[Effect of total hypothermia on the fatty acid composition of blood phospholipids of rats and sousliks and light irradiation on chemical processes in lipid extract].

Effect of hypothermia on the fatty acid composition of rat and souslik blood phospholipids is studied. Different reaction of these animals to cooling is revealed: in rats no changes were observed in the fatty acid composition of blood phospholipids, whereas in the hibernating there were significant changes in the content of individual fatty acids (FA). The content of monoenic acids in sousliks decreased almost by 50%, while the content of saturated acid (C18) and of polyenic acids C18 : 2omega6 and C20 : 4omega6 rose significantly. Such changes seem to be the mechanism that promotes maintenance of the organism viability under conditions of a decreased level of metabolism, heart rhythm, and body temperature and is evolutionarily acquired. At the same time, the observed changes in the content of individual FA do not lead to sharp changes in such integrative parameters as the total non-saturation of phospholipids, which determines liquid properties of chylomicrons and other lipolipoprotein transport particles of the souslik blood. There are studied absorption spectra of blood lipid extracts of rats and sousliks under effect of light as well as effect of light upon the FA composition of lipid extracts of these animals. The FA composition of lipid extracts has been established to remain practically constant, whereas the character of changes of spectra under action of light indicates the presence in the extracts of oxidation-reduction reactions. The obtained data allow suggesting that in the lipid extract there occurs cooperation both of the phospholipid molecules themselves and of them with other organic molecules, which makes it possible for fatty acids to participate in processes of transport both of electrons and of protons. This novel role of FA as a participant of the electron transfer might probably be extrapolated to chemical reactions (processes) occurring inside the membrane.

[Changes of gas exchange parameters and of functional-biochemical properties of erythrocytes in dynamics of experimental anemia in rats].

In experiments on Wistar male rats, on a specially constructed computer installation, O2 consumption by the animals in comparison with changes of hematological, biochemical, and rheological blood properties is studied after anemization--acute bloodletting (12-15% of the total blood mass). An increase of the O2 consumption by the organism and tissues by 18-28% has been revealed for the first 7 days after the bloodletting, in spite of a pronounced decrease of hematocrit, and of the amount of erythrocytes and hemoglobin in peripheral blood by 20-25% of the initial level. There was a 5-10-fold increase of the content of immature erythrocyte forms--reticulocytes and a progressive rise of cell acidic resistance, which is characteristic of young erythrocyte forms. An increase of O2 consumption at a decrease of the blood oxygen capacity (a low hemoglobin level) seems to be due to the more efficient transport and yield of O2 to tissues. At the 3rd 7th day after the bloodletting, activity of Na,K-ATPase has been shown to increase by 60% and 20%, respectively. Analysis of the erythrocyte rheological properties has shown that the maximal firmness of aggregates (Uq) and the aggregation rate (1/T) decrease progressively beginning from 3 days after the bloodletting; index of deformability (I(max)) turned out to be elevated by 7-11%, probably due to an increase of the cell membrane elasticity. The conclusion is made that changes of erythrocyte rheological properties are interconnected with changes of the Na,K-ATPase activity and are directed to optimization of blood circulation in large vessels and the capillary network.

[Changes of physiological and biochemical characteristics of rat erythrocytes after blood loss].

In experiments of Wistar male rats, changes are studied of erythrocyte hematological, biochemical (activitities of transport ATPases), and rheological properties (capability for aggregation and deformability) 7 days after bloodletting of 12-15 % of the total blood mass. It has been shown that alongside with an elevation of erythrocyte volume and of the number of immature cells - reticulocytes, there was a statistically significant increase of Na,K-ATPase and Ca-ATPase activities in the whole erythrocytes and their membrane preparations - ghosts, the increment of activity in the case of Na,K-ATPase being essentially higher in the whole cells. This indicates the appearance of an enzyme activator inside the erythrocytes. There are also revealed a decrease of firmness of erythrocyte aggregates, a deceleration of spontaneous aggregation, and an increase of index of erythrocyte deformability. The conclusion is made that changes of erythrocyte rheological properties are interconnected with changes of the Na,K-ATPase activity and are directed to optimization of blood circulation in large vessels and capillary network.

