Development of the Ontogenetic Method in Studying Evolution of Contractile Functions

Practically all organism's visceral organs and systems performing contractile function as well as the somatomotor apparatus of higher animals, regardless of the type of muscles and character of control of their activity, start their work at early stages of ontogenesis with autorhythmic contractions. This activity is endogenous, as it does not have any external rhythmic analogs. Two fundamentally different components can be distinguished in the endogenous rhythm: the basic ones, specific of each system, and the secondary ones, built over the basic rhythms that reflect oscillatory processes in the whole organism and serve the basis for integration of endogenous periodic processes. Formation and synchronization of the secondary rhythms is the earliest stage of coordination of the automatically working systems. The broadening of possibilities for regulation and age-dependent inhibition of the autorhythm provide a transition to reflex-determined forms of activity. In various contractile systems, stages of evolution of neuromuscular relationships, from the independent autorhythm to the voluntary control of contractions, find their reflection.     

Effect of change in levels of motor activity and innervation on basic and secondary rhythms of rat heart rate and respiration in ontogenesis

Changes in the heart basic rhythm, its rhythmical variations on periodograms, and level of spontaneos motor activity were studied on offspring of white rats from newborn to 3-week age at transition from the state of active wakefulness to narcosis as well as under conditions of blockade of M-cholinoreceptors with atropine. It is shown that the endogenous rhythmical activity can be regulated not only by a change in frequency of basic rhythms, but also by action on all parameters and properties of their rhythmical variations and secondary rhythms. The changes in power of the heart secondary rhythms exceed considerably the frequency oscillations of basic rhythms during blockade of cholinergic innervation or a change in the motor activity level that affects both the basic rhythm circulation and respiration and their variations--secondary rhythms. The atropine blockade of M-cholinoreceptors at the studied ages changes the heart beating rhythm within the limits of 10% of bradicardia in newborns to tachycardia in the 3-week old animals. At the same time, power of the cardiac rhythm secondary oscillations changes several times. These data indicate that the cholinergic mechanisms play the key role in formation of the secondary rhythms and their correlation with motor activity.     

Effect of change in levels of motor activity and innervation on basic and secondary rhythms of rat heart beatings and respiration in ontogenesis

Changes in the heart basic rhythm, its rhythmical variations on periodograms, and level of spontaneous motor activity were studied on offspring of white rats from newborn to 3-week age at transition from the state of active wakefulness to narcosis as well as under conditions of blockade of M-cholinoreceptors with atropine. It is shown that the endogenous rhythmical activity can be regulated not only by a change in frequency of basic rhythms, but also by action on all parameters and properties of their rhythmical variations and secondary rhythms. The changes in power of the heart secondary rhythms exceed considerably the frequency oscillations of basic rhythms during blockade of cholinergic innervation or a change in the motor activity level that affects both the basic rhythm circulation and respiration and their variations—secondary rhythms. The atropine blockade of M-cholinoreceptors at the studied ages changes the heart contraction rhythm within the limits of 10% of bradycardia in newborns to tachycardia in the 3-week old animals. At the same time, power of the cardiac rhythm secondary oscillations changes several times. These data indicate that the cholinergic mechanisms play the key role in formation of the secondary rhythms and their correlation with motor activity.     

Secondary rhythms of automatically functioning systems

In wakeful rats at the age from newborn to 3 weeks there were studied interrelations of rhythmical oscillations of heart rate, respiration rate, and periodic spontaneous motor activity. In all studied systems, these oscillations are coordinated and occur in several frequency diapasons. Frequencies in the near-minute diapason (the period from 30 to 90 s) are the most constant and do not change with age. Regular oscillations are the most stable in newborns. Bursts of motor activity usually are irregular, but episodically the distinct near-minute rhythm is traced. Studies of the character of interaction of the heart activity, respiration, and periodic somatomotor excitation allow stating that the main coordination pathway of spontaneous autorhythmic functions in early postnatal ontogenesis is formation of secondary rhythms. Possible ways of formation of the secondary rhythms are considered.     

