Effects of the watch system of job management on central hemodynamic parameters and the constant potential of the brain

The effects of the watch system of job management on central hemodynamic parameters and the constant potential of the brain were studied in sailors during a long voyage. Twenty crew members were examined during a 120-day translatitudinal voyage. The studies were performed on days 4–6, 40–42, 73–75, and 107–109 of the voyage. It was found that the role of the peripheral regulatory loop in maintaining physiological functions increases during the second half of the voyage and that the functional activity before a watch determines the changes in the parameters by the end of the watch. For each stage of the study, the baseline value of the constant potential of the brain is an important element of functional activity. The system of ratios between parameters before and after a watch that is formed in the early period of the voyage breaks up during the second month, the general reactivity of the body after a watch being independent of the reactivity before the watch; the reactivity is stochastic and is mainly controlled by central mechanisms. In the second month of the voyage, the first signs of a strategy aimed at making the functioning more economical are observed in crew members. The second and third months of the voyage are characterized by a considerable strain of the mechanisms of adaptation, activity, and reactivity in sailors. During the third month of the voyage, overfatigue develops.Translated from Fiziologiya Cheloveka, Vol. 31, No. 2, 2005, pp. 58–68.Original Russian Text Copyright © 2005 by Myznikov, Shcherbina.     

Compensation and Adaptation in Sailors during Voyages of Different Lengths

Data on central hemodynamics and predictions of a factor model of the recovery period of a functional test described by the dynamics of _s potentials are used to compare physiological changes in sailors during voyages of different lengths (75 and 157 days). The causes and conditions of fatigue and overfatigue in sailors during long voyages are discussed, as well as the phases of adaptation. The results of _s -metry are used to characterize the mechanisms determining the interaction with the environment in sailors during voyages of different lengths and changes in these mechanisms as dependent on voyage duration.     

The Use of Omegametry in Sailors during Long-Term Voyages

The _S -metry method has been standardized for the usual working cycle of specialists on board a ship on the basis of data obtained during three long-term sea voyages in different oceanic areas. The response values have been divided into intervals whose limits are multiples of the standard deviation of a normal distribution ( ranges) and the response has been analyzed qualitatively. An approach to estimating the physiological activity and reactivity in sailors is proposed, and an averaged profile of the standard omegametric series in sailors is presented.     

Cardiac activity of freshwater crayfish at wakefulness, rest, and “animal hypnosis”

In laboratory experiments, simultaneous continuous recording of the circadian cycle of behavioral reactions and cardiac activity of freshwater crayfish Astacus astacus and Procambarus clarkii was carried out. A non-invasive fiber-optic method of recording of the heart rate (HR) was used. The obtained data were analyzed by the method of variational pulsometry (VP). It was revealed that certain values of HR and characteristics of VP corresponded to the physiological states of active wakefulness and rest. It was found that during long immobilization of crayfish it is possible to identify the states of operative rest and sleep by the animal behavioral reactions and parameters of cardiac activity. Crayfish were studied in the state of artificially evoked immobilization (“animal hypnosis”). During this state, a high HR level, an increase of indexes of tension and autonomic equilibrium, and changes of other VP characteristics were observed. It is suggested that the different level of cardiac activity in different physiological states of crayfish (active wakefulness, operative rest, sleep, and “animal hypnosis”) is regulated by nervous influences analogous to sympathetic and parasympathetic influences in vertebrates. It was concluded that freshwater crayfish as a representative of the highly organized invertebrates can serve an effective model for studying mechanisms of sleep-like states and “animal hypnosis” in animals.     

Ultraslow information control systems in the integration of life activity processes in the brain and body

The published data and the results of studies of the Department of Human Neurophysiology, revealing the place and importance of ultraslow information-control systems in the study of mechanisms for the integration of interorgan and intersystemic interactions, with the leading role of CNS and the autonomic nervous system, are summarized. The existing notions of the universality and commensurability of amplitude-time parameters, ultraslow bioelectric potentials (USBPs) recorded in the brain and the brain-controlled systems and organs have been considered. Experimental justifications for including one of the USBP types, a stable potential in the millivolt range in the vertex-tenar derivation (the omegametry method) in the psychophysiological approach are provided. This approach consists of choosing complementary integral psychological and physiological parameters permitting the study of the contingency of the mechanisms that control the functional state (wakefulness level) with specific features of the organization of higher mental functions and adaptive behavior, as well as in differentiating diagnostic markers: (a) the balance level and disintegration of intersystemic interaction in the body; and (b) disturbances of compensatory-adaptive possibilities and the adaptation reserve of the body. The prospects of using this approach in theoretical and applied studies on developmental psychophysiology, child psychoneurology, and functional neurology of chronic diseases of the nervous system have been considered.     

