Erythrocyte function of rats under emotional stress

The effect of neurogenic stress of the conflict-of-afferent-excitations-type on the oxidizing erythrocyte properties and qualitative and quantitative red blood changes has been studied. Neurogenic stress was demonstrated to significantly affect the erythrocyte functional state in rats. Activation of free-radical oxidation of erythrocyte membrane lipids took place, provoking changes in their permiability and disorders of oxygen fixation and release. It is suggested that these changes may be the underlying mechanism of the developing tissue hypoxia and play a leading role in the pathogenesis of cardiovascular diseases.     

Disorders of spermatogenesis in chronic emotional stress in rats

The experiments on rats demonstrated that chronic emotional stress led to spermatogenesis impairment. The animals were put into restrainers and subjected to subcutaneous electrical stimulation 3 hours daily for 7 days. As a result of this stress the weight of thymus significantly decreased and weight of adrenal glands increased. Also there was a tendency of testes and seminal vesicles to weight decrease. Light microscopy showed significantly more plugs of degenerated spermatids and spermatocytes in seminiferous tubules of stressed animal tested in comparison with control rats. Spermatogenesis index was also reduced in experimental group. The present study showed that germ cells injury took place at the stage of spermiogenesis.     

Respiratory rhythm of rats under acute emotional stress

Irregularity of the rhythm of breathing, the breathing rate, blood pressure and heart rate were studied in rats under acute emotional stress induced by non-periodic stimulation of the skin and ventromedial hypothalamus. The irregularity of the rhythm of breathing was substantially increased during stimulation of the hypothalamus up to short-term respiratory arrests in animals predisposed to emotional stress. Disturbances of the rhythm of breathing may be one of objective prognostic criteria of the animals' survival or lethality under emotional stress.     

Action of alcohol in chronic emotional pain stress in rats

Male albino rats were exposed to daily emotional painful stress (EPS) for 4 weeks. The arterial blood pressure of the stressed animals increased and the dynamics of the heart rate changed after functional loading (hypokinesis during one or two hours) as compared with the control group. The increase of the heart weight and activation of cytochrome oxidase activity in the cerebral cortex and hippocampus of rats exposed to EPS were also demonstrated. The use of 20% ethyl alcohol instead of drinking water during EPS partially prevented vegetative disturbances and activation of hippocampal cytochrome oxidase and fully prevented the heart hypertrophy and activation of the enzyme in the cortex. Alcoholization resulted in the increased weight of the spleen and brown adipose tissue and thymus involution. A possible mechanism of the antistress action of alcohol linked with normalization of intensified lipid peroxidation under stress is discussed.     

Resistance factor in emotional stress in the brain of rats

The authors review the results of extraction from the brain of emotional stress-resistant donor rats of fractions containing "factor" that causes the increased resistance to stress in recipient rats predisposed to stress. Brain homogenates of donor rats were subjected to thermal treatment, gel filtration on Sephadex G-15 and lyophilization. The fractions extracted are low-molecular weight, thermostable, resistant to pronase hydrolysis and significantly (P less than 0.05) increase the resistance of recipient rats to stress.     

Tissue specificity of lipid peroxidation under emotional stress in rats

The intensity of lipid peroxidation and activity of antioxidant system enzymes in the blood plasma, brain and cardial muscle of laboratory rats under 40 days of isolation and violation of diurnal cycle was studied. The obtained data show that on the background of concentration changes in NO changes also take place in the intensity of lipid peroxidation process, indicated by changes in the concentration of TBA-active products and diene conjugates. The changes taking place in the activity of superoxidedismutase, catalase, succinatdehydrogenase, creatine kinase and aldolase under stress were studied. The resulting data show that isolation of animals and violation of diurnal cycle are the factors causing a significant reduction in the energy metabolism in the brain and heart tissue cells and resulting in oxidative stress that, in its turn, may become the reason for development of toxic radicals. Furthermore, prolonged stress may result in irreversible processes that are considered to be the reasons for significant pathologies of the cardiovascular system.     

Effect of dipeptide vilon on emotional stress resistance in rats

Effects of synthetic thymomimetic vilon on open field behaviour, immediate early gene c-Fos expression in paraventricular hypothalamus properties of organs sensitive to emotional stress, and characteristics of albumin in the blood plasma in male Wistar rats, were investigated and are discussed in the article. It is shown that intraperitoneal vilon injection rises the resistance against emotional stress according to prognostic indexes open field behaviour. Vilon administration also inhibits hypertrophy of the adrenals, involution of the thymus, and elevates concentration of albumin in the blood plasma. The number of Fos-immunoreactive neurons in the paraventricular hypothalamus was lower after vilon administration especially in rats resistant against emotional stress.     

Effect of emotional stress on the cardiac rhythm variability in rats

A degree of irregularities of the heart rhythm was studied by two methods: chaos-analysis and the HRV (heart rate variability) analysis. Our study shows an individual response in 3 groups of animals: 1--animals with low initial level of chaos (correlation dimension (PD2 < 2); 2--animals with high level of chaos (PD2 > 4); and animals with middle level of chaos (2 < PD2 < 4). The first two groups proved to be more sensitive to stress than the third group. Moreover we found that the electrical stability of the heart as measured by the fibrillation threshold, was higher for the chaos third group. The animals of the first two groups had low cardiac stability and high risk of stress-induced cardiac disturbances.     

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.     

Brain adrenoreceptors in rats with inherited arterial hypertension due to emotional stress

For the study of genetic and physiological mechanisms of inherited stress-sensitive arterial hypertension, specific binding of ligands of alpha 1-, alpha 2- and beta-adrenoceptors was measured in 2 strains of rats: Wistar normotensive and ISSAH rats (rats with inherited stress-sensitive arterial hypertension). The maximal binding sites (Bmax) and apparent dissociation constants (Kd) were studied with the alpha 1-adrenergic antagonist 3H-prazosin, alpha 2-adrenergic agonist 3H-clonidine and 3H-dihydroalprenolol, a beta 1-receptor antagonist. Four brain regions were investigated: frontal cortex, hypothalamus, pons and medulla oblongata. In comparison with normotensive controls, hypertensive rats had significantly greater density of the alpha 1-adrenoceptors in the medulla oblongata. However, the number of hypothalamic alpha 1-adrenoceptors was significantly reduced in these animals. The same significantly lower alpha 2-adrenoreceptor density was found in the hypothalamus and the pons, and lower, beta-adrenoceptors density in the medulla oblongata. It was concluded that brain adrenoceptors are involved in the mechanisms of development of inherited stress-sensitive hypertensive syndrome.     

Features of lung tissue cell membrane lipid composition under acute emotional stress in rats

The lipid composition of the lung plasmatic membrane in rats which have been under the acute emotional pain stress action is studied. These results are compared with the control group of animals. It is shown that at acute stress the changes of lipid composition of the lung plasmatic membranes are manifested in decrease the phospholipids and increase of cholesterol levels. The correlation of phospholipids/cholesterol in plasmic membranes in the lungs decreases at stress. At the same time the decrease of triglyceroles and diglyceroles contents is observed as well as the increase of fat acids' number. The changes that take place in the lipid contents of the lung plasmatic membranes at acute stress can play an essential role in the mechanism of cell damage development.     

Glucose tolerance of postnatally stress-sensitized albino rats following chronic emotional stress in adulthood]

Male albino rats were used to study the effect of electrical stimulation in the postnatal phase (day 1--15) leading to short-time convulsions and cyanosis lasting about 10 min in 5-month-old animals upon the development of glycemic dysregulation induced by emotional stress. The studies involving i.p. glucose administration show that a 3-week stress influence on postnatally stimulated animals caused heavier changes of glycemic regulation than with non-pretreated animals. These results suggest a stress sensitization occurring in the postnatal phase and are discussed in connection with the "stress-sensitive risk personality" by R. BAUMANN. Further studies have shown that the postnatal stress sensitiveness is reversible and cannot only be compensated by a rest period of several weeks but may even cause stress resistance on renewed stressing for three weeks.     

c-fos Gene expression during emotional stress in rats: blocking by delta sleep-inducing peptide

An emotional stress induces an obvious immediate early gene c-fos expression in the brain limbic structures in the rats predisposed to emotional stress. Administration of the delta-sleep-inducing peptide (DSIP) was shown to inhibit the c-fos expression. It led to an obvious inhibition of the c-fos expression in paraventricular nuclei of the hypothalamus, medial and lateral parts of the septum of rats predisposed to emotional stress. This mechanism seems to play an important role in the DSIP anti-stress effects.     

Lipid peroxidation in emotional stress in rats: correlation with parameters of open field behavior]

TBA-reactive products were measured in the brain, liver, and heart of Wistar rats in control conditions and after 24 h immobilization. Animals were subjected to the open field test before and after the immobilization. Behavior patterns, gastric mucosa alterations and MDA accumulation in organs suggested that immobilization as well as food and water deprivation were all strong stressor stimuli. Initial open field behavior characteristics were significantly correlated with MDA contents in various tissues under emotional stress.     

Self-regulation of autonomic homeostasis in emotional stress

Emotional stress is considered to be one of the basic pathogenetic factors causing diseases of the cardiovascular system [1]. Its particular example is the examination stress, which develops in some students expecting an examination. In this case the reactions of the autonomic system in some persons can be oppositely directed and reach a magnitude that puts an organism on the borderline between norm and pathology [2]. There-fore, the qualitative and quantitative estimation of the character of the reaction of the autonomic system to stress in students and the development of the methods of its correction are relevant.     

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.     

Stability of the cardiovascular functions of different genetic strains of rats subjected to emotional stress

The level of catecholamines was measured in various brain parts in rats of August and Wistar lines, characterized by different stability of cardio-vascular functions in emotional stress. In norm, the August line has a higher content of dopamine (DA), in the mid-brain in particular; the Wistar line has a higher content of noradrenaline (NA) in the hypothalamus. In susceptible animals, which showed different cardio-vascular disorders during 30 hours of immobilization (48% of the Wistar line and 90% of the August), and in animals resistent against emotional stress, the changes in the initial level of catecholamines were observed, both common and specific for two lines. An assumption is made that the stability of cardio-vascular functions in the emotional stress is provided for by an intensive metabolism of the NA-synthesizing neurones in the brain isthmus, and by a moderate activity of the DA-synthesizing neurones of the mid-brain; the susceptibility to cardio-vascular disorders in the emotional stress is due to increase in the activity of the DA-synthesizing mid-brain neurones, the decrease in the activity of the DA-hydroxilase and the exhaustion of NA in the hypothalamus.