Tag Archives: fenamiphos

Assessment of the effect of monohydroxy alcohols, unsaturated fatty acids, organophosphate compounds on the enzymatic ATP-hydrolysis in the cell membranes of the smooth muscle of the rat colon

A. A. Kaplia, S. V. Midyk1, S. V. Khyzhnyak1

1National University of Life and Environmental Sciences of Ukraine, Kyiv;
e-mail: kaplyaalex@gmail.com

The differences of the structural-functional stability of ATP-hydrolases to the action of the short-chain aliphatic monohydroxy alcohols and long-chain unsaturated fatty acids (UFAs) with wide range of the membrane-acting effectiveness were evaluated in the colonic smooth muscle (CSM) cellular membranes. It was shown that Mg2+,ATP-hydrolase was more resistant to all tested aliphatic compounds than Na+,K+-ATPase. There was  a clear relationship between  inhibitory efficiency, chain length (number of carbons) increase and relative polarity decrease  in the series of straight-chain alcohols. Secondary alcohol 2-propanol turned out to be the weaker inhibitor than primary alcohol 1-propanol. The I50 value (мМ) for ATРases decreased in the following succession: ethanol > 2-propanol > 1-propanol > 1-butanol. UFAs were the stronger inhibitors (I50 of μM range) than alcohols (mM range). Oleic acid inhibited Na+,K+-ATPase with lower efficiency than was detected for arachidonic acid according to the differences in double bonds number; I50 for Mg2+,ATP-hydrolase activity was the same for studied UFAs. As well, the organophosphate pesticide fenamiphos proved to be a weak ATPase inhibitor. Comparison of the enzymatic pair of the CSM ATP-hydrolases seems applicable for evaluation of the specific membrane-acting effect of bioactive compounds on Na+,K+-ATРase activity from the standpoint of its role in mediating of electro-mechanical coupling in intestinal smooth muscles.