Perisynaptic asymmetry of glia: new insights into glutamate signalling.

Synaptically released glutamate activates extrasynaptic receptors; such actions are controlled by glutamate uptake. Recent experimental findings show that there are many more glutamate transporters on the postsynaptic than presynaptic side of the vicinity of central synapses. This asymmetry favours activation of axonal, as opposed to dendritic, extrasynaptic glutamate receptors, thus imposing rule on information processing in the brain.