Brain Sciences (Jul 2015)

Identification and Characterization of GABAergic Projection Neurons from Ventral Hippocampus to Amygdala

  • Robert Lübkemann,
  • Judith Eberhardt,
  • Friedrich-Wilhelm Röhl,
  • Kathrin Janitzky,
  • Sven Nullmeier,
  • Oliver Stork,
  • Herbert Schwegler,
  • Rüdiger Linke

DOI
https://doi.org/10.3390/brainsci5030299
Journal volume & issue
Vol. 5, no. 3
pp. 299 – 317

Abstract

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GABAergic local circuit neurons are critical for the network activity and functional interaction of the amygdala and hippocampus. Previously, we obtained evidence for a GABAergic contribution to the hippocampal projection into the basolateral amygdala. Using fluorogold retrograde labeling, we now demonstrate that this projection indeed has a prominent GABAergic component comprising 17% of the GABAergic neurons in the ventral hippocampus. A majority of the identified GABAergic projection neurons are located in the stratum oriens of area CA1, but cells are also found in the stratum pyramidale and stratum radiatum. We could detect the expression of different markers of interneuron subpopulations, including parvalbumin and calbindin, somatostatin, neuropeptide Y, and cholecystokinin in such retrogradely labeled GABA neurons. Thus GABAergic projection neurons to the amygdala comprise a neurochemically heterogeneous group of cells from different interneuron populations, well situated to control network activity patterns in the amygdalo-hippocampal system.

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