Effect of motor activity of different intensity upon the blood composition and respiratory function in domestic animals during their first months of life

Responses of the blood content, breathing function and gaseous metabolism to changes of motional activity level in calves in the first 30 days of a postnatal period were investigated. Keeping of calves in conditions natural for mature animals at different motor activity levels as compared with the locomotion limitation leads to a lesser reduction of hemoglobin content, haematocrit ratio, red cells and reticulocytes count in blood of calves during first 30 days of life. In comparison with calves with additional motor activity, 10-day old calves with natural motor activity and locomotion limitation showed an increase of the protein level and reduction of glucose and cholesterol in the blood. Locomotion limitation of calves during the first 30 days of postnatal period caused reduction of the blood oxygen carrying capacity (erythrocytes and reticulocytes count) with simultaneous decrease of breathing function and gaseous metabolism efficiency (breathing output, minute ventilation, carbon dioxide output and oxygen uptake).     

Changes in the neuroendocrine regulation of adaptive behavior in rats subjected to stress in the late prenatal ontogenesis]

Female rats were subjected from the 14th to 17th day of pregnancy to immobilisation under conditions of 1-hour daily bright illumination. On the 20th day, contents of testosterone and estradiol was decreased with no sex difference in their level in the pregnant female rats' blood and in the amniotic fluid. Sex differences were flattened in 1-month litter both in the androgen and oestrogen contents and in adaptive behaviour. In prenatally stressed males, motor activity was inhibited and anxiety was enhanced as compared with the control. At one and a half months of age, the consequences of the prenatal stress disappeared and then reappeared after sexual maturation but with an opposite trend. Adaptive behaviour of adult males was less flexible and revealed no age-dependent oscillations inherent in the control animals. Prenatal stress while preventing the maximal raise of sex steroids in the blood shifts sex differentiation of the adaptive behaviour toward demasculinization.     

The effect of infrared and X-ray radiation on the production of reactive oxygen species in blood and induction of cytogenetic damage in the bone marrow of mice in vivo

The goal of the present work was to study the effect of infrared light (IRL) at a wavelength of 850 nm modulated by a frequency of 101 Hz with a mode of power 22 mW/cm2 and X-rays with a voltage of 200 kV at a dose rate of 1 Gy/min on the production of reactive oxygen species (ROS) in blood cells using luminol-dependent chemiluminescence, as well as on the induction of a cytogenetic damage in bone marrow cells of mice by the in vivo micronucleus test. The experiments performed have shown: 1) the level of the ROS production in blood of the mice exposed to IRL and X-rays at an adapting dose of 0.1 Gy reaches the peak value after 0.5 h and drops to the ROS level in untreated animals 5 h after either exposure; 2) irradiation of mice with IRL and X-rays at a dose of 0.1 Gy induces adaptive responses both in blood cells and bone marrow cells of mice. These adaptive responses were revealed only 5 h after both exposures, when the level of ROS production decreased to the ROS level in untreated animals; they are equal in magnitude and dynamics and persist up to 2 months.     

Conditioned reactions to time of hypothalamic neurons. The perifornical nucleus]

In 40% of the 52 neurones of the hypothalamic perifornical nucleus in alert rabbits conditioned trace reactions of the activational (52%) and inhibitory (48%) type were recorded in the course of elaboration of a conditioned motor reflex to time. The sign and pattern of the trace responses were determined by the nature of cell reactions to actual paired stimuli. After 50 to 70 pairings, the unit trace conditioned reaction to time persisted for a period of 10 to 15 successive omissions. Trace responses were observed most frequently in the 5th of 8th omissions. In some cases conditioned enhancement of cell activity coincided with the conditioned motor response to time. This fact together with the maximal development of a summery trace cellular response at the moment of formation of conditioned motor reactions attests the participation of neurones of the perifornical nucleus in maintaining conditioned motor activity.     

