Physiological Support of Goal-Directed Activity in Human

The effectiveness of goal-directed human behavior and the processes underlying organization of such activity are the subjects of various biomedical studies. Here we review both classical and modern evidence on the fundamental principles of goal-directed human activity. Facts are presented about the basic mechanisms that ensure the effectiveness of goal-directed behavior and determine its physiological cost.

Structure of the Useful Adaptive Result in the Systemic Organization of Physiological Functions as a Subject of Scientific Analysis: History and Prospects of Research

The concept of "useful adaptive result", a key concept in the theory of functional systems by P. K. Anokhin, is discussed. A large body of works devoted to this problem, in the historical aspect and on the basis of results of own researches, allows concluding that useful adaptive results of the system organization of physiological functions include not only the event arising as a result of activity of the system, but also the physiological cost of this activity. The ratio of the physiological cost and performance indicators gives an idea of the effectiveness of system activity and is its integral characteristic. The main approaches to estimation of physiological cost and efficiency of activity are discussed, as well as possibilities of using methods of applied mathematics (correlation and cluster analysis, artificial neural network technology) to describe system organization of physiological functions in healthy people. The question of the use of the proposed regulations to describe the system organization of physiological functions in patients with Parkinson's disease and epilepsy is considered.

Correlation between Cognitive Performance and Interhemispheric Asymmetry of EEG Alpha Rhythm during Lateralized Presentation of Visual Information against the Background of Optical Stimulation

The effect of lateralized optical stimulation with a frequency of 10 Hz on the effectiveness of cognitive task performance (n-back test) was studied in 33 healthy subjects (right-handed men). Test visual information was presented to the right or left visual hemifield under normal conditions and against the background of optical stimulation with a frequency of 10 Hz. The absolute values of the spectral power of the high (10-13 Hz) subrange of alpha-rhythm of EEG (SPα2) were calculated. When test information was sent to the right hemisphere against the background of stimulation, an increase in task performance was revealed in subjects with low SPα2. This was accompanied by an increase in SPα2 in some cortical areas of the contralateral (left) hemisphere and, as a result, an increase in left-side dominance of SPα2. The findings indicate the possibility of using lateralized optical stimulation to improve cognitive task performance, in particular, by changing the interhemispheric asymmetry of the EEG alpha2-rhythm.

Formation of Different Strategies of Competitive Foraging Behavior in Rats

We studied competitive interactions of rats during instrumental foraging behavior. Two groups of animals were revealed: rats with predominance of operant actions for getting food reinforcements (donors) and kleptoparasites that more often get food after instrumental acts of the partners. Intergroup differences began to appear and increased from 3-4 paired experiments. It was revealed that at the individual stage of learning the instrumental skill, donor rats were faster in learning and showed high foraging activity with shorter latency in comparison with kleptoparasites, which were initially slower and performed a large number of inter-signal actions in the form of unconditioned peeking into the feeder.

[Clinical and neurophysiological parameters in patients with epilepsy in the long-term period after COVID-19]

OBJECTIVE

Clinical and psychophysiological assessment of the dynamics of the condition of patients with epilepsy in 4-6 months after the coronavirus infection.

MATERIAL AND METHODS

An open controlled prospective comparative outpatient clinical and physiological study of patients diagnosed with epilepsy after suffering from COVID-19 (after 4-6 months) of moderate severity (n=16), patients diagnosed with epilepsy who did not suffer from COVID-19 (n=7), a control group (n=11) after confirmed COVID-19 (after 4-6 months). All groups were in the age range 23 to 50 years. Clinical/neurological and somatic research included: anamnesis, neurological examination, questioning, ECG, EEG, clinical and psychometric tests.

RESULTS

There was an increase in the representation of epileptiform activity in the background EEG and more pronounced activity in provoking samples compared with background recording in 26.5% of patients who had suffered COVID-19 compared with the group of patients with epilepsy who had not suffered COVID-19. The detection of rare epileptic seizures in 18.8% of cases in the group of epilepsy patients, who underwent COVID-19, indicates an increase in epileptogenesis and a decrease in therapeutic control over seizures. At the same time, 87.5% of patients in this group showed a statistically significant increase in the influence of the sympathetic nervous system on the regulation of heart rhythm and an increase in anxiety and depression.

CONCLUSION

The results can complement the understanding of the neuropsychiatric status of patients with epilepsy after COVID-19, which provides prerequisites for the development of optimal recovery directions in the rehabilitation period to maintain drug remission of epilepsy and reduce the possible progression of the disease.

[Impact of COVID-19 on some neurological and psychological features in epilepsy]

The new coronavirus infection spread around the world in a very short time and turned into a pandemic with a wave-like flow for more than two years. COVID-19infection affects selectively various organs and systems, including the nervous system; neurological manifestations have been reported, including anosmia, encephalopathy, stroke, epileptogenic disorders, which necessitates studies of the course of brain diseases, among which epilepsy occupies a significant place.

