Signaling the brain in systemic inflammation: role of sensory circumventricular organs.
The sensory circumventricular organs (CVOs) are specialized brain regions that lack a tight blood-brain barrier. A role for these brain structures in signaling the brain during systemic inflammation is based on the following sets of observations. In spite of some conflicting data from literature, lesions of CVOs have been shown to block several components of brain controlled illness responses (i.e. fever or neuroendocrine modifications). Receptors for inflammatory cytokines and for bacterial fragments are constitutively expressed in cells within the sensory CVOs. The expression of most of these receptors is upregulated under conditions of systemic inflammation. Cellular responses in theses brain areas can be recorded and documented after stimulation of these respective receptors. Such responses include changes in electrical activity of neurons, induction of transcription factors leading to modifications in gene expression during inflammation and to a localized release of secondary signal molecules. These molecules may influence or even gain access to neural structures inside the blood-brain barrier, which can normally not directly be reached by circulating cytokines or bacterial fragments.
Roth
Joachim
J
Department of Veterinary-Physiology, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392-Giessen, Germany. joachim.roth@vetmed.uni-giessen.de
Harré
Eva-Maria
EM
Rummel
Christoph
C
Gerstberger
Rüdiger
R
Hübschle
Thomas
T
D000818:Animals; D001921:Brain / Q000503:physiopathology*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D011749:Pyrogens / Q000502:physiology; D012679:Sense Organs / Q000473:pathology*; D015398:Signal Transduction; D018746:Systemic Inflammatory Response Syndrome / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D015533:Transcriptional Activation
D015850:Interleukin-6; D011749:Pyrogens