Article date: February 1970
By: T. GODFRAIND, M. LESNE in Volume 38, Issue 2, pages 345-352
. The accumulation and release of 3H‐digitoxin, 3H‐digoxin and 3H‐ouabain by isolated guinea‐pig intestinal smooth muscle has been studied and compared with a pharmacological action due to inhibition of the sodium pump.
. The uptake of labelled cardiac glycosides can be described by means of an exponential function. The t of uptake was similar for the three compounds and did not depend on the concentration.
. Analysis of the curve relating the uptake of cardiac glycosides at equilibrium to the bath concentration enabled a non‐saturable and a saturable binding site to be distinguished.
. In contrast to the uptake observations, the onset of the pharmacological effect was dependent on the concentration, and furthermore the t½; for this effect was shorter.
. The release of cardiac glycosides proceeded more slowly than the uptake.
. The uptake of a labelled glycoside was reduced in the presence of another glycoside. The amount of displaceable glycoside was nearly equivalent to the capacity of the saturable binding site.
. The significance of these results is discussed.
. The accumulation and release of 3H‐digitoxin, 3H‐digoxin and 3H‐ouabain by isolated guinea‐pig intestinal smooth muscle has been studied and compared with a pharmacological action due to inhibition of the sodium pump.
. The uptake of labelled cardiac glycosides can be described by means of an exponential function. The t of uptake was similar for the three compounds and did not depend on the concentration.
. Analysis of the curve relating the uptake of cardiac glycosides at equilibrium to the bath concentration enabled a non‐saturable and a saturable binding site to be distinguished.
. In contrast to the uptake observations, the onset of the pharmacological effect was dependent on the concentration, and furthermore the t½; for this effect was shorter.
. The release of cardiac glycosides proceeded more slowly than the uptake.
. The uptake of a labelled glycoside was reduced in the presence of another glycoside. The amount of displaceable glycoside was nearly equivalent to the capacity of the saturable binding site.
. The significance of these results is discussed.
DOI: 10.1111/j.1476-5381.1970.tb08522.x
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