Secondary Rhythms of Cardiac Activity in Rat Ontogeny

Endogenous periodic oscillations of the heart beat rate are described in rat pups aged 3–4, 7–8, 10–11, 13–14, 21–22 days and 1.5 month after birth. These oscillations have all characteristic features established earlier for the secondary rhythms of endogenous contractile activity in the wall of various regions of the gastrointestinal tract and for bursts of spontaneous somatomotor excitation in the early postnatal ontogeny of rats: a multi-stage organization, inconstancy, irregularity of components. In frequency spectra of secondary oscillations of the heart rate obtained by means of fast Fourier transform of R–R intervals of the periodogram, age-related changes of the spectral frequency power are demonstrated in 4 ranges, 0.01–0.03, 0.03–0.1, 0.1–1.0, and 1.0–2.5 Hz, which correspond to the about-one-minute, decasecond, and about-one-second waves of the heart rhythm oscillations and to sinus arrhythmia. It is shown that the dominating frequencies of the secondary rhythms in each range do not have regular age-related changes, which is characteristic of all endogenous secondary rhythms.     

Organization of endogenous rhythms of motor functions (To the 100-Anniversary of A.V. Voino-Yasenetskii)

Two categories of endogenous rhythmical activity of somatic and visceral muscle are considered: the basic rhythms determined by morphofunctional and age-related characteristics of an organ or system and the secondary rhythms characterized by wide spreading in different systems, age-related stability, and many-level organization. In early ontogenesis, both forms of rhythmical activity has the common goal—to provide homeostasis of the growing organism under conditions of limited external afferentation and imperfection of adaptive regulatory mechanisms. Formation of the secondary rhythms is considered as the way and the result of coordination of functions that have endogenous rhythmicity.     

Temporal structuring of delivery in the absence of a photoperiod: preparturient myometrial activity of the rhesus monkey is related to maternal body temperature and depends on the maternal circadian system.

No convincing evidence exists that the shift from myometrial contractures to contractions, which determines the synchronized 24-h rhythm in the dynamics of the primate uterus, may be attributed to an endogenous circadian rhythm. We therefore wished to ascertain whether a 24-h periodic shift would also occur in the myometrial activity of animals kept under constant conditions. We studied five pregnant rhesus monkeys, kept in continuous darkness from 56-77 days gestational age until delivery at 117-167 days gestational age. During the last week before delivery we determined the individual phase, level, and amplitude of circadian changes in maternal body temperature and 24-h myometrial activity patterns in the form of contractions. In all five monkeys, a rhythm with a period of 24-h characterized the temporal incidence of preparturient contraction activity. A consistent phase lag of 6-7 h from the temperature crest was observed in four out of the five animals. The circadian phase of all individual rhythms was idiosyncratic among animals. We conclude that endogenous rhythms in body temperature and preparturient myometrial activity are truly circadian. In addition, these rhythms are either interdependent or subject to the same maternal timekeeping mechanism, supporting the hypothesis that the exact time of the day at which birth occurs in the rhesus monkey depends on the maternal circadian system.     

Development of hamster circadian rhythms. I. Within-litter synchrony of mother and pup activity rhythms at weaning

The circadian wheel-running activity rhythms of individual hamster pups raised and maintained in constant dim light were measured beginning at 18 days of age. Records of the postweaning free-running activity rhythm were used to determine the phase of a pup's rhythm on the day of weaning and its phase relationship to its mother's rhythm. Although raised in constant light, the rhythms of pups within a litter were approximately synchronous and in phase with their mother's activity rhythm. These results indicate that the circadian oscillator underlying the activity rhythm is functional prior to weaning and is entrained by some as yet unidentified aspect of maternal rhythmicity. Furthermore, the results suggest that even in the absence of external entraining cycles, behavioral rhythms, and perhaps physiologic rhythms as well, of a mother and her offspring are normally synchronized.     

