114. Neural and behavioral responses to low-grade inflammation

• Published in: Brain, behavior, and immunity Vol. 26; p. S32
• Main Authors: Tarr, A.J, Chen, Q, Wang, Y, Sheridan, J.F, Quan, N
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.09.2012
• Subjects: Allergy and Immunology; Psychiatry
• ISSN: 0889-1591; 1090-2139
• DOI: 10.1016/j.bbi.2012.07.138

Neural and behavioral responses after peripheral immune challenge have been observed in numerous studies using relatively high pharmacological doses of lipopolysaccharide (LPS). However, little attention has been given to the effects of LPS dose ranges that simulate low grade-inflammation on CNS-related biology and behavior. The current studies were designed to characterize neural and behavioral responses to low-grade inflammation. Results showed burrowing and open field activities were significantly impaired following a single i.p. injection of 10 μg/kg, but not 1 μg/kg of LPS. In addition, following repeated 1 μg/kg LPS administration for 10 days, animals showed LPS-induced motor deficits in the open field starting on day 4 that continually worsened by day 10’s assessment of activity. When examining the effects of repeated low-dose LPS administration on burrowing behavior, animals showed signs of LPS tolerance following repeated doses of 1 μg/kg LPS. To correlate behavior with CNS activity, c-Fos activation was determined in the PVN, NTS, CeA, and VLM. Data revealed there was a dose-dependent activation in all brain areas examined. Furthermore, animals that received 1 μg/kg of LPS for 8 days had a PVN c-Fos activation that approached levels found following a single 10 μg/kg LPS injection. These data demonstrate neural and behavior responses can be induced by low-grade inflammation and chronic exposure to sub-threshold levels of LPS sensitizes the host to subsequent exposures of very low levels of LPS.