[Mechanism of ethonium effect on membrane preparations of brain Na+, K+-ATPase]. / K mekhanizmu deistviia étoniia na membrannye preparaty Na+, K+-ATPazy mozga.

The effect of ethonium, a local anesthetic, on the membrane preparations of brain N+, K+-ATPase was studied by fluorescent, radioisotopic, electron-microscopic and electrophysiological methods. Ethonium is established to affect the formation of an intermediate phosphorylated product and has no pronounced destructive effect on the membrane. It changes the fluorescence intensity of 2-toluidinonaphthalen-6-sulphonate (TNS), astrafloxin (AF) and fluorene probes in a suspension of the Na+, K+-ATPase preparations, which evidences for ethonium-induced changes in the structure of membrane fragments.

[Effect of ethylenediamine derivatives on Na+, K+-ATPase and K+-p-nitrophenyl phosphatase activity of brain enzyme preparations]. / O vliianii riada proizvodnykh etilendiamina na Na+, K+-ATP-aznuiu i K+-n-nitrofenilfosfataznuiu aktivnosti fermentnykh preparatov mozga.

The activity of Na+, K+-ATPase preparations was studied as affected by ethonium and its analogs. Ethonium is found to be able of producing a strong inhibitory effect on the Na+, K+-ATPase and K+-n-nitrophenyl phospnatase activities (I50 = 2.5.10(-5) and 6.5.10(-5) M, respectively). The inhibition is irreversible under experimental conditions and is reduced when the concentration of protein and sodium ions in the incubation medium rises. A dependence is found between the inhibitory effect of the analogs and the length of their hydrocarbon radical (the inhibition maximum corresponds to bisquarternary ammonium compound with the hydrocarbon radical consisting of 10 links) and some kinetic characteristics of this effect are studied. It is supposed that the mechanism of the inhibitory effect is due to the ethonim binding by the hydrocarbon radical in the preparation hydrophobic zone, the electrostatic interaction being not excluded.