Circadian activity rhythms in cockroaches. 3. The role of endocrine and neural factors

The control of circadian activity rhythms (diurnal rhythms) in insects has been suggested to result by periodic neuroendocrine secretions. More specifically, Harker ('56) claimed that the locomotor rhythm in the cockroach, Periplaneta americana, is timed by a secretory “clock” located in the subesophageal ganglion. Later experiments by Harker indicated that this “clock” function failed unless the retrocerebral organs were left intact; allatectomy was said (no evidence given) to abolish a rhythm. The procedure for demonstrating a “clock” function in the ganglion involved transplanting it from a rhythmic donor into the hemocoel of an arrhythmic host and observing that the host subsequently became rhythmic. This result (without explicit information about the phase of the rhythm) does not warrant the conclusion that the ganglion acts as a clock. Therefore, I have attempted to confirm and extend these important results. Employing techniques essentially identical to Harker's, and using the same species of roach, I have been unable to find any evidence to support the original claim: (1) in 20 test animals, implantation of ganglia from rhythmic donors failed to re-instate a rhythm, and (2) allatectomy (22 cases) or removal of the entire retrocerebral complex (20 cases) did not interfere with the rhythm. The results of another series of experiments show that the cockroach brain is involved in the control of the activity rhythm. When the brain is surgically bisected (mid-sagittal) through the pars intercerebralis, arrhythmic activity patterns are immediately evoked. These continue for many weeks, but in a few cases rhythms ultimately “regenerate”.     

Rhythmic processes in early embryogenesis timed by cell division

he data on rhythmic processes in early embryogenesis coinciding with cell divisions are considered. Possible mechanisms which determine the rhythm frequency and are its motive power are discussed, as well as the role of individual rhythmic processes in the regulation of consecutive cell cycle events. A suggestion is put forward that these rhythmic processes are transformed during subsequent development in circum-hour rhythms of some biochemical, physiological and biophysical processes discovered in the cells and organs of adult organism.     

Seasonal variations in daily rhythms of activity in athletic horses

Circadian rhythms reflect extensive programming of biological activity that meets and exploits the challenges and opportunities offered by the periodic nature of the environment. In the present investigation, we recorded the total activity of athletic horses kept at four different times of the year (vernal equinox, summer solstice, autumn equinox and winter solstice), to evaluate the presence of seasonal variations of daily activity rhythms. Athletic Thoroughbred horses were kept in individual boxes with paddock. Digitally integrated measure of total activity of each mare was continuously recorded by actigraphy-based data loggers. Horse total activities were not evenly distributed over the day, but they were mainly diurnal during the year. Daily activity rhythms showed clear seasonal variations, with the highest daily amount of activity during the vernal equinox and the lowest during the winter solstice. Interestingly, the amount of activity during either photophase or scotophase changed significantly throughout the year. Circadian analysis of horse activities showed that the acrophase, the estimated time at which the peak of the rhythm occurs, did not change during the year, it always occurred in the middle of the photoperiod. Analysing the time structure of long-term and continuously measured activity and feeding could be a useful method to critically evaluate athletic horse management systems in which spontaneous locomotor activity and feeding are severely limited. Circadian rhythms are present in several elements of sensory motor and psychomotor functions and these would be taken into consideration to plan the training schedules and competitions in athletic horses.     

Circahoralian (Ultradian) metabolic rhythms

This review presents data concerning metabolic rhythms with periods close to one hour (20 to 120 min): their occurrence, biochemical organization, nature, and significance for adaptations and age-related changes of cells and organs. Circahoralian (ultradian) rhythms have been detected for cell mass and size, protein synthesis, enzyme activities, concentration of ATP and hormones, cell respiration, and cytoplasm pH. Rhythms have been observed in bacteria, yeasts, and protozoa, as well as in many cells of metazoans, including mammals, in vivo and in cell cultures. In cell populations, the rhythms are organized by direct cell-cell communication. The biochemical mechanism involves membrane signal factors and cytoplasmic processes resulting in synchronization of individual oscillations to a common rhythm. Phosphorylation of proteins is the key process of coordination of protein synthesis and enzyme activity kinetics. The fractal nature of circahoralian rhythms is discussed as well as the involvement of these rhythms in adaptations of the cells and organs. Senescent decrease in rhythm amplitudes and correspondingly in cell-cell communication has been observed. The possibility of remodeling these changes through the intercellular medium has been predicted and experimentally shown. Perspectives for studies of the organizers and disorganizers of cell-cell communication in the intercellular medium along with appropriate receptors are discussed with special emphasis on aging and pathology. One perspective can be more precise definition of the range of normal biochemical and physiological state with the goal of correction of cellular functions.     