Comparison of the blood redox status between long-distance and short-distance runners

Exercise increases the production of reactive oxygen species, which may damage a number of cell constituents. Organisms have developed a sophisticated antioxidant system for protection against reactive oxygen species. Our aim was to compare the adaptive responses of antioxidant mechanisms and the blood redox status of two groups of athletes, long-distance and short-distance runners. Thiobarbituric acid reactive substances, catalase activity and total antioxidant capacity was measured in the serum, while reduced and oxidized glutathione as well as their ratio were determined in blood hemolysates. Serum catalase activity (P<0.001) was found to be three times higher in long-distance compared to short-distance runners (25.4 vs. 8.9 micromol x min(-3) x ml(-1)), whereas the two groups did not differ in the other markers. Catalase activity also correlated significantly with maximal oxygen consumption in long-distance runners. In conclusion, we report here that long-distance and short-distance runners exhibit similar blood redox status judged by several oxidative stress indices, except for the much higher activity of catalase in long-distance runners. This different effect of the two training modules on catalase activity of long-distance runners might be partly due to the high oxygen load imposed during their repeated prolonged exercise bouts.     

The kinetics of steroidogenesis activator polypeptide in the rat adrenal cortex. Effects of adrenocorticotropin, cyclic adenosine 3':5'-monophosphate, cycloheximide, and circadian rhythm

The behavior of steroidogenesis activator polypeptide (SAP), a recently described modulator of cholesterol side-chain cleavage activity (Pedersen, R. C., and Brownie, A. C. (1987) Science 236, 188-190), was investigated in rat adrenocortical cells using a specific radioimmunoassay. In response to a maximal dose of adrenocorticotropic hormone (ACTH) (1 nM) or of 8-Br-cAMP (1 mM), an increase in intracellular SAP begins rapidly (less than 1 min) and reaches half-maximal and maximal levels (16-fold greater than basal) at 3 and 15 min, respectively. A plateau at this maximal concentration of SAP is then maintained. The levels of intracellular SAP content and of corticosterone output exhibit a similar dose-dependent response to ACTH (EC50 = 25 and 30 pM, respectively). Treatment of ACTH-stimulated cells with cycloheximide reverses the rise in SAP (t1/2 congruent to 5-7 min). In vivo the SAP content of adrenals from quiescent rats is concordant with the circadian rhythm of the pituitary-adrenal axis; at the apex (1800 h), adrenal SAP is 13-fold higher than at the nadir (0800 h), paralleling 2- and 7-fold variations in cholesterol side-chain cleavage activity and serum corticosterone levels, respectively. At both time points, SAP levels rise in response to stress. Of the rat tissues examined, only the major steroid-forming organs (adrenal cortex and gonads) had significant levels of immunoreactive, cAMP-responsive SAP, while cAMP-unresponsive immunoreactivity was also detectable in the thymus, spleen, and brain. Considered together with the biological activity previously demonstrated for SAP in vitro, these data are consistent with its role as a cAMP-dependent, cycloheximide-sensitive modulator of steroid biosynthesis.     

Interrelationship of the cardiovascular and digestive systems in the genesis of experimental atherosclerosis]

In chronic experiments (up to 2 years) on dogs on atherogenic diets the motor activity of the gastrointestinal tract, cholesterol, the phospholipid level in the blood and in the intestinal secretion as well as the morphology of the small intestine and the vascular system were examined. At the early stages of atherosclerosis (up to 4 months) the rise of the blood cholesterol level was followed by an increase in the periods of the activity of the gastrointestinal tract, a rise of cholesterol discharge by the small intestine, and the development of the hypertrophic process in the mucous membrane. At the later stages a change in the mucous membrane of the small intestine was observed with development of a dystrophic-atrophic process, a disturbance of motor activity of the gastrointestinal tract and of the correlations between the cholesterol content in the blood and its discharge by the small intestine. This period was characterized by a high and persistent hypercholesterolemia and pronounced atherosclerotic changes in the vascular system.     

Changes in motor unit discharge rate are not associated with the amount of twitch potentiation in old men.