Structural investigation of cold activity and regulation of aspartate carbamoyltransferase from the extreme psychrophilic bacterium Moritella profunda

Aspartate carbamoyltransferase (EC 2.1.3.2) is extensively studied as a model for cooperativity and allosteric regulation. The structure of the Escherichia coli enzyme has been thoroughly analyzed by X-ray crystallography, and recently the crystal structures of two hyperthermophilic ATCases of the same structural class have been characterized. We here report the detailed functional and structural investigation of the ATCase from the psychrophilic deep sea bacterium Moritella profunda. Our analysis indicates that the enzyme conforms to the E. coli model in that two allosteric states exist that are influenced by similar homotropic interactions. The heterotropic properties differ in that CTP and UTP inhibit the holoenzyme, but ATP seems to exhibit a dual regulatory pattern, activating the enzyme at low concentrations and inhibiting it in the mM range. The crystal structure of the unliganded M. profunda ATCase shows resemblance to a more extreme T state reported previously for an E. coli ATCase mutant. A detailed molecular analysis reveals potential features of adaptation to cold activity and cold regulation. Moreover, M. profunda ATCase presents similarities with certain mutants of E. coli ATCase altered in their kinetic properties or temperature relationships. Finally, structural and functional comparison of ATCases across the full physiological temperature range agrees with an important, but fundamentally different role for electrostatics in protein adaptation at both extremes, i.e. an increased stability through the formation of ion pairs and ion pair networks at high physiological temperatures, and an increased flexibility through enhanced protein solvation at low temperatures.     

Early stages in the organization of cardiovascular control

Our studies have revealed a number of unexpected characteristics of the immature cardiovascular system of the infant rat. Sympathetic and parasympathetic divisions of the autonomic system appear to have different timetables for the development of tonic and phasic activities. These different timetables of development result in unusual physiological organizations at particular stages in postnatal life. We have described some of the features of one of these: the infant rat's cardiac rate responses in the second week after birth include a high resting rate, decreased rates in response to several (but not all) forms of activation, and two forms of phasic activity, a bradycardia and a tachycardia, that are related to naturally occurring behavioral states and have not been described in adults. The nature of this age-specific autonomic organization was explored further and found to be embedded in the infant's relationship with its mother and in her role as a supplier of nutrient in particular. The mechanisms by which nutrient intake regulates autonomic cardiovascular control during this stage of life have been partially explored by analytic experiments and the results are described along with the possible adaptive value of this regulatory system.     

Dynamics of spatial synchronization of EEG parameters during relaxation and their relationship with regulation of heart rate

EEG parameters were analyzed in a wide frequency range for the estimation of the possible functional importance of different EEG components in the formation of relaxation. Sixty-five subjects aged 17–20 years were involved in the investigation. The relaxation session with monopolar EEG recording and autonomic parameters recording was carried out for each subject. During the relaxation significant changes were observed in all analyzed EEG ranges. Two types of changes of EEG coherence in the wakefulness-relaxation shift of state were distinguished, and correlation of the type of dynamics with the LF/HF ratio, showing the balance of sympathetic and parasympathetic parts of the autonomic nervous system, was found.     

Central neural control of sympathetic nerve activity in heart failure following exercise training

Typical characteristics of chronic congestive heart failure (HF) are increased sympathetic drive, altered autonomic reflexes, and altered body fluid regulation. These abnormalities lead to an increased risk of mortality, particularly in the late stage of chronic HF. Recent evidence suggests that central nervous system (CNS) mechanisms may be important in these abnormalities during HF. Exercise training (ExT) has emerged as a nonpharmacological therapeutic strategy substitute with significant benefit to patients with HF. Regular ExT improves functional capacity as well as quality of life and perhaps prognosis in chronic HF patients. The mechanism(s) by which ExT improves the clinical status of HF patients is not fully known. Recent studies have provided convincing evidence that ExT significantly alleviates the increased sympathetic drive, altered autonomic reflexes, and altered body fluid regulation in HF. This review describes and highlights the studies that examine various central pathways involved in autonomic outflow that are altered in HF and are improved following ExT. The increased sympathoexcitation is due to an imbalance between inhibitory and excitatory mechanisms within specific areas in the CNS such as the paraventricular nucleus (PVN) of the hypothalamus. Studies summarized here have revealed that ExT improves the altered inhibitory pathway utilizing nitric oxide and GABA mechanisms within the PVN in HF. ExT alleviates elevated sympathetic outflow in HF through normalization of excitatory glutamatergic and angiotensinergic mechanisms within the PVN. ExT also improves volume reflex function and thus fluid balance in HF. Preliminary observations also suggest that ExT induces structural neuroplasticity in the brain of rats with HF. We conclude that improvement of the enhanced CNS-mediated increase in sympathetic outflow, specifically to the kidneys related to fluid balance, contributes to the beneficial effects of ExT in HF.     