Correlation between level of aggressiveness of personality and characteristics of EEG frequency components

In a group of 80 adults of both sexes, we studied the correlation between the characteristics of aggressiveness of the individual (diagnosed using the Buss-Durkee questionnaire) and parameters of the frequency components (rhythms) of EEG recorded in the resting state from leads C3 and C4 according to the 10–20 system. Despite the natural high interindividual variability, the higher spectral powers of nearly all EEG frequency components (δ-, θ-, α-, and β rhythms) and coefficient of reactivity of the α rhythm corresponded in general to lower indices on the scales of the Buss-Durkee questionnaire and smaller values of the index of aggressiveness and index of hostility. These correlations probably reflect a significant dependence of both characteristics of aggressiveness of personality and amplitude parameters of the EEG rhythms on hereditary factors. Both these aspects of the neurodynamic constitution of the individual are to a significant extent determined by the specificity of organization and functioning of a few neurotransmitter (in particular, aminergic) and neurohumoral systems. Neirofiziologiya/Neurophysiology, Vol. 38, Nos. 5/6, pp. 448–457, September–December, 2006.     

Cerebroid Ganglion is the Presumptive Pacemaker of the Circadian Rhythm of Electrical Response to Light in the Crayfish

One of the most widely studied circadian rhythms in invertebrates is that of light responsiveness whose underlying mechanisms seem to involve different groups of oscillators which act as pacemakers. Although, in crayfish, there are clear circadian rhythms in the electroretinogram (ERG) amplitude, the precise location of the pacemaker system driving this rhythm is uncertain. Some data suggest that the circadian pacemaker could be located in a group of neurosecretory cells of the supraesophageal ganglion (the cerebroid ganglion or brain) and that the sinus gland plays a determinant role in the generation and expression of this rhythm through periodic release of pigment-dispersing hormone (PDH). The aim of this work is to examine the role of the brain in the expression of the ERG circadian activity. The hypothesis we test is that the electrical activity at the brain level has a circadian behavior in the firing pattern of spontaneous multiunit activity (MUA) and in visual evoked potentials (VEPs). The results indicate that there are robust circadian rhythms in both MUA, recorded from several regions of the brain, and in the averaged VEPs recorded from the protocerebrum area. These rhythms are 180° out of phase to one another. The rhythm of VEPs showed a main peak at midnight which was in close phase relationship with the ERG amplitude rhythm.     

Interrelations between Peculiarities of the Motivational Sphere of a Personality and Characteristics of the Current EEG

In a group of 70 adult subjects of both sexes, we estimated the levels of the need for achievement and its motivation (interpreted as generalized characteristics of the state of the motivational sphere of a personality and diagnosed using questionnaires of Orlov and Mehrabian) and examined the correlations of these estimates with spectral powers (SPs) of the frequency components (rhythms) of the current background EEG (С3 and С4 leads according to the 10–20 system). Despite the fact that naturally high interindividual variability exists, high estimates of the need for achievement correlated with medium values of the SPs of most EEG frequency components (δ, θ, α, and β₁ rhythms), low SPs of the β₂ and γ rhythms, and higher values of the coefficient of reactivity (CR) of the α rhythm. A high level of the need for achievement corresponded to higher SPs of the θ and γ rhythms and high CR of the α rhythm, a medium SP of this EEG component, and lower SPs of the δ and β rhythms. The coefficient of interhemisphere asymmetry of the α rhythm was the highest at low values of the studied psychological indices. Interrelations that we found in our study can be explained as follows: both the characteristics of the need for achievement and motivation typical of a certain personality and the amplitude parameters of the EEG rhythms observed in this individual depend significantly on genetically determined factors (in particular, on neurochemical ones). These peculiarities of neurodynamic constitution of the individual are, to a considerable extent, due to the specificity of organization and functioning of a few neurotransmitter (aminergic, in particular) and neurohumoral systems. Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 61–69, January–February, 2009.     

