Bone marrow hemopoiesis at emotional stress reactions of various intensity upon a background of exposure to low dose ionizing radiation

Rats preliminary exposed to 0.9 Gy of ionizing radiation showed disturbances in the development of adaptive reactions of blood system to emotional stress, compensatory capacity of the blood system being decreased. A degree of the disturbances directly depended on the duration and intensity of the emotional stress: at the prolonged intensive emotional stress a sharp decrease in the adaptive and compensatory capacity of blood system was found; at short intensive or moderate stress the changes in the adaptive and compensatory capacity of hemopoiesis were less pronounced. A combined action of low-dose ionizing radiation and short weak emotional stress did non affect the adaptive and compensatory capacity of hemopoietic system.     

Effect of mexidol on hemopoietic system in conditions of an emotional stress after exposure to ionizing radiation

The emotional stress after an irradiation can complicate the current of radiative defeats. At an emotional stress developing in early terms after an irradiation in low doses, are reduced adaptive and compensator capabilities of hemopoietic system. The emotional stress after a lethal dose irradiation inhibits the post-radiation recovery of haemopoiesis, aggravates the course of acute radiation disease and decreases the efficiency of the radioprotector--indralin. These disorders are especially pronounced under a prolonged and intensive stress. The use of the mexidol, having anxiolytic and antistress by activity, made it possible to arrest completely disturbances in the development of adaptive reactions to stress in the blood system and to normalize its compensatory potentialities in animals under conditions of combined influence of intensive long-term emotional stress and of low-dose irradiation. In the case of lethally irraiated animals, the treatment of stressed animals with mexidol favorably influenced the course of acute radiation disease, enhanced recovery processes in the blood system. Under these conditions, the use of mexidol completely removes the negative effect of emotional stress in indralin-protected animals. The pharmacological correction by mexidol from displays of an intensive emotional stress, developing after an irradiation in various doses, can be a part in system of medical measures.     

The adaptive reactions in hemopoietic system of the irradiated mice of two lines, differing in the level of emotionally-stress reactions on the emotional stress

On lines of the mice genetically differing on the sensitivity on emotional stress (steady--of the mouse of the line C57BL/6 or sensitive--of the mouse of the line BALB/c), the research of the development of the adaptive reactions in the system of the blood on the emotional stress influencing animals on the background of the preliminary irradiation in a low dose (0.9 Gy) is carried out. The unirradiated mice of the line C57BL/6 adequately reacted on the stress, that was shown in a moderate behavioural reaction during the period of stress, and the development of high-grade adaptive reactions in the hemopoietic system. Among the mice of the line C57BL/6 in conditions of the combined influence of ionizing radiation and of the emotional stress was not revealed of the infringements of the adaptive reactions of the hemogenesis. As opposed to these data, among unirradiated mice of the line BALB/c the sharply expressed behavioural reactions during the stress were marked, that was accompanied by incomplete development of the adaptive reactions in the system of a blood on the stress. Under the influence of stress on the previously irradiated animal line BALB/c was observed the inhibition of the medullar hemopoiesis.     

Structure and functional changes in the gastric intramural nervous plexus in emotionally stressed rats exposed to low doses of long-term ionizing irradiation and lead

Changes in the catecholamine content in adrenergic fibres, acetylcholinesterase activity, and in the energy metabolism enzymes lactate dehydrogenase and succinate dehydrogenase in neurons of the gastric intramural plexus during emotional stress in rats a day after combined exposure to prolonged (30 days) ionizing radiation in a total dose 1.0 Gy and 0.6 mg/kg lead were studied. A decrease in catecholamines in adrenergic fibres and acetylcholinesterase and lactate dehydrogenase activity in neurons was observed. An enhanced sensitivity of the gastric intramural plexus after the prolonged exposure to small doses of ionizing radiation and lead in conditions of emotional stress was suggested.     

Comparative analysis of the stability of cardiovascular system functions in immobilized rats of different strains

The dynamics of arterial pressure and heart rate was studied in rats of different genetic lines (non-linear, Wistar, Way and August) during immobilization emotional stress. Different lines were characterised by different stability and ability of adaptation to emotional stress. Prognostic criteria were specified that enable to foresee at an early stage of emotional stress the disturbances of cardio-vascular control. The conclusion is made that resistancy against cardio-vascular disturbances during emotional stress is of genetic nature as well as may be due to characteristics of individual growth.     

