Kinetics of /sup 13/N-ammonia uptake in myocardial single cells indicating potential limitations in its applicability as a marker of myocardial blood flow

Journal Article · Fri Feb 01 00:00:00 EST 1985 · Circulation; (United States)

DOI:https://doi.org/10.1161/01.CIR.71.2.387· OSTI ID:5776851

Rauch, B; Helus, F; Grunze, M; Braunwell, E; Mall, G; Hasselbach, W; Kuebler, W

To study kinetics and principles of cellular uptake of /sup 13/N-ammonia, a marker of coronary perfusion in myocardial scintigraphy, heart muscle cells of adult rats were isolated by perfusion with collagenase and hyaluronidase. Net uptake of /sup 13/N, measured by flow dialysis, reached equilibrium within 20 sec in the presence of sodium bicarbonate and carbon dioxide (pH 7.4, 37 degrees C). Total extraction, 80 sec after the reaction start, was 786 +/- 159 mumol/ml cell volume. Cells destroyed by calcium overload were unable to extract /sup 13/N-ammonia. Omission of bicarbonate and carbon dioxide reduced total extraction to 36% of control. /sup 13/N-Ammonia uptake could also be reduced by 50 muM 4,4' diisothiocyanostilbene 2,2' disulfonic acid, by 100 micrograms/ml 1-methionine sulfoximine, and by preincubation with 5 muM free oleic acid. These results indicate that in addition to metabolic trapping by glutamine synthetase, the extraction of /sup 13/N-ammonia by myocardial cells is influenced by cell membrane integrity, intracellular-extracellular pH gradient, and possibly an anion exchange system for bicarbonate. For this reason, the uptake of /sup 13/N-ammonia may not always provide a valid measurement of myocardial perfusion.

• Research Organization: Universitaet Heidelberg, Federal Republic of Germany
• OSTI ID: 5776851
• Journal Information: Circulation; (United States), Vol. 71:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
AMMONIA
UPTAKE
BLOOD FLOW
BIOLOGICAL MARKERS
MYOCARDIUM
BIOCHEMICAL REACTION KINETICS
CARBON DIOXIDE
CELL MEMBRANES
DYNAMIC FUNCTION STUDIES
IMINES
ION EXCHANGE
LABELLED COMPOUNDS
NITROGEN 13
ORGANIC SULFUR COMPOUNDS
PERFUSED ORGANS
PH VALUE
RATS
SODIUM CARBONATES
STILBENE
SULFONIC ACIDS
TRACER TECHNIQUES
ALKALI METAL COMPOUNDS
ANIMALS
AROMATICS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBON COMPOUNDS
CARBON OXIDES
CARBONATES
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CHALCOGENIDES
ELECTRON CAPTURE RADIOISOTOPES
HEART
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MAMMALS
MEMBRANES
MINUTES LIVING RADIOISOTOPES
MUSCLES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SODIUM COMPOUNDS
VERTEBRATES
560301* - Chemicals Metabolism & Toxicology- Cells- (-1987)
551001 - Physiological Systems- Tracer Techniques