Kinetic identification of an intracellular calcium compartment sensitive to phosphate and dinitrophenol in intact isolated rabbit aorta

Journal Article · Tue Jul 01 04:00:00 EDT 1986 · Circ. Res.; (United States)

DOI:https://doi.org/10.1161/01.RES.59.1.85· OSTI ID:5089028

Hai, C M; Phair, R D

Previous work from this laboratory revealed the presence of at least three distinct intracellular calcium compartments in intact segments of rabbit aorta. In this study one of these intracellular compartments is shown to be sensitive to dinitrophenol and to increased extracellular phosphate. Intact aortic segments were loaded with /sup 45/Ca in bicarbonate-buffered physiologic salt solution for 1 hour, and then transferred to a flow-through chamber perfused with physiologic salt solution. Effluent from the chamber was collected for 8 hours, and /sup 45/Ca efflux curves were analyzed using compartmental analysis. When aortic segments were loaded and washed out in dinitrophenol, the slowest component of the efflux curve was less prominent; in high phosphate it was more prominent. The rate constant changes required to account for these data were primarily in the exchange between the cytosolic and slowest intracellular calcium compartment, suggesting that the slowest calcium compartment resolved during the 8-hour washout was mitochondrial. This compartment contained 5.4 +/- 3.2 nmol calcium/g wet wt. tissue. The calcium flux across its membranes was 0.32 +/- 0.04 nmol min-1g-1. Because this flux is much smaller than the plasma-membrane calcium flux, we suggest that, in normal physiological circumstances, plasma-membrane extrusion is more important for the removal of Ca from the smooth muscle cytosol than is uptake into this slow intracellular compartment.

• Research Organization: Johns Hopkins Univ., Baltimore, MD
• OSTI ID: 5089028
• Journal Information: Circ. Res.; (United States), Journal Name: Circ. Res.; (United States) Vol. 1; ISSN CIRUA
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
AORTA
AROMATICS
ARTERIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BLOOD VESSELS
BODY
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
COMPARTMENTS
DAYS LIVING RADIOISOTOPES
DINITROPHENOL
ELEMENTS
EVEN-ODD NUCLEI
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANE TRANSPORT
METABOLISM
METALS
NITRO COMPOUNDS
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PHENOLS
PHOSPHATES
PHOSPHORUS COMPOUNDS
RABBITS
RADIOISOTOPES
SENSITIVITY
TRACER TECHNIQUES
VERTEBRATES