Biomaterial Database

Subatmospheric closing pressures in individual microvessels of rats and frogs. 1995

P J MacPhee, and C C Michel

Department of Physiology and Biophysics, St Mary's Hospital Medical School, Imperial College of Science, Norfolk Place, London, UK.

1. We have investigated the hypothesis that ascending vasa recta (AVR) in the rat renal medulla are able to remain open when the external pressure is greater than the internal. 2. Individual vasa recta were cannulated in anaesthetized rats with Evans Blue albumin solution and then occluded downstream prior to the first branchpoint. When the intraluminal pressure was lowered, the lumina collapsed at a mean pressure of approximately -4.0 cmH2O for both AVR and descending vasa recta. 3. The studies were extended to include microvessels from rat spinotrapezius muscle and mesentery and frog mesentery; mean closing pressures were -3.2, -4.2 and -5.3 cmH2O, respectively. 4. Subatmospheric closing pressures may allow small differences in hydrostatic pressure alone to drive fluid uptake into the AVR.

UI	MeSH Term	Description	Entries
D007679	Kidney Medulla	The internal portion of the kidney, consisting of striated conical masses, the renal pyramids, whose bases are adjacent to the cortex and whose apices form prominent papillae projecting into the lumen of the minor calyces.	Kidney Papilla,Kidney Medullas,Kidney Papillas,Medulla, Kidney,Medullas, Kidney,Papilla, Kidney,Papillas, Kidney
D008643	Mesentery	A layer of the peritoneum which attaches the abdominal viscera to the ABDOMINAL WALL and conveys their blood vessels and nerves.	Mesenteries
D008833	Microcirculation	The circulation of the BLOOD through the MICROVASCULAR NETWORK.	Microvascular Blood Flow,Microvascular Circulation,Blood Flow, Microvascular,Circulation, Microvascular,Flow, Microvascular Blood,Microvascular Blood Flows,Microvascular Circulations
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D011896	Rana temporaria	A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.	European Common Frog,Frog, Common European,Common European Frog,Common Frog, European,European Frog, Common,Frog, European Common
D005070	Evans Blue	An azo dye used in blood volume and cardiac output measurement by the dye dilution method. It is very soluble, strongly bound to plasma albumin, and disappears very slowly.	Azovan Blue,C.I. 23860,C.I. Direct Blue 53,Evan's Blue,Blue, Azovan,Blue, Evan's,Blue, Evans,Evan Blue
D006874	Hydrostatic Pressure	The pressure due to the weight of fluid.	Hydrostatic Pressures,Pressure, Hydrostatic,Pressures, Hydrostatic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001160	Arterioles	The smallest divisions of the arteries located between the muscular arteries and the capillaries.	Arteriole
D014699	Venules	The minute vessels that collect blood from the capillary plexuses and join together to form veins.	Venule