[Abstract Title]. - Society for Neuroscience

Disclosures: N. Grissom, None; J. Singaravelu, None; H. Chung, None; S. Bhatnagar,
None; S. Luz, None.
Poster
283. Stress-Regulated Pathways II
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 283.13/PP9
Topic: E.06.f. Stress modulated pathways
Title: Somatostatin-2 receptors in the basolateral amygdala of rats modulate behavioral priming
and anxiety-like responses
Authors: *D. L. GASKINS, P. L. JOHNSON, P. E. KELLY, A. D. DIETRICH, W. A.
TRUITT, A. SHEKHAR;
Dept. of Psychiatry, Indiana Univ. Sch. Med., Indianapolis, IN
Abstract: Previous studies from our laboratory have shown that Urocortin I (Ucn1), a CRF
receptor agonist, given repeatedly into the basolateral complex of the amygdala (BLA) at subanxiogenic
doses (priming) enhance synaptic transmission and results in long-term anxiety-like
behaviors in social interaction (SI) as well as the elevated plus maze tests. The development of
this behavior profile is similar to that which is observed in individuals who are vulnerable to
anxiety disorders and are exposed to chronic stress. To determine the neurotransmitter system
involved we used the RT-Profiler PCR array screen and found the somatostatin-2 receptor
(sstr2) mRNA to be significantly down regulated in the BLA after Ucn1 priming. Emerging
evidence suggests that the sstr2 has a role in depression and anxiety. Therefore, the present study
was conducted to investigate the role of sstr2 activation in the BLA on anxiety using the sstr2
agonist BIM-23027. Three experiments were conducted: BIM-23027 alone, pre-treatment with
BIM-23027 prior to an acute anxiogenic dose of Ucn1 (an acute stress-like challenge), and pretreatment
with BIM-23027 prior to Ucn1 priming. For all experiments male wistar rats were
implanted bilaterally with chronic guide cannulae targeting the BLA and allowed to recover. For
the first experiment, SI was measured 30 minutes after a bilateral injection of either vehicle or 1
of 5 doses of BIM-23027(either100 fmole/100 nl/side or 1, 10, 30, or 90 pmol/100 nl/side). For
the second experiment rats were infused with vehicle or BIM-23027 (30 or 90 pmoles/100
nl/side) 30 min prior an acute anxiogenic dose of Ucn1 (100 fmoles/100 nl/side). SI was
measured 30 min after the Ucn1 injection. Thirdly, rats were infused with vehicle or BIM-23027
(90 pmoles/100 nl/side) 30 minutes prior to vehicle or Ucn1 (6 fmoles/100 nl/side) priming. SI
was measured on injection days 1, 3, and 5 during priming, as well as 3 days after the last
Ucn1/Veh injection. BIM-23027 alone did not significantly alter SI. However, 90 pmoles of
BIM-23027 did block the reduction of SI induced by an acute anxiogenic dose of Ucn1. In the