Na sup + -Ca sup 2+ exchange in sarcolemmal vesicles from bovine superior mesenteric artery

Journal Article · Tue Mar 01 00:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6948761

Kahn, A M; Allen, J C; Shelat, H ^[1]

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1. Univ. of Texas Medical School, Houston (USA) Baylor College of Medicine, Houston, TX (USA)

These studies were designed to determine whether a Na{sup +}-Ca{sup 2+} 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 Mg{sup 2+} aggregation and differential centrifugation technique. An inwardly directed Ca{sup 2+} gradient stimulated {sup 22}Na{sup +} efflux and an outwardly directed Ca{sup 2+} gradient stimulated {sup 22}Na{sup +} uptake. Similarly, an inwardly directed Na{sup +} gradient stimulated {sup 45}Ca{sup 2+} uptake. Ca{sup 2+} transport were not due to voltage coupling between the two ions. Hence, a Na{sup +}-Ca{sup 2+} exchanger is present in these vesicles. These data demonstrate similarities between this mesenteric arterial smooth muscle Na{sup +}-Ca{sup 2+} exchanger and that found in other excitable tissues. These vesicles also contain a Na{sup +}-H{sup +} exchanger, which has been found in the sarcolemma of other vascular smooth muscle cells. When Na{sup +} uptake was stimulated via Na{sup +}-H{sup +} exchange, the subsequent uptake of Ca{sup 2+} via Na{sup +}-Ca{sup 2+} exchange was tripled. In conclusion, these studies unequivocally demonstrate that sarcolemmal-enriched vesicles from bovine superior mesenteric artery contain a Na{sup +}-Ca{sup 2+} exchanger. This transport system is homologous to that found in other excitable tissues, can be linked to Na{sup +}H{sup +} exchange activity, and is present in the sarcolemma itself.

• OSTI ID: 6948761
• Journal Information: American Journal of Physiology; (USA), Vol. 254:3; ISSN 0002-9513
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
CALCIUM 45
UPTAKE
MEMBRANE TRANSPORT
BIOCHEMICAL REACTION KINETICS
SODIUM 22
ACRIDINE ORANGE
ARTERIES
CATIONS
CATTLE
ENZYME INHIBITORS
MAGNESIUM COMPOUNDS
MEMBRANE PROTEINS
ACRIDINES
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
AMINES
ANIMALS
AROMATICS
AZAARENES
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BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
DYES
EVEN-ODD NUCLEI
HETEROCYCLIC COMPOUNDS
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PROTEINS
PYRIDINES
RADIOISOTOPES
REACTION KINETICS
RUMINANTS
SODIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques