Chapter 4: The biological clock in flame and sleep switch alterations

The word inflammation derives from Latin inflammare, meaning to set in flame, and signifies the heat and redness related to an increased blood flow and vasodilation in the affected tissue. Although vasodilation, edema, and extravasation of white blood cells are the hallmarks of inflammation, its definition has become broader and has been more loosely applied to tissue reactions to injuries. With the discovery of molecules that mediate inflammation and, in particular, the extensive number of cytokines that regulate the cellular response to inflammation, an inflammatory component is now frequently ascribed to neurodegenerative diseases that were traditionally considered as noninflammatory. This is due to the production of proinflammatory cytokines in activated microglial cells and astrocytes in such diseases. The classical hallmarks of inflammation are, however, lacking. © 2007 Springer Science+Business Media, LLC. All rights reserved.