Age and Sex Characteristics of the Blood Cytokine Profile in Rats Subjected to Prenatal Stress

Parameters of blood cytokine profile in male and female rats subjected to prenatal stress on the model of swimming in cold water (10°C, 5 min, days 10-16 of gestation) were studied. Prenatal stress had no significant effects on the blood levels of IL-6 and IL-10 cytokines. The blood concentration of proinflammatory cytokine TNFα in 60-day-old rats was higher than in age-matched controls. Stress led to a lower level of anti-inflammatory IL-4 in the blood of 30-day-old males compared to controls. In female rats subjected to prenatal stress, the concentration of IL-4 decreased on day 21, but increased by day 60 of postnatal ontogeny. Specific effects of prenatal stress on the blood cytokine profile in male and female animals at different periods of ontogeny were revealed. Different and even opposite changes in blood cytokine levels could be largely mediated by sex- and age-specific features of immune functions after prenatal stress.

Behavior of In Utero Stressed Rats in the Elevated Plus Maze Test during Different Periods of Postnatal Ontogeny

We studied the effect of prenatal stress (dams were forced to swim in cold water (10°C; 5 min) from day 10 to 16 of gestation) on the behavioral parameters of the offspring in an elevated plus maze on days 21, 30, and 60 of life (suckling, infantile, and juvenile ages, respectively). Females at the suckling age demonstrated suppressed orientation and exploratory activity and increased anxiety, which returned to normal by the infantile and juvenile periods. Prenatally stressed males in juvenile age were characterized by reduced anxiety (assessed by the time spent in the closed and open arms of the plus maze). Thus, the effect of prenatal stress on the behavioral parameters manifested differently depending on the sex and stage of postnatal ontogeny. The modulatory effects of prenatal stress on the analyzed behavioral parameters were more pronounced in females at early stages of postnatal ontogeny (suckling and infantile ages).

Changes in the Level of Methylation of a Group of microRNA Genes as a Factor in the Development and Progression of Non-Small Cell Lung Cancer

We studied changes in the level of methylation of a number of microRNA genes hypermethylated in non-small cell lung cancer and its histological subtypes as well as the relationship of methylation of a group of microRNA genes with clinical and morphological features of the tumor with smoking status. A significantly high level of methylation of 7 genes (MIR124-1/3, MIR125B-1, MIR129-2, MIR137, MIR1258, and MIR339) was revealed in adenocarcinoma and squamous cell lung cancer in comparison with samples of adjacent histologically unchanged lung tissue. In squamous cell lung cancer, a significantly high level of methylation of the MIR124-2 gene in the tumor was also shown. In addition, differences in the methylation profile of adenocarcinoma and squamous cell carcinoma at stages III-IV of the oncological process were revealed. A high level of methylation of the MIR137 and MIR1258 genes was shown for adenocarcinoma and MIR339, MIR129-2, and MIR124-2 for squamous cell carcinoma. Significant differences in the level of methylation of MIR124-2 and MIR375 genes were revealed for smoking patients with squamous cell lung cancer.

Effect of Repeated Stress Exposures on the Blood Cytokine Profile in Rats with Different Behavioral Parameters

Changes in the blood cytokine profile were studied in rats with different behavioral patterns in the open-field test during chronic stress on the model of daily 4-h immobilization over 8 days. The level of proinflammatory cytokines IL-1α and IFNγ in behaviorally active and passive animals changed insignificantly under these experimental conditions. Repeated stress exposures were accompanied by a progressive decrease in the plasma level of IL-2 and IL-5 in passive rats; these changes were most pronounced on day 8 of the study. Active animals were characterized by a tendency toward reduction of IL-2 content, but significant decrease in IL-5 concentration on days 3 and 8 of restraint stress. Blood levels of IL-1β and IL-6 in rats remained practically unchanged after single immobilization, but progressively increased during further stress exposures and reached maximum on day 8 of stress. The content of the anti-inflammatory cytokine IL-4 in rats was constant, but blood concentration of IL-10 increased during repeated stress exposures. These changes were most pronounced on day 8 in passive animals and on days 3 and 8 of restraint stress in active animals. These data indicate that the direction of variations in the blood cytokine profile of rats under conditions of chronic stress depends on the baseline parameters of behavior and frequency of stress exposures.

