The effect of delta-sleep-inducing peptide on the Ca-transporting system of the sarcoplasmic reticulum and activity of the myocardial antioxidant enzymes

It is demonstrated that immobilization stress against the background of lowered catalase activity impairs the function of the sarcoplasmic reticulum Ca pump, particularly at high Ca²⁺ levels. the membranes of intracellular Ca²⁺ depots are destroyed much more rapidly than in the control, which results in Ca²⁺ release. Administration of delta sleep-inducing peptide to control animals results in a 30% increase in catalase activity for an unchanged level of superoxide dismusase and markedly improves the function of the Ca-transporting system at elevated levels of free Ca²⁺. A long-term stress after administration of the peptide not only causes no damage to the Ca-transporting system but actually increases its efficiency (compared with the control) at a high catalase level. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 248–251, March, 1996 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Effect of emergent and long-term adaptation to physical strength on the resistance of Ca-transporting system of myocardial sarcoplasmic reticulum

Experiments were carried out on rats adapted to physical exercise (on the next day after completion of 4, 11, 15, and 30 swimming sessions). Catalase and superoxide dismutase activities were similar in all rats. The resistance of Ca transport into sarcoplasmic reticulum to high Ca²⁺ concentrations and autooxidaton increased starting from 4 swimming sessions, and to thermal inactivation from 11 sessions; the maximum resistance was attained after 15 sessions 1.5- to 2-fold surpassing the initial level. Maximum initial rate of Ca²⁺-transport (155% of the control) was observed after 30 swimming sessions. In acute physical strength and at the initial stages of adaptation (4 swimming sessions) functional properties of myocardial Ca-transporting system were preserved under optimal conditions, but can be readily disturbed by adverse factors. Translatedfrom Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 1, pp. 40–44, January, 1998 Original     

Opposite effect of adaptation to physical exercise on myocardium and skeletal muscle. Ca-transporting system of the sarcoplasmic reticulum and antioxidant defense enzymes

Adaptation to physical exercise was achieved via 60-min sessions of swimming at 32°C for 45 days, the duration of swimming being increased from 15 to 60 min during the first 14 days. Under these conditions, against the background of reduced catalase and superoxide dismutase activity the Ca-transporting system of the sarcoplasmic reticulum in the heart is shown to work more effectively: Ca²⁺ transport is characterized by a higher initial rate and is inactivated 1.5 times more slowly byin vitro-induced lipid peroxidation and not inhibited by high concentrations of free Ca²⁺. In the skeletal muscle, on the other hand, catalase and superoxide dismutase activity rise, but this does not improve the functioning of the Ca pump: the initial rate of Ca²⁺ transport drops, its resistance to autooxidation is not increased in comparison with the control, and the resistance of the Ca²⁺-transporting system to the inhibiting influence of free Ca²⁺ is lowered. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 6, pp. 623–628, June, 1996     

Ca-transporting system of the left ventricular sarcoplasmic reticulum in the rat heart and damage to its membrane during ischemia and reperfusion

Ischemia and reperfusion of various duration are shown to result in a nonlinear increase in the level of free Ca in myocardial homogenates. A striking dissociation has been observed in the effect of ischemia and reperfusion on the rate of Ca transport in the sarcoplasmic reticulum, on the one hand, and the permeability of its membranes on the other. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 2, pp. 130–135, February, 1994     

Correction of disturbances of cardiac electrical stability in postinfarction cardiosclerosis with a polyunsaturated fatty acid-enriched diet

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 115, N ^o 4, pp. 343–345, April, 1993     

Adaptation to periodic hypoxia and a diet supplemented with polyunsaturated class ω-3 fatty acids enhance the resistance of Ca2+ transport in the myocardial sarcoplasmic reticulum to free-radical oxidation