This study examined, in nine old men (82 +/- 4 yr), whether there is an association between the magnitude of change in motor unit discharge rate and the amount of twitch potentiation after a conditioning contraction (CC). The evoked twitch force and motor unit discharge rate during isometric ramp-and-hold contractions (10-18 s) of the triceps brachii muscle at 10, 20, and 30% of the maximal voluntary contraction were determined before and 10 s, 2 min, 6 min, and 11 min after a 5-s CC at 75% maximal voluntary contraction. After the CC, there was a potentiation of twitch force (approximately twofold), and the discharge rate of the 47 sampled motor units declined (P < 0.05) an average of 1 Hz 10 s after the CC, compared with the control condition. The CC had no effect on the variability (coefficient of variation) of both force and discharge rate, as well as the electromyographic activity recorded over the triceps brachii and biceps brachii muscles. In contrast to our earlier study of young men (Klein CS, Ivanova TD, Rice CL, and Garland SJ, Neurosci Lett 316: 153-156, 2001), the magnitude of the reduction in discharge rate after the CC was not associated (r = 0.06) with the amount of twitch potentiation. These findings suggest an age-related alteration in the neural strategy for adjusting motor output to a muscle after a CC.     

Immunohistochemical expression of FGF-2, PDGF-A, VEGF and TGF beta RII in the pancreas in the course of ischemia/reperfusion-induced acute pancreatitis.

Acute pancreatitis leads to pancreatic damage followed by subsequent regeneration. The aim of our study was to evaluate the presence of growth factors in the course of spontaneous pancreatic regeneration after ischemia/reperfusion (I/R)-induced pancreatitis. METHODS: In rats, I/R was evoked by clamping of splenic artery for 30 min followed by reperfusion. Rats were sacrificed 1, 5, 12 h or 1, 2, 3, 5, 7, 9 or 21 days after removal of vascular clips. Pancreatic blood flow (PBF), plasma lipase, interleukin-1beta (IL-1beta), interleukin-10, pancreatic cells proliferation and morphological signs of pancreatitis were determined. Pancreatic presence of fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor (VEGF), platelet-derived growth factor-A (PDGF-A) and transforming growth factor-beta type II receptor (TGFbeta RII) was detected by immunohistochemisty. RESULTS: Exposure to I/R led to the development of acute necrotizing pancreatitis followed by regeneration. Morphological features showed maximal pancreatic damage between the 1(st) and 2(nd) day of reperfusion. It was correlated with a maximal increase in plasma lipase, and pro-inflammatory IL-1beta concentration, as well as, a reduction in PBF and pancreatic DNA synthesis. I/R increased FGF-2 content in pancreatic acinar cells between the 12(th) and 24(th) h, and between 5(th) and 9(th) day of reperfusion. At the 2(nd) day the presence of FGF-2 in pancreatic acinar cells was reduced. After I/R PDGF-A appeared in pancreatic vessels from the 12(th) h to 5 (th) day of reperfusion. PDGF-A was not observed in pancreatic acinar cells in the control or in I/R group. In pancreatic ducts, the presence of PDGF-A was reduced between the 1(st) and 3(rd), and between 7(th) and 9(th) day of reperfusion. In acinar cells, VEGF content was increased after I/R at the time between the 1(st) and 24(th) h, and between 3(rd) and 7(th) day of reperfusion. At the 2(nd) day of reperfusion, VEGF was not detected in the pancreatic acinar cells. Moreover, VEGF was found in the inflammatory infiltration, in the tubular complexes between the 2(nd) and 5(th) day, and in granulation tissue at the 9(th) day of reperfusion. In pancreatic acinar cells, I/R caused an increase in TGFbeta RII presence between the 5(th) and 24(th) h, and between 7(th) and 9(th) day of reperfusion. Between the 2(nd) and 5(th) day of reperfusion the acinar presence of TGFbeta RII was reduced. In the pancreatic ducts, the presence of TGFbeta RII was increased after I/R from the 1(st) h to 9(th) day of observation. Four weeks after induction of acute pancreatitis, the pancreatic regeneration was completed and the presence of growth factors tested returned to control value. CONCLUSIONS: The presence of FGF, VEGF, PDGF-A and TGFbeta RII is modified in the course of I/R-induced acute pancreatitis. Maximal content of FGF, VEGF and TGFbeta RII has been observed in early stage of pancreatic regeneration suggesting the involvement these factors in pancreatic recovery.     

