The factor structure of the functional state of boys aged 13–14 years

We determined the independent factors that reflect the fundamental characteristics of the functional state (FS) in adolescents aged 13–14 years (n = 162): the sympathetic regulation and parasympathetic regulation of FS, physical working capability; the efficiency of cognitive performance; the hemodynamic basis of cognitive activity; nonspecific resistance to upper respiratory tract infections. Using the systematic approach, we investigated the physiological basis of these factors and determined the indices suitable for estimating the FS of adolescents at different stages of puberty. We observed progressive dynamics of FS parameters related to factors listed above in boys of the same chronological age at different puberty stages. Beginning from stage II to stage IV, we observed a heterochronic and nonlinear decrease in the tension of system of autonomic FS regulation, an increase in the efficiency of cognitive activity and its hemodynamic supply, as well as an improvement of anaerobic working capability.     

Psychophysiological indices in six-to eight-year-old children under information load depending on anxiety as a stable individual characteristic

The study of psychophysiological indices in children aged six to eight years under information loads of various complexity showed that anxious subjects were characterized by a high level of nonspecific activation at rest and a shift of the autonomic balance towards a relative domination of the tone of the sympathetic division of the autonomic nervous system (ANS). The information load in the “auto-rate” mode caused in children aged six to eight years an increase in the level of nonspecific activation and the activity of sympathetic regulation and an inhibition of parasympathetic regulation. An information load in the “maximum rate of work” mode caused a decrease in the quantitative and qualitative indices of mental activity in comparison with that under comfortable conditions and a subsequent increase in autonomic shifts and the level of situational anxiety. The decrease in the efficiency of intellectual work performed at a maximum rate against the background of a high level of nonspecific activation and an increase in situational anxiety in both groups apparently reflected an increase in the activity of the modulating cerebral system due to the domination of the nonproductive activation system related to defensive behavior. At the same time, in children with a high personal anxiety, autonomic manifestations of activation and situational anxiety in both modes of work were more distinct and the efficiency of work lower than in subjects with a low anxiety. This indicates that, in anxious children, due to the excess activation of the sympathetic division of the ANS, the information load has a higher physiological cost. Thus, children with a high level of personal anxiety under intense information loads are characterized by a larger increase in the activity of the sympathetic division of the ANS and the attenuation of the effect of the parasympathetic division; a considerable increase in situational anxiety; low efficiency of activity; and, hence, its high physiological cost.     

The morphological features and functional state of the adolescent organism under conditions of adaptation to the north

Features of physical development and constitution, functional parameters of the cardiorespiratory system (PWC₁₇₀ and maximal oxygen consumption), and sympathetic and parasympathetic influences on the regulation of blood circulation were studied in 12–16-year-old children of newcomers under conditions of adaptation to the Tyumen North. The percentage of adolescents with an excessive or a deficient body weight, growth lag, and delayed puberty was increased. The girls had a decreased efficiency. Age- and sex-related differences of the morphological and physiological parameters of subjects under study were found.     

Changes in inflammatory activity,heart rate variability,and biochemical indices in young athletes during the annual training cycle

Inflammatory activity, heart rate variability (HRV), and biochemical and functional indices were assessed in young ski racers during the preparation, competition, and recovery periods of an annual training cycle. During the preparation period, autohemodilution (decreased red blood cell count (RBC) and hematocrit (Ht) levels) and a decrease in the systemic inflammatory activity (C-reactive protein) occurred, without significant differences in the HRV or serum protein and lipid profile. During the competition period, the systemic inflammatory activity increased by 50% (p = 0.047), eliminating differences from the control group, and the HRV indices (SDNN, HF, TP, and IT) decreased (p ≤ 0.013), indicating an increase in the sympathetic effects on the HRV. During the recovery period, hematological indices (Ht and RBC), inflammatory activity, and fibrinogen levels decreased, and the parasympathetic effects on the heart increased. These findings allowed us to conclude that mental and physical activation led to a moderate increase in the systemic inflammatory activity and a shift in the sympathovagal balance towards increased sympathetic activity, providing a nonspecific contribution to the physiological regulation of biochemical (lipoproteins and immunoglobulins) and hematological indices in the athletes. However, similar changes in many biochemical and hematological indices in both groups during the year indicated the important role of a common, probably seasonal, factor in the regulation.     

