| Abstract No.: | C-E3170 |
| Country: | Canada |
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| Title: | EFFECTS OF CHRONIC INTERLEUKIN-1β EXPOSURE ON SICKNESS BEHAVIOUR, NEUROENDOCRINE AND CYTOKINE ALTERATIONS |
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| Authors/Affiliations: | 1 Julie Gibb*; 1 Shawn Hayley; 1 Hymie Anisman;
1 Carleton University, Ottawa, ON, Canada
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| Content: | The acute administration of interleukin-1 beta ( IL-1β), a potent pro-inflammatory cytokine, has been shown to induce sickness behaviour, increase circulating corticosterone and other pro-inflammatory cytokines, as well as increase the expression of cytokine mRNA in several brain regions. However, less is known regarding the behavioural and neurochemical effects of sub-chronic or chronic IL-1β exposure. Objectives: In the present investigation, using both bolus injections as well as continuous infusion, the effects of acute and chronic IL-1β administration were observed on subsequent behavioural, neuroendocrine and cytokine variations. Materials and Methods: Acute (1 day) and subchronic (5 day) bolus injections of IL-1β were administered to assess the effects on sickness behaviour and plasma corticosterone and cytokines. Additionally, as limited information is available concerning continuous IL-1β infusion, sickness behaviour, plasma corticosterone and cytokine mRNA expression within the pre-frontal cortex, hippocampus and paraventricular nucleus of the hypothalamus were observed following 3 and 7 day continuous infusion using Alzet minipumps. Results: Interestingly, although high levels of sickness behaviour were observed with 5 days of treatment, circulating levels of corticosterone as well as IL-1β and tumor necrosis factor alpha (TNF-α) were attenuated relative to the acute cytokine exposure. Similarly, 7 days of continuous IL-1β infusion also diminished plasma levels of corticosterone relative to 3 days of infusion, despite the continued elevation of sickness behaviour. Continuous infusion of IL-1β also provoked dramatic increases in central pro-inflammatory cytokine mRNA expression within several brain regions that have been related to depression, and this effect persisted throughout the 7 days. Conclusion: It appears that although the peripheral effects of IL-1β may be curtailed with continued cytokine treatment, the central and behavioural effects seem to persist. This effect might have implications for the development of cytokine-induced behavioural pathologies and well as neurological disorders. |
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