A mutation in NLA, which encodes a RING-type ubiquitin ligase, disrupts the adaptability of Arabidopsis to nitrogen limitation

Abundant nitrogen is required for the optimal growth and development of plants, while numerous biotic and abiotic factors that consume soil nitrogen frequently create a nitrogen limitation growth condition. To cope with this, plants have evolved a suite of adaptive responses to nitrogen limitation. However, the molecular mechanism governing the adaptability of plants to nitrogen limitation is totally unknown because no reported mutant defines this trait. Here we isolated an Arabidopsis mutant, nla (nitrogen limitation adaptation), and identified the NLA gene as an essential component in this molecular mechanism. Supplied with insufficient inorganic nitrogen (nitrate or ammonium), the nla mutant failed to develop the essential adaptive responses to nitrogen limitation, but senesced much earlier and more rapidly than did the wild type. Under other stress conditions including low phosphorus nutrient, drought and high temperature, the nla mutant did not show this early senescence phenotype, but closely resembled the wild type in growth and development. Map-based cloning of NLA revealed that this gene encodes a RING-type ubiquitin ligase, and nla is a deletion mutation which does not code for the RING domain in the NLA protein. The NLA protein is localized to the nuclear speckles, where this protein interacts with the Arabidopsis ubiquitin conjugase 8 (AtUBC8). In the nla mutant, the deletion of the RING domain from NLA altered its subcellular localization, disrupted the interaction between NLA and AtUBC8 and caused the early senescence phenotype induced by low inorganic nitrogen. All the results indicate that NLA is a positive regulator for the development of the adaptability of Arabidopsis to nitrogen limitation.     

Cardiovascular responses to repeated exposures to intermittent noise. Tentative validation of the law of initial value

Eighteen female undergraduate subjects were submitted three times to an intermittent 55 min. pink-noise made of 6 x 5 min. periods at 103 dB (A), alternating with 5 x 5 min periods at 40 dB (A). Arterial blood-pressure was measured by the auscultatory method during the last minute before each noise-step (initial value) and during the first minute following it. Concomitant values of heart-rate (continuously recorded) were also taken into account in the same way. Arterial blood pressure as well as heart-rate homeostatic response to both types of noise-steps obey the Law of initial value, respectively in 38 p. 100 and 33 p. 100 of the cases, but the Law fails to reveal adaptive changes in responses from the first to the third exposure to acoustical stress.     

Gender differences in changes of motor cortex excitability during elevated blood lactate levels

Gender differences in cortical excitability have been detected by using transcranial magnetic stimulation (TMS). The present study was carried out to compare the effects of high blood lactate levels, induced by performing a maximal exhausting exercise, on the excitability of the primary motor cortex in young male and female athletes. The study was carried out on 21 young males and 20 females from the Middle Distance Track Team of our university. Before the exercise, at the end, as well as 5 and 10 min after the conclusion, venous blood lactate and glucose were measured and excitability of the motor cortex was evaluated by using TMS. We observed a similar enhancement of excitability of primary motor cortex, concomitantly with an increase of blood lactate, in both young male and female athletes. However, the improvement was significantly higher (p < 0.05) in women (37.4% ± 3.97) than in men (42.0% ± 6.43), suggesting a greater sensitiveness of female cerebral cortex to blood lactate.     