Rheologic properties of mammalian erythrocytes: relationship to transport ATPases.

Rheologic properties of erythrocytes and activities of their Ca(2+)-ATPase and Na+, K(+)-ATPase were analyzed together with standard erythrocyte values in seven mammalian species (man, rat, mouse, rabbit, hamster, guinea pig and dog). The number of erythrocytes in the blood of animals investigated correlated inversely with the mean cell volume (MCV) (r = -0.936, P = 0.002) and the mean cell hemoglobin content (MCH) (r = -0.923, P = 0.003). MCV and MCH also showed a high direct correlation with each other (r = 0.907, P = 0.005). The maximal erythrocyte deformability (DImax) measured with ektacytometry was inversely proportional to the MCV and MCH (r = -0.854, P = 0.014, and r = -0.940, P < 0.002, respectively). The MCV was also linearly related with the Na+, K(+)-ATPase activity (r = -0.791, P = 0.034). The major parameters of osmoscan (O' and Omax) and their derivatives (O'-Omin, Omax-Omin) were shown to be in a direct correlation with each other and with the activity of Na+, K(+)-ATPase in the whole erythrocytes except for the rabbit Na+, K(+)-ATPase. The activity of Ca(2+)-ATPase in the whole erythrocytes significantly correlated only with the O' and O'-Omin values. Thus, the activities of transport ATPases in mammalian red cells seem to be adjusted to the level required to maintain particular rheologic properties of the cells of one or other species.

Species variability of erythrocyte transport ATPases in mammals.

Na+, K(+)-ATPase, and Ca(2+)-ATPase in whole erythrocytes from five species of mammals (rat, mouse, guinea pig, golden hamster, rabbit) after cell treatment with Tween 20 (7.5 mg/ml) varied over a wide range: from 3.0 +/- 0.9 mumol Pi/hr/ml cells in rabbit to 27.3 +/- 4.9 mumol Pi/hr/ml cells in mouse for Na+, K(+)-ATPase and from 8.0 +/- 1.6 mumol Pi/hr/ml cells in hamster to 47.2 +/- 4.9 mumol Pi/hr/ml cells in mouse for Ca(2+)-ATPase. Differences were less pronounced in red cell ghosts. Fatty acid and phospholipid compositions of erythrocyte membranes were similar for all species. Nevertheless, the activity of Ca(2+)-ATPase in ghosts significantly correlated (r = -0.884) with the ratio of PC + SM/PE + PS in red cell membranes. Rabbit membranes had the lowest content of arachidonate. Rat hemolysate activated Na+, K(+)-ATPase in the ghosts from the animals of any species investigated, whereas the enzyme activation by the homohemolysate was characteristic only of the rat, mouse, and guinea pig ghosts. The data obtained suggest that there are differences in both activity and intracellular control of transport ATPase in erythrocytes of different mammals.

[A comparative study of the properties of ouabain-sensitive phosphatase in rat erythrocyte ghosts and spectrin-free membranes]. / Sravnitel'noe izuchenie svoistv uabain-chuvstvitel'noi fosfatazy v teniakh i besspektrinovykh membranakh éritrotsitov krysy.

The removal of the membrane skeleton proteins (MSP), chiefly spectrin and actin, from the rat erythrocyte ghosts was shown to result in a decrease of both the total Na, K-ATPase activity and a partial reaction of the enzyme, namely the phosphatasic one. Besides, modulating effects of the effectors promoting the enzyme conformational transitions (ATP and Mg2+) on the ouabain-sensitive K-phosphatase is changed. For instance, a pronounced activation of the K-phosphate in a high-potassium medium in the presence of 1 mM ATP disappeared and the degree of the enzymatic activity enhancement in response to increasing MgCl2 concentrations (from 1.5 to 6 mM) is decreased. The data obtained are discussed from the viewpoint of possible involvement of the erythrocyte MSP in the catalytic of Na, K-ATPase.

