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Circumventricular organs (CVOs), small structures bordering the ventricular spaces in the midline of the brain, have common morphological and endocrine-like characteristics that distinguish them from the rest of the nervous system. Among their unique features are cellular contacts with two fluid phases--blood and cerebrospinal fluid--and neural connections(More)
Most circumventricular organs (CVOs) have unusually dense and permeable capillary networks that facilitate secretion of or tissue penetration by circulating substances, unlike other nervous system structures wherein blood-brain barrier (BBB) properties of the capillary endothelium limit solute permeability. In this brief review, I shall discuss new facts(More)
  • P M Gross
  • 1991
From recent morphological and physiological studies of capillaries, I shall review four new or revised concepts about blood-tissue communication in the subfornical organ (SFO) and area postrema (AP). First, the capillary systems of SFO and AP exhibit subregional differentiation correlated topographically with cytoarchitecture, densities of immunoreactivity(More)
These seven specialized circumventricular structures of the mammalian brain represent windows with individual­ ized structural characteristics permitting intimate contact between blood and cerebrospinal fluid, neurones and spe­ cialized ependyma-glia. These "Seven Windows of the Brain", like the seven lucky deities of Japan, may each have a specific patron(More)
The differentiated cytoarchitecture, neurochemistry, and capillary organization of the rat dorsal vagal complex prompted this comprehensive investigation of microvascular physiology in 11 subdivisions of area postrema, 5 subnuclei of nucleus tractus solitarii (NTS), the dorsal motor nucleus of the vagus nerve, and 4 other gray matter structures in the(More)
Blood volume, blood flow, and blood-to-tissue transfer of an amino acid in circumventricular organs, such as the median eminence and subfornical organ, and the pituitary gland of conscious rats were measured by using quantitative autoradiographic techniques and computer-assisted processing of the tissue images. Retained erythrocyte and plasma volumes(More)
The differentiated cytology, cytochemistry, and functions within subdivisions of the tuber cinereum prompted this morphometric and physiological investigation of capillaries in the median eminence and arcuate nucleus of albino rats. Morphometric studies established that the external zone of the median eminence had 3–5 times the number and surface area of(More)
This study was performed to determine whether exercise produces vasodilatation in regions of the brain that are associated with motor functions despite the associated vasoconstrictor effect of hypocapnia. Total and regional cerebral blood flow (CBF) were measured with microspheres in dogs during treadmill exercise of moderate intensity. Flow was also(More)
We used labeled microspheres to measure bone and marrow blood flow under control conditions and during several interventions. In dogs, blood flow to compact cortical bone (femoral diaphysis) was 2 +/- 0.1 ml.min-1. 100 g-1, and in hematopoietic marrow (femur), flow was 24 +/- 5 ml.min-1. 100 g-1. Hematopoietic cancellous bones (sternum, ilium) received(More)
Physiological and morphometric studies were conducted on the microvascular endothelium of four individual cerebral structures having different neural activities--the inferior colliculus, sensorimotor cortex (both gray matter regions), genu of the corpus callosum (white matter), and the subfornical organ (a circumventricular organ) of rats. The physiological(More)