Use of a Physiological Monitoring Model for Comprehensive Evaluation of Adaptive Capacities in Schoolchildren during Learning: I. Influence of Various Motor Activity Regimens on Cardiac Rhythm Indices in Junior Schoolchildren

The dynamics of changes in the indices of the autonomic regulation of cardiac rhythm was studied in junior schoolchildren during adaptation to physical exercise. An analysis of variation pulsometry parameters throughout the school year showed the role of the sympathetic and parasympathetic parts of the autonomic nervous system in the formation of body adaptive reactions to various motor activity regimens.     

Effectiveness of physical exercises for regulation of the functional state of six- to eight-year-old anxious children

The study aimed at optimizing the functional state (FS) of anxious six- to eight-year-old children showed that integrated use of physical exercises of a mainly aerobic character, relaxation training, respiratory exercises, and functional music is more effective in the long-term aspect than selective use of these means. Only physical exercises exert a marked influence in the FS of six- to eight-year-old anxious children under a stressful informational load. The use of other means of optimizing the FS appears to be less effective. The high effectiveness of physical exercises is determined by adaptive changes in the mechanisms of FS regulation in anxious children. Apparently, long-term adaptation to an adequate muscular activity ensures improved functioning of, and a better interaction between, the activating and inactivating structures of the modulating brain system located at different levels of the CNS, in particular, in the frontal cortical areas. It is emphasized that the peculiarities of the influence of different means of regulation of the FS on the body of anxious elementary school children are, largely determined by the immaturity of the frontothalamic regulatory system and the specifics of the functional organization of the limbic brain structures.     

Efficiency of use of physical exercises for management of the functional state of 6-8 year-old anxious children

In the research directed on optimisation of a functional state (FS) of disturbing children of 6-8 years, complex application of physical activities of mainly aerobic character, relaxation training is shown, that, respiratory exercises and functional music in long-term aspect selective use of considered means possesses more efficiency. At selective influence the expressed influence on FS disturbing children of 6-8 years in the conditions of intense information loading is rendered only by physical exercises. Application of other ways of optimisation FS is less effective. High effectiveness of use of physical exercises is caused by adaptable changes of mechanisms of regulation FS of disturbing children. Apparently, long-term adaptation to adequate muscular activity provides improvement of functioning and perfection of interaction activating and nonactivating structures of modulating system of the brain, localised on different levels the central nervous system (CNS) and, in particular, frontal departments of a bark. It is underlined, that features of influence of various receptions of regulation FS on an organism of disturbing children of younger school age are substantially caused by immaturity frontocortical-thalamic regulating system and specificity of the functional organisation limbic brain structures.     

Autonomic contribution to endothelin-1 increase during laboratory anger-recall stress in patients with coronary artery disease

