Prior laparotomy or corticosterone potentiates lipopolysaccharide-induced fever and sickness behaviors.

Stimulating sensitized immune cells with a subsequent immune challenge results in potentiated pro-inflammatory responses translating into exacerbated sickness responses (i.e. fever, pain and lethargy).

Pain intensity and duration can be enhanced by prior challenge: initial evidence suggestive of a role of microglial priming.

Unlabelled: Activation of spinal microglia and consequent release of proinflammatory mediators facilitate pain. Under certain conditions, responses of activated microglia can become enhanced. Enhanced microglial production of proinflammatory products may result from priming (sensitization), similar to macrophage priming.