Correlation of Physiological Parameters in Rats after Stress Exposure under Conditions of Antigenic Stimulation with Lipopolysaccharide Administration

We studied correlation dependences between physiological parameters in rats in 3 h, 1 day, and 8 days after administration of LPS (100 μg/kg) at the end of 24-h immobilization stress. In 3 h after LPS administration against the background of stress exposure, significant correlations of metabolic parameters with the relative weight of the adrenal glands and the perceptual component of nociception in rats were revealed. A direct relationship between the concentration of the proinflammatory cytokine TNFα and anti-inflammatory IL-4 was also found in these animals. On the first day after LPS injection, correlations were revealed, predominantly positive, only between the indicators of the cytokine blood profile. In the late post-stress period after antigenic exposure, no correlations between the studied physiological parameters were found. It can be hypothesized that immune modulation through systemic administration of LPS prevents persistent excessive stress of physiological functions at the later stages after stress exposure.

Analysis of Endogenous Spectral Power of EEG Alpha-Range Biopotentials during Mnestic Activity under Conditions of Rhythmically Organized Optical Stimulation

We studied the effect of optical stimulation (10 Hz) on the effectiveness of mnestic activity in the n-back task in healthy subjects (n=32). EEG was recorded at all stages of the examination. The absolute values of the spectral power of the 10 Hz frequency (μV2) of the alpha range were calculated. According to the results of the test without optical stimulation, the examinees were divided into groups with high (group 1) and low (group 2) task performance. In the initial state, the spectral power of 10 Hz was significantly higher in group 1 subjects. Under conditions of screen flickering, the results became poorer in group 1 and better in group 2 in comparison with the results under normal conditions. These changes were accompanied by an increase in the spectral power of 10 Hz only in group 2 subjects. These findings can provide the basis for the development of practical recommendations for improving the mnestic functions in patients with consideration for the individual characteristics of their initial EEG.

[Neurophysiological and functional neuroimaging methods in the assessment of migraines and epilepsy with vertigo]

A review of the current literature shows that the combined use of neurophysiological and structural-functional neuroimaging methods has significantly expanded the understanding of the mechanisms of migraine with vestibular dysfunction: functional and structural disorders were found in brain regions involved in multisensory vestibular control and Central vestibular processing. Analysis of numerous studies shows that epilepsy can also cause vestibular symptoms, they can occur both without epileptic markers, and in combination with epileptic paroxysms. In isolated epileptic vertigo, according to studies widely presented in the literature, epileptic activity was most often detected by EEG data in the temporal regions, to a lesser extent in the parietal regions. In these studies, neuroimaging findings of foci of reduced substance density were found, which could be a consequence of deafferentation, as well as violations of connections with the focus of neuronal activity. In the absence of structural abnormalities, numerous studies have shown using magnetic resonance spectroscopy, diffusion MRI, and PET that the physiological basis for impaired neuronal metabolism was a decrease in synaptic activity, a violation of maintaining the difference in membrane potentials on the surface of the hippocampus, or changes in neighboring tracts of the white matter of the brain.

Blood Cytokine Concentration in Rats during Antigenic Treatment after a Single Long-Term Stress Exposure

We studied changes in the blood cytokine profile of rats 3 h, 1 day, and 8 days after acute stress on the model of 24-h immobilization followed by LPS administration (100 μg/kg intraperitoneally). The concentration of proinflammatory cytokines (particularly of IL-1β and TNFα) significantly decreased at the early stage after stress exposure and physiological saline injection, but increased in the follow-up period and practically did not differ or even surpassed the control level by the end of observations. Under these conditions, the blood content of anti-inflammatory cytokine IL-10 increased most significantly on day 1 of the post-stress period. Restraint stress followed by LPS administration was accompanied by a decrease in the level of proinflammatory cytokines at the early (IFNγ and TNFα) and late stages (IL-1β) of the experiment. Directed modulation of the immune status in animals after acute stress was followed by a significant increase in the content of IL-10 on days 1 and 8, as well as by a tendency toward elevation of IL-4 concentration by the end of the study. The directionality and degree of changes in the cytokine profile of mammalian tissues depend on the type of extreme exposure, duration of the post-stress period, and specific effects of exogenous pathogenic factors in the whole body.

[Neurophysiological and clinico-biological features of internet addiction]

AIM

To analyse neurophysiological and some physiological characteristics of people with Internet addiction.

MATERIAL AND METHODS

Two groups of subjects were studied: with Internet-addiction lasted no more than two years and the control group. Spectral-correlation parameters of EEG, functional asymmetry of EEG parameters, and heart rate variability were recorded. The comparison was performed in three states: eyes-closed, eyes-open conditions and after a 15-minute Internet session.

RESULTS AND CONCLUSION

The shift in the balance of the regulation of the heart rate towards the predominance of the sympathetic nervous system is accompanied by a functional state of increased activation, anxiety as indicated by the parameters of the electric activity of the brain and the shift in the functional asymmetry of the brain in the spectral power of the fast EEG rhythms in the right hemisphere.

