Traditionally, microglia have been considered to act as macrophages of the central nervous system. While this
concept still remains true it is also becoming increasingly apparent that microglia are involved in a host of nonimmunological
activities, such as monitoring synaptic function and maintaining synaptic integrity. It has also become apparent
that microglia are exquisitely sensitive to perturbation by environmental challenges. The aim of the current review
is to critically examine the now substantial literature that has developed around the ability of acute, sub-chronic and
chronic stressors to alter microglial structure and function. The vast majority of studies have demonstrated that stress
promotes significant structural remodelling of microglia, and can enhance the release of pro-inflammatory cytokines from
microglia. Mechanistically, many of these effects appear to be driven by traditional stress-linked signalling molecules,
namely corticosterone and norepinephrine. The specific effects of these signalling molecules are, however, complex as
they can exert both inhibitory and suppressive effects on microglia depending upon the duration and intensity of exposure.
Importantly, research has now shown that these stress-induced microglial alterations, rather than being epiphenomena,
have broader behavioural implications, with the available evidence implicating microglia in directly regulating certain aspects
of cognitive function and emotional regulation.
Keywords: Acute stress, chronic stress, depression, glia, inflammation, microglia, mood disturbance, neuroinflammation, neuroplasticity,
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