ELECTRIC-MAGNETIC STIMULATION PREVENTS STRESS-INDUCED DETERIORATION OF SPATIAL MEMORY.

In response to physical and psychological stressors, neurobiological processes are activated to maintain homeostasis. Stress alters the activity of the hypothalamic-pituitary-adrenal (HPA) axis. The mechanism for this effect is not yet clear. For the formation of moderate stress, the Chronic Immobilization Stress (CIS) model was chosen to perform the restriction of movement activity 2 hours every day for 20 days continuously. The impacts of CIS on cognitive function (elevated multi branch maze test) and Glucocorticoid receptor (GluR) levels in the hippocampus were studied in adult rats of both sexes. Electromagnetic stimulation (EMS) is an effective and non-invasive treatment method. After the end of CIS, the parameters of EMS (10000-15000 Hz, 1.5 m/Tesla, for 20 min, 10 days) on cognitive function and GluR changes were established in intact and gonadectomized rats. The study's goals were to determine the effect of CIS on spatial learning and GluR content in the hippocampus; b. the capacity of EMS to prevent or restore disorders developed in response to stress; and c. whether emerging stress responses are gender dependent. It has been revealed that immobilization stress increases the maze passing time and the number of errors in both male and female rats. The effect of stress was more significant in male rats than in female rats. Gonadectomy increased the maze passage time regardless of sex. EMS for ten days has a positive effect on spatial learning. In females subjected to stress, the time to complete the maze path was fully restored to the level of intact rats, although in males this time remained relatively high. The time spent to pass the trajectory was increased after ten days of stress without EMS. As a result of immobilization stress, in both intact and gonadectomized rats, the GluR content had decreased in the hippocampus but was restored after EMS. The CIS induced a reduction of GluRs in the hippocampus that is manifested as the deterioration of spatial memory. EMS restored GluR expression and had a facilitative effect on the performance of the intended task. The effects of EMS on GluRs were minimal in absence of sex hormones.

GENDER RELATED DIFFERENCES IN SEX HORMONE-MEDIATED ANXIOLYTIC EFFECTS OF ELECTROMAGNETIC STIMULATION DURING IMMOBILIZATION STRESS.

Physical and psychological stressors activate the hypothalamic-pituitary-adrenal axis (HPA). Elevated glucocorticoid levels over a long time harm neurocognitive and neurobiological development and cause deleterious effects. The effects of glucocorticoids depend not only on the concentration and duration of action, but also on the period of life when the effect occurs and gender. Electromagnetic stimulation (EMS) is a non-invasive treatment for some neurodegenerative diseases. The main objective of the study was to investigate the therapeutic effects of EMS on immobilization-induced depressive behavior (moderate stress) depending on sex hormones in an open field test. Experiments were conducted on rats both gender (n=36, 4-6 months old, 190- 220 g). The rats were group-housed in standard box cages (12-hour light-dark cycle, food and water were available ad libitum). Female and male rats were divided into 2 groups: intact and gonadectomized (n=9 in each group). Six rats from each group were immobilized 2 hours a day during 10 days. Effects of EMS were studied in all group of rats. For EMS, the following parameters were used: 15000 Hz frequency, 1,5 m/Tesla, during 20 min, 10 days. Parameters of psycho-emotional behaviour was studied in the Open - field test. Data reliability was assessed using parametric and non-parametric techniques, with the use of one- and two- way layout of factorial analysis (ANOVA). Chronic immobilization for 10 days reduced the motor-exploratory activity in male rats compared to females. EMS restored data to baseline in female but not male rats. Intact male rats had a high number of vertical stands than females. Immobilization stress significantly reduced these data in male rats compared to females. Repeated EMS within 10 days reduced the vertical stands to zero. In gonadectomized rats, immobilization reduced the number of crossed squares. Against the background of EMS, the number of crossed squares decreased again compared to gonadectomized unstressed and immobilized rats. Against the background of EMS, immobilized female rats showed a longer grooming duration compared to males. It was suggested that the adaptive mechanisms are more pronounced in intact female rats than in males. The effect of EMS on stress-induced motivational-emotional parameters of behavior depends on peripheral sex hormones.