Correlation Connections between Individual-and-Typological Features, Indices of Performance of Goal-Directed Activity, and Heart Rate Variability Parameters

Correlation analysis of the performance of goal-directed activity and heart rate variability parameters in people with different individually-typological features was conducted on the model of endosurgical training. It was found that people with low level of intro-extroversion and neuroticism, but high index of situational anxiety were more successful during goal-directed behavior. The subjects with low level of neuroticism finished the tasks more quickly, both at the beginning and at the end of the observations. It was established that the number of mistakes in subjects with low personal anxiety on the 10th day of training was lower than in high-anxious individuals. It is shown that people with high rate of intro-extroversion are characterized by more pronounced increase in parasympathetic influences during basic endosurgical training. Hence, the achievement of the result in extroverts in these experimental conditions is provided by lower physiological penalty than in introverts. The definition of psychophysiological indices could be recommended for inclusion in the complex of measures for the assessment of proficiency in the training of endosurgeons.

State of Stress-Marker Organs in Rats after a Single Exposure to Long-Term Stress and Treatment with Lipopolysaccharide

We studied the effect of LPS on the state of stress-marker organs in rats at various periods after a single exposure to long-term stress on the model of 24-h immobilization. The animals were intraperitoneally injected with LPS in a dose of 100 μg/kg immediately after the negative emotiogenic exposure. Changes in physiological parameters were evaluated 3 h, 1 day, and 8 days after immune stimulation. Acute stress was accompanied by a decrease in the weight of the thymus during all stages of the post-stress period. An increase in the relative weight of theadrenal glands in animals under these conditions was observed only on day 8 after restraint stress. The induction of immune reactions due to systemic treatment with LPS was shown to prevent involution of the spleen in the late stage after a single exposure to long-term stress (day 8). Hypertrophy of the adrenal glands, which serves as one of the typical reactions of mammals to negative emotiogenic factors, was not revealed during the post-stress period after antigenic stimulation. These data hold much promise for the development of new approaches to the use of immunoactive substances to prevent or reduce the severity of physiological changes after emotiogenic loads.

[Neurophysiological approaches to the diagnosis and treatment of vestibular disorders in migraine and epilepsy]

The review considers the results of domestic and foreign studies of modern neurophysiological diagnosis of vestibular disorders in migraine and epilepsy. Currently, there is a large number of physiological and clinical methods to evaluate the functions of the peripheral and central parts of the vestibular sensory system. However, among the tests, the samples for the assessment of the physiological state of horizontal semicircular canals and associated stem canals predominate. In recent years, neurophysiological techniques that reflect the work of the structures of the nervous system, previously inaccessible to direct study, are being actively introduced. Modern effective neurophysiological methods of rehabilitation of patients with migraine-associated and other various vestibular disorders have been developed. Further study of neurophysiological approaches to the diagnosis of vestibular disorders in migraine and epilepsy will significantly expands the current understanding of neurophysiological mechanisms of brain functions.

Neurological Deficit and Structural Changes in Lymphoid Structures of the Tracheal Wall in the Immediate Stage of Experimental Hemorrhagic Stroke in Rats with Different Behavioral Activity

Specific features of neurological deficit and changes in the cellular composition of tracheal lymphoid structures during the immediate stage (day 1) of hemorrhagic stroke were studied in rats with various behavioral parameters. Modeling of hemorrhage in the left caudate nucleus of the brain was followed by the development of motor disturbances in the forelimb use asymmetry test and corner rotation paradigm. These animals preferred to use the left forelimb (ipsilateral to the side of hemorrhage) to lean on the cylinder wall. The frequency of using the right forelimb or both forelimbs was reduced under these conditions. The number of left-sided rotations increased, while the percentage of right-sided rotations decreased. The observed changes were accompanied by immune dysfunction. It was manifested in the depletion of lymphoid aggregates of the tracheal wall in lymphocytes and plasma cells. The severity of abnormal neurological symptoms and disturbances in immune homeostasis during the immediate stage of hemorrhagic stroke was greater in behaviorally passive rats than in active specimens.

Blood Cytokine Profile in Rats with Various Behavioral Characteristics after a Single Exposure to Long-Term Stress

Changes in the blood cytokine profile of rats with different behavioral activity were evaluated in various periods after stress exposure on the model of 24-h immobilization. Behaviorally active animals exhibited only a tendency to a change in the concentration of study cytokines in the dynamics after experimental stress. Stress exposure in passive specimens was accompanied by a decrease in the content of pro- and anti-inflammatory cytokines. These changes were most pronounced at the early stages of the post-stress period and persisted until the end of observations. After a single exposure to long-term immobilization, cytokine level in the peripheral blood of behaviorally passive animals was much lower than in active rats. Variations in immune indexes of mammals depend on the initial parameters of their behavior and duration of the post-stress period. Differences in the blood cytokine profile during negative emotiogenic exposures in passive and active rats are probably related to the specifics of immune reactivity in specimens with various sensitivities to stress.

