Acta physiologica et pharmacologica Bulgarica最新文献

We intended to study the effect of swimming exercise on the brain, liver and heart malondialdehyde (MDA) levels which are the last product of oxidation, and to compare them with the brain, liver and heart MDA levels of controls. The experiments were carried out on 20 Wistar rats which were fed with a standard laboratory chow diet ad libitum. Rats were distributed in two groups, control group (n = 10) and exercise group (n = 10). The exercise group rats were exposed to swimming exercise for 30 minutes. After this animals in each group were sacrificed by decapitation, their brain, liver and heart tissues were quickly removed. MDA levels of the brain, liver and heart were determined according to the method in which MDA reacts with thiobarbituric acid. Results were evaluated by the Mann-Whitney U test. The liver and heart MDA levels in the exercise group were (29.59+/-6.73 and 10.49+/-1.90 nmol/g tissue, respectively) significantly higher than in the control group (21.78+/-3.46 and 8.86+/-1.25 nmol/g tissue, p<0.01 and p<0.05, respectively). However, the brain MDA levels were similar in both groups (exercise group 19.37+/-5.50 nmol/g tissue and control group 16.58+/-2.44 nmol/g tissue; p=0.325). It is concluded that swimming exercise might cause oxidative stress.

Oxygen uptake efficiency slope (OUES) is an index meant to provide an objective measure of cardiopulmonary function at submaximal exercise. The aim was to study the exercise performance and OUES in obese children performing standardized exercise. Sixty children aged 6-17 years performed incremental treadmill exercise test. They were divided into two groups matched by age, sex and height: thirty obese subjects (15 girls/15 boys; BMI = 27.4+/-1.7 m x kg(-2)) and 30 controls (BMI = 18.8+/-1.0 m x kg(-2)). Perceived exertion was assessed by means of CR-10 Borg scale. The duration of the exercise for the obese children was significantly shorter than for controls (p = 0.010) but obese children had greater absolute values for oxygen uptake (VO2 peak mL x min(-1) = 1907+/-249 vs. 1495+/-208; p = 0.013) which, adjusted for body mass, decreased significantly (VO2/kg mL x min(-1) x kg(-1) = 29.2+/-1.4 vs. 33.6+/-1.3; p < 0.001). OUES correlated strongly with VO2 peak (r = 0.91) and oxygen pulse (r = 0.80), as well as with anthropometric variables height (r = 0.88) and age (r = 0.83). Extremely high correlation was found between OUES calculated for 100% of exercise duration and OUES at the anaerobic threshold (r = 0.979; p < 0.001). No significant differences were found between the studied groups concerning the absolute values of OUES. Obese children rated perceived exertion significantly higher than controls (Borg score 6.2+/-0.4 vs. 5.2+/-0.4; p = 0.001). In conclusion, the absolute metabolic cost of exercise and perceived exertion were higher in the obesity group. OUES is an objective measure of cardiopulmonary reserve that doesn't require a maximal effort but it is considerably dependent on anthropometric variables which impedes its interpretation as exercise index in childhood.

An inverse relationship between HDL-c plasmatic levels and Li+ flux (Na+-Li+ exchange mediated) has been reported in normotensive individuals with hypertensive ancestors as well as in essential hypertensive subjects. This lipoprotein reaction with plasmatic membrane components induces modifications in membrane transport mechanisms as well as in cellular enzymes. In this paper we present data on Li+ flux (Na+-Li+ exchange mediated) in red blood cells from normotensive individuals without hypertensive ancestors. Kinetic analysis of Li+ efflux as a function of Na+(extracell) concentration was carried out. Vmax and Km values were determined. HDL-c plasmatic levels were also determined. Vmax showed a significant inverse correlation with HDL-c levels. No significant correlation of Km values with HDL-c levels was observed. The data presented support previous data showing that variable Vmax is sensitive to cellular environmental factors. Otherwise the Km variable not influenced by these factors is sensitive to hereditary influences.

The aim of the present work was to study the antioxidant activity of the new derivative of succinic acid-succinate mono[(2-dimethyl-amino) ethyl ether] of succinic acid (yackton) under conditions of hypoxic and hemic hypoxia as well as to examine in vitro the antiradical activity of this preparation. Hypoxia in the rats was modelled by: (i) allowing the rats to breath a gas mixture with 7% O2 and 93% N2 for 30 minutes (hypoxic hypoxia), and (ii) injecting the rats sodium nitrite subcutaneously in a dose of 60 mg/kg body weight (hemic hypoxia). Yackton was injected intraperitoneally to both groups 30 minutes before the extreme influence in a dose of 140 mg/kg body weight. Then in homogenates and in post-mitochondrial fractions of liver, heart, lungs, brain we studied the content of secondary products of lipid peroxidation (LPO), activity of antioxidant enzymes superoxide dismutase (SOD) and catalase, and the activity of enzymes responsible for the maintenance of reduced glutathione (GSH) glutathione reductase (GR-ase) and glutathione peroxidase (GP-ase). In vitro studies were made on the antiradical activity of yackton in reaction with the stable radical diphenylpicrylhydrazine (DPPH) as well as on the reaction velocity of the preparation with DPPH, and its period of semi-transformation in a non-radical form. It was shown that yackton treatment before hypoxic and hemic hypoxia decreased lipid peroxidation (LPO) level and increased SOD activity. After the yackton injection the state of glutathione system was normalized in comparison with its state at hypoxic and hemic hypoxia. Yackton had no antiradical properties in vitro. We concluded that yackton promotes optimization of prooxidant-antioxidant homeostasis of the organism under the hemic and hypoxic hypoxia acting as antioxidant of a non-direct action.

Natural sulfated polysaccharides (SPs) derived from brown seaweed comprise a complex group of macromolecules with a wide range of important physiological properties. SPs have been shown to bind and directly regulate the bioactivity of growth factors and cytokines such as basic fibroblast growth factor, interferon, various enzymes and transforming growth factor. Myostatin is a member of the transforming growth factor-beta (TGF-beta) family that acts as a negative regulator of skeletal muscle mass. In this work we demonstrated that SPs isolated from the brown seaweed Cystoseira canariensis bind to the myostatin protein in serum.

This paper deals with the effects of high (microwave) and extremely high (millimetre waves, MMW) frequency electromagnetic fields on the membrane processes and ion channels, molecular complexes, excitable and other structures. Microwaves as well as millimetre waves are widely used in medical practice and in everyday life. The existence of interaction between the exogenous and endogenous electromagnetic fields with biological systems is now a subject of intense discussion. The most contentious question is the existence of a possible specific (non-thermal) effect of microwaves, unrelated to that caused by increased temperature. Although numerous data have been published on the possible non-thermal effects of the studied electromagnetic fields on different kinds of living systems, only little understanding is gained about the modes of microwave action. Here we review data, which provide evidence that non-thermal microwave effects do exist and may play a significant role. This evidence is based on research at all biological levels, from cell-free systems through cells, tissues and organs, to animal and human organisms.

Angiotensin II (ANG II) significantly increased noradrenaline (NA) uptake by cortical, hypothalamic and hippocampal synaptosomes thus activating noradrenergic neurotransmission. ANG II did not affect NA uptake by striatal synaptosomes. The interaction between AT1 receptors and noradrenergic neurons and the involvement of brain noradrenergic neurotransmitter system in ANG II-induced drinking in rats is suggested by the increase of NA uptake in hypothalamus and frontal cortex which are rich in AT1 receptors and are of importance for drinking behavior. The ANG II-receptor antagonists losartan, EXP 3174, sarmesin and saralasin decreased NA uptake in all brain regions studied as compared to the uptake in the same brain regions of ANG II-injected animals thus antagonising the effect of ANG II. There is no relationship between the inhibition of ANG II-induced water intake and the changes of NA uptake under the effect of the ANG II-receptor antagonists.

The OLETF rat develops microangiopathic complications similar to human diabetes and is considered a useful model of Type 2 DM. Erythrocyte, platelet and leucocyte abnormalities described in diabetic patients are thought to play a role in the development of diabetic microangiopathy. This study was designed to investigate whether OLETF rats show hematological alterations and the effect of sucrose treatment on metabolic and blood parameters. Hematological parameters, body weight, food and water intake, fasting and non-fasting blood glucose (BG) and HbA1c were measured in OLETF rats treated for two months with 30% sucrose added to drinking water. Non-treated OLETF rats and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats were used as controls. In the control OLETF rats the number of platelets (Plt) and red blood cells (RBC) was higher, while the mean cell volume (MCV) and the mean cell hemoglobin content (MCH) were lower compared with LETO. Mean cell hemoglobin concentration (MCHC) was significantly higher in the diabetic rats. Sucrose administration decreased food intake and body weight and increased fasting blood glucose and HbA1c. It resulted in a decrease of RBC, Hb, Hct, MCV and MCH compared with control OLETF, while Plt count increased significantly. Our results point to significant alterations in erythrocyte count and morphology and Plt count in diabetic OLETF rats compared with non-diabetic LETO. Sucrose administration accelerated the development of diabetes, affected blood cells inducing the suppression of RBC and an increase in Plt count and some of its effects persisted after sucrose withdrawal.

Cholecystokinin (CCK) is a classical brain-gut peptide that exerts a variety of physiological actions in the gastrointestinal tract and central nervous system. CCK occurs in several molecular forms of varying aminoacid length, the sulphated octapeptide (CCK-8) being the predominant form in the brain. CCK mediates its effects through interaction with specific receptors subdivided in two subtypes--CCK-A (present in the periphery and in few selected brain nuclei) and CCK-B (the predominant receptor subtype in the brain). CCK is implicated in variety of behavioral functions as satiety, anxiety, exploratory and locomotor activity and learning and memory. After a brief description of the distribution, molecular forms, release, inactivation, etc. of CCK in the brain, the present review summarizes the recent data on the role of CCK in learning and memory. The memory-enhancing effects of CCK have been demonstrated in various types of memory. Data showing that CCK-A receptors mediate mnemonic while CCK-B receptors mediate amnestic effects are also presented.