Brain-endocrine interactions: a microvascular route in the mediobasal hypothalamus.
Blood-borne hormones acting in the mediobasal hypothalamus, like those controlling food intake, require relatively direct access to target chemosensory neurons of the arcuate nucleus (ARC). An anatomical substrate for this is a permeable microvasculature with fenestrated endothelial cells in the ARC, a system that has awaited comprehensive documentation. Here, the immunofluorescent detection of endothelial fenestral diaphragms in the rat ARC allowed us to quantitate permeable microvessels throughout its rostrocaudal extent. We have determined that permeable microvessels are part of the subependymal plexus irrigating exclusively the ventromedial (vm) ARC from the subadjacent neuroendocrine median eminence. Unexpectedly, permeable microvessels were concentrated proximal to the pituitary stalk. This marked topography strongly supports the functional importance of retrograde blood flow from the pituitary to the vmARC, therefore making a functional relationship between peripheral long-loop, pituitary short-loop, and neuroendocrine ultra-short loop feedback, altogether converging for integration in the vmARC (formerly known as the hypophysiotrophic area), thereby so pivotal as a multicompetent brain endocrinostat.
Ciofi
Philippe
P
Institut National de la Santé et de la Recherche Médicale Unité 862, Neurocentre Magendie, 146 rue Léo Saignat, F-33077 Bordeaux Cedex, France. philippe.ciofi@inserm.fr
Garret
Maurice
M
Lapirot
Olivier
O
Lafon
Pierrette
P
Loyens
Anne
A
Prévot
Vincent
V
Levine
Jon E
JE
D000595:Amino Acid Sequence; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000098:blood supply / Q000378:metabolism; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004703:Endocrine System / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D007031:Hypothalamus / Q000098:blood supply / Q000378:metabolism*; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008473:Median Eminence / Q000098:blood supply / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D055806:Microvessels / Q000378:metabolism* / Q000502:physiology; D010902:Pituitary Gland / Q000098:blood supply / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002352:Carrier Proteins; D008565:Membrane Proteins; C470505:PLVAP protein, rat