Effects of the blockade of the system of opioid peptides on changes in emotional/behavioral reactions of rats induced by the action of extrahigh-frequency electromagnetic radiation in the norm and under conditions of hypokinetic stress

We studied the effects of pharmacological blockade (by injections of naloxone) of the system of opioid peptides on changes in emotional/behavioral reactions of rats in the open-field test. These changes were caused by the isolated action of low-intensity electromagnetic radiation (EMR) of extrahigh frequency (EHF) and its combination with experimentally induced hypokinetic stress. We conclude that one of the mechanisms of physiological effects of low-intensity EHF EMR is an increase in the functional activity of the system of regulatory opioid peptides; this results in adaptive modifications of the emotional/behavioral reactions under new conditions of the open-field test and provide an anti-stress effect under conditions of hypokinetic stress. Neirofiziologiya/Neurophysiology, Vol. 38, No. 1, pp. 52–60, January–February, 2006.     

Participation of angiotensin II in the establishment of negative emotional reactions

In waking rats and rabbits systemically injected angiotensin II was shown to participate predominantly in the mechanisms of negative emotional reactions. The effects of angiotensin II were observed at the behavioural level as well as at the neuronal one. Depending on the dose and the time of injection of angiotensin II and its specific antagonist saralasin they inhibited or facilitated elaboration and extinction of automatized conditioned active avoidance independently of arterial, pressure changes, the pain threshold being altered. Injection of angiotensin II abolished individual behavioural reactions of the animals in response to stress factors and increased their resistability to emotional stress. The negative emotional reactions were found to induce changes of chemosensitivity of neurones of the parafascicular complex of the medial thalamus and the midbrain reticular formation during microionophoretic application of angiotensin II. A supposition is made about the increase of angiotensin II brain synthesis under conditions of emotional stress.     

Medical protection during radiation accidents: some results and lessons of the Chernobyl accident

Actions of medical radiation protection of liquidators of consequences of on Chernobyl atomic power station accident are analysed. It is shown, that during the early period of the accident medical protection of liquidators was provided by administration of radioprotectors, means of prophylaxis: of radioactive iodine incorporation and agent for preventing psychological and emotional stress. When carrying out decontamination and regenerative works, preparations which action is caused by increase of nonspecific resistance of an organism were applied. The lessons taken from the results of the Chernobyl accident, have allowed one to improve the system of medical protection and to introduce in practice new highly effective radioprotective agents.     

Disruptions in the blood system upon exposure to low-dose ionizing radiation depending on duration of emotional stress

In experiments on rats, disturbances in the development of blood system adaptive reactions on emotional stress were found. Under the combined effect of preliminary (before stress) exposure to 0.8 Gy of gamma-radiation and the emotional stress of various duration (2, 4 and 8 days), a compensatory capability of the blood system decreased. The degree of the disturbances directly depended on the duration of the emotional stress.     

Estimation of long-time effects of Chernobyl AES accident on behavior markers in a small rodent population

Differences in behaviour reactions in "open field" and glycemia under conditions of immobilisation stress of vole (Microtus oeconomus, Pallas) from two groups ("Yanov" and "Lelev") were investigated. Rodents were ensnared from two populations reproduced for a long time (11 years) in the areas of ChNPP Exclusion Zone with different level of radioactive contamination. The radiation absorbed dose for animals of "Yanov" group (external and internal irradiation) was 11-20 times higher than that of "Lelev" group. Males and females from the area with worse radioecological condition had higher vertical and horizontal locomotion. The level of emotional reactions of "Yanov" males was lower than the "Lelev" one. Statistically significant variation in female emotional reaction was found, but it had not the same directions. In both groups higher locomotion activity and lower emotionality were associated with male sex. The males of both groups showed similar fasting glucose level and glycemic response after 30-min. immobilisation. Our data provide the additional evidence of existence of long-time genetic effects in small rodent populations permanently reproduced on radiation contaminated areas.     

Delta sleep-inducing peptide in the blood and hypothalamus of rats with various resistance to emotional stress

Enzyme immunoassay was used to study delta-sleep peptide content in blood and hypothalamus in rats of Wistar lines under acute emotional stress. It was found that the content of delta-sleep peptide in blood and hypothalamus of stable rats was higher as compared with rats predisposed to emotional stress. After 1.5-hour emotional stress the content of delta-sleep peptide increased in blood and hypothalamus both in stable rats and predisposed ones. After 3-hour stress there was an increase in delta-sleep peptide content in hypothalamus, and contrary to its decrease in blood in both stable and predisposed animals. It is supposed that delta-sleep peptide along with other oligopeptides is one of the factors determining individual animal resistance to emotional stress, which is supported by significant delta-sleep peptide increase in hypothalamus in stable rats.     

Blood albumin in mechanisms of individual resistance of rats to emotional stress

Serum albumin parametres in the rats with various prognostic resistance against emotional stress in the control and in conditions of experimental emotional stress were investigated. Analysis of action of peptides raising the animals' resistance against emotional stress (DSIP and SEMAX) in rats with different prognostic resistance against emotional stress, on the serum albumin characteristics, was carried out.     

Effect of etimizol on behavioral responses, brain serotonin concentration and plasma corticosteroid levels

The influence of ethymisol on behavioural reactions was studied on 100 albino rats in the "open field" and "passive avoidance" tests. It was shown that a 5 mg/kg dose of this neurotropic drug with synaptic effect, changes behavioural reactions, lowers the general emotional stress and emotional memory of the electro-cutaneous stimulation. Simultaneously the level of corticosteroids in the blood plasma significantly rises, while the serotonin content in the hypothalamus decreases. A direct correlation between the changes in the emotional stress and the content of corticosteroids in blood plasma is noted. The effects of ethymisol partially persists after adrenalectomy. Ethymisol in optimal doses may be used for regulation and lowering of emotional stress.     

Physiologically adequate experimental model of aggression and emotional stress

A simple adequate experimental model of aggression and emotional stress has been elaborated, based on mild fixation of rats tails in the cage wall. It is shown that in a group of rats, in these conditions a continuous aggressive behaviour arises, leading to the development of emotional stress. The elaborated experimental model has no defects, characteristic of other models of aggression and stress. It demands neither a prolonged training of animals nor special expensive equipment; it allows simultaneous use in experiments of a great number of animals, creates conditions for natural aggressive-defensive behaviour of rats without provoking artificial manipulations. The proposed model allows to study the pathogenesis of emotional stress, mechanisms of resistivity and predisposition to it and also search and testing of biologically active substances, enhancing resistance to emotional stress.     

Immediate-early genes in the cerebral mechanisms of emotional stress

Immediate-early genes (IEGs) induction is one of the primary neuronal responses to emotional stress. In experiments with different types of stressors the brain structures with the most pronounced immediate early genes expression were identified. Biochemical, physiological and genetical mechanisms of the IEGs expression in the central nervous system during emotional stress are discussed in the article. Investigation of characteristics and conditions of the IEGs induction showed that immediate early genes induction is crucial for organization of neuroendocrine and hormonal responses during emotional stress. In situations that require adaptation and learning IEGs induction in brain is especially strong. The present data permit us to think that immediate early genes participate in formation of the long-lasting circulation of the negative emotional excitation in limbic system. Animals resistant and predisposed to psycho-emotional stress have different patterns of IEGs expression in conflict situations leading to emotional stresses. Immediate-early genes induction is especially pronounced in brains of sensitive to stress individuals. It is proved that differential approach with regard to individual differences in IEGs expression is preferential in emotional stress research. Neglect of this fact has led to contradictions in results of various authors. The investigation of the IEGs properties can help to define prospective ways of the effective coping with emotional stress and prevention of its dangerous consequences.     

急性恐惧应激对大鼠行为、激素水平及脑Erk1/2活化表达的影响

目的:探讨急性恐惧应激对大鼠情感行为、激素水平及不同脑区Erk1/2活化表达的影响。方法:采用足电击 白噪声刺激方式建立急性恐惧应激大鼠模型,观察其情感行为的改变;放射免疫法及荧光分光光度法检测血浆和脑组织激素水平;Westernblot检测Erk1/2的活化表达。结果:应激后大鼠旷场活动性降低、拒俘反应性增加、惊吓反应增强(P<0.01);血浆及脑组织去甲肾上腺素、5-羟色胺、皮质醇水平增高,而肾上腺髓质素水平降低(P<0.01);海马、纹状体、前额皮质、小脑等脑区磷酸化Erk1/2蛋白的表达均显著增高(P<0.01)。结论:急性恐惧应激可以显著影响大鼠的情感行为和激素水平,Erk1/2蛋白磷酸化水平的增高可能参与了急性恐惧应激所致的情感行为异常。     

Japanese Quail’s Genetic Background Modulates Effects of Chronic Stress on Emotional Reactivity but Not Spatial Learning

Chronic stress is known to enhance mammals’ emotional reactivity and alters several of their cognitive functions, especially spatial learning. Few studies have investigated such effects in birds. We investigated the impact of a two-week stress on Japanese quail’s emotional reactivity and spatial learning. Quail is an avian model widely used in laboratory studies and for extrapolation of data to other poultry species. As sensitivity to chronic stress can be modulated by intrinsic factors, we tested juvenile female Japanese quail from three lines, two of them divergently selected on tonic immobility duration, an indicator of general fearfulness. The different emotional reactivity levels of quail belonging to these lines can be revealed by a large variety of tests. Half of the birds were submitted to repeated unpredictable aversive events for two weeks, whereas the other half were left undisturbed. After this procedure, two tests (open field and emergence tests) evaluated the emotional reactivity of treated and control quails. They were then trained in a T-maze for seven days and their spatial learning was tested. The chronic stress protocol had an impact on resting, preening and foraging in the home cage. As predicted, the emotional reactivity of treated quails, especially those selected for long tonic immobility duration, was higher. Our spatial learning data showed that the treatment enhanced acquisition but not memorization. However, intrinsic fearfulness did not seem to interact with the treatment in this test. According to an inverted U-shaped relationship between stress and cognition, chronic stress can improve the adaptability of birds to a stressful environment. We discussed the mechanisms possibly implied in the increase of emotional reactivity and spatial abilities.     

Differential effects of emotional and physical stress on the central and peripheral secretion of neurohypophysial hormones in male rats

The effects of various stressful conditions on the levels of oxytocin (OT) and vasopressin (VP) in plasma and cisternal cerebrospinal fluid (CSF) of male rats were investigated. Three experimental models were used: exposure to a novel environment for 5 min, immobilization for 15 min, and ether inhalation for 10 min resulting in anaesthesia. Novelty and immobilization induced a slight but significant increase in OT levels in the CSF immediately after the stress. The effect of ether was considerably more pronounced. The concentration of VP in the CSF was elevated only by ether stress. In plasma, the level of OT was increased immediately following immobilization and ether stress but not after novelty stress, whereas VP only showed a delayed response 20 min after immobilization. These results indicate a rapid preferential release of OT in the periphery in response to physical and pharmacological stress. In addition, they provide evidence that release of OT into the CSF is triggered by physical, pharmacological as well as emotional stress, while the central release of VP is rather resistant to emotional stress. The data suggest that OT is a stress hormone in the central nervous system.     

Sexual conflict situation in the rat--model of emotional stress

It has been shown on female Wistar rats, that as a result of three months sexual deprivation, in a cage of special construction, they may develop an emotional stress leading to a change in mobility and to a discordance in the functional system maintaining the optimal level of sexual hormones in their organism. A design has been presented of a cage for creating a sexual conflict situation, which is a new model of emotional stress.     

The prediction of resistance to emotional stress based on the individual testing of behavior

On the basis of the elaborated experimental model for testing of emotional interaction of animals individual typification of behaviour was established according to which all experimental male rats of August line were subdivided into groups: I--rats manifesting behaviour of avoidance, "victims" of electrocutaneous stimulation; II--without definite behaviour with respect to the "victim" rat; III--rats, preferring the behaviour determining electrocutaneous stimulation of the "victim" rat. All typified animals were subjected to emotional stress with the use of the elaborated experimental model of aggressive-conflict behaviour. Stability against emotional stress of each group of animals was studied. Significant differences were established of stability degree to emotional stress of the rats of three groups manifesting different types of behavioural reaction in conditions of emotional interaction. The most stable were rats of the I group, the least--of the III group; rats of the II group were in the middle position. Typification on the basis of testing of emotional interaction of animals allows to prognosticate individual stability against emotional stress.