RESUMEN
Activity of Na,K-ATPase (Na+,K+-adenosine triphosphatase, EC 3.6.3.9) in the whole erythrocytes was studied in dynamics of the complete rat alimentary starvation for 1, 3, 5, 7-8, and 10-12 days with water drinking ad libitum. There has been established a change of the erythrocyte Na,K-ATPase activity depending on the phase of starvation (the period connected with a certain level of metabolism). After the state on an empty stomach and adaptation to endogenous nutrition (the 0-I phase), from the 3rd to the 7-8th starvation day, the II phase, the period of compensated adaptation occurs (the euglycemia is preserved, the plateau level is preserved, the plateau level is achieved for protein loss and hormonal stimulation). Changes of the Na,K-ATPase activity level within the limits of the II phase were insignificant (p < 0.05), but loses of potassium content in plasma and erythrocytes have been from the 5th starvation day. The III phase (the 12-13th day) is the beginning of the terminal period and is characterized by a decrease of the Na,K-ATPase activity (the oubain-sensitive activity) and of Mg2+-ATPase (the oubain-independent activity), by a decrease of the plasma sodium level (prior to that, this level remained practically unchanged). Ad causes of the revealed decrease of the ATPase activities at the long-term starvation, there are considered aging of population of circulating erythrocytes (the absence of reticulocytes and young erythrocytes), depletion of cell energetic resources (hypoglycemia and glycopenia), effect of endogenous oubain, and endotoxemia.
Asunto(s)
Adaptación Fisiológica , Eritrocitos/enzimología , Privación de Alimentos/fisiología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Inanición/sangre , Animales , Masculino , Potasio/sangre , Ratas , Sodio/sangre , Inanición/enzimología , Inanición/fisiopatología , Factores de TiempoRESUMEN
Apoptosis is a common mechanism of programmed cell death in virtually all nucleated cells. In spite of the fact that platelets and erythrocytes are the only enucleated cells in mammals they contain most of the apoptosis machinery of other cells and undergo similar apoptotic processes as nucleated cells except those connected with nuclear and chromatin transformation. Here we compare the mechanisms of platelet and erythrocytes apoptosis induced by different stimuli namely, stimulation ofthrombin and collagen receptor (T/C), inhibitor of BclX family proteins (ABT-373) for platelets, tert-butylhydroperoxide (tBH) and calcium ionophore (A-23187) for erythrocytes. Induction of platelet apoptosis by both methods (T/C and ABT-373) lead to strong phosphoetydilserine (PS) externalization, loss of the mitochondrial membrane potential (DeltaPsim), proteolytic cleavage of some cytoskeletal and regulatory proteins, and microparticle (MP) formation. However, there are clear differences between mechanisms of platelet apoptosis induced by TC and ABT-373. T/C induced apoptotic reaction is very fast (reach the maximum at 5 min), whereas ABT-373 induced reaction is more prolonged (first apoptotic evidence appears only after 30 min and reach the maximum after 3 hours). MP formation is much more pronounced in T/C than in ABT-373 stimulated platelets, whereas caspase 3 activation is much more stronger in ABT-373 than in T/C stimulated platelets. The main differences between these two apoptotic pathways are connected with aIIbp3 integrin, which activation appears only after T/C stimulation. For tBH experiments on erythrocytes we established optimal conditions (0.25x1012 cells/L, and strong, 1500 RPM stirring) for elucidation of apoptotic processes and found two independent ways of erythrocytes apoptotic processes; calcium independent, connected with met hemoglobin (metHb) formation (tBH stimulation), and calcium dependent pathway (A-23187 stimulation). Erythrocytes apoptosis induced by tBH is characterized by formation ofmetHb, cell shrinkage, fast (95 % during 3 hours) PS externalization, yield of hemoglobin, probably by vesicle (MP) formation. These cells are transformed to stomatocytes, become highly rigid, and could not be lysed even in pure water. All these reactions are calcium independent. Whereas increase of intracellular calcium concentration by A-23187 connected with formation of exinocytes, less pronounced (17 % during 3 h, 35 % during 15 h) PS externalization and rigidity (lysed in 50 mOsm buffer).