[The effect of hemolysate and calcium ions on transport ATPase activity in guinea pig erythrocytes]. / Vliianie gemolizata i ionov kal'tsiia na aktivnost' transportnykh ATFaz éritrotsitov morskoi svinki.

Influence of 0.1, 0.3 and 1.0 microM Ca++ on Na,K-ATPases in different membrane preparations of guinea pig erythrocytes was studied both in presence and in absence of haemolysate. The incubation with the haemolysate and 0.1 or 0.3 microM Ca++ increased significantly the activity of the Na,K-ATPase in all membrane preparations used. The increasing Ca++ concentrations (up to 1 microM) led to the loss of the activating effect of the haemolysate in membrane preparations with lack of a part of the cytoskeleton proteins, and also decreased sharply its activity in all the preparations in absence of haemolysate. The latter also increased the Ca-ATPase activity irrespectively of the integrity of cytoskeleton structures (may be because of calmodulin action). The results obtained suggest that the cytoskeleton structures mediate the intracellular Na,K-ATPase activator action.

[A comparative study of the intracellular regulation of transport ATPase activity in non-nucleated erythrocytes]. / Sravnitel'noe issledovanie vnutrikletochnoi reguliatsii aktivnosti transportnykh AFTaz v bez''iadernykh éritrotsitakh.

Removing the basic cytoskeleton proteins (spectrin, 4.1 and 2.1 band proteins) from the unnuclear erythrocyte membranes of four mammalian species (mouse, hamster, guinea, pig and rabbit) made no changes in Na,K-ATPases, while the specific activity of Ca-ATPases was decreased (the decreasing was of a range of 60-90% depending on the species, in values per mg of protein). The specific activity of the Na,K-ATPase (per ml of cells) varied from 20 to 30% in different species. Incubation of ghosts with erythrocyte haemolysates from rat led to a markedly expressed activation of the Na,K-ATPase in in erythrocytes of all species studied, while the incubation with erythrocyte haemolysate of the same species caused activation of the enzyme in mouse and guinea pig ghosts only. The data obtained support a concept of intracellular Na,K-ATPase activator (probably a protein) having no absolute species specificity. They also show that normal transport function of ATPases in unnuclear erythrocytes needs integrity of the membrane skeleton.

[The activity of transport ATPases and the characteristics of the protein-lipid composition of the membranes of anuclear erythrocytes in a number of mammals]. / Aktivnost' transportnykh ATFaz i nekotorye kharakteristiki belkovo-lipidnogo sostava membran bez''iadernykh éritrotsitov riada mlekopitaiushchikh.

The activity of Na,K-ATPase and Ca-ATPase of the intact erythrocytes and their membrane preparations and also fatty acid, phospholipid and protein content of erythrocyte membrane of guinea pig, mouse, rabbit and hamster have been examined. The activity of Na,K- and Ca-ATPase in intact erythrocytes varies significantly among different species while the level of activity of these enzymes in their membrane preparations differs slightly. Together with the results of investigations of chemical composition of the erythrocyte membrane of these species which show the principal homogeneity of their fatty acid, phospholipid and protein composition, these data indicate the existence of the system of intracellular modulators, that maintain the activity of these enzymes on the species specific level.

[Na, K-ATPase activity in the erythrocyte membrane preparations and kidneys of spontaneously hypertensive rats]. / Aktivnost' Na, K-ATFazy v membrannykh preparatakh éritrotsitov i pochkakh spontanno gipertenzivnykh krys.

The enzyme activity in the cortex and medulla of the SHR was 1.5-2.0-fold lower than that of the WKY and Wistar rats. The Na, K-ATPase and Ca-ATPase activities were by 25 and 15% lower in the erythrocyte ghosts of the SHR than in normotensive rats. Removal of protein of the membrane skeleton from the erythrocyte membranes abolished the difference in the enzyme activity of normo- and hypertensive rats. The lower Na, K-ATPase activity in the SHR kidney seems to be an etiological factor in development of primary hypertension.

[The activity and properties of K-pNPphosphatase in membrane preparations of erythrocytes with different polypeptide compositions in Wistar, Wistar-Kyoto and SHR strain rats]. / Aktivnost' i svoistva K-pNFfosfatazy v membrannykh preparatakh éritrotsitov s razlichnym polipeptidnym sostavom u krys linii Vistar, Vistar--Kioto i SHR.