Age-dependent changes of the circadian system

This review summarizes the current knowledge on changes of the circadian system in advanced age, mainly for rodents. The first part is dedicated to changes of the overt rhythms. Possible causes are discussed, as are methods to treat the disturbances. In aging animals and humans, all rhythm characters change. The most prominent changes are the decrease of the amplitude and the diminished ability to synchronize with a periodic environment. The susceptibility to photic and nonphotic cues is decreased. As a consequence, both internal and external temporal order are disturbed under steady-state conditions and, even more, following changes in the periodic environment. Due to the high complexity of the circadian system, which includes oscillator(s), mechanisms of external synchronization and of internal coupling, the changes may arise for several reasons. Many of the changes seem to occur within the SCN itself. The number of functioning neurons decreases with advancing age and, probably, so does the coupling between them. As a result, the SCN is unable, or at least less able, to produce stable rhythms and to transmit timing information to target sites. Initially, only the ability to synchronize with the periodic environment is diminished, whereas the rhythms themselves continue to be well pronounced. Therefore, the possibility exists to treat age-dependent disturbances. This can be done pharmacologically or by increasing the zeitgeber strength. So, some of the rhythm disturbances can be reversed, increasing the magnitude of the light-dark (LD) zeitgeber. Another possibility is to strengthen feedback effects, for example, by increasing the daily amount of activity. By this means, the stability and synchronization of the circadian activity rhythm of old mice and men were improved. (Chronobiology International,17(3), 261-283, 2000)     

Peculiarities of EEG in Subjects with Coronary-Prone (Type A) Behavior

In a group including 72 adults of both sexes, we studied correlations between the estimates of the so-called coronary-prone personality type (type A) diagnosed using the Jenkins questionnaire and the spectral powers (SPs) of the frequency components (rhythms) of background EEGs recorded in the resting state (leads C3 and C4 according to the 10-20 system). Despite natural high interindividual variability, estimates that characterized the subject as belonging to the behavioral type A corresponded, on average, to relatively low SPs of the δ, θ, and α EEG components, intermediate values of the β₁ rhythm SP and coefficient of reactivity of the α rhythm, and higher SPs of the high-frequency (β₂ and γ) rhythms. Estimates characterizing type B personality corresponded to significantly higher δ-rhythm SPs, intermediate SPs of the θ and α rhythms, and smaller SPs of the β and γ rhythms. The interhemisphere asymmetry coefficient for the α rhythm was usually negative in type-A individuals and positive in the cases of types B and AB. The peculiarities observed are probably determined, to a certain extent, by the fact that both the characteristics of the behavioral types of the personality and the amplitude parameters of EEG rhythms depend significantly on inherited (in particular neurochemical) factors. Such peculiarities of the neurodynamic constitution of the individual are determined, to a considerable extent, by the specificity of organization and functioning of a few neurotransmitter (in particular aminergic) and neurohumoral systems.     

Identification of rhythmic subsystems in the circadian cycle of crassulacean acid metabolism under thermoperiodic perturbations

Leaves of the Crassulacean acid metabolism (CAM) plant Kalancho? daigremontiana Hamet et Perrier de la Bathie show overt circadian rhythms in net CO2 uptake, leaf conductance to water and intercellular CO2 concentration, which are entrained by periodic temperature cycles. To probe their sensitivity to thermoperiodic perturbations, intact leaves were exposed to continuous light intensity and temperature cycles with a period of 16 h, applying a set of different baseline temperatures and thermodriver amplitudes. All three overt rhythms were analyzed with respect to their frequency spectra and their phase relations with the thermodriver. For most stimulation protocols, stomatal conductance and net CO2 change were fully or partially entrained by the temperature pulses, while the internal CO2 concentration remained dominated by oscillations in the circadian range. Prolonged time series recorded for up to 22 d in continuous light underline the robustness of these circadian oscillations. This suggests that the overt circadian rhythm of net CO2 uptake in CAM results from the interaction of two coupled original systems: (i) an endogenous cycle of CO2 fixation in the mesophyll, showing very robust periodic activity, and (ii) stomatal movements that respond to environmental stimuli independently of rhythmic processes in the mesophyll, and thus modulate the gas exchange amplitude.     

