Resumen:
n important area of the brain aversive circuitry is the lateral septum
(LS), together with its principal connections to diverse Hippocampal
regions. The aim of this work was to evaluate whether the LS-Hippocampus
network participates in the increased anxiety-like behavior produced by
a previous defeat experience. The neural activation of different
regions of the Hippocampus was assessed by the number of Fos positive
cells in animals previously defeated. A notable elevation in the
expression of this protein was observed in CA1, CA2, CA3, and Dentate
Gyrus, for both dorsal and ventral Hippocampus. The local administration
of a glucocorticoid receptor (GR or type II) antagonist, but not of a
mineralcorticoid receptor (MR or type II) antagonist, into the LS before
the stressful stimuli prevented a rise in the number of Fos positive
cells, especially in the ventral portion of the Hippocampus.
Furthermore, to evaluate the role of these hippocampal portions in the