Biomaterial Database

Na+-Ca2+ exchange in sarcolemmal vesicles from bovine superior mesenteric artery. 1988

A M Kahn, and J C Allen, and H Shelat

Department of Medicine, University of Texas Medical School, Houston 77025.

These studies were designed to determine whether a Na+-Ca2+ exchanger is present in sarcolemmal vesicles from bovine superior mesenteric artery and, if so, to determine whether this transport system is qualitatively similar to that found in other excitable tissues. Vesicles, preferentially enriched in sarcolemma, were prepared by a Mg2+ aggregation and differential centrifugation technique. An inwardly directed Ca2+ gradient stimulated 22Na+ efflux and an outwardly directed Ca2+ gradient stimulated 22Na+ uptake. Similarly, an inwardly directed Na+ gradient stimulated 45Ca2+ efflux, and an outwardly directed Na+ gradient stimulated 45Ca2+ uptake. Ca2+ gradient-stimulated Na+ transport and Na+ gradient-stimulated Ca2+ transport were not due to voltage coupling between the two ions. Hence, a Na+-Ca2+ exchanger is present in these vesicles. The Na+ gradient-dependent component of Ca2+ uptake (Na+-Ca2+ exchange) was stimulated by rendering the vesicles electropositive inside, and Na+-Ca2+ exchange activity was inhibited by amiloride and quinidine in a dose-dependent fashion. These data demonstrate similarities between this mesenteric arterial smooth muscle Na+-Ca2+ exchanger and that found in other excitable tissues. In the absence of added Ca2+, amiloride-sensitive 22Na+ uptake in the vesicles was stimulated by an outwardly directed proton gradient, and an inwardly directed Na+ gradient stimulated proton efflux. Thus these vesicles also contain a Na+-H+ exchanger, which has been found in the sarcolemma of other vascular smooth muscle cells. When Na+ uptake was stimulated via Na+-H+ exchange, the subsequent uptake of Ca2+ via Na+-Ca2+ exchange was tripled. In conclusion, these studies unequivocally demonstrate that sarcolemmal-enriched vesicles from bovine superior mesenteric artery contain a Na+-Ca2+ exchanger.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008638	Mesenteric Arteries	Arteries which arise from the abdominal aorta and distribute to most of the intestines.	Arteries, Mesenteric,Artery, Mesenteric,Mesenteric Artery
D011802	Quinidine	An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.	Adaquin,Apo-Quinidine,Chinidin,Quincardine,Quinidex,Quinidine Sulfate,Quinora,Apo Quinidine,Sulfate, Quinidine
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
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D004563	Electrochemistry	The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.	Electrochemistries
D000584	Amiloride	A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)	Amidal,Amiduret Trom,Amiloberag,Amiloride Hydrochloride,Amiloride Hydrochloride, Anhydrous,Kaluril,Midamor,Midoride,Modamide,Anhydrous Amiloride Hydrochloride,Hydrochloride, Amiloride,Hydrochloride, Anhydrous Amiloride,Trom, Amiduret
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
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D012508	Sarcolemma	The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Sarcolemmas