In coronary artery disease (CAD), endothelin-1 (ET-1) is released by activated macrophages and thereby contributes to coronary plaque rupture and triggered cardiac events. The multifactorial regulation of ET-1 includes stimulated release by cytokines and autonomic factors. Laboratory stress provokes alteration in autonomic tone and prolonged ET-1 mediated endothelial dysfunction. The objective of the study is to determine the autonomic contribution to an increase in ET-1 in response to laboratory stress in patients with CAD. Patients (n = 88) with chronic stable CAD instrumented with hemodynamic monitor, digital electrocardiogram (ECG) monitor and indwelling catheter for blood sampling completed a laboratory protocol that included initial rest (30 min), baseline (BL: 10 min), and anger recall stress (AR: 8 min). Change from BL to AR was determined for (a) parasympathetic activity (by spectral analysis of ECG); (b) sympathetic activity (by circulating catecholamines); and (c) ET-1. AR provoked increases from BL in catecholamines, and a decrease in parasympathetic activity. Multivariate analysis with change in parasympathetic activity and catecholamines, while controlling for age and use of β-blockers, revealed a significant odds ratio (OR = 3.27, 95% CI 1.03, 10.41 P = 0.04) for an increase in ET-1 associated with parasympathetic withdrawal; no other variables were significant. The predominant influence of parasympathetic activity on anger/stress-provoked increase in ET-1 is consistent with the cholinergic antiinflammatory pathway. Future examination of autonomic influences on atherosclerotic leukocytes, endothelial cell function and the dynamics of ET-1 are warranted.     

Characterization of a neuronal growth factor from mouse heart-cell-conditioned medium

A fraction of medium conditioned by embryonic mouse heart cells in culture promotes the growth of sympathetic and parasympathetic neurons in vitro. The factor stimulates neurite outgrowth, elevates specific activities of tyrosine hydroxylase and choline acetyltransferase in sympathetic ganglion explants, and enhances survival of dissociated sympathetic neurons in culture. The growth-promoting activity, which has a profound effect on survival of mouse sympathetic and parasympathetic neurons but little effect on mouse sensory neuron survival, is sensitive to trypsin and elevated temperature, suggesting association with a polypeptide or protein. Unlike nerve growth factor (NGF), the conditioned medium fraction is insensitive to anti-NGF antiserum, and fosters growth of mouse parasympathetic neurons. Consequently, the conditioned medium appears to contain a new nerve growth-promoting factor.     

Psychophysiological factors of school readiness in six-year-old children

The research was carried out in accordance with the principles of biomedical ethics in healthy six-year-old children (n = 120). The following psychophysiological factors determining the school readiness of six-year-old children were identified in the course of the research: selectivity of voluntary attention (factor I); general work capacity (factor II); physiological maturity (factor III); and sensorimotor coordination of voluntary movement (factor IV). Factors I, II, and IV are related to the activities of the information, energy, and regulatory units of the central nervous system singled out by Luria in the context of the structural-functional model of performance of the brain as a substrate of mental activity. The research has revealed an interrelation between some indicators of school readiness and the parameters of the capacity for physical work.     

Mechanisms of adaptation to physical exertion and the effect of carbon dioxide excess on their formation

4% CO2 addition to normoxic gas medium increased the activity, mass and functional capacity of the left ventricular myocardium, enhanced the stability of acetylcholine (AC) and noradrenaline (NA) storage in the myocardial tissues and stimulated myocardial response to these mediators during physical training of rats (swimming for 2 months). When the duration of the training period was prolonged to 3 months, CO2 had a decreasing effect on the myocardial activity, AC concentration and storage stability, as well as on the myocardial response to AC. The possibility of reducing signal and increasing metabolic CO2 effects during physical training is considered. The importance of intensified heart regulation by sympathetic and parasympathetic mechanisms during adaptation and the role of mechanism dissociation with the decrease in the degree of adaptation are discussed.     

Torpor and ultradian rhythms require an intact signalling of the sympathetic nervous system

During entrance into torpor heart and respiration rates are greatly reduced in parallel with the reduction of metabolic rate, suggesting an involvement of parasympathetic control. We compared the effect of parasympathetic inhibition with the effect of sympathetic inhibition on spontaneous torpor behaviour in the Djungarian hamster. Hamsters were acclimated to short photoperiod and displayed their standard torpor pattern as observed from T_b records. Parasympathetic inhibition was achieved by a subcutaneous implant of 21-day release pellets with Atropine and the sympathetic noradrenergic pathway was inhibited with a single injection of 6-Hydroxydopamine. Atropine treatment did not affect the occurrence and quality of spontaneous daily torpor at all. However, the reversible sympathetic inhibition by 6-Hydroxydopamine injection resulted in a complete disappearance of torpor for about 6 days. These results conclude that the onset of daily torpor requires an intact noradrenergic signalling of the sympathetic nervous system. We further observed that parasympathetic as well as sympathetic blockade resulted in an immediate abolishment of ultradian rhythms of body temperature. This suggests that the expression of ultradian oscillations in body temperature require a continued interaction of sympathetic and parasympathetic activity.     

