[Abstract Title]. - Society for Neuroscience

for 14 days to allow for direct social confrontation between the pair. In each pairing, a dominantsubordinate
hierarchy was clearly established, assessed by measures of defense strategies utilized
during conflicts. Subordinate mice were next individually transferred to a standard small mouse
cage (IE) or to a large rat cage containing running wheels and a variety of enrichment objects
(EE). After 2 weeks of IE or EE housing, submissive animals were reintroduced to the pair
housing for two additional weeks. The test mice were then injected i.p. with 0.1mg/kg LPS. After
60 min, mice were rapidly decapitated, trunk blood was collected, and brains were examined for
proinflammatory cytokine (PIC) activity via qRT-PCR. In basal state, IE-exposed mice showed
significantly elevated levels of TNFα and IL-1b in forebrain and hippocampus compared to EEexposed
mice. IE mice also showed a significantly diminished PIC response to LPS compared to
EE mice.
Chronic stressful conditions similar to the current experiment are known to adversely affect
immune function. In IE-housed subordinate mice, the immune system showed chronic elevations
of basal activity and a blunted response to immune challenge. In contrast, the EE-housed
subordinate mice exhibited normal basal immune function and normal response to LPS,
suggesting that EE reduces the deleterious influence of social stress on immune function.
Disclosures: M.L. Lehmann , None; R. Brachman, None; M. Herkenham, None.
Poster
280. Stress and the Brain: Stress and Neuroimmunology I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 280.2/NN2
Topic: E.06.c. Stress and neuroimmunology
Support: Canadian Institutes of Health Research
Title: The interactive effects of an immune challenge and psychosocial stressor provoke
contextually dependant behavioral and neurochemical alterations
Authors: *J. E. GIBB, M.-C. AUDET, B. P. WANN, H. ANISMAN;
Carleton Univ., Ottawa, ON, Canada
Abstract: The concomitant application of a psychosocial stressor and an immune challenge
interactively influences neurochemical processes that could, if sustained, lead to the development
of behavioral disorders. When immune activation, either through the administration of the
bacterial endotoxin lipopolysaccharide [LPS], synthetic double stranded RNA, Poly I:C, or
exogenous cytokines, is elicited following exposure to a psychosocial stressor (e.g., social
disruption), typical inflammatory-induced increases of sickness behavior, as well as circulating