Regulation of microglia - potential new drug targets in the CNS.

Microglia respond to any disturbance in the CNS which poses a threat to physiological homeostasis. Although these responses are secondary, mainly to neuronal alterations, the way the microglial response evolves in many situations promotes further damage to the CNS. The list of clinical conditions in which this situation is a major problem is continuously growing and includes neurodegenerative diseases, stroke, trauma, demyelinating disorders and neuropathic pain. The significance of microglia for the pathogenesis of neurological and neuropsychiatric conditions has led to a rapidly expanding search for therapeutic possibilities to regulate microglial activity. As will be clear from this review, treatments which are currently available appear to offer some positive effects but are still far from satisfactory. A major challenge is to understand the mechanisms that determine whether activated microglia will develop into a cytotoxic or a cytoprotective component.