Summarized effect of different kinds of neurotransmitters, neuromodulators and chemokines on the extension and retraction percentage of microglia in spinal dorsal horn. The ratio of extended or retracted processes and distances of microglia at time 30 min to 0 min after drug application are shown. ATP are applied at 1 or 10 mM; Glu, AMPA, NMDA, DHK, SP, GABA, Glycine, 5-HT, NA, Carbachol and Morphine are applied at 1 mM; MCP-1, FKN, NGF, BDNF, IL-1β, IL-6 and TNF-α are applied at 10 ng/ml. The results of application of 10 mM Glu, AMPA, NMDA, DHK, SP, GABA, Glycine, 5-HT, NA, Carbachol and Morphine and 100 ng/ml MCP-1, FKN, NGF, BDNF, IL-1β, IL-6 and TNF-α are similar. ATP 1, ATP 1 mM; ATP 10, ATP 10 mM; Glu, Glutamate; DHK, dihydrokainate; NA, noradrenalin; SP, Substance P; MCP-1, monocyte chemoattractant protein-1; FKN, fractalkine; NGF, nerve growth factor; BDNF, brain-derived neurotrophic factor; IL-1β, interleukin-1β; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.