, Issue 2, 11 February 2011, Pages 308–313