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Astrocytes have traditionally been considered ancillary, satellite cells of the nervous system. However, work over the past decade has revealed that they interact with the vasculature to form a gliovascular network that might organize not only the structural architecture of the brain but also its communication pathways, activation, thresholds and(More)
Little is known about the expression and possible functions of unopposed gap junction hemichannels in the brain. Emerging evidence suggests that gap junction hemichannels can act as stand-alone functional channels in astrocytes. With immunocytochemistry, dye uptake, and HPLC measurements, we show that astrocytes in vitro express functional hemichannels that(More)
Defining the microanatomic differences between the human brain and that of other mammals is key to understanding its unique computational power. Although much effort has been devoted to comparative studies of neurons, astrocytes have received far less attention. We report here that protoplasmic astrocytes in human neocortex are 2.6-fold larger in diameter(More)
We tested the hypothesis that astrocytic glycogen sustains axon function during and enhances axon survival after 60 min of glucose deprivation. Axon function in the rat optic nerve (RON), a CNS white matter tract, was monitored by measuring the area of the stimulus-evoked compound action potential (CAP). Switching to glucose-free artificial CSF (aCSF) had(More)
1. We determined the intracellular Na+ concentration ([Na+]i) and mechanisms of its regulation in cultured rat hippocampal astrocytes using fluorescence ratio imaging of the Na+ indicator SBFI-AM (acetoxymethylester of sodium-binding benzofuran isophthalate, 10 microM). Dye signal calibration within the astrocytes showed that the ratiometric dye signal(More)
White matter of the mammalian CNS suffers irreversible injury when subjected to anoxia/ischemia. However, the mechanisms of anoxic injury in central myelinated tracts are not well understood. Although white matter injury depends on the presence of extracellular Ca2+, the mode of entry of Ca2+ into cells has not been fully characterized. We studied the(More)
CNS glycogen, contained predominantly in astrocytes, can be converted to a monocarboxylate and transported to axons as an energy source during aglycaemia. We analysed glycogen regulation and the role of glycogen in supporting neural activity in adult mouse optic nerve, a favourable white matter preparation. Axon function was quantified by measuring the(More)
White matter (WM) of the mammalian brain is susceptible to anoxic injury, but little is known about the pathophysiology of this process. We studied the mechanisms of anoxic injury in WM using the isolated rat optic nerve, a typical central nervous system WM tract. Optic nerve function, measured as the area under the compound action potential, rapidly failed(More)
1. We studied regulation of intracellular Na+ concentration ([Na+]i) in cultured rat hippocampal neurones using fluorescence ratio imaging of the Na+ indicator dye SBFI (sodium-binding benzofuran isophthalate). 2. In standard CO2/HCO3(-)-buffered saline with 3 mM K+, neurones had a baseline [Na+]i of 8.9 +/- 3.8 mM (mean +/- S.D.). Spontaneous, transient(More)
The excitatory transmitter glutamate (Glu), and its analogs kainate (KA), and D-aspartate (D-Asp) produce significant pH changes in glial cells. Transmitter-induced pH changes in glial cells, generating changes in extracellular pH, may represent a special form of neuronal-glial interaction. We investigated the mechanisms underlying these changes in(More)