Papers of the Week

Psychological stress is a trigger for the development of irritable bowel syndrome (IBS) and associated symptoms including abdominal pain. Although IBS patients exhibit increased activation in the limbic brain, including the amygdala, the underlying molecular and cellular mechanisms regulating visceral nociception in the central nervous system (CNS) are incompletely understood. In a rodent model of chronic stress, we explored the role of microglia in the central nucleus of amygdala (CeA) in controlling visceral sensitivity. Microglia are activated by environmental challenges such as stress, and are able to modify neuronal activity via synaptic remodeling and inflammatory cytokine release. Inflammatory gene expression and microglial activity are negatively regulated by nuclear glucocorticoid receptors (GR), which are suppressed by the stress-activated pain mediator P38 MAPK.