NORMALIZING EFFECT OF ELECTROMAGNETIC STIMULATION ON BLOOD QUANTITATIVE INDICES IN DEPRESSED RATS ON THE BACKGROUND OF OXYTOCIN.

Depression is linked to systemic inflammation. There is an association between blood cell count and/or hematological inflammatory markers with depression symptoms. Oxytocin reduces the activity of brain regions that produce anxiety and might involve in the rehabilitation of depressive-like behavior. Repetitive EMS is used in the treatment of moderate depression. So, the goal of this investigation was to study the quantitative characteristics of blood cells after EMS on the background of oxytocin premedication of in depressed rats. In the implementation of the project the depressed rats (250-450 g) were used (n=20). For each task two groups of the animal were conducted: experimental group (with EMS) and control group (without EMS). For repetitive (10-days) EMF exposure, the following parameters were used: 10000 -15000 Hz frequency, 1,5 m/Tesla, for 15 min. An animal model of depression was received by subcutaneous injection of Clomipramine from 8 to 21 days of neonatal development. The blood counts were performed 2 months later after clomipramine injection using blood HumaCount 30 TS. This analyzer allows quantifying the number of red blood cells, white blood cells (agranulocytes and granulocytes), platelets, hemoglobin, the hematocrit in 1 ml blood of rats. The hematological analysis was performed 2 weeks later after oxytocin (4 mcg/per animal during 10 days) injection and EMS. The obtained results were processed using an adequate statistical program. In clomipramine -induced depressed rats, EMS independently or with simultaneous injection of Oxytocin caused normalization of blood cells count (Red blood cells, white blood cells and Platelets). More important was the simultaneous impact of EMS and oxytocin. In depressed rats, the oxytocin alone, or together with EMS can restore the blood cell imbalance.

POSSIBLE EFFECTS OF ELECTRIC-MAGNETIC STIMULATION ON HYPOTHALMIC-HYPOPHISIAL-ADRENAL AXIS: BEHAVIOURAL STUDY.

The goal of this investigation was to study the effect of the electric-magnetic stimulation (EMS) on the activity of the HPA axis, which can change behavior activity. The experiments were conducted on mongrel, albino male rats, weighing 150- 200 g (n=14). Proceeding from the goals set, the experimental group (dexamethasone-treated-1mg/ per animal for 10 days) and the control group of rats were involved in the experiments. Each group was divided into subgroups. Some rats from the subgroup were given EMS. The Control group of rats received the same amount of saline. Electro-Magnetic stimulation parameters: 10000 -15000 Hz frequency, 1,5 m/Tesla, for 15 min, during 10 consecutive days. The Forced Swimming, the Open Field, and the Active Wheel Tests were choosing for monitoring of behavior indicators. The obtained results were processed using an adequate statistical program. 1. In FST on the background of dexamethasone injection, the time of immobilization (p<0.01) was increased, the active swimming time (p<0.05), the time of the struggling (p<0.05) and the time spent under the water (p<0.05) were decreased. This fact indicates the development of depressive-like behavior. The EMS reduced immobility time in the FST (p<0.01) and increased struggling behavior (p<0.05), swimming in the FST (p<0.05), and the time spent under the water in the dexamethasone-treated rat. The Injection of Dexamethasone caused changes in motivational-emotional behavior in Open Field Test: all parameters of research-motor activity were reduced compared to normal (untreated) rats. The EMS after dexamethasone injection enhanced behavior activity of rats: research-motivated activity. We can assume that EMS strengthens self-regulatory mechanisms, which increases the resistance of the organism to stress factors, in this case, under the conditions of artificial administration of dexamethasone. 3. After 10 days of administration of dexamethasone, the locomotor activity of rats was significantly reduced during the 24-hour active wheel test. On the background EMS the motor activity dramatically increased in dexamethasone-treated rats It is possible to assume that EMS exerts antidepressant effects against the background of dexamethasone injection and inhibits the activity of the hypothalamic-pituitary-adrenal system. Against the background of high doses of dexamethasone, EMS causes the body to become more active, change the depressive-like behavior, reduces the alarm response, and increases research activity. We suppose that EMS suppresses the GRs expression (negative feedback) which reduces the activity of the HPA axis, and recover behavioral disorders induced by depression.