A nucleoside triphosphate-dependent deoxyribonucleic acid-breakdown system in Mycobacterium smegmatis, and the effect of iron limitation on the activity of this system

1. The presence of a nucleoside triphosphate-dependent DNA-breakdown system was demonstrated in extracts of Mycobacterium smegmatis. Its activity was increased substantially by iron limitation, apparently after the fall in DNA content that took place under these conditions. A maximal activity of about 0.2mumole of deoxyribonucleotide/30min./mg. of protein was found in crude extracts. 2. After slight purification by streptomycin treatment, the enzyme showed maximal activity with undenatured DNA (K(m) approximately 200mug./ml.), ATP (K(m) approximately 1.2mm) or UTP, CTP and GTP giving lower activity and pyrophosphate giving none, and Mg(2+) ions (optimum concn. 12mm). The optimum pH was 8.5. 3. In the assay system there was proportionality between enzyme concentration and rate of reaction, but the rate fell off with time. 4. ATP was broken down in the reaction and monodeoxy-ribonucleotides were among the products, but the presence of some oligodeoxy-ribonucleotides was not excluded and the degree of phosphorylation of the primary products was uncertain.     

Changes in the content and concentration of cytoplasmic and nuclear proteins in nerve and glial cells of hypothalamic nuclei at different times of water deprivation

The data obtained show that searching activity of animals increases at an early stage (24 hrs) of water deprivation (WD) and is accompanied by an increase in the content of cytoplasmic proteins. WD up to 3 days produces further rise of motor searching activity with simultaneous increase of protein content not in the cytoplasm alone but in the nuclei of neurons and glial cells as well. During long-term periods of WD (5 days), motor activity considerably decreases, the animals showing signs of depression. The content and concentration of proteins significantly decrease in all studied components of neurons and glia of the hypothalamic nuclei under study. Existence of correlation between protein content (cytoplasmic and nuclear) and behavior of animals is discussed.     

Glucose infused through the portal vein enhances liver gluconeogenesis and glycogenesis from [3-14C]pyruvate in the starved rat

After a pulse of [3-14C]pyruvate, 24 hr starved rats were infused through the portal vein with two different doses of glucose (7.8 or 20.8 mg/min) or the medium, and blood was collected from the inferior cava vein at the level of the suprahepatic veins. The highest dose of glucose enhanced the appearance of [14C]glucose in blood from the 2nd to the 20th min after tracer delivery. It also enhanced production of [14C]glycogen and concentration of glycogen in the liver after 5 and 20 min. At 20 min of glucose infusion the appearance of [14C]glyceride glycerol in liver as well as liver lactate concentration and lactate/pyruvate ratio were increased. The low dose of glucose used enhanced liver values of [14C]glycogen, [14C]glycogen specific activity and glycogen concentration. Our results support the hypothesis that in the starved rat glucose is converted into C3 units prior to being deposited as liver glycogen and based on the liver zonation model (Jungermann et al., 1983) it is proposed that glucose stimulated gluconeogenesis by shifting the liver to the cytosolic redox state as a secondary consequence of increased glycolytic activity.     

Aggressive behavior, its adaptive function and mechanisms of development of psychosomatic disorders and diseases of adaptation

A correlation between physiologic and behavioral responses to emotional stress and agonistic conflict (triad model), as well as ideas of autonomic-humoral support of subsequent activity suggest that motor activity and situational aggressive behavior are essential final stages of stress reaction and, therefore, mechanisms of adaptation. Failure in final the stage of adaptive response causes mobilization changes to be directed against the host organism itself. This phenomenon forms the basis for psychosomatic disorders. Aggression seems to be an adaptive response not only from ethologic, but from physiologic point of view as well. It has some elements of homeostatic control (together with non-homeostatic functions). Homeostatic role of aggression may be in "elimination" of mobilization metabolic changes caused by stress reaction and physical activity by means of expressive emotional response. Aggression as a non-homeostatic factor has an ethologic function.     

Early postnatal chronic intermittent hypoxia modifies hypoxic respiratory responses and long-term phrenic facilitation in adult rats