A higher K-pNPPase activity was found in erythrocyte membrane preparations from the SHR as compared with the Wistar rats. Removal of peripheral proteins from the membrane skeleton depressed the K-phosphatase activity and eliminated the difference between the SHR and Wistar rats. No activating effect of the ATP and Ca on the enzyme was found. The data obtained suggest that the proteins of the erythrocyte membrane skeleton are connected with regulation of the enzyme transport in the erythrocyte membranes of the SHR via a modulating effect of intracellular ATP and Ca.

[The effect of the membrane skeleton of non-nucleated erythrocytes on the properties of transport ATPases]. / Vliianie membrannogo skeleta bez''iadernykh éritrotsitov na svoistv transportnykh ATFaz.

Removal of spectrin and other proteins of membrane skeleton from rat erythrocyte membranes resulted in a significant loss of Na,K-ATPase and Ca-ATPase activities, and even more of respective phosphatase activities. At the same time the modulating influence of ATP and Ca2+ on the enzymes disappeared. These ATPase activities were reconstituted by addition of concentrated spectrin to spectrin-depleted membranes. The activating influence of Ca2+ on ouabain-resistant and ouabain-sensitive phosphatases in ghosts could be discovered only in the presence of ATP. The highest activities of both the phosphatases were revealed when both ATP (0.5 mM) and Ca2+ (10-30 mM) were present simultaneously in the incubation medium. These data show that the functioning of transport ATPases in non-nuclear erythrocyte membranes is related to the membrane skeleton: regulating influence of intracellular ATP and Ca2+ on enzymes seems to be realized through the proteins of the skeleton.

[Ionic homeostasis and erythrocyte deformability in patients with primary arterial hypertension]. / Ionnyi gomeostaz i deformiruemost' éritrotsitov u bolnykh s pervichnoi arterial'noi gipertenziei.

Erythrocyte Na, K-ATPase was examined for its activity and relation to the concentration of the complexon EDTA in 39 patients with arterial hypertension (AH), 12 subjects with borderline hypertension, and 18 normotensives. The ionic composition and deformability of erythrocytes were also studied. As compared to normotensives, the patients with Stage I AH displayed a significantly lower activity of erythrocyte Na, K-ATPase, which may suggest that there is an enzyme inhibitor in the blood of the patients. According to the enzyme activity, the patients with Stage II AH were divided into two subgroups: 1) those with a lower activity and 2) those with a higher activity than healthy subjects. The patients with a Stage II AH who showed a lower activity of Na, K-ATPase exhibited a more elevated erythrocyte sodium level, whereas those who had a high activity of the enzyme displayed a decreased erythrocyte deformability. In addition, a positive correlation between erythrocyte sodium concentrations and Na, K-ATPase activity, as well as erythrocyte deformability was found in normotensives, whereas a negative correlation was established in AH patients.

[Effect of bilateral renal ischemia on the sodium, potassium ATPase activity of the kidneys and erythrocytes in rats]. / Vliianie dvukhstoronnei ishemii pochek u krys na aktivnos't Na,K-ATFazy v pochkakh i éritrotsitakh.

The renovascular hypertension in the Wistar rats was induced by clipping both renal arteries. Within 3-4 weeks arterial pressure (AP) increased to maximal values. According to AP, the rats were divided into two groups: with AP less than or equal to 170 mm Hg and greater than 170 mm Hg. In 5-6 or 10-11 weeks the animals were decapitated and the Na,K-ATPase activities in the wholesome erythrocytes, their ghosts, and the cortex and medulla of kidneys were studied. Changes of the enzyme activity were only found in the medulla. A decreased enzyme activity (-20%) was revealed in the rats with AP less than or equal to 170 mm Hg within 5-6 weeks after renal ischemia, the activity increasing again in 10-11 weeks after the operation. The decreasing of Na,K-ATPase activity within 5-6 weeks after renal ischemia could be a mechanism of adaptation of the salt-water balance in animals.