Biomaterial Database

Cellular and paracellular calcium transport in rat ileum: effects of dietary calcium. 1978

H N Nellans, and D V Kimberg

The mechanism of calcium transport and its modulation by dietary Ca restriction in rat ileum have been investigated employing an in vitro voltage-clamp technique. Ca fluxes directed from mucosa-to-serosa (J(Ca)ms) and serosa-to-mucosa (J(Ca)sm) exhibit components consistent with both cellular and paracellular pathways. The cellular Ca fluxes are both dependent on medium Na and are abolished at 10 degrees C. In addition, a cellular component of J(Ca)ms displays voltage dependence. A low-calcium diet, which induces the formation of 1,25-dihydroxycholecalciferol, causes a marked increase in both cellular J(Ca)ms and Ca influx from media to cells with little absolute effect on the paracellular pathway. This evidence is consistent with the existence of electrogenic Na-Ca exchange pumps at both brush-border and basolateral membranes, driven in part by the Na electrochemical gradient. Dietary Ca conditioning may control the direction of net Ca transport by modulation of the saturable influx process at the brush border.

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D008297	Male		Males
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008871	Microvilli	Minute projections of cell membranes which greatly increase the surface area of the cell.	Brush Border,Striated Border,Border, Brush,Border, Striated,Borders, Brush,Borders, Striated,Brush Borders,Microvillus,Striated Borders
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002136	Calcium, Dietary	Calcium compounds in DIETARY SUPPLEMENTS or in food that supply the body with calcium.	Dietary Calcium
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
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
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23