Different sensitivity of Na(+),K(+)-ATPase and Mg(2+)-АТРase to ethanol and arachidonic acid in rat colon smooth muscle under pretreatment of cellular membranes with Ds-Na

Abstract

The methodological procedure provides the detection of the relatively high Na

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 rat colon

“…In general, the relative inhibitory pattern of these aliphatic monohydroxy alcohols for the studied ATP-hydrolases corresponded to that previously established for ethanol and 1-butanol [15]. The data of inhibitory efficiency of the short-chain aliphatic monohydroxy alcohols and their polarity characteris tics are summarized in Table 1 [15,[17][18][19]. A decrease in the I 50 value corresponds to an increase in the sensitivity to inhibition.…”

“…The isolation of the nonmitochondrial membrane fraction from rat CSM, protein concentration, membrane permeabilization by Ds-Na pretreatment, ATPase activities and inorganic phosphate were determined as described earlier [13,15]. Male Wistar rats were fed with the standard diet of the vivarium and deprived of food the day before the experiment.…”

“…Final detergent dilution was 80-100 times. The membrane pretreatment with Ds-Na according to Jorgensen and Sweadner procedure for excitable tissues, kidney, etc., used for CSM membranes, is based on the precautions, noted earlier [13,15]. It allows measuring relatively high for crude smooth muscle membranes the latent Na + ,K + -ATPase activity of functional protein-lipid complexes of enzymes at optimal protein/ Ds-Na pretreatment, but at insignifi cant detergent concentration in the incubation mixture.…”

“…More informative is a comparative study of the influence of the modifiers with a predicted membrane action on different enzymatic systems of the ATP-hydrolysis with principally different catalytic mechanism and structural organization, viz, P-type Na + ,K + -ATPase vs ouabaininsensitive Mg 2+ -ATP-hydrolase. This research considering the recent data [15] educes and broadens understan ding of the features that determine the specific effects on ATP-hydrolases of two groups of the aliphatic compounds: short-chain monohydroxy alcohols and unsaturated fatty acids (UFAs).…”

“…Thus, the aim of this study is to compare the relative structure-function resistance in membrane of the ATPases (Na + ,K + -ATPase vs Mg 2+ -АТРase), affected by the solvents and lipophilic modifiers: primary and secondary alcohols (1-propanol and 2-propanol) and oleic acid (OlA), to determine their efficiency in a series of aliphatic compounds differed by polarity, hidrofobicity and number of the double bond [15]. In addition, a standardized approach is applied for evaluation of the action of biologically active compounds on the example of an organophosphate insecticide fenamiphos (FP) or ethyl 3-methyl-4-(methylsulfanyl)phenyl isopropylphosphoramidate (ACD/IUPAC Name).…”