Experimental Study of Heart Functionality during Treatment of Chronic Heart Failure in Rats of Different Age Groups with Levosimendan (Experimental Study).

Levosimendan is effective in the therapy of chronic heart failure in both mature and old rats, but the duration of its therapeutic effect differs in these age groups. In 15 days after treatment, the myocardium in old rats maintained augmented functionality, whereas in old animals, functional potencies returned to the levels observed prior to the therapy. Stimulation of tissue respiration with combined administration of L-carnitine and α-lipoic acid against the background of levosimendan treatment prolonged its therapeutic effect in mature, but not in old rats.

Role of Monoaminergic Systems of the CNS in Different Periods after Status Epilepticus and Its Relation to Cerebral Hemodynamics.

Changes in the monoaminergic mechanisms in the brain at different terms after status epilepticus are determined by diverse causes and depend on the role of monoamines in the implementation of specific postictal rearrangements in CNS. Two mutually aggravating pathways cause disorders of monoaminergic mechanisms in the brain in 24 h after epileptic status: high spike-wave activity accompanied by hypocirculation that form a vicious circle; the resulting deficiency of monoamine consolidates the self-sustaining epileptic circuit. Increased activity of monoaminergic mechanisms in 5 days after epileptic status is a result of compensatory-restorative reorganization of neuronal networks and is not accompanied by spike-wave activity and hemodynamics disorders, but high convulsive readiness persists. Disturbances of monoaminergic mechanisms in 30 days after epileptic status prolong convulsive readiness that can serve as a pathogenetic basis for delayed cerebral disorders.

[The effect of status epilepticus on autonomic regulation of the heart and its functional capabilities in different postictal periods]. / Vliianie épilepticheskogo statusa na vegetativnuiu reguliatsiiu serdtsa i ego funktsional'nye vozmozhnosti v raznye postiktal'nye periody.

AIM: To study the postictal changes in the autonomic regulation of the heart rhythm and its functional capabilities in different periods after epistatus and to assess the risk of life-threatening arrhythmias. MATERIAL AND METHODS: The study was conducted on Wistar rats after epileptic status (ES). Telemonitoring of EEG and ECG was performed in the online mode using the system of the company 'ADInstruments'. Functional stress test with dobutamine was used. RESULTS: ES leads to a long-lasting disturbance of autonomic regulation (AR) of the heart and reduces its functional capabilities. The heart's AR balance is shifted towards sympathetic tonus 5 days after ES. This increases the predictors of life-threatening arrhythmias. The decrease in SWD activity increases the activity of parasympathetic tonus 10 days after ES. However, this is due to the tension of regulation mechanisms and the risk of life-threatening arrhythmias. CONCLUSION: The high degree of seizure activity of the brain in the ES predetermines prolonged postictal disorders of the AR heart, which reduce its functional capabilities and increase the risk of life-threatening arrhythmias.

Functional Capacity of the Heart in Progressive Convulsive Readiness.

Different levels of progressive convulsive readiness variously influence the dynamics of changes in heart rate variability parameters, inotropic and lusitropic reserves of the myocardium, which reflects the dependence of cardiac function on the level of convulsive readiness. Its increase is accompanied by a shift in autonomic balance towards potentiation of sympathetic influences on the heart, as well as a decrease in not only systolic, but also diastolic function, which reduces functional capacity of the heart and can lead to decompensation and prenosological state.

[Circadian changes in the structure of cardiac rhythm during pre-symptomatic and symptomatic stages of Parkinson's disease]. / Tsirkadnye izmeneniia struktury ritma serdtsa na dosimptomnoi i simptomnoi stadiiakh bolezni Parkinsona.

AIM: To study circadian regulation of heart rhythm during the pre-symptomatic (PS) and early symptomatic (ESS) stages of Parkinson's disease (PD) and determine the functionally most unfavorable periods during which there is a risk of life-threatening arrhythmias. MATERIAL AND METHODS: The studies were performed on C57BL/6 mice. ECG monitoring was performed in online mode using a wireless telemetry system (ADInstruments Australia). RESULTS: Characteristics of circadian changes heart rate during PS and ESS of PD were detected. During PS changes in the autonomic regulation of the heart occur at night. The increase at this time of the parasympathetic tone indicates compensatory mechanisms that prevent changes in the total power spectrum. However, they can't prevent the high risk of life-threatening arrhythmias. The early symptomatic stage leads to the changes in mechanisms of not only sympathetic, but also parasympathetic regulation of the heart, increase in sympathetic tone and disturbed structure of the heart rhythm over most of the day. The decrease in the total power of the spectrum indicates a decrease in the adaptive capacity of the cardiovascular system. The increase in the intervals of QT, QTc and Tpeak Tend, indicates a risk of life-threatening arrhythmias. CONCLUSION: PD predetermines complications of circadian autonomic regulation of the heart during PS and ESS, which can become the pathogenetic basis for severe cerebrocardial disorders.

Effect of Progressive Heart Failure on Cerebral Hemodynamics and Monoamine Metabolism in CNS.

Compensated and decompensated heart failure are characterized by different associations of disorders in the brain and heart. In compensated heart failure, the blood flow in the common carotid and basilar arteries does not change. Exacerbation of heart failure leads to severe decompensation and is accompanied by a decrease in blood flow in the carotid and basilar arteries. Changes in monoamine content occurring in the brain at different stages of heart failure are determined by various factors. The functional exercise test showed unequal monoamine-synthesizing capacities of the brain in compensated and decompensated heart failure. Reduced capacity of the monoaminergic systems in decompensated heart failure probably leads to overstrain of the central regulatory mechanisms, their gradual exhaustion, and failure of the compensatory mechanisms, which contributes to progression of heart failure.