Chronobiology in 1975.

A spectrum of rhythms with several frequencies importantly characterizes not only the central nervous system but also the neuroendocrines and endocrines, other structures and organs, beyond the level of the cell to subcellular structures; it has a wide bearing since chronobiologic methods and facts relate to both basic research and its bearing on major problems of our day. Perhaps most important, computer analysis of data series allows study of temporal structure, progressive and rhythmic variations in life processes and in their responses to environment and drugs. By such methods coupled to modern data collection and/or self-measurement, chronobiology is particularly promising in the following areas, cited as illustrative rather than comprehensive examples: 1. Work hygiene: optimization of work schedules by adjustment of regular schedules and in particular of shift-work to the individuals' physical and mental rhythms. Experimentally, differences in manner of schedule change can account for the difference between the life span shortening and lengthening. 2. Population control: improved methods for detecting the neural as well as neurohormonal regulation of ovulatory cycles should aid efficient family planning by the recognition of a spectrum of rhythms and its synchronization with socio-ecologic factors acting, perhaps, via olfactory and/or other sensory modalities; 3. Nutrition: optimizing the utilization of ever scarcer food supplies and also the benefit from both oral and parenteral medications by meal timing; 4. Education: providing a do-it-yourself system for monitoring individual health in the context of secondary and adult education and as the basis for preventive health care; and, in another context, taking individual mental rhythms as well as morningness-eveningness into account in teaching and learning; 5. Health care: Any risk, e.g., from blood pressure rhythm alteration (perhaps preceding by years intermittent labile elevation) will be detected earlier and more efficiently by multiple measurements readily obtained by autorhythmometry. Results of such an endeavor provide at any one time indices that can be compared with an individualized rhythmometric reference standard as well as peer group rhythm parameters. The rhythm-determined average is more reliable than the single measurement. Other individualized characteristics of a rhythm, such as measures of extent of change or timing of change, may constitute an early warning signal and could be monitored by self-measured or preferably automatically-collected data. Timely and timed treatment can then be sought to prevent, in the case of blood pressure, elevation and consequent debilitating disease such as coronary infarction and stroke. 6. Therapy: One can strive toward the more specific correction of any pathogenic rhythm alteration when such can be recognized by modern methods of data collection and data analysis...     

Circadian rhythms of melatonin in European starlings exposed to different lighting conditions: relationship with locomotor and feeding rhythms

In passerine birds, the periodic secretion of melatonin by the pineal organ represents an important component of the pacemaker that controls overt circadian functions. The daily phase of low melatonin secretion generally coincides with the phase of intense activity, but the precise relationship between the melatonin and the behavioral rhythms has not been studied. Therefore, we investigated in European starlings (Sturnus vulgaris) (1) the temporal relationship between the circadian plasma melatonin rhythm and the rhythms in locomotor activity and feeding; (2) the persistence of the melatonin rhythm in constant conditions; and (3) the effects of light intensity on synchronized and free-running melatonin and behavioral rhythms. There was a marked rhythm in plasma melatonin with high levels at night and/or the inactive phase of the behavioral cycles in almost all birds. Like the behavioral rhythms, the melatonin rhythm persisted for at least 50 days in constant dim light. In the synchronized state, higher daytime light intensity resulted in more tightly synchronized rhythms and a delayed melatonin peak. While all three rhythms usually assumed a rather constant phase relationship to each other, in one bird the two behavioral rhythms dissociated from each other. In this case, the melatonin rhythm retained the appropriate phase relationship with the feeding rhythm. Accepted: 10 December 1999