THE ACOUSTIC RANGE ELECTRIC-MAGNETIC FIELD EFFECT ON THE PASSIVE AVOIDANCE TASK IN DEPRESSED RATS.

Depression linked to memory problems, such as forgetfulness or confusion. Stress and anxiety can also lead to poor memory. Memory processes are affected by repeated electric-magnetic stimulation (EMS). The current study aimed to explore the effects of EMS on locomotor activity and cognitive function in clomipramine-induced depressed rats. In the implementation of the project, the depressed rats and albino intact rats (250-450 g) were used (n=20). An animal model of depression was received by subcutaneous injection of Clomipramine from 8 to 21 days of neonatal development. The control group received a saline injection in the same period of life. The determination of depression and anxiety reaction of rats was performed 2 months later after clomipramine injection in open field and Forced Swim Tests. For studying EMS effects on the cognitive function of depressed rats, a passive avoidance test was used. During the initial phase, the animal learns that moving to the dark compartment has negative consequences (rat receives a mild foot shock-12 imp/min; 1.5mA). Animals were tested 1, 3, 5, 14 and 30 days after learning test in the chamber. Data reliability was assessed using parametric and non-parametric techniques, with the use of the one-way layout of factorial analysis. In pilot experiments, we have obtained the optimal parameters of repeated EMS (10000 -15000 Hz frequency, 1,5 m/Tesla, during 15 min, 10 days), which fully or partially Inhibit depressive-like ECoG and behavior activity in rats. On the background of EMS, in depressed rats, in the learning test, the latent period of entrance into the dark chamber decreased (p<0.01) compared to non-stimulated ones. The EMS before the learning test of depressed rats, did not affect the performance of the retention test 24 h, 3, 5 days later. The effects of EMS on the passive avoidance retention test were impaired only 14 days after the learning test. Non-stimulated depressed rats did not "make mistake", they had remembered the learning test 1 month later. Both stimulated or non-stimulated control, non-depressed rats attenuated the performance of passive avoidance on the14 day after the learning test. The behavior of rats also was different in the lit section. The number of attempts to enter into the dark section changed. The research activity was increased both in the depressed and non-depressed rats on the background of EMS compared to non-stimulated ones. We might think, that either the control rats have learned better the instrumental reflex (to perform a passive avoidance reaction) or due to the high degree of depression, the locomotor-exploratory activity of animals is decreased (p<0.01), which causes the test to be properly performed. The latter assertion is confirmed by data, received in the open field test. Therefore, the acoustic range EMS decreases fear and anxiety degree and consequently, increases the locomotor-exploratory activity and attenuates retention of passive avoidance task. Thus, the acoustic EMS reduces the level of fear and anxiety, and therefore, increases motor activity, which worsens the clomipramine. It offers clinicians a novel alternative for the treatment of this disorder.

POSSIBLE IMPLEMENTATION OF GABAERGIC AND GLUTAMATERGIC SYSTEMS IN REALIZATION OF ANTIEPILEPTIC EFFECTS OF ACOUSTIC RANGE ELECTRO - MAGNETIC FIELDS.

Seizure is a clinical manifestation of a hyperexcitable neuronal network, in which, the electrical balance underlying the normal neuronal activity is altered pathologically-excitation (Glutamatergic activity) predominates over inhibition (GABAergic activity). Arresting of seizure activity is carried out by restoration of neurotransmitter balance. This process has a direct relation with ion channel permeability in cell and ion transmembrane movement. Low frequency EMS may have a neurostimulating and neuromodulating effect that is based on electromagnetic induction of electric field in the brain. Under the conditions of certain amplitude, frequency and relaxation time low-frequency electromagnetic field (EMF) induces depolarization of separate neurons, and changes the total cortical excitability in case of repeatedly carried out procedures. It was shown that the exposure of acoustic range EMS in GEPRs treated with GABA-A or GABA-B receptors antagonists decreased behavior seizure activity in response to audiogenic stimuli. Injection of Glutamate receptor agonist on background EMS causes seizure activity, but seizure manifestations have less degree compared to non-stimulated rats. Thus, in response to electromagnetic stimulation, the reduction or complete cramping of seizures can be explained by a change in the activity of the neurotransmitter systems.