[The influence of growing seizure readiness on the autonomic regulation of the heart]. / Vliianie narastaiushchei sudorozhnoi gotovnosti na vegetativnuiu reguliatsiiu serdtsa.

AIM: To study the functional state of the heart in a progressive increase of seizure readiness (SR) due to pentylenetetrazole kindling. MATERIAL AND METHODS: The study was carried out on male rats of the Wistar line. Simultaneous telemetric monitoring of electrocardiogram and electroencephalogram on-line was used. Individual SR of animals in 7- and 27 day pentylenetetrazole kindling was determined. RESULTS: The decrease in the index of LF/HF after 7 days of kindling reflects a compensatory reaction of the autonomic nervous system. However, the increase in SI indicates that the result obtained at the price of considerable stress regulation mechanisms. The increase in QTc, Tpeak Tend and reduced SDNN and TP suggest that compensatory mechanisms cannot prevent the high risk of life-threatening arrhythmias. High SR after 27 days of kindling is accompanied by a shift of autonomic balance towards the growth of tone of the sympathetic system which may lead to decompensation and prenosological state. CONCLUSION: The characteristics of autonomic regulation of the heart in progressive SR are important for fundamental and clinical cardioneurology.

Functional State of the Heart during Spontaneous Nonconvulsive Seizure Activity at Various Times of the Day.

Circadian peculiarities of HR regulation and functional capacities of the heart in WAG/Rij rats with genetically determined absence epilepsy are related to spike-wave activity of the brain. The number of spike-wave discharges (SWD) is maximum at night, early morning, and evening time and decreases to minimum at 08.00-16.00. At night, functional capacities of the heart are reduced and stress test at night induces ischemic changes in the myocardium at a lower functional load than in the daytime (low level of SWD activity). The decrease in the number of SWD and spike-wave index during the daytime contributes to the central mechanisms of autonomic regulation of the heart. However, these capacities are reduced against the background of increased seizure activity during nighttime.

[DYNAMICS DAILY VARIABILITY OF HEART RATE AND BLOOD PRESSURE IN CHRONIC HEART FAILURE].

Analysis of results the telemetry monitoring of daily dynamics of heart rate variability in the control and experimental rats with chronic heart failure (CHF) has revealed different mechanisms of vegetative regulation of heart rate. In animals with chronic heart failure found a significant worsening of cardiac dysfunction at night and in the morning, accompanied by an increase in the variability of systolic and pulse pressure as well as the number of QTc intervals longer than 220 ms and Tpeak-Tend. This indicates the maximal high risk of fatal ventricular arrhythmias, leading to sudden cardiac death.

[Violation of cerebral hemodynamics in the cardiac dysfunction caused by chronic heart failure].

UNLABELLED: OBJECTEVE: To study changes of cerebral haemo dynamics at the progressing kardialny dysfunction caused by chronic heart failure. MATERIAL AND METHODS: Authors executed all researches on male Wistar rats. Used methods: echocardiography and ultrasound Doppler study of the brain vessels is performed using US-apparatus Mindray M5, using linear sensor 10 MHz (Mindray, China); magnetic resonance imaging of brain and heart of experimental animals with chronic heart failure. Applied functional tests. RESULTS: In the early stage of cardiac decompensation does not change the blood flow in the carotid and basilar arteries, but seizure readiness (SR) of the animals increased. Preservation of reactivity to hypercapnic and compression tests, suggests that the increase in SR is not associated with circulatory disorders in the brain. Exacerbation of heart failure (HF) leads to severe decompensation, including a decrease in blood flow in the carotid and basilar arteries. Metabolic cascade of autoregulation in these animals areaktiven and myogenic greatly reduced. In this case revealed a progressive increase in the SR. CONCLUSION: Inefficiency of the heart at different stages of HF is not the same effect on the reserves of the autoregulation of cerebral hemodynamics, which affects the formation and aggravation of SR. Moreover, its rise in various stages of decompensation is not always caused by cerebral ischemia.

[Enhancing the reparative potentials of the cellular structures in the hypothalamus by the preliminary adaptation of animals to hypoxia and stress]. / Povyshenie reparativnykh vozmozhnostei kletochnykh struktur gipotalamusa putem predvaritel'noi adaptatsii zhivotnykh k gipoksii i stressu.

Effects of preliminary adaptation of rats to hypoxic hypoxia and short-term stress environments on the dynamics of the repair changes of RNA and proteins in the cellular structures of supraoptic (SON) and paraventricular (PVN) nuclei of hypothalamus are studied. Adaptation to hypoxia and short-term stresses is found to increase the potential of protein-synthetizing system of neuro- and gliocytes of SON and PVN. It prevented a marked decrease in the RNA and proteins contents during a post-stress period and increased an intensity of the repair processes in the nuclei being tested. Experimental findings are indicative of a heterochronic pattern of repair processes in hypothalamic neurosecretory structures which to a great extent can be related with their potentials to rearrange the intracellular metabolism for maximum functional maintenance during stresses.

[Neurochemical and morphological studies of hypothalamic structures in stress]. / Neirokhimicheskie i morfologicheskie issledovaniia struktur gipotalamusa pri stresse.

Using cytospectrophotometric as well as cyto- and karyometric techniques, we measured neuronal volumes of the supraoptic and paraventricular nuclei of the hypothalamus of white rats exposed to hypokinesia of varying duration. Also, we measured RNA and total protein in those structures. It was found that at early stages of hypokinesia accompanied by the stress-reaction neurosecretory cells of the supraoptic and paraventricular nuclei were asynchronously involved in the organization of the reaction. The effects detected in the supraoptic and paraventricular nuclei during prolonged hypokinesia differed significantly from the above affects which seems to be associated with adaptive changes in the structures described.