Signs Of Chronic Stress Research Articles

Психологические предикторы прокрастинации студентов-психологов

Background. Nowadays procrastination can be seen as irrational procrastination, ine\ective planning or, more broadly, unproductive self-regulation. In modern scienti]c literature, there are no convincing data that would clarify both the nature of the procrastination phenomenon and the psychological predictors of its occurrence. ^e analysis of the relationship between procrastination and a number of psychological characteristics presented in this paper makes it possible to ]ll this gap. Objective. ^e study aims to identify psychological predictors of procrastination in educational activities among psychology students in di\erent learning conditions (full-time and distance learning). Sample. ^e study involved 460 students of the Faculty of Psychology at Lomonosov Moscow State University (42 male and 418 female) aged 16 to 28 years (average age — 19.63), who participated in the study. Methods. ^e study was conducted in two stages — (I) full-time and (II) distance learning. 2 sections were made at each of the stages: (1) under normal conditions during the semester and (2) under stressful conditions during the examination session. Research methods included the scale of general procrastination by K. Lay (Varvaricheva, 2010); the scale of general procrastination by B. Tukman (Kryukova, 2009) and a number of methods aimed at assessing the psychological characteristics of respondents (anxiety, perfectionism, laziness, chronic stress). Results. ^e obtained regression models indicate that procrastination can be considered as disturbed self-organization: initiating and planning one’s actions, irrational postponing (control over action during planning, laziness and personal anxiety acted as predictors to procrastination). When changing the conditions of activity (distance learning), procrastination can act as a strategy of “saving strength” in a situation of increased consumption of internal resources. In this case, the predictors of procrastination are signs of chronic stress and low demands on oneself (low perfectionism). Conclusion. ^e predictors of procrastination in psychology students under normal learning conditions include low control over action during planning, laziness and high personal anxiety. In a distance learning setting, predictors of procrastination include low standards and self-requirements (low perfectionism) and chronic stress.

Colocalized neurotransmitters in the hindbrain cooperate in adaptation to chronic hypernatremia

Chronic hypernatremia activates the central osmoregulatory mechanisms and inhibits the function of the hypothalamic–pituitary–adrenal (HPA) axis. Noradrenaline (NE) release into the periventricular anteroventral third ventricle region (AV3V), the supraoptic (SON) and hypothalamic paraventricular nuclei (PVN) from efferents of the caudal ventrolateral (cVLM) and dorsomedial (cDMM) medulla has been shown to be essential for the hypernatremia-evoked responses and for the HPA response to acute restraint. Notably, the medullary NE cell groups highly coexpress prolactin-releasing peptide (PrRP) and nesfatin-1/NUCB2 (nesfatin), therefore, we assumed they contributed to the reactions to chronic hypernatremia. To investigate this, we compared two models: homozygous Brattleboro rats with hereditary diabetes insipidus (DI) and Wistar rats subjected to chronic high salt solution (HS) intake. HS rats had higher plasma osmolality than DI rats. PrRP and nesfatin mRNA levels were higher in both models, in both medullary regions compared to controls. Elevated basal tyrosine hydroxylase (TH) expression and impaired restraint-induced TH, PrRP and nesfatin expression elevations in the cVLM were, however, detected only in HS, but not in DI rats. Simultaneously, only HS rats exhibited classical signs of chronic stress and severely blunted hormonal reactions to acute restraint. Data suggest that HPA axis responsiveness to restraint depends on the type of hypernatremia, and on NE capacity in the cVLM. Additionally, NE and PrRP signalization primarily of medullary origin is increased in the SON, PVN and AV3V in HS rats. This suggests a cooperative action in the adaptation responses and designates the AV3V as a new site for PrRP’s action in hypernatremia.

Glucocorticoids in tuatara (Sphenodon punctatus): Some influential factors, and applications in conservation management

Glucocorticoid (GC) hormones promote basic life processes, regulate life-history transitions, and help individuals cope with challenges and stressors, thereby playing an important fitness role. Here, we review recent evidence for several factors that influence plasma concentrations of corticosterone (CORT), the main GC in tuatara (Sphenodon punctatus), and discuss the application of CORT as a physiological tool to monitor conservation efforts. Observational studies show an association between CORT concentrations and seasonal reproductive activity, ambient temperature, and ecological habitat parameters (including presence of rats/seabird abundance, sex-ratio, and genetic diversity), and experimental studies show a positive influence of acute temperature increase on the CORT response. Recently, CORT physiology has been applied as a monitoring tool in tuatara translocation programmes. No signs of chronic stress in CORT profiles were observed during standard short- and long-term translocation and rat eradication procedures, giving confidence that current conservation efforts are supportive in population recovery. These results provide a foundation for comparative understanding of stress physiology in reptiles, and will be critical for managing future population viability of tuatara in a changing environment.

