Figure 1:

Interleukin-6 signaling pathways

Figure 1 illustrates the two IL-6 signaling pathways. The trans signaling pathway is regarded as the more plausible mechanism for a relationship between IL-6 and depression due to the important role of trans signaling in the central nervous system. However, mechanisms exist through which classical signaling could influence the central nervous system, including the role of classical IL-6 signaling on immune regulation (which may influence other inflammatory signaling chemicals that then interact with the brain) and the presence of membrane IL-6 receptors on some microglia.