Cellular Composition of the B- and T-Cell-Dependent Areas in the Small Intestine during the Post-Stress Period (Experimental Study)

A quantitative study of lymphoid cells in the B- and T-cell-dependent areas of intestinal lymphoid nodules and mesenteric lymph nodes in behaviorally passive and active rats was performed at various periods after acute stress on the model of 1-h immobilization with simultaneous electrocutaneous stimulation. Stress exposure is accompanied by a decrease in the number of lymphoid cells in immunogenic structures of the gastrointestinal tract. Post-stress changes in the cytoarchitectonics of B- and T-cell-dependent areas in mesenteric lymph nodes of animals are less pronounced than in lymphoid nodules. Quantitative changes in lymphoid cells of B-cell-dependent areas in the small intestine of rats are greater than in T-cell-dependent areas. Changes in the cellular composition of immunogenic structures in the digestive system are most significant at the early stages of the post-stress period (1st week). Passive rats are characterized by significant changes in the cytoarchitectonics of B- and Tcell-dependent areas in the small intestine after extreme exposure, which illustrates functional exhaustion of the lymphoid tissue in stress-predisposed specimens.

Proteomic Characteristics of Blood Serum in Rats with Different Behavioral Parameters after Acute Stress

We studied proteome profile of blood serum of Wistar rats with different behavioral activity immediately and in 1 and 3 days after acute stress on the model of 12-h immobilization during the nighttime. Comparative analysis of 2D-electrophoretograms revealed differences in the expression of serum proteins in non-stressed (control) and stressed (experimental) rats. We found 22 protein spots that characterized the proteomic features of blood serum in rats with different prognostic resistance to stress. Mass-spectrometry of isolated spots identified 6 functional proteins. Persistent proteome changes in the blood of animals at different stages after acute stress were determined. The specificity of proteomic characteristics of blood serum was shown in behaviorally passive and active rats during the post-stress period. These data extend the concept on specific protein markers for the formation of a negative emotional state and adaptive-and-compensatory processes in mammals with different sensitivity to stressogenic factors.

Effect of Metabolic Stress on Coenzyme Q10 Content in Tissues of Active and Passive Rats

The dynamics of coenzyme Q10 concentration in the blood plasma, liver, and brain of passive and active rats was studied on the model of metabolic stress. This parameter was shown to differ in rats with various patterns of behavior. Dietary consumption of coenzyme Q10 in doses of 10 and 100 mg/kg body weight was followed by changes in its content in experimental animals.

Effect of Coenzyme Q10 on Proteomic Profile of Rat Brain Amygdala during Acute Metabolic Stress

Differences in the proteomic profiles of the brain amygdala in rats with different prognostic resistance to stress were found on the model of metabolic stress. Differential expression of tropomodulin-2, GTP-binding protein SAR1, peroxiredoxin-2, calcineurin B homologous protein 1, Ras-related protein Rab-14, glutathione S-transferase omega-1, Tcrb protein, and NADH dehydrogenase [ubiquinone] iron-sulfur protein 8 (mitochondrial) was shown to depend on the behavioral pattern of animals and stage of the study. Specific features were observed in the involvement of the amygdala in the stress response of specimens with various behavioral characteristics.

Effect of Acute Emotional Stress on Proteomic Profile of Selected Brain Areas and Lysosomal Proteolysis in Rats with Different Behavioral Activity

We compared proteome profiles of selected brain areas (cortex, amygdala, hippocampus, and reticular formation) and measured cathepsins B and D activity in liver lysosomal fraction in rats with different behavioral activity under conditions of emotional stress. In passive rats, the expression of some proteins in various brain regions was changed and baseline cathepsin B activity was higher than in active animals. Taken together, the results attest to differences in the adaptive response formation in rats, depending on behavioral features.

[Effect of melatonin on antioxidant enzyme activities in blood erythrocytes of rats during acute emotional stress]

