Avtor/Urednik		Prebil, Mateja; Chowdhury, Helena H; Zorec, Robert; Kreft, Marko
Naslov		Changes in cytosolic glucose level in ATP stimulated live astrocytes
Tip		članek
Vir		Biochem Biophys Res Commun
Vol. in št.		Letnik 405, št. 2
Leto izdaje		2011
Obseg		str. 308-13
Jezik		eng
Abstrakt		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 0.5mM) was 53s, whereas 17s was recorded by raising extracellular concentration of d-glucose from 0 to 10mM, 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 (1mM) decreases cytosolic glucose concentration with a time constant of approximately 145s. The mechanism of this change is discussed.
Deskriptorji		ASTROCYTES GLUCOSE CYTOSOL SPECTROMETRY, FLUORESCENCE ADENOSINE TRIPHOSPHATE CELLS, CULTURED PLASMIDS TRANSFECTION