Autonomic Cardiac Rhythm Regulation and Temperament in Infancy

The specific features of the cardiac rhythm (CR) and temperament were studied in 92 children aged from 15 to 31 months. The average cardiac interval in a recumbent position and its variability (standard deviation) were determined. The parasympathetic tone (PT) was determined by analyzing the CR wave structure according to CR spectrum power within the range of 0.2 to 1.2 Hz. The sympathetic tone was measured by subtracting the PT contribution from the spectrum power within the range of 0 to 0.2 Hz by means of regression. The children's temperament was measured using their parents' questionnaires. Repeated examination showed the stability of the CR characteristics. The PT was shown to correlate with the children's motor activity (0.52), approaching a new subject (0.39), distraction (–0.34), and the age of entering a nursery (–0.35). The results evidenced a relationship between the parasympathetic tone and the behavioral activity during the first years of life and the role of the parasympathetic tone in physiological regulation of approach/avoidance responses and sustained attention.     

Autonomic control of heart rate differs with electrocortical activity and chronic hypoxaemia in fetal lambs

We aimed to determine the effects of the electrocortical (ECoG) cycle on fetal heart rate and its autonomic control under normoxaemic and hypoxaemic conditions. Heart rate was measured and selective pharmacological blockade was used to quantify sympathetic and parasympathetic tone in low voltage (LV) and high voltage (HV) ECoG. We studied 3 groups of fetal lambs: 6 normal-sized, normoxaemic fetuses (control); 5 growth-retarded, normoxaemic carunclectomy fetuses (carunclectomy-normoxaemic); and 5 growth-retarded, hypoxaemic carunclectomy fetuses (carunclectomy-hypoxaemic). We found slower heart rate in LV compared to HV ECoG in all groups. This was explained by greater parasympathetic tone in LV in all groups, and by a complementary change of sympathetic tone in control fetuses. Hypoxaemic fetuses had slower heart rate than normoxaemic fetuses in both ECoG states. This was due to augmented parasympathetic tone (in LV ECoG) and reduced sympathetic tone (in LV and HV ECoG). We conclude that complementary changes of autonomic tone underly the normal variation of fetal heart rate with the ECoG cycle, with the parasympathetic arm dominant in LV and the sympathetic arm dominant in HV ECoG. In chronic hypoxaemia, complementary changes of autonomic tone contribute to slowing of fetal heart rate. Increased parasympathetic tone and decreased sympathetic tone may enhance cardiac efficiency when the oxygen supply is chronically reduced.     

Autonomic Activity Assessed by Heart Rate Spectral Analysis Varies with Fat Distribution in Obese Women

Obesity in humans has been associated with altered autonomic nervous system activity. The objective of this study was to examine the relationship between autonomic function and body fat distribution in 16 obese, postmenopausal women using power spectrum analysis of heart rate variability. Using this technique, a low frequency peak (0.04-0.12 Hz) reflecting mixed sympathetic and parasympathetic activity, and a high frequency peak (0.22-0.28 Hz) reflecting parasympathetic activity, were identified from 5-minute consecutive heart rate data (both supine and standing). Autonomic activity in upper body (UBO) vs. lower body obesity (LBO)(by waist-to-hip ratio) and subcutaneous vs. visceral obesity (by CT scan) was evaluated. Power spectrum data were log transformed to normalize the data. The results showed that standing, low-frequency power (reflecting sympathetic activity) and supine, high-frequency power (reflecting parasympathetic activity) were significantly greater in UBO than in LBO, and in visceral compared to subcutaneous obesity. Women with combined UBO and visceral obesity had significantly higher cardiac sympathetic and parasympathetic activity than any other subgroup. We conclude that cardiac autonomic function as assessed by heart rate spectral analysis varies in women depending on their regional body fat distribution.     