The effect of the epiphyseal hormone melatonin on the activity of antioxidant enzymes, glutathione peroxidase (GPx), glutathione reductase (GR), and Cu/Zn-superoxide dismutase (Cu/Zn-SOD) was studied in peripheral blood erythrocytes of behaviorally passive and active Wistar rats. Acute emotional stress was modeled by immobilization of animals for1 h with simultaneous electrocutaneous stimulation. Basal activity of antioxidant glutathione enzymes in erythrocytes of behaviorally passive rats was higher than that in active animals. Administration of melatonin (2 mg/kg, intraperitoneally) was accompanied by a decrease in the activity of GPx and GR in erythrocytes from non-stressed passive animals. After experimental stress, passive rats demonstrated a significant increase in the activity of Cu/Zn-SOD and GPx in peripheral blood erythrocytes. The absence of stress-induced changes in functional activity of antioxidant defense enzymes in the blood of behaviorally active animals suggests a relatively constant oxidative status of tissues in these animals under stress conditions. Melatonin administration had little effect on stress-induced changes in functional activity of the erythrocyte antioxidant system in passive rats. Active specimens pretreated with melatonin before stress exposure were characterized by activation of study antioxidant enzymes. Quantitative parameters of the erythrocyte antioxidant defense enzymes did not differ in behaviorally active and passive rats subjected to experimental stress after melatonin injection. Thus, exogenous melatonin abolishes differences in the activity of study antioxidant enzymes in erythrocytes of animals with different behavioral parameters under basal conditions and after experimental stress. In passive rats melatonin mainly reduced the initial tension of oxidative processes. By contrast, administration of this hormone to active specimens is followed by an increase in functional activity of the antioxidant enzyme system under conditions of acute stress.

[Studying the Persistence of Blood Flow Oscillations in Rat Kidneys]

This work was designed to study the nonlinear dynamics of fluctuations in renal blood flow of rats under basal conditions and in the perturbed state. An intramuscular injection of aspirin in 0.9% physiological saline (0.5 mg per 100 g body weight) served as a perturbation factor. Capillary blood flow in the right kidney of a rat was measured by the method of laser Doppler flowmetry. The persistence of these time series was estimated by the Hurst method. Our study revealed the persistence of time series under basal conditions (Hurst index H = 0.817 ± 0.041). Statistical parameters of the perturbed series were shown to differ significantly from those observed in the initial state. However, the perturbed series remained persistent. The Hurst index for these series was H = 0.677 ± 0.057. A decrease in this index was insignificant (as compared to that for the baseline index).

[Analysis for the Persistence of Various Regimens of Heart Rate Dynamics by Computer Modeling]

A computer modeling revealed the following three regimens of heart rate dynamics: linear dynamics, "1st degree chaos", and "2nd degree chaos". This work was designed to study the persistence of these regimens by the method of Hurst. Our investigation showed that the Hurst index is highest for "2nd degree chaos" (H = 0,671 ± 0,028). The Hurst index for the "1st degree chaos" regimen was lower than that for "2nd degree chaos" (H = 0,473 ± 0,015). An increased persistence of cardiac rhythmogenesis in the "2nd degree chaos" regimen illustrates the non-stationarity and prognostic instability of these processes, which contributes to a high risk of heart diseases.

[DYNAMICS OF CYTOKINE CONCENTRATION IN THE BLOOD OF RATS WITH VARIOUS BEHAVIORAL CHARACTERISTICS AFTER ACUTE EMOTIONAL STRESS]

This work was designed to study a change in cytokine content in the peripheral blood of behaviorally passive and active Wistar rats at various time intervals after acute stress on the model of night-time immobilization. A decrease in the concentration of most pro- and anti-inflammatory cytokines in passive animals was most pronounced immediately and, particularly, 3 days after stress exposure. Variations in the blood cytokine profile after experimental stress were lower in behaviorally active specimens. A statistically significant decrease was observed only in the amount of a proinflammatory cytokine IL-1α and anti-inflammatory cytokines IL-4 and IL-13. As differentiated from passive rats, these changes in active specimens were most pronounced 1 day after negative emotiogenic exposure. Our results illustrate a specific involvement of immunoactive substances in the systemic regulation of physiological functions and development of individual resistance to the negative consequences of stress.

[Monitoring of human physiological functions during the daily night sleep]

The basic somnological methodology, which is extensively used in the present time, focuses only on clinical practice. However, this approach is not appropriate for monitoring of physiological functions during natural sleep under home conditions. Our work was designed to develop a new information-and-equipment device for the reliable study of human physiological functions during sleep in the real everyday life. The information complex is a new portable microprocessor device and original software, which is constructed on the basis of PC and provides a control of vital physiological functions during sleep in the real everyday life. We developed a new methodology for the objective comprehensive study of sleep under real day-to-day conditions. This approach allows us to identify the phase structure of sleep and to control cardiovascular functions and breathing on the basis of a cross-correlation analysis of the heart rate and respiratory rate (that reflects the degree of emotional strain). The information system for control of sleep under living conditions is composed from interrelated units, which perform the following functions: registration, identification, and analysis of the phase structure of sleep; wake-up of a subject in a certain time during the pre-determined optimal phase of sleep (as regards the psychophysiological state of this subject); and interruption of a long-lasting hazardous phase of sleep. Due to a complex analysis of physiological functions, the information system provides monitoring of sleep under real living conditions and interruption of hazardous phases of sleep that can be accompanied by serious cardiovascular disorders (i.e., leading to cerebral stroke, myocardial infarction, and sudden death).

