Localization of GABA-A Receptor Subunits in the Hippocampus

The hippocampal formation is important for acquisition of short-term memory. In the hippocampus two classes of neurons can be distinguished: output pyramidal cells releasing excitatory amino acid(s) and GABAergic local- circuit interneurons that regulate input, computation and output of pyramidal cells via inhibitory GABA A receptors. Different GABA A receptor subtypes consisting of different subunits exist in the hippocampus. In the present project the precise subcellular distribution of alpha4 and alpha5 GABA A receptor subunits in the hippocampus should be investigated with a quantitative immunogold method. It will be investigated whether these subunits are present in synaptic and/or extrasynaptic sites on the pyramidal cells, whether they are selectively present in distal and proximal dendrites, somata and/or axon-initial segments of pyramidal cells. In addition it will be investigated whether interneurons also express these subunits in order to communicate with each other.