Changes of locomotor, exploratory and emotional behavior in animal model of depression induced by deficiency of brain monoamine content.

The character of changes of open field behavior was not studied extensively in animal model of depression with deficiency of brain monoamine/serotonin content and obtained results are controversial. Both, enhancement and invariability of locomotor activity has been obtained. Additional investigation of this question is motivated also by insufficient study of exploratory and emotional behaviors in animal model of depression of this type. Animal model of depression was developed by chronic administration of Clomipramine and/or Melipramine in rat pups from postnatal day 7 (P7) and/or 14 (P14) to P21 and/or P28, respectively. Studies of open field behavior were started in adult age rats i.e. 8-12 weeks after the end of treatment. Control animals were the same age old. Two-week period of postnatal development starting at the P7 and/or P14 appeared equally sensitive to early antidepressant treatment. Modeled animals exhibited significant increase of horizontal locomotor activity. Frequency of center entrance and the time of staying in the center of open field were increased significantly indicating that animal models of depression can not percept really the level of stressfulness of novel surroundings. All of these changes indicate also to the significant level of exploratory behavior in modeled animals. Postnatal exposure of rat pups to Clomipramine or Melipramine produces significant increase of locomotor activity but dos not induces behavioral 'despair' or "refractory loss of interest" at mature age.

[Mechanisms involved in anticonvulsive effect of pregnancy in an animal model of epilepsy].

Interrelation between pregnancy and epilepsy is one of the pressing problems of current neurology. Those mechanisms, which suppress or amplify the seizure reactions in pregnancy, have not been yet determined experimentally. Investigation of the interrelation between the epileptic fits and pregnancy in women is complicated by the bioethical considerations, as well as by the antiepileptic therapy. Therefore, in order to solve this problem, an implementing the animal models seems expedient; moreover that this problem is scarcely investigated so far. The goal of present work was investigation of impact of gestation and the postpartum period on initiation and development of convulsive reactions in the experimental animal model. Epileptic reactions were significantly suppressed during gestation (2 and 3 weeks). The data on the changes are concerned behavioral reactions and EEG seizure activity. Therefore, generalization of the seizure activity is blocked during pregnancy.

Influence of water deprivation on morphological peculiarities of the neuronal organization in hypothalamic supraoptic and paraventricular nuclei of the rats.

In the present study a histochemical investigation of the SO and PV nuclei of the hypothalamic-pituitary neurosecretory system are presented at different periods of the water deprivation. The experiments were carried out on laboratory rats (n = 50), weighing 200-250 grams. The experimental and control animals days was maintained at different feeding ration. The control rats (I) were given food and water, the experimental animals (II, III, IV, V) for five days were given the dry food only. Following the 5-day water deprivation, the animals of the Groups III, IV, and V, had given free access to water for 15, 30, and 45 days. In order to investigate histological properties, the animals were rapidly beheaded. In order to reveal a neurosecrete, the 5-10 mm thick slices of the hypothalamus and pituitary gland were stained with the Nissle method. Evaluation of the morphological-functional state of the HPNSS a working scheme of the neurosecretory cycle has been utilized. Analysis of the above data allows concluding that following prolonged water deprivation, recovery level of the structural-metabolic components in the hypothalamic SO and PV nuclei is not uniform. Deeper morphological changes occur in the large-granular region than in the small-granular one, where no significant changes are found; respectively, these cells recover much earlier. Capacity for restoration of the structural-metabolic complex varies and depends on functional properties of the cellular content of these nuclei.