[Taste perception during clinical symptom complex of gastroesophageal reflux disease]

Taste perception is an important criterion for the state of the oral mucous membrane in patients with gastroesophageal reflux disease. The tongue, as an organ of taste, is characterized by serious changes in the functional state after injury with acid-containing substrates due to reflux. The specific features of taste perception and possibility for their correction were studied in 75 patients with this disorder. The type of changes in activity of tongue taste receptors and taste thresholds in patients before and after therapy were estimated by means of advanced gustometry and functional mobility technique. Specific changes in sensory function of the oral cavity were shown to be associated with acid aggression. Our results illustrate the possibility of taste correction in patients with gastroesophageal reflux disease. Taking into account some features of the general disease, it can be concluded that the introduction of Parodontax-F toothpaste and Emalan into combined therapy is accompanied by the improvement of taste perception. Correction of dysgeusia is an important criterion for the improvement of the quality of life of patients.

Biochemical changes in rats with different behavioral characteristics under conditions of metabolic stress

Food deprivation is an extreme state of the functional feeding system, which is reflected in the character of changes in the activity of central and peripheral components selectively included in the system. We studied the dynamics of coenzyme Q10 levels and spectrum of omega-3 and omega-6 polyunsaturated fatty acids in the blood serum, liver, and brain as well as LPO intensity in the serum and liver in behaviorally passive and active rats under conditions of food deprivation. Our results indicate that adaptive and compensatory processes during acute metabolic stress depend on the initial behavioral characteristics of the animals.

Dynamics of changes in nociceptive reactions of rats after peripheral administration of lipopolysaccharide

The type of changes in nociceptive reactions of rats was studied at various time intervals after intraperitoneal injection of LPS in a dose of 30 μg/kg. The perceptual component of nociception in animals was evaluated from the tail-flick latency in response to light-heat stimulation. The emotional component of nociception in rats was determined from the vocalization threshold during electrocutaneous stimulation of the tail. The tail-flick latency of animals under conditions of light-heat stimulation was shown to decrease 1 day after peripheral administration of LPS, which illustrates an increase in the perceptual component of nociception at the relatively early stage of antigenic stimulation. A significant decrease in the tail-flick latency and vocalization threshold in rats in response to nociceptive stimulation was observed on day 7 after LPS injection. These changes demonstrate an increase in the perceptual and emotional components of nociception at the late period after antigen exposure. Our results indicate that antigenic stimulation due to peripheral administration of LPS is followed by the increase in nociceptive sensitivity of rats. LPS-induced variations in the emotional and perceptual components of nociception in animals suggest the existence of specific mechanisms for systemic regulation of pain. They probably depend on the period of study and type of immune reactions during antigenic stimulation.

Cytokine levels in rat blood and brain structures after administration of lipopolysaccharide

We compared cytokine profile of rat serum and brain structures after immune status modulation by LPS (30 μg/kg intraperitoneally). The content of inflammatory (IL-1α, IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) and anti-inflammatory (IL-4 and IL-10) cytokines in biological samples of animals was measured on days 1 and 7 after antigenic stimulation. LPS administration reduced the levels of both inflammatory and anti-inflammatory cytokines in the peripheral blood of the rats, especially on the 1st day. LPS administration was also accompanied by specific changes in cytokine content in the dorsal hippocampus and anterior cingulate cortex. Antigenic stimulation increased the level of anti-inflammatory cytokines IL-4 and IL-10 in the examined brain tissues, the changes were most pronounced on day 1 after LPS injection. No significant changes in the levels of proinflammatory cytokines in the brain tissue of animals were found at the above terms after LPS injection. Thus, peripheral LPS administration to rats shifts the balance between the inflammatory and anti-inflammatory cytokines in the CNS structures towards the latter.

[Effect of melatonin on lipid peroxidation in the blood of rats with various behavioral characteristics during acute emotional stress]

This work was designed to study the effect of melatonin on lipid peroxidation in the peripheral blood of behaviorally passive and active Wistar rats. Immobilization of rats with simultaneous electrocutaneous stimulation (1 h) served as a model of acute stress. After intraperitoneal injection of melatonin (2 mg/kg) the intensity of lipid peroxidation in the blood plasma remained practically unchanged in passive specimens, but increased in active animals. Stress exposure was followed by specific variations in free radical processes in the blood (passive rats, inhibition; active specimens, no changes). Administration of melatonin contributed to a decrease in the intensity of lipid peroxidation in the blood of stressed rats (as compared to control specimens receiving this neurohormone). Therefore, the effect of melatonin on free radical processes depends on the initial behavioral characteristics and physiological state of animals. These data illustrate the importance of an individual approach to studying the systemic mechanisms for organization of functions in mammals. Key words: melatonin, emotional stress, lipid peroxidation, blood plasma, rats with various behavioral characteristics.

