Astrocyte Sodium Signalling and Panglial Spread of Sodium Signals in Brain White Matter.

Astrocyte Sodium Signalling and Panglial Spread of Sodium Signals in Brain White Matter. Neurochem Res. 2017 Feb 18;: Authors: Moshrefi-Ravasdjani B, Hammel EL, Kafitz KW, Rose CR Abstract In brain grey matter, excitatory synaptic transmission activates glutamate uptake into astrocytes, inducing sodium signals which propagate into neighboring astrocytes through gap junctions. These sodium signals have been suggested to serve an important role in neuro-metabolic coupling. So far, it is unknown if astrocytes in white matter-that is in brain regions devoid of synapses-are also able to undergo such intra- and intercellular sodium signalling. In the present study, we have addressed this question by performing quantitative sodium imaging in acute tissue slices of mouse corpus callosum. Focal application of glutamate induced sodium transients in SR101-positive astrocytes. These were largely unaltered in the presence of ionotropic glutamate receptors blockers, but strongly dampened upon pharmacological inhibition of glutamate uptake. Sodium signals induced in individual astrocytes readily spread into neighboring SR101-positive cells with peak amplitudes decaying monoexponentially with distance from the stimulated cell. In addition, spread of sodium was largely unaltered during pharmacological inhibition of purinergic and glutamate receptors, indicating gap junction-mediated, passive diffusion of sodium between astrocytes. Using cell-type-spe...
Source: Neurochemical Research - Category: Neuroscience Authors: Tags: Neurochem Res Source Type: research