Spatial training in the Morris water maze induces differential changes in interleukin-1 beta(IL-1β) expression in hippocampal and extra-hippocampal tissue
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Mallimo, Elyse M. Spatial training in the Morris water maze induces differential changes in interleukin-1 beta(IL-1β) expression in hippocampal and extra-hippocampal tissue. Retrieved from https://doi.org/doi:10.7282/T3348HGX
TitleSpatial training in the Morris water maze induces differential changes in interleukin-1 beta(IL-1β) expression in hippocampal and extra-hippocampal tissue
DescriptionIt is now well accepted that the brain and the immune system are intimately linked and that cytokines, small proteins secreted by cells of the immune system, exert diverse effects on CNS function. Of particular importance in this regard is the proinflammatory cytokine interleukin-1 beta (IL-1β) which is critically involved in peripheral and central inflammatory responses. Although early research surrounding the biological effects of IL-1β has focused on its detrimental role in cognitive function, emerging data strongly suggest that physiologically-low levels of IL-1β are required for hippocampal-dependent learning and long-term memory formation. In light of these observations, the present series of experiments were conducted in order to better characterize the spatio-temporal expression of IL-1β during spatial learning in the Morris water maze (MWM). To that end, IL-1β (protein) expression was measured in the dorsal hippocampus at different time points and after one or three sessions of spatial training in the MWM (experiment 1). Moreover, because spatial navigation may depend on a distributed network of structures besides the hippocampus, IL-1β expression was also measured in the prefrontal cortex (PFC). Results from experiment 1 are suggestive of a coordinated modulation of IL-1β between the dorsal hippocampus and PFC that persists for at least the first three days of spatial training. In light of these observations and because microglial cells represent a primary source of IL-1β in the CNS, experiment 2 was conducted in order to determine whether learning induced changes in microglial activation. Results from experiment 2 reveal a training-specific downregulation of microglial cell activity in the PFC and are in agreement with a physiological role for microglia in the normal healthy brain. Finally, a third experiment was conducted in order to determine whether massed spatial training induces the expression of IL-1β, and other components of the IL-1 system.