Glutamate-receptor-induced modulation of GABAergic synaptic transmission in the hippocampus

There is a large body of evidence about the short- and long-term changes in GABAergic transmission in the hippocampus produced by the action of different endogenous neuromodulators and in particular neurotransmitters. Both intrinsic hippocampal cells and afferent fibres coming into the hippocampus from various parts of the CNS release substances that are capable of changing inhibitory transmission. This review surveys current understanding of the action of glutamate on the inhibitory transmission mediated in the hippocampus via GABA(A) receptors. Here we pay special attention to the molecular and cellular mechanisms leading to spatio-temporal changes of the glutamate concentration in the extracellular space and to the localization and identity of glutamate receptors involved in this direct modulation of inhibition.