Unexplained fatigue and irritability - differential diagnosis and practical procedures for signs of exhaustion

Chronic fatigue is a frequent complaint, but only leads to a medical consultation when consequences like sleep disturbance and reduced productivity become debilitating. Fear of a somatic disorder is usually prominent. However, the symptoms are usually physical and psychological signs of chronic stress. There is often a lack of awareness of stressors or conflicts, which would allow such a conclusion. Therefore, a few somatic investigations are recommended, since the list of possible somatic causes is long. Otherwise the patient should be prepared and motivated for a psychosocial counselling.

The physical, mental and hormonal responses to short-term intensified training in well-trained cyclists with a high carbohydrate nutritional intervention

Background: Short periods of intensified training (IT) are a regular feature in a cyclist’s training programme. The aim of this study was to monitor changes in performance, mood state and plasma hormones during short term IT in well-trained cyclists and the effects of a carbohydrate nutritional intervention. Methods: Thirteen highly trained male cyclists (age: 25±6 y, V I‡O2max: 72±5 ml/kg/min) participated in two 9-day periods of intensified training while ingesting either high (HCHO) or low (LCHO) carbohydrate (CHO) beverages before (24 g vs 2 g CHO), during (60 g/h vs 20 g/h CHO) and after (44 g vs 10 g CHO) every training session. All training sessions were monitored with SRM power meters and heart rate (HR) monitors. Performance was assessed throughout IT with maximal oxygen uptake (V I‡O2max) and 1 h time trial (TT). Mood state questionnaires (POMS and DALDA) were completed daily to monitor total mood disturbance (TMD). Venous blood samples were collected before and immediately after each TT and analysed for brain-derived neurotrophic factor (BDNF), cortisol (CORT), testosterone (TEST), CORT/TEST ratio, adrenocorticotrophic hormone (ACTH) and prolactin (PRL). Results: Weekly training volume and intensity (time spent in the three highest HR zones) increased significantly during IT (9.3±2.4 h to 23.5±3.4 h/week for volume and 2.6±2.5 to 6.5±4.0 h/week for intensity). Total energy intake and dietary CHO were significantly higher in HCHO than LCHO (4148±766 vs 3501±616 kcal/d and 679±105 vs 505±107 g/d CHO). TMD was elevated during IT (p<0.05). Overall, POMS TMD was significantly higher in LCHO than HCHO (p=0.04). Performance in the a€–V I‡Oa€—_2max exercise protocol fell significantly with IT in both conditions (p<0.05): peak power (391±37 to 375±38 W), maximum HR (190±10 to 179±8 bpm) and completion time (31:15±03:12 to 30:00±03:30 min:s). No significant changes in TT performance were observed over IT, or between conditions. However, absolute mean power during TT decreased non-significantly in both conditions (-1.2 W (-1%) and -7.2 W (-3%) for HCHO and LCHO, respectively). Mean HR tended to decrease from TT1-TT3 in LCHO (p=0.06). Pre-exercise CORT and BDNF tended to be lower after IT in both conditions (p=0.07) and pre-exercise ACTH tended to be lower in LCHO than HCHO (p=0.06). Post-exercise CORT, ACTH, BDNF, CORT/TEST ratio and PRL concentrations decreased with IT (p<0.05), with no difference between conditions. The post-exercise increase in PRL seen at TT1 did not occur at TT3; instead PRL concentrations fell from 373 to 348 mIU/L. Post-exercise TEST was lower in LCHO than HCHO (13.2±3.6 vs 14.6±3.8 nmol/L; p=0.03).  Discussion: A relatively short period of IT resulted in significant disturbances in mood state and minor performance decrements. LCHO resulted in significantly greater TMD than HCHO. Previous studies have reported significant declines in performance with similar exercise protocols; yet this group of well-trained athletes showed a level of resistance to the substantial increase in training load. However, hormonal changes present signs of chronic stress, including decreased post-exercise PRO, BDNF, CORT, ACTH and CORT/TEST suggesting these cyclists may have exhibited early signs of overreaching.

The Major Brain Endocannabinoid 2-AG Controls Neuropathic Pain and Mechanical Hyperalgesia in Patients with Neuromyelitis Optica

Recurrent myelitis is one of the predominant characteristics in patients with neuromyelitis optica (NMO). While paresis, visual loss, sensory deficits, and bladder dysfunction are well known symptoms in NMO patients, pain has been recognized only recently as another key symptom of the disease. Although spinal cord inflammation is a defining aspect of neuromyelitis, there is an almost complete lack of data on altered somatosensory function, including pain. Therefore, eleven consecutive patients with NMO were investigated regarding the