Functional state of the cardiovascular system in 13-year-old adolescents with different types of autonomic nervous regulation

The features of the functional state of cardiovascular system in 13-year-old children with different types of autonomic nervous regulation were studied. Children with normotonic and parasympathetic types of autonomic regulation were found to have the highest adaptation capacities. The autonomic nervous system influences the bioelectrical processes in myocardium, the duration of cardiac cycle phases, and cerebral blood flow. Schoolchildren aged 13 years with higher sympathetic activity have shorter duration of the cardiac cycle, the phase of isometric contraction, and diastole. They have a lower pulse blood flow rate and a higher tone of large and medium cerebral vessels. No relationship was revealed between the initial autonomic nervous regulation of heart rate and the type of adaptation of myocardium to physical dynamic loads, as well as the type of adaptation of cerebral circulation to mental stress.     

Psychophysiological factors of readiness children of 6 years to education at school

Research was spent according to principles of biomedical ethics. Healthy children of 6 years have taken part in him (n = 120). In the course of research the psychophysiological factors defining readiness of children of 6 years to education at school are identified: "selectivity of voluntary attention" (the factor I); "the general working capacity" (the factor II); "a physiological maturity" (the factor III); "sensorimotor coordination of voluntary movement" (the factor IV). Factors I, II, IV correspond with activity of three blocks of the brain allocated with A.R. Lurija within the limits of structurally functional model of work of a brain as a substratum of mental activity. The carried out research has revealed interrelation of some indicators of readiness for education at school with parametres of physical working capacity.     

Regulation of cardiac rhythm in hibernating mammals

The dramatic fall in heart rate exhibited by mammals entering hibernation begins before there is any noticeable fall in body temperature. The initial, progressive decrease in heart rate is the result of a cyclic parasympathetic activation that induces skipped beats and regular asystoles as well as slows the even heart beat. As body temperature subsequently falls, the parasympathetic influence is progressively withdrawn and periods of parasympathetic and sympathetic dominance alternate and give rise to regular periods of arrhythmia (tachycardia followed by bradycardia), and occasional long asystoles or periods of highly irregular cardiac activity. Superimposed on this is a vagally-mediated, respiratory sinus arrhythmia that is accentuated in species that breathe episodically. These events give way to a uniform heart rate in deep hibernation at low temperatures where both parasympathetic and sympathetic tone appear absent. The complete absence of tone is not a function of reduced temperature but is reflective of the state of deep, steady state hibernation. The elevation in heart rate that accompanies the onset of arousal is the result of dramatic increases in sympathetic activation that precede any increases in body temperature. As body temperature then rises, sympathetic influence is slowly withdrawn. Arrhythmias are also common during natural arousals or shifts from lower to warmer hibernation temperatures as periods of parasympathetic and sympathetic dominance again alternate en route to re-establishing a steady state in euthermia. The mechanism behind, and the biological significance of, cardiac changes mediated through orchestrated arrhythmias remain unknown.     

Ontogenetic features of autonomic homeostasis in children according to the data of variation pulsometry

A method of variation pulsometry was used to determine the vegetative homeostasis state in 20 children aged from 4 to 14. Normotonic type of the cardiac rhythm regulation was observed in a group of children aged 4-5. In children aged 12-14 the effect of sympathetic area of the vegetative nervous system decreased while the effect of the parasympathetic one increased. The tension index, effect of the humoral regulation channel and the degree of cardiac rhythm control centralization decreased.