Influence of Cardiac Glycosides on Electrolyte Exchange and Content in Cardiac Muscle Cells

Nayler, Winifred G.; Noack, E.

doi:10.1007/978-3-642-68163-9_18

Cited by 3 publications

(2 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…p inhibition, or tne non-lnhibited portion of 80diu. pump molecules can in part compenaate -by increased activity -for the ouabain-inactivated pump molecules (12). Sodium pump activity in chicken heart auacle cella ia a uatainad despite the formation of a conaiderable amount of glycoalde raceptor -ouabain -complexe •• This could explain the experimental find!ng that no or disproportionally small inhibition of sodium pump activity and change of cellular Na+ and K+ have been .…”

mentioning

confidence: 98%

“…Sodium pump activity in chicken heart auacle cella ia a uatainad despite the formation of a conaiderable amount of glycoalde raceptor -ouabain -complexe •• This could explain the experimental find!ng that no or disproportionally small inhibition of sodium pump activity and change of cellular Na+ and K+ have been . ea8ured at therapeutie levela of cardiac glycosides (2,12,13).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Quantitative correlation of cardiac glycoside binding to its receptor and inhibition of the sodium pump in chicken heart cells in culture

Werdan

Zwiβler

Wagenknecht

et al. 1983

Biochemical Pharmacology

View full text Add to dashboard Cite

The Machaniam of positive inotropic action of cardiac glycoaidea is still a matter of controvera1 (1). The disagreement aainly relatee to the queation whether increaaed force of contraction la cauaed by, and therefore neceasarily accompanied by, an inhibition of the sodium pump. At therapeutic levels of the drug . RodiuM pump has been deaeribed aa not inrlueneed, inhibited or even stimulated. depending on the apeciea invastigated, the drug applled and. the method used (1,2). The problem is further complicated by the preaenee of two different binding aites ror cardiae glycoaides. In rat heart, occupation of the high affinity site being linked to positive inotropic effect without inhibition of (Na++ K+)-ATPase aetivity or active (86Rb +)_uptake aa meaaure of sodium pump aetivity (3). In fev of the e~peri.ent6 deacribed, how ever, haa inhibition or atimulation of the aodium pump by cardiae glycoaides been correlated quantitatively with the pereentage of binding sites oeeupied b y cardiac glycoside molecu les . Methods: Huscle and non ~uscle cells from hearts of 9.12 day_old c hi ck embryos haye been prepared and separately cultured a8 described in detail for rat heart cells (4,5).Experiments have been ~arried out with museie cells after 2-~ days in c~!tu re, with non muscle cells after 1 aubcultivation (splitting rati o 1:2). At that time, muscle ce lla had forMed a synchronously beating monolayer, non musc le cells wer@ at conflue nc y. For measurement of {3H)_ouabain binding, (86Rb ++ K+)-uptake and cellular K+, cells (0.2-2.0 mg proteinjfla.sk) were incubated in Ilepes buffered (20 mM, pli 7.40)

show abstract

mentioning

confidence: 98%

mentioning

confidence: 99%

Quantitative correlation of cardiac glycoside binding to its receptor and inhibition of the sodium pump in chicken heart cells in culture

Werdan

Zwiβler

Wagenknecht

et al. 1983

Biochemical Pharmacology

View full text Add to dashboard Cite

show abstract

Effects of Cardiac Glycosides at the Cellular Level

Herzig¹,

Lüllmann²

1989

Antiarrhythmic Drugs

View full text Add to dashboard Cite

α-Amanitin prevents the positive inotropic effect of cardiac glycosides in-vitro

Bazzani

Arletti

Bertolini

1983

Journal of Pharmacy and Pharmacology

View full text Add to dashboard Cite

We recently observed that cycloheximide and actinomycin prevent the positive inotropic effect of ouabain on atria and ventricle strips. On the other hand, they neither affect the force of contraction of the myocardium, nor modify the activity of other positive inotropic agents such as Ca2+ and noradrenaline (Arletti et a1 1983). We inferred that either the synthesis of a short-lived protein is required for the inotropic effect of ouabain, or that at least part of its effect is due to the stimulated synthesis of some protein(s).In an attempt to clarify this point we studied the influence of a-amanitin, which specifically inhibits mammalian DNA-dependent RNA polymerase (Fiume 1972), on the inotropic activity of ouabain and of digoxin. MethodsMongrel guinea-pigs (350-450 g) and rats of a Wistar strain (Morini, S.Polo d'Enza, Reggio Emilia, Italy) were decapitated and their hearts rapidly removed and placed in previously gassed (97% Oz -3% COa) standard Tyrode solution having the following composition (mM. )NaCI 115.0; KCl 4.7; CaCIy HzO 3.66;MgS04 .7H20 1.2; KH2P04 1.2; NaHC03 25-0; glucose 10.0; pH 7.4. Strips (2.10 mm) of the right ventricle were mounted vertically in a double-chambered bath (volume = 20 ml) perfused at 32+0-2 "C with Tyrode.One end of the ventricle strips was secured to the bottom of the chamber by means of platinum electrodes and the other end was attached to a force-displacement transducer (MARB, Pistoia, Italy). Resting tension was set at 0.8 g, and maintained at the same value for the duration of the experiment. The preparations were stimulated electrically at a constant rate (1 Hz) by square-wave pulses, of 5 ms duration, that exceeded threshold voltage by 20%. Pulses were delivered by a pulse generator (WP1 301-105; New Haven USA) connected to an isolation unit. The signal from the transducer was recorded via a dc preamplifier (MARB, Pistoia, Italy) on an oscilloscope monitor.Experiments started after a 1 h equilibration period. Ouabain and digoxin (Aldrich-Europe, Beerse, Belgium) were diluted with Tyrode solution to the desired concentration and left in the bath for 1 h. a-Amanitin (gift of Prof. Th. Wieland, Max-Plank Institut, Heidelberg) was also dissolved in Tyrode and added to the perfusion medium 5 min before glycosides. Student's t-test was used for the statistical analysis of data.

show abstract

Influence of Cardiac Glycosides on Electrolyte Exchange and Content in Cardiac Muscle Cells

Cited by 3 publications

References 92 publications

Quantitative correlation of cardiac glycoside binding to its receptor and inhibition of the sodium pump in chicken heart cells in culture

Quantitative correlation of cardiac glycoside binding to its receptor and inhibition of the sodium pump in chicken heart cells in culture

Effects of Cardiac Glycosides at the Cellular Level

α-Amanitin prevents the positive inotropic effect of cardiac glycosides in-vitro

Contact Info

Product

Resources

About