Asunto(s)
Apoptosis/genética , Plaquetas/metabolismo , Proteínas del Citoesqueleto/metabolismo , Eritrocitos/metabolismo , Apoptosis/efectos de los fármacos , Plaquetas/citología , Plaquetas/efectos de los fármacos , Calcimicina/farmacología , Calcio/metabolismo , Caspasa 3/genética , Caspasa 3/metabolismo , Micropartículas Derivadas de Células/efectos de los fármacos , Micropartículas Derivadas de Células/metabolismo , Proteínas del Citoesqueleto/genética , Eritrocitos/citología , Eritrocitos/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Hemoglobina A/metabolismo , Humanos , Cinética , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Metahemoglobina/metabolismo , Especificidad de Órganos , Fosfatidilserinas/metabolismo , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/genética , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Receptores de Colágeno/agonistas , Receptores de Colágeno/genética , Receptores de Colágeno/metabolismo , Receptores de Trombina/agonistas , Receptores de Trombina/genética , Receptores de Trombina/metabolismo , Transducción de Señal/efectos de los fármacos , Factores de Tiempo , Proteína bcl-X/antagonistas & inhibidores , Proteína bcl-X/genética , Proteína bcl-X/metabolismo , terc-Butilhidroperóxido/farmacologíaRESUMEN
Comparative study has been carried of effect of the three-day long starvation, running, and their combination on morphological parameters of rat blood, lipid metabolism, and activity of blood Na,K-ATPase. Different effect has been shown of these stress factors on the blood erythrocyte composition. Starvation is accompanied by the most pronounced release of stored erythrocyte into blood, which results in a significant decrease both of the total amount of reticulocytes and the complete absence of reticulocytes of the I stage of maturity (the youngest). The running on treadmill led to a significant increase of the total amount of blood reticulocytes and to multiple increase of immature reticulocytes (RC-I and RC-II), which can indicate some stress of the bone marrow erythroid stem line. The curve of acid resistance of blood reticulocytes has shown the animal to experience the greatest stress at a combination of starvation and running. Starvation and running produced different effects on blood lipid characteristics. The content of triacylglycerides (TAG) in blood rose by 40% at starvation and decreased by 30% at running, a similar tendency being found for index of atherogeneity. The fatty acid composition of blood phospholipids at running and its combination with starvation practically did not differ from control. A change of Na,K-ATPase, which is so characteristic of reaction to various kinds of stress, sharply fell at starvation (by 22%), but increased at running (by 13%) and decreased markedly at combination of these actions. Absorption spectra of lipid extracts of the whole blood of the rats submitted to various stress actions showed that extracted from blood (at different amount depending on the kind of action) is an organic substance with coupled bonds, which absorbs light in the diapason of 360-620 nm. The absorption of light in the diapason of 400-410 nm has been found to belong to the Soret band of ferroheme and ferriheme. The shift of the Soret band indicates electron transitions in the iron cation. By the change and disappearance of the Soret band, it is possible to judge about the processes occurring in the lipid extract. The disappearance of the Soret band in the lipid extract indicates formation in it of steady radicals as a result of the ferriheme disintegration due to accumulation of energy in porphyrin, which does not seem to occur in the blood cell membranes. The iron atom in the ferriheme molecule is known to accept electron and yields a part of energy probably to porphyrin. Then ferriheme yields electron and becomes ferriheme with excess of energy in porphyrin. Hence, at admission of the next electron to the iron atom the porphyrin molecule is to get rid of the energy obtained earlier to prevent its disintegration. The heme is possible to be an accumulator and distributor of energy in tissue.
Asunto(s)
Hemo , Hierro , Lípidos/sangre , Reticulocitos , Animales , Ácidos Grasos/sangre , Hemo/análisis , Hemo/metabolismo , Hemina/metabolismo , Hierro/análisis , Hierro/metabolismo , Luz , Masculino , Fosfolípidos/sangre , Condicionamiento Físico Animal , Porfirinas/sangre , Ratas , Recuento de Reticulocitos , Reticulocitos/citología , Reticulocitos/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/sangre , Inanición/sangre , Inanición/metabolismoRESUMEN
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.
Asunto(s)
Anemia/metabolismo , Hemorreología , Consumo de Oxígeno , Intercambio Gaseoso Pulmonar , Reticulocitos/metabolismo , Animales , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas Wistar , ATPasa Intercambiadora de Sodio-Potasio/metabolismoRESUMEN
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.
Asunto(s)
ATPasas Transportadoras de Calcio/metabolismo , Agregación Eritrocitaria/fisiología , Eritrocitos , Hemorragia/sangre , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Animales , Recuento de Eritrocitos , Membrana Eritrocítica/enzimología , Membrana Eritrocítica/fisiología , Eritrocitos/citología , Eritrocitos/enzimología , Eritrocitos/fisiología , Masculino , Ratas , Ratas WistarRESUMEN
AIM: To study activity of angiotensin converting enzyme (ACE) in blood serum of patients with stable effort angina. MATERIAL AND METHODS: ACE activity was measured in 11 patients (age 35-45, mean 46.5+/-1.6 years) with typical class II-III effort angina without hypertension or contractile insufficiency of the myocardium previously not treated with ACE inhibitors. Diagnosis was verified by angiography (7 patients), data of 24 hour ECG monitoring and exercise tests. Control group comprised 13 practically healthy subjects (age 36-54, mean 48.3+/-2.09 years). RESULTS: ACE activity in controls was 32.5-57 micromol/min/l (mean 46.2+/-2.0 micromol/min/l), in patients -- 48-110 micromol/min/l (mean 73.5+/-5.9 micromol/min/l), p<0.001. More than 2/3 of patients (7 of 11) had ACE activity above upper limit of norm.