The effect of etafenone on the subcellular distribution of calcium and some oligoelements in heart muscle. Ultracytochemical and x-ray microanalytical study.

In order to detect the subcellular localization of calcium in the myocardium of laboratory animals (rats and guinea-pigs) under the influence of 2'-(2-diethylaminoethoxy)-3-phenyl-propiophenone (etafenone, Baxacor) (4 mg, 20 mg and 100 mg/kg body weight) two ultracytochemical methods, with lead acetate and with potassium pyroantimonate, were used. In addition, X-ray microanalysis of myocardial fragments was performed. The correlation of ultrastructural, ultracytochemical and X-ray microanalytical findings provides direct evidence of the hypothesis that etafenone acts on myocardium as a so-called "calcium antagonist". The subcellular targets of etafenone action are mainly the sarcoplasmic reticulum and mitochondria. Etafenone modifies also the concentration of copper, zinc and selenium in myocardium. The effect of etaferone on myocardial calcium and oligoelements appears to be dose-dependent.