Immune System in the Brain: A Modulatory Role on Dendritic Spine Morphophysiology?

Figure 2

Microglia are activated in the brain parenchyma and mediate the synthesis and release of proinflammatory and anti-inflammatory cytokines, prostanoids, complement system molecules, and free radicals such as nitric oxide, affecting other cells including astrocytes, oligodendrocytes, and neurons. The signal established between microglial cells and neurons through the expression of CD200-CD200R maintains the microglia in a nonactivated state, and, when this signal is interrupted, microglia are immediately activated and initiate the generation and release of inflammatory mediators. PGE2: prostaglandin-E2; IFN-R: interferon-receptor; TNF-α: tumor necrosis factor-alpha; TNFR: tumor necrosis factor receptor; IL-1β: interleukin-1 beta; IL-6: interleukin-6; IL-10: interleukin-10; IL-4: interleukin-4; NGF: nerve growth factor.