D. M. Nozdrenko¹, O. M. Аbramchuk², V. M. Soroca¹, N. S. Miroshnichenko¹

¹Educational and Scientific Centre “Institute of Biology”,
Taras Shevchenko National University of Kyiv, Ukraine;
²Lesya Ukrainka Eastern European National University, Lutsk, Ukraine;
e-mail: ddd@univ.kiev.ua

Combined effect of aluminum chloride and quercetin solutions on the enzymatic activity and contraction dynamics of muscle fiber bundles of the Rana temporaria m. tibialis anterior was investigated. It was shown that these complexes inhibit muscle contraction. Linear reduction of Ca²⁺,Mg²⁺-ATPase activity induced by all of the used concentrations of AlCl₃ – quercetin was demonstrated. It was found that complex of quercetin with AlCl₃ has a greater inhibitory effect on muscle contraction dynamic and causes greater reduction during all periods of stimulation in comparison to the separate effect of the investigated compounds. All the studied concentrations of AlCl₃ and quercetin solutions (AlCl₃: 10^-4-10^-2 M; quercetin: 10^-6-10^-5 M) caused concentration depended contraction strengths and lengths reduction. The decrease in strength and length of muscle contractions was of constant and mostly linear nature within observed timeframe as well as within each periods of contraction. The changes were least pronounced within pretetanic period, but were profound within terminal period of muscle activity. The changes in dynamic contraction properties and Ca²⁺,Mg²⁺-ATPase activity of sarcoplasmic reticulum under effect of the investigated compounds was minimal in the beginning of the muscle’s response to stimulus, prior to muscle strength reaching stable contraction level.