Identification and Characterization of GABAergic Projection Neurons from Ventral Hippocampus to Amygdala.
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.
Institute of Anatomy, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. robertluebkemann@hotmail.de.
Robert
R
Lübkemann
Institute of Anatomy, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. judith.eberhardt@st.ovgu.de.
Judith
J
Eberhardt
Institute of Biometry and Medical Informatics, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. friedrich-wilhelm.roehl@med.ovgu.de.
Friedrich-Wilhelm
FW
Röhl
Clinic of Neurology, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. kathrin.janitzky@med.ovgu.de.
Kathrin
K
Janitzky
Institute of Anatomy, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. sven.nullmeier@med.ovgu.de.
Sven
S
Nullmeier
Institute of Biology, Department of Genetics and Molecular Neurobiology, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. oliver.stork@ovgu.de.|Center of Behavioral Brain Science, D-39120 Magdeburg, Germany. oliver.stork@ovgu.de.
Oliver
O
Stork
Institute of Anatomy, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. herbert.schwegler@med.ovgu.de.|Center of Behavioral Brain Science, D-39120 Magdeburg, Germany. herbert.schwegler@med.ovgu.de.
Herbert
H
Schwegler
Institute of Anatomy, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany. ruediger.linke@med.ovgu.de.
Rüdiger
R
Linke
GABAergic; amygdala; fear; hippocampus; memory