Melatonin effects on serum cytokine profiles of rats with different behavioral parameters in acute emotional stress

The effects of melatonin (epiphyseal neurohormone) on the serum cytokine profiles of rats with different behavioral characteristics were studied after acute emotional stress. One-hour immobilization of animals with simultaneous electrocutaneous stimulation of subthreshold intensity served as the stress model. Acute stress exposure of animals with active behavior led to reduction of the peripheral blood concentrations of pro-inflammatory (IL-1α, IL-1β, IL-2, IFN-γ, granulomonocytic CSF) and anti-inflammatory (IL-4, IL-10) cytokines. Passive rats exposed to emotional stress developed a pronounced increase of pro-inflammatory IL-1β concentration. Reduction of pro-inflammatory cytokine levels in active rats exposed to stress was less pronounced after intraperitoneal preinjection of melatonin (2 mg/kg). In passive animals, exogenous melatonin inverted the poststress changes in the serum levels of pro-inflammatory IL-2 cytokine and of anti-inflammatory IL-4 and IL-10 cytokines. The modulatory effect of melatonin on the cytokine profiles of rats with different behavioral parameters seemed to contribute to adaptation of animals to emotional stress exposure.

Effect of interleukin-1β on peripheral blood leukocytes in rats with various behavioral characteristics during acute stress

We studied the effect of a pro-inflammatory cytokine IL-1β (5 μg/kg intraperitoneally) on blood leukocytes in Wistar rats various behavioral characteristics during acute emotional stress (1-h immobilization with simultaneous delivery of subthreshold electrocutaneous stimulation). Stress exposure was accompanied by a decrease in the total number of peripheral blood leukocytes in rats. Active animals were characterized by the increase in neutrophil count during stress. The number of eosinophils in passive specimens was shown to decrease under these conditions. Emotional stress was followed by a decrease in the lymphocyte index (by Shaganin) of active rats and increase in the leukocyte intoxication index (according to Kalf-Kalif) of passive specimens. Stress-induced changes in leukocytes differed after pretreatment with IL-1β. The number of blood leukocytes increased in animals receiving a cytokine injection before stress exposure. Exogenous IL-1β inverted (in active rats) or prevented (in passive specimens) a change in the percentage of various types of blood leukocytes, which was found after stress exposure. These data contribute to the understanding of peripheral mechanisms for the involvement of immunomodulatory cytokines in the systemic organization of physiological functions in specimens with different prognostic resistance to a similar stress exposure.

[A review of current methods for nutrimetabolomic and proteomic research in biochemistry of nutrition]

At present biochemistry of nutrition involves the use of OMICs to investigate food quality, safety, bioactivity and nutrition mechanisms. In this context, nutrimetabolomics is one of the latest directions of nutrition development and provides a better understanding of the influence of nutritional factors on the metabolic pathways of the organism. Proteomic methods play an important role in nutrimetabolomics and allow to detect, identify and quantify proteins under different conditions. Variety of technical and methodological advances, improvements in bioinformatics and possibility of tandem use of different methods helps to solve a number of basic and applied science's problems. Currently huge amount of qualitative and quantitative data on the structure, functions and activities of proteins and their interactions is accumulated. Proteomics aims to establish and characterize a complete set of proteins of the organism. This review summarizes the basic applications of proteomics used in nutrimetabolomic researches. The advantages and disadvantages of the most common techniques of protein separation and sample ionization, types of mass analyzers, basic approaches to the identification of proteins and most widely used databases of known biological sequences are overviewed with a critical assessment of challenges and potential applications.

ATP concentration in the cingulum bundle of rats during stimulation of the ventromedial hypothalamus

We measured the concentration of ATP in the posterior cingulum bundle of Sprague-Dawley rats during electrical stimulation of the negative emotiogenic zone in the ventromedial hypothalamus. Electrostimulation of the ventromedial hypothalamus in animals was accompanied by an increase in systolic and diastolic blood pressure, which illustrates the autonomic response to this treatment. Variations in BP of rats were followed by an increase in ATP content in the posterior cingulum bundle. After stimulation of the ventromedial hypothalamus, ATP concentration in the cingulum bundle reached the maximum levels of 1.3±0.3 μM (n=4) and 1.67±0.43 μM (n=10) and remained high for 42.6±7.5 sec. The enhanced release of ATP in the cingulate region of the brain is probably related to the involvement of this structure into emotional reactions. ATP plays a role of the major energy source and signal molecule, which provides the adequate biochemical and physiological processes and cell-to-cell interaction in CNS upon the exposure to negative emotiogenic factors.