Cytokines and the brain

The relationships between cytokines and the brain involve two different compartments including the peripheral cytokines which are synthesized in response to inflammatory, immune or allergic reactions and the central or cerebral cytokines whose production is related to neuronal plasticity phenomena activated during development. These molecules are also involved in regeneration mechanisms and central inflammatory or auto-immune reactions. These two compartments play an important role in physiological, behavioural and neuroendocrine alterations occurring during inflammatory and infectious syndromes. Although these two compartments are separated by the blood-brain barrier, they can act in a coordinated fashion. The release of cytokines in the periphery induces cerebral cytokine production via afferent sensory nervous pathways. Central cytokines, by acting on their cellular targets, are then responsible for the physiological, behavioural and neuroendocrine cerebral alterations observed during infectious and inflammatory phenomena.