Chronic foot shock induces hyperactive behaviors and accompanying pro- and anti-inflammatory responses in mice

Box PSYCH, Department of Psychiatry, University of Rochester, 300 Crittenden Blvd, Rochester, NY 14642, USA.
Journal of Neuroimmunology (Impact Factor: 2.47). 06/2007; 186(1-2):63-74. DOI: 10.1016/j.jneuroim.2007.03.003
Source: PubMed


Behavioral and accompanying physiological and immunological changes were investigated at various times during chronic irregular mild foot shock (CMFS) in adult male BALB/c mice. CMFS induced a significant hyperlocomotor activity in a familiar environment as well as increased consumption of chocolate milk (a favored drink) throughout the 5-week stress period. Unlike other chronic stress models, CMFS did not induce depressive-like behaviors. Hyperactivity was associated with transient elevations of pro-inflammatory cytokines (TNFalpha and IL-1beta) and IL-2 and more sustained (IL-10) or later (arginase activity) elevations in anti-inflammatory mediators in the spleen (serum levels below levels of detection) suggesting a transition from a pro-inflammatory state to an anti-inflammatory state during CMFS. Similar increases in brain levels of IL-2 and arginase activity were also detected and may contribute to CMFS-induced hyperactivity as both of these mediators have been shown to induce hyperactivity. To our knowledge, this is the first time that increased arginase activity has been documented during a stress paradigm. Altogether, the data indicate that CMFS induces behavioral changes distinct from other chronic stress models. CMFS is associated with multiple dynamic immunological changes, suggesting involvement of multiple factors in chronic stress-induced behavioral changes.

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    • "One reason for these results might be an imbalance between central pain-inhibitory effect of stress and stress-induced sensitization of cutaneous nerve fibers [29], [30] leading to thermal allodynia [31], [32]. It is well known that stress induces local expression of cytokines [33]–[35]. Especially the pro-inflammatory cytokines like NGF, IL-6, IL-1, IL-12, IL-18, TNF-a [36]–[40] are able to exert a sensitization effect on cutaneous neural fibers. Our results do not provide insights into a possible contribution of peripheral or central effects of stress-induced cytokine expression. "
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    Full-text · Article · Aug 2013 · PLoS ONE
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    • "Recent studies described similar phenomenon in several laboratory mouse strains [109-111]. While various effects of chronic stress on general locomotion in rodents were described [34,96,112-1115], lighting conditions employed during testing were reported to be a significant factor of general activity in the stressed animals [116-118]. "
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    • "Physical and psychological stress is a known risk factor for numerous human diseases, such as autoimmune diseases and cancer (Reiche et al., 2004; Shi et al., 2003; Cao et al., 2007; Frieri, 2003; Yang and Glaser, 2002). The immunological consequences of stress and the mechanisms by which stress compromises the immune system are important areas of study. "
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