The relationship between the level of accumulation of lipid peroxidation products and the status of the Ca²⁺-transporting system in the sarcoplasmic reticulum of the rat myocardium is studied against the background of two cardioprotective factors, namely adaptation to periodic hypoxia and a diet enriched in polyunsaturated fatty acids of the ω-3 class. It is shown that the diet leads to an increase of level of lipid peroxidation products by 1.8 times in the heart and by 19 times in the liver, whereas a adaptation has no effect on the level of lipid peroxidation products in either of these organs. At the same time, the combined action of both factors considerably enhances the resistance of the myocardial Ca²⁺-transporting system to free radical-induced oxidation. Inin vitro experiments it is shown that adaptation to periodic hypoxia results in a more than twofold deceleration of Ca²⁺ transport inhibition during the oxidation induction by the Fe²⁺/ascorbate system; the diet causes a 3.5-fold deceleration of such inhibition. The results show that the accumulation of a high level of lipid peroxidation products is not always followed by damage to the Ca²⁺-transporting system in the myocardial sarcoplasmic reticulum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 7, pp. 42–45, July, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Adaptation to stress enhances the resistance of the calcium pump in rat myocardial sarcoplasmic reticulum

The development of adaptation during stress is studied. At the early stages, adaptation exerts no protective effect: the activities of superoxide dismutase and catalase and the resistance and the Ca-transporting system of the myocardial sarcoplasmic reticulum to heat inactivation and high calcium concentrations decline. At the end of adaptation, superoxide dismutase and catalase activities increase, the function of the sarcoplasmic reticulum Catransporting system is improved, and the resistance of this system to high Ca concentrations increases compared with that in the control (1.4-fold) and during the early stages of adaptation (1.6-fold). The resistance to heat inactivation increased 1.5-fold compared with the control. Three days after the completion of adaptation, the activities of these enzymes and the resistance of Ca transport to heat inactivation and high Ca concentrations are lower than immediately after adaptation, but higher than in the control group and during the early adaptation period. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 3, pp. 272–276, March, 1997     

Effect of amiodarone on functional state of sarcoplasmic reticulum in rat myocardium

Function of sarcoplasmic reticulum was studied in rat papillary muscles treated with amiodarone. An extra stimulus (0.5 Hz) was delivered to the muscle 0.225 sec after application of a regular stimulus. Postextrasystolic potentiation was evaluated in control myocardial samples and samples treated with amiodarone. The preparation significantly increased all the parameters of postextrasystolic contraction. It was concluded that amiodarone potentiates the ability of sarcoplasmic reticulum to accumulate Ca²⁺ ions.     

Ca2+ transport of the skeletal muscle sarcoplasmic reticulum during readaptation of rats after a 40-day load relief on the hind paws

The rate of Ca²⁺ accumulation in the sarcoplasmic reticulum of the skeletal muscle (m. gastrocnemius lateralis, m. vastus medialis, andm. soleus) is studied in rats under conditions of functional off-loading of the hind paws (suspending animals by the tail). The rate of Ca²⁺ transport in the sarcoplasmic reticulum is shown to be stepped up in all these muscles. In the sarcoplasmic reticulum ofm. gastrocnemius lateralis andm. vastus medialis the Ca²⁺ transport rate reliably drops, which does not occur inm. soleus. During a 2-week period of readaptation of animals suspended for 40 days, the Ca²⁺-transporting function of them. soleus sarcoplasmic reticulum gradually recovers to reach the control values, whereas the time course of recovery of Ca²⁺-pump activity in the sarcoplasmic reticulum ofm. gastrocnemius lateralis andm. vastus medialis has a phasic pattern. Translated fromByulleten' Eksperimental'noi Biologii i Meditsity, Vol. 118, N ^o 12, pp. 591–595, December, 1994 Presented by A. I. Grigor'ev, Member of the Russian Academy of Medical Sciences     

Ca2+ transport in the myocardial sarcoplasmic reticulum of rats during antiorthostatic off-loading and during readaptation

The rate of Ca²⁺ accumulation in the myocardial sarcoplasmic reticulum is studied in experiments on rats under conditions of hind paw functional off-loading by suspending animals by the tail for 1 to 40 days, as well as during a 2-week period of readaptation after a 40-day load relief. The rate of Ca²⁺ transport in the myocardial sarcoplasmic reticulum reliably drops (by 33%) after 40 days of suspension. At earlier stages of off-loading Ca-pump activity in the sarcoplasmic reticulum does not change reliably. After resumption of the loads in animals suspended for 40 days, the transporting function of the myocardial sarcoplasmic reticulum rapidly reverts to the control level, which is indicative of a reversible pattern of load relief-induced changes in the rate of Ca²⁺ transport. Translated fromByulleten' Eksperimental'noi Biologii i Meditsity, Vol. 118, N ^o 12, pp. 596–599, December, 1994 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Adaptation to physical exercise increases expression of Ca-ATPase gene in myocardial sarcoplasmic reticulum

