Organum vasculosum laminae terminalis

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The organum vasculosum laminae terminalis ( OVLT ) is a circumventricular organ . It lies rostral to the hypothalamus and is part of the lamina terminalis .

function

The function of the OVLT is not yet fully understood. It is believed to be involved in the regulation of thirst and hunger as well as in the development and regulation of fever . Endogenous pyrogens such as interleukin-1 (IL-1) induce the increased synthesis and expression of cyclooxygenase 2 (Cox-2) in the OVLT . This enzyme synthesizes, among other things, the eicosanoid prostaglandin E2 (PGE2) from arachidonic acid .

PGE2 stimulates firstly the macrophages to produce other pyrogens such as tumor necrosis factor-α (TNF-α) and interleukin-1 and binds to the other at the prostanoid - receptor EP3 in median nucleus preopticus , the thermoregulatory center of the hypothalamus. The preoptic nucleus, in turn, projects via GABAergic neurons into the central cave gray ( periaqueductal gray , PAG) and into the raphe nuclei , from where thermogenesis is controlled.

Clinical relevance

Specific antipyretic analgesics are the selective COX-2 inhibitors (such as celecoxib ), some of which have been withdrawn from the market. These inhibit the cyclooxygenase 2 in the OVLT and thus have a central nervous effect lowering fever (antipyretic) and analgesic (analgesic).

literature

Original works:

  • Blatteis CM and Sehic E. Fever: how many circulatin pyrogens signal the brain? News Physiol Cri 12: 1-9, 1997
  • Andrej A. Romanovsky et al. The organum vasculosum liminae terminalis in immune-to-brain febrigenic signaling: a reappraisal of lesion experiments. Am J Physiol Regul Integr Comp Physiol 285: R420-R428, 2003

Books (general standard works):

  • Pharmacology and Toxicology, Aktories et al., Urban & Fischer, 9th edition 2005
  • Neuroscience, Purves et al., Sinauer Verlag, 3rd edition 2004