水面和水下长航对艇员肠道菌群影响的比较及意义探讨

比较研究和水下两种长期航行条件对航艇和核潜艇艇员肠道菌群的影响并对其意义进行初步探讨。结果显示两种长航条件均对人体肠道菌群产生显著影响,可打破肠道微生态平衡,但两者所致的肠道菌群构成变化的特点不同。提示不同长航条件可造成不同的微生态失调,需区别对待。     

High-dimensional coexistence of temperate tree species: functional traits, demographic rates, life-history stages, and their physical context

Theoretical models indicate that trade-offs between growth and survival strategies of tree species can lead to coexistence across life history stages (ontogeny) and physical conditions experienced by individuals. There exist predicted physiological mechanisms regulating these trade-offs, such as an investment in leaf characters that may increase survival in stressful environments at the expense of investment in bole or root growth. Confirming these mechanisms, however, requires that potential environmental, ontogenetic, and trait influences are analyzed together. Here, we infer growth and mortality of tree species given size, site, and light characteristics from forest inventory data from Wisconsin to test hypotheses about growth-survival trade-offs given species functional trait values under different ontogenetic and environmental states. A series of regression analyses including traits and rates their interactions with environmental and ontogenetic stages supported the relationships between traits and vital rates expected from the expectations from tree physiology. A combined model including interactions between all variables indicated that relationships between demographic rates and functional traits supports growth-survival trade-offs and their differences across species in high-dimensional niche space. The combined model explained 65% of the variation in tree growth and supports a concept of community coexistence similar to Hutchinson's n-dimensional hypervolume and not a low-dimensional niche model or neutral model.     

Physiological and Psychological Expression of Personality Types

In this study, we analyzed the physiological and psychological states of female college students using the typological theory of Carl Jung. It was suggested that the expression of psychological typological characteristics (psychotypological actualization) is associated with the actual autonomic, somatic, and psychological condition of the subject. The analysis of the relationships of the psychotypological actualization with the psychophysiological state pointed to their differentiation in relation to the psychotypological trait whose expression (actualization) was analyzed. Actualization of the basic Jungian traits, extroversion and introversion, was characterized by a stable state of the physiological systems. Low actualization of extroversion–introversion was accompanied by unfavorable (at the low limit of the physiologically normal range) autonomic and somatic states. Actualization of the psychological trait judging–perceiving was associated with moderate state and trait anxiety, completely excluding cases of low and high anxiety. Actualization of the intuition–sensation trait was linked with reduced adaptational capacity of the subject. Actualization of the thinking–feeling trait was not associated with the physiological condition of the subjects.     

The functional state of the sympathoadrenal system and the autonomic regulation of the cardiac rhythm in younger schoolchildren

A comparative analysis of functional states of the sympathoadrenal system (SAS) and its reactions to isometric muscular effort was performed in seven-year-old schoolchildren of both sexes with different types of cardiac regulation. Children with a predominance of sympathetic influences displayed a higher excretion of noradrenaline and a lower excretion of dopamine than their counterparts with normal or vagal tone. A graded isometric exercise changed the functional state of the SAS in a manner dependent on the initial autonomic tone, baseline excretion of catecholamines, and sex. Boys displayed more strained reactions of the SAS than girls did, which was associated with a decrease in its reserve potential, especially pronounced in the states of vagal and normal tones. This suggests imperfect mechanisms of adaptation to static loads.     

