[Abstract Title]. - Society for Neuroscience

hyperpolarizes BLA neurons corresponding to the induction of an outward ionic current most
likely through Gβγ activation of Kir3.x family channels. Based on our data, we speculate that
somatostatin responses are through sst2 receptors, would be inhibitory to BLA projection cells,
and that reduction in sst2 receptor expression by Ucn1-priming would bias these neurons toward
hyperexcitability. Currently, experiments on primed animals are in progress to test this
hypothesis.
Disclosures: A. Molosh, None; W. Truitt, None; P. Kelley, None; A. Dietrich, None; S. Fitz,
None; G. Oxford, None; A. Shekhar, None.
Poster
283. Stress-Regulated Pathways II
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 283.24/PP20
Topic: E.06.f. Stress modulated pathways
Support: NIMH MH60668
NIMH MH069558
Title: Chronic stress selectively reduces hippocampal volume in rats
Authors: *F. J. HELMSTETTER 1,2 , T. LEE 1 , T. JAROME 1 , S.-J. LI 2 , J. J. KIM 3 ;
1 Dept Psychol, Univ. of Wisconsin Milwaukee, Milwaukee, WI; 2 Med. Col. of Wisconsin,
Milwaukee, WI; 3 Univ. of Washington, Seattle, WA
Abstract: It is well-documented that stress can exert physiological changes in the hippocampus,
a structure implicated in the formation of long-term declarative memory in humans and spatial
memory in rodents. As it increases in duration and/or intensity, uncontrollable stress will
exacerbate neuronal endangerment in rodent hippocampus and correlate with hippocampal
volume reduction in humans, particularly in posttraumatic stress disorder (PTSD) patients such
as combat veterans. However, since human imaging studies cannot address the causal link
between stress and hippocampal changes, the notion of stress-induced diminution of
hippocampal volume remains controversial.
To address these issues, the present study used a longitudinal, within-subjects design and
compared hippocampal volumes in rats before and after exposure to chronic stress. Twenty
Long-Evans rats (weight: 300-325 g) initially received a magnetic resonance imaging (MRI)
scan to acquire T1-weighted brain images (spatial resolution: .068 x .068 x .75 mm) at 9.4T and
then were divided into two groups: stress (n=10) and control (n=10). For 21 days, the stress