Gene expression of the key enzyme of the myocardial sarcoplasmic reticulum Ca²⁺-pump, SERCA-2a isoform was assayed in rats during adaptation to physical exercise (forced swimming). The expression was measured by Northern blot hybridization with subsequent densitometry of the autoradiograms. The signal of mRNA encoding SERCA-2a was referenced to the mRNA signals of marker proteins (S4 and S9 ribosomal proteins, cytoskeletal β-actin and glyceraldehyde-3-phosphate dehydrogenase). The SERCA-2a gene expression gradually increased during adaptation as evidenced by the increased content of SERCA-2a mRNA in particular higher intensity (optical density) of the mRNA signals in autoradiograms. The adaptation-induced increase in the power of the sarcoplasmic reticulum Ca²⁺-pump can be attributed to activated synthesis and accumulation of SERCA-2a isoform. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 7, pp. 24–28, July, 1999     

Effect of endothelin-1 on DNA synthesis in the myocardium of albino rats during early postnatal ontogeny

Effect of intraperitoneal injection of endothelin-1 on DNA synthesis in the myocardium of newborn albino rats was studied by³H-thymidine autoradiography. Endothelin-1 injected in a single dose of 10 μg/kg stimulated proliferative processes: the index of labeled nuclei and labeling intensity increased. Repeated (5 times) administration of endothelin-1 in doses of 1 and 10 μg/kg increased labeling intensity, but did not change the index of labeled nuclei. The data suggest that endothelins, are involved in morphogenesis of the myocardium during the early postnatal ontogeny. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 12, pp. 623–626, December, 2000     

Effect of a micellar preparation of polyunsaturated phosphatidylcholine on platelet aggregationin vitro

Platelet aggregation was studied after incubation of cells with polyunsaturated phosphatidylcholine in platelet-rich plasma from healthy donors and coronary patients. The aggregation capacity of cells was found to be reduced after preincubation with the above drug. Statistical processing of the results using Student's and Van der Varden's tests showed more expressed effects of polyunsaturated phosphatidylcholine on cell aggregation in coronary patients than in donors. Translated fromByulleten's Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 199–203, February, 1996 Presented by Yu. M. Lopukhin, Member of the Russian Academy of Medical Sciences     

Effect of atriopeptides on proliferative processes in albino rat myocardium at the early stage of postnatal ontogenesis

The effect of atriopeptide AP-II and its 6-amino-acid acyclic fragment (7–12) AP-H-6-OH on proliferative processes in the myocardium of 5-day-old albino rats is examined 24 h after a single administration (200 nmol/kg intraperitoneally) by autoradiography with³H-thymidine and by analysis of mitotic regime. A significant decrease in the amount of DNA-synthesizing cells in the right atrium, right ventricle, and interventricular septum is recorded after administration of AP-II. Changes in DNA synthesis are attended by significant changes in the amount of cells in different phases of mitosis, indicating a decrease in the number of mitotic cells and a metaphasal delay. Administration of AP-H-6-OH causes no significant changes in DNA synthesis in the myocardium at the early stage of postnatal ontogenesis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 9, pp. 321–324, September, 1996     

Effects of supplementing the rat diet with selenium on the efficiency of essential linoleic acid metabolism

Examination of the fatty-acid composition of lipids contained in the liver, spleen, blood plasma, aggregated lymphatic follicles of the small intestine, and mesenteric lymph nodes of rats fed diets supplemented with selenium revealed an appreciable effect of this element on the efficiency with which linoleic acid was metabolized to arachidonic acid, which was reflected in an increased 20:4/18:2 ratio. In contrast, Se was found to have little or no effect on levels of lipid peroxidation products in tissues and blood serum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8, pp. 136–138, August, 1994     

Effect of hypogeomagnetic field on tissue and intracellular reorganization of mouse myocardium

Structural reorganization of the myocardium is observed in CBA mice under conditions of hypogeomagnetic field (reduction by 10⁵ times). Changes in tissue architectonics manifest themselves in a reduced capillary/cardiomyocyte volume ratio against the background of hemodynamic disturbances. Intracellular disturbances result from impaired regeneration processes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 10, pp. 455–459, October, 1997