Dynamics of P300 component of acoustic evoked potential in postraumatic unconsciousness

In order to reveal features of the brain reactions to external stimuli in the course of consciousness recovery after a severe craniocerebral injury, component P300 of acoustic evoked potential was analyzed in 9 patients with chronic and 32 patients with reversible unconsciousness. In patients with chronic unconsciousness, P300 parameters displayed a linear correlation with the current functional state. However, this component remained significantly different from its normal shape and varied only in a narrow range. In patients with reversible unconsciousness, time course of changes in amplitude and latency between recovery stages was of linear character with a tendency to normalization. The findings suggest that, in reversible unconsciousness states, processing of sensory information at different recovery stages may be performed with various functional systems that determine varying quality of processing, whereas changes in chronic unconsciousness are caused by a decrease in the number of active elements within the same functional system.     

Developmental plasticity in the cardiovascular system of fish,with special reference to the zebrafish

During development the circulatory system of vertebrates typically starts operating earlier than any other organ. In these early stages, however, blood flow is not yet linked to metabolic requirements of tissues, as is well established for adults. While the autonomic nervous system becomes functional only quite late during development, in the early stages control of blood flow appears to be possible by blood-borne and/or local hormones. This study presents methods based on video-imaging techniques and fluorescence microscopy to visualize cardiac activity, as well as the vascular bed of developing lower vertebrates, and tests the idea that environmental factors, such as hypoxia, may modify cardiac activity, or even the early formation of blood vessels in embryos and larvae. In zebrafish larvae, adaptations of cardiovascular activity to chronic hypoxia become visible shortly after hatching, and the formation of some blood vessels is enhanced under chronic hypoxia. Exposure of early larval stages of zebrafish to a constant water current induces physiological adaptations, resulting in enhanced swimming efficiency and increased tolerance towards hypoxia. Furthermore, application of hormones such as NO can modify cardiac activity as well as peripheral resistance, and they can stimulate blood vessel formation. In consequence, even during early development of fish or amphibian larvae, the performance of cardiac muscle and of skeletal muscle can be modified by environmental influences and peripheral resistance can be adjusted. Even blood vessel formation can be stimulated by hypoxia, for example, or by the presence of specific hormones. Thus, at approximately the time of hatching the physiological performance of vertebrate larvae is already determined by the combined action of environmental influences and of genetic information.     

Control of cardiovascular variability during undisturbed wake-sleep behavior in hypocretin-deficient mice

The central neural mechanisms underlying differences in cardiovascular variability between wakefulness, non-rapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS) remain poorly understood. These mechanisms may involve hypocretin (HCRT)/orexin signaling. HCRT signaling is linked to wake-sleep states, involved in central autonomic control, and impaired in narcoleptic patients. Thus, we investigated whether HCRT signaling plays a role in controlling cardiovascular variability during spontaneous behavior in HCRT-deficient mice. HCRT-ataxin3 transgenic mice lacking HCRT neurons (TG), knockout mice lacking HCRT peptides (KO), and wild-type controls (WT) were instrumented with electrodes for sleep recordings and a telemetric blood pressure transducer. Fluctuations of systolic blood pressure (SBP) and heart period (HP) during undisturbed wake-sleep behavior were analyzed with the sequence technique, cross-correlation functions, and coherent averaging of SBP surges. During NREMS, all mice had lower SBP variability, greater baroreflex contribution to HP control at low frequencies, and greater amplitude of the central autonomic and baroreflex changes in HP associated with SBP surges than during wakefulness. During REMS, all mice had higher SBP variability and depressed central autonomic and baroreflex HP controls relative to NREMS. HP variability during REMS was higher than during NREMS in WT only. TG and KO also had lower amplitude of the cardiac baroreflex response to SBP surges during REMS than WT. These results indicate that chronic lack of HCRT signaling may cause subtle alterations in the control of HP during spontaneous behavior. Conversely, the integrity of HCRT signaling is not necessary for the occurrence of physiological sleep-dependent changes in SBP variability.     

Seven-day dry immersion: Interrelationship between the changes in the water-electrolyte balance and cardiovascular responses

The results of an experiment with a seven-day dry immersion are presented. Eight healthy men were examined before, during, and after the exposure. It was shown that the primary response involved hemodynamic and water-electrolyte changes. The mechanisms of cardiovascular adaptation to the immersion conditions were revealed. In particular, some electrophysiological shifts in the propagation of myocardial excitation were found, leading to an increase in the variance of natural small oscillations of the electric potential of the heart. The revealed significant reduction of the functional reserves of the cardiovascular regulatory mechanisms during adaptation to dry immersion is of great practical importance. The results suggest that the water-electrolyte balance shifts induced by dry immersion are the basis and the first phase of further changes in the autonomic regulation and functional state of the myocardium.