D. M. Nozdrenko, L. V. Korchinska, V. M. Soroca

Educational and Scientific Centre Institute of Biology,
Taras Shevchenko National University of Kyiv, Ukraine;
e-mail: ddd@univ.kiev.ua

The results of an experimental study of organo­phosphorus insecticides, including pirimiphosmethyl, diazinon and chlorpyrifos caused a decline of the contraction properties in m. tibialis anterior fiber bundles of Rana temporaria, as well as sarcoplasmic reticulum Ca²⁺,Mg²⁺-ATPase enzymatic activity reduction are outlined in this paper. Concentration-dependent strengths response diminishing in isolated skeletal muscle fiber bundles as a result of non-cholinergic influence of organophosphorus insecticides were found. A decrease of Ca²⁺,Mg²⁺-ATPase enzymatic activity in sarcoplasmic reticulum was observed after administration of each insecticide. The most significant inhibition of this enzyme was observed when using chlorpyrifos.