Measurement of Ca channel activity of isolated adult rat heart cells using /sup 54/Mn

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(89)90327-5· OSTI ID:6470488

Haworth, R A; Goknur, A B; Berkoff, H A

Isolated adult rat heart cells incubated with 5 microM Mn in a medium with 1 mM Ca showed a rapid phase of Mn binding plus a slow phase of Mn uptake. The rapid phase was extracellular binding, as judged by its temperature-insensitive removal by ethylene glycol bis(beta-aminoethyl ether) N, N'-tetraacetic acid. The slow linear phase represented cellular uptake, as judged by its release with digitonin plus the ionophore A23187. Isoproterenol increased the linear rate of Mn uptake and induced spontaneous beating activity in some cells. Both effects were inhibited by nitrendipine. Electrical stimulation of the cells in suspension increased the linear rate of cellular Mn uptake. The increase was potentiated by isoproterenol, and inhibited by nitrendipine or verapamil. Stimulation-dependent Mn uptake (per milligram protein) was greater for cells from 5- to 6-week-old rats than for 8- to 9-month-old female retired breeder rats, in the presence of isoproterenol. Ryanodine increased the stimulation-dependent Mn uptake in the presence of isoproterenol, but not in its absence. We conclude: (i) that cellular uptake of /sup 54/Mn is a good probe of Ca channel function; (ii) that isoproterenol promotes Mn influx by the channel in isolated heart cells; (iii) that cells from young rats (5-6 weeks) have a higher beta-adrenergically induced Ca channel activity than cells from mature rats (8-9 months); and (iv) that ryanodine promotes Ca channel activity (perhaps indirectly) in the presence of isoproterenol.

• Research Organization: Univ. of Wisconsin, Madison (USA)
• OSTI ID: 6470488
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 268:2; ISSN ABBIA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETIC ACID
AGE DEPENDENCE
ALKALINE EARTH METALS
ANIMALS
BIOELECTRICITY
BODY
CALCIUM
CARBOXYLIC ACIDS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
DRUGS
ELECTRICITY
ELEMENTS
HEART
IN VITRO
ISOTOPE APPLICATIONS
MAMMALS
MANGANESE
MEMBRANE PROTEINS
METALS
MONOCARBOXYLIC ACIDS
MUSCLES
MYOCARDIUM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PORINS
PROTEINS
RATS
RODENTS
TRACER TECHNIQUES
TRANSITION ELEMENTS
UPTAKE
VASODILATORS
VERTEBRATES