Acute isocapnic intermittent hypoxia elicits time-dependent, serotonin-dependent enhancement of phrenic motor output in anesthetized rats (phrenic long-term facilitation, pLTF). In adult rats, pLTF is enhanced by chronic intermittent hypoxia (CIH). To test the hypothesis that early postnatal CIH induces persistent modifications of ventilation and pLTF, we exposed male Sprague-Dawley rat pups on their first day of life to a CIH profile consisting of alternating room air and 10% oxygen every 90 s for 30 days during daylight hours (RAIH) or to comparable exposures consisting of room air throughout (RARA). One month after cessation of CIH, respiratory responses were recorded using whole body plethysmography, and integrated phrenic nerve activity was recorded in urethane-anesthetized, vagotomized, paralyzed, and ventilated rats at baseline and after exposures to three 5-min hypoxic episodes [inspired O2 fraction (FiO2)=0.11] separated by 5 min of hyperoxia (FiO2=0.5). RAIH rats displayed greater normoxic ventilation and also increased burst frequency compared with RARA rats (P<0.01). Ventilatory responses to hypoxia and short-term phrenic responses during acute hypoxic challenges were reduced in RAIH rats (P<0.01). Although pLTF was present in both RAIH and RARA rats, it was diminished in RAIH rats (minute activity: 74+/-2% in RARA vs. 55+/-5% in RAIH at 60 min; P<0.01). Thus we conclude that early postnatal CIH modifies normoxic and hypoxic ventilatory and phrenic responses that persist at 1 mo after cessation of CIH (i.e., metaplasticity) and markedly differ from previously reported increased neural plasticity changes induced by CIH in adult rats.     

Effect of gangliosides on adenylyl cyclase activity in the cortex and striatum of rats

By studying the effects of gangliosides (G) on learning and memory we have found that i.p. administration of G led to a decrease in AC activity in the cortex (Cx) and striatum (Str) as well as in the threshold of the sensitivity of striatal neurons to the effect of cholinergic agonists. G also modified the sensitivity of AC from the Cx and Str to such agents as Gpp[NH]p and forskolin. The aim of this work was to analyze the correlation between the changes in the activity of AC in the Cx and Str, concentration of G in these brain structures as well as formation of motor reactions of newborn rats during the first month of postnatal ontogenesis. It was found that new born rats develop normal body rotation by sixth day, locomotion by fifteenth day and stabilization of locomotor activity and supporting body balance by 20–22nd day. As shown previously, the concentration of gangliosides in the Cx and Str is gradually increasing during the first month of animal development. The activity of AC (pmol cAMP/min/mg of protein) in the Cx was found to decrease from 34.75 to 4.09 and in the Str from 46.00 to 11.67 during the first week after birth. However in the periods of formation of general behavioural reactions we observed a statistically significant increase in AC activity: in the Str on 10th and 26th days (p < 0.01) and in the Cx from 10th to 19th days (p < 0.05) compared to the AC activity on 5th and 30th days. Thus, formation of locomotor activity and posture‐tonic reactions during development of rats in early postnatal ontogenesis correlates with increasing concentration of G and basal activity of AC. Supported by RFBR (99‐04‐49751) and RAS (99‐06‐287).     

Exercise responses in pregnant sheep: oxygen consumption, uterine blood flow, and blood volume

In an attempt to explore the acute maternal responses to exercise we measured oxygen consumption, uterine blood flow, and blood volume in 13 chronically catheterized pregnant sheep at rest and while exercising on a treadmill. With maximal exercise O2 consumption increased 5.6 times, from a resting value of 5.8 +/- 0.3 (SE) to 32.1 +/- 2.8 ml X min -1 X kg -1, cardiac output increased 2.7 times, from 149 +/- 8 to 404 +/- 32 ml X min -1 X kg -1, and arteriovenous oxygen content difference increased 2.1 times, from 3.9 +/- 0.2 to 8.0 +/- 0.4 ml X dl -1. Total uterine blood flow decreased from a mean resting value of 292 +/- 6 to 222 +/- 19 ml X min -1 X kg fetus -1 near exhaustion during prolonged (40 min) exercise at 70% maximal oxygen consumption. Maternal blood volume decreased 14% (P less than 0.01) from 67.5 +/- 3.7 to 57.8 +/- 3.6 ml X kg -1 during this exercise period, with a 20% decrease in plasma volume without a change in red cell volume. We conclude that uterine blood flow decreases during maternal exercise. However, hemoconcentration helps to maintain a relatively constant oxygen delivery to the uterus.