Changes in beta-adrenergic receptors in the neurohypophysis and intermediate lobe of the rat have been characterized under physiological and stress conditions. Classical immobilization stress (IMO) was also combined with the immersion of rats into water (IMO + COLD stress). Both types of stress were applied for 30, 60 or 150 min. The intensity of stress stimuli were controlled by measuring the level of plasma ACTH. Changes in the level of plasma ACTH indicate that both types of experimental protocol induced reliable and reproducible stress conditions. Binding studies dealing with beta-adrenergic receptors in the intermediate lobe and neurohypophysis were performed in saturation binding studies by using of 125l-iodopindolol. Binding parameters, maximal binding capacity (Bmax) and dissociation constant (Kd) were assessed by nonlinear analysis with computer program Viewfit. In the neurohypophysis, no changes of Kd were found in the stressed animals. However, maximal binding capacity was decreased significantly with the increased exposure to the stress. In the intermediate lobe Kd values were slightly decreased and Bmax values decreased gradually with increasing duration of stress exposure. Our findings suggest that the process of receptor desensitization of beta-adrenergic receptors can also be detected under stress conditions in the neurohypophysis and intermediate lobe of the pituitary gland where it could contribute to the mechanisms involved in stress reactions.
We measured faecal cortisol metabolites of a free-ranging riparian population of red deer to investigate potential effects of season, ambient temperature, precipitations and water level on the annual secretion pattern. Individuals may cope with environmental challenges through the secretion of stress hormones (glucocorticoids) which allows the integration of environmental change and life history traits by means of an adaptive feedback mechanism. Adaptations regard cyclic day-to-day activities, short-term environmental stressors or long-term ecological pressures. We detected a clear seasonal pattern of glucocorticoid metabolites secretion, with higher levels in winter and lower levels in summer. The model relating glucocorticoids secretion to minimum ambient temperature was the best fit to our dataset, although the observed pattern might as well be due to declining nutritional intake and reduction of metabolic rate in the cold season. We observed an improvement of the fit when stochastic events (flash flood) were included in the model, and discussed their role as potential contingent environmental stressors.
The present study was carried out to search whether organophosphate pesticides affect the mechanical properties of the thoracic aorta. Wistar fema le rats (aged 6-8 weeks) were assigned randomly to a control group and groups treated with either dichlorvos or chlorpyriphos for 90 days at a dose of 5 mg/kg/day. After that period, animals were killed and thoracic aorta strips in longitudinal direction were isolated. The stress, strain and elastic modulus were obtained from the strips. Our results showed that chronic administration of chlorpyriphos and dichlorvos caused downward shift of the stress-strain relations compared to the control curve. The elastic modulu s-stress curve revealed distinct characterist ics in the low and high stress regions. A power function was used to simulate the low stress region while a line was fit to the high stress region. Curve fitting procedure illustrated that both pesticides influenced mainly the high stress region, but they had diverse effects at the low stress region. The results also imply that chlorpyriphos and dichlorvos decrease the strength of the aorta and therefore might influence the response of the aorta to mechanical loading induced by blood pressure. and B. Guvenc Tuna ... [et al.].
The experimental evidence for the antipyretic action of arginine vasopressin (AVP) in guinea-pigs can be summarized as follows: The febrile response to a bacterial pyrogen can be reduced by a microinfusions of exogenous AVP into the ventral septal area of the limbic system. Immunohistochemical studies indicate increased activity of AVP terminals in the ventral septal area (VSA) and in parvocellular AVP neurones of the hypothalamic paraventricular nucleus (PVN) in several stressful situations accompanied by reduced febrile responses (late stage of pregnancy, immobilization, cold adaptation, osmotic stimulation). Also the peripheral and/or central release of AVP measured in some of these situations is increased. Electrical stimulation of the PVN suppresses fever, this suppression can, at least partly, be cancelled by simultaneous intraseptal application of the vasopressinergic VI receptor antagonist. The documented AVP pathways from the PVN to the septum receive noradrenergic afferents from the lower brainstem. Chronic destruction of these afferents by microinjections of 6-hydroxydopamine (6-OHDA) significantly reduced the fever responses to pyrogen application, while microinfusion of noradrenaline (NA) enhances the fever reaction.
The analgesic effects of intracerebroventricularly (i.c.v.) administered dynorphin A(l-13) and its analog dynorphin A(l-10)amide using the hot plate test were studied in mice. Both dynorphins applied i.c.v. by the freehand method had an analgesic effect but no effect was seen when applied i.c.v. through an implanted cannula. Moreover, freehand i.c.v. injection of saline increased the time of immobility in the forced swimming test and glycaemia levels compared with intact mice. In contrast to the freehand injection, saline administration through an implanted cannula did not influence the immobility of animals in forced swimming test when compared with the intact controls. These results suggest that 1) the freehand method is very stressful procedure of administration which could influence the effects of dynorphins in the hot plate test and 2) dynorphins exert an analgesic effect in the hot plate test only when combined with a stressor (freehand i.c.v. injection).
Fluctuating asymmetry (FA), the small and random departures from perfect symmetry of an organism's bilateral traits, has been used as a measurement of developmental stability and an indicator of stress in endangered populations. We were interested in testing if the level of developmental stability is the same in different populations experiencing the same conditions, as the use of FA as an indicator of ecological stress is only meaningful if this is true. In order to do this, the effect of thermal stress on wing size FA over a range of temperatures was determined on three different lines of Drosophila melanogaster: two lines were maintained at one of two different constant temperatures (18°C or 28°C) and one under a fluctuating thermal regime (18°C and 28°C) for eight years. The differences in viability of these lines, when reared at a range of different temperatures, are associated with the temperature conditions they previously experienced. All lines showed a similar increase in FA at the two ends of the thermal range but with significantly different mean values. The two units of wing development (compartments) differed in their FA response depending on the selective history of each line. We discuss the implication of our results for the use of FA as an indicator of ecological stress.
Our aim was to investigate the influence of microgravity on the sensitivity of the skin to mechanical stimulation, epidermal thickness, peripheral nerve density in the upper dermis, and serum levels of a stress marker in a rat hindlimb suspension (HS) model. Thirty 8-week-old male Wistar rats were randomly divided into 3 groups: HS, n=10; sham HS, n=10; control, n=10. The suspension system was attached to rat tails in both the HS and sham-HS groups, but the hindlimbs were suspended only in the HS group. The HS and sham-HS groups were treated for 4 weeks. In behavioral tests using von-Frey filaments (n=5 in each group), mechanical hypersensitivity developed in the HS and sham HS groups. Serum corticosterone levels increased significantly in the HS and sham HS groups compared to the control group, and no changes in epidermal thickness or peripheral nerve density were observed immediately after the removal of HS (n=5 in each group). These data indicated that the mechanical hypersensitivity observed in the HS group was not caused by microgravity or inactivity, but rather by restraint stress. We suggest that microgravity does not affect skin sensitivity and histology in these animals., Y. Tanaka, ... [et al.]., and Obsahuje seznam literatury
Dynorphin A (1-13) and its analog dynorphin A (1-10) amide were applied intracerebroventricularly in male ICR mice. Both dynorphins did not reveal any analgesic activity in tail-flick test under normal (non-stressed) conditions. However, in combination with stress (forced swimming or whole body vibration) both dynorphins prolonged tail- flick latencies when compared with stressed saline controls. Naloxone inhibited the effect of dynorphins in forced swimming test. Neither dynorphin A (1-13) nor dynorphin A (1-10) amide increased tail-flick latencies when combined with weak immobilization stress. Our results suggest that the analgesic effects of dynorphins are potentiated by strong stressors.
A sense of purpose in life is inextricably linked with a firm conviction of exercising control over it, and having one’s priorities set straight. Health in turn, is affected by stress, by salutogenetic factors, as presented by A. Antonovsky. Disturbances of sense of purpose in life result in psychosomatic disorders. Hypothesis: there is a relevant statistical correlation between the level of sense of purpose in life and noopsychosomatic disorders. Methods: 1) Crumbaugh-Maholick Purpose-in-Life Test, 2) K. Mausch Questionnaire of Psychosomatic Ailments. Test group: 683 pedagogy students from the University of Szczecin. There is a relevant statistical correlation between the level of sense of purpose in life and psychosomatic disorders. The research results require comparison with other post-soviet countries, as well as democratic ones.
Negativní vliv tíživé prosociální aktivity, byl předmětem řady psychologických výzkumů. Péče o staré lidi, nevyléčitelně nemocné, umírající se za určitých okolností může stát značně zatěžující činností, jejíž důsledky se mohou projevit v oblasti zdraví poskytovatele této péče. Péče o umírajícího člověka nebo člověka starého, imobilního, často s postupující demencí, je pro pečujícího velmi náročná. Péče o chronicky nemocné, nevyléčitelně nemocné, se může stát dlouhodobě zatěžující aktivitou. Péče o umírajícího pacienta, práce s rodinnými příslušníky, kterým umírá jejich bližní, je situací extrémní zátěže. Vypjaté emoční reakce, zvláště hněv, různé formy agrese, jsou situace, které se zvládají velmi obtížně.
Obecně lidé, kteří se angažují v pomáhajících profesích, jsou díky tomuto faktu ohroženi ve všech oblastech zdraví – fyzické, psychické i sociální. Poskytování péče nevyléčitelně nemocným je situací značné dlouhodobé zátěže – říkáme jí chronický stres. Působení chronického stresu jakékoli kvality může mít na člověka poměrně negativní vliv. Výzkumy naznačují, že v pozadí mnoha nemocí je přítomen faktor chronické, dlouhodobé zátěže – kardiovaskulární onemocnění, narušená funkce imunitního systému, nespecifické bolesti zad, onemocnění trávícího traktu. Samostatnou speciální problematikou je syndrom vyhoření. and The negative impact of the onerous prosocial activity has been examined in a great bulk of psychological research studies. Under certain conditions, taking care of the elderly, terminally ill, and the death ward might be quite a demanding activity. Its consequences may be reflected in the health condition of the care provider. Caring for a dying or an immobile elderly person, often with a progressive dementia, is very challenging for the provider. Servicing a chronically ill or terminally ill people might become a long-term burden. Servicing a dying person and working with his or her family relatives is an extremely burdening situation. The extreme emotional reactions, primarily anger and various kinds of rage, are unusually thorny to manage.
Consequently, people that are engaged in helping these people are generally endangered in all spheres of their health, i.e. physical, mental and social. Providing care to terminally ill is burdensome in the long run. It is known as chronic stress. Any kind of chronic stress has a potentially negative impact on human beings. Previous research indicates that long-term chronic burden might cause cardiovascular diseases, disorders of immunity, non-specific backaches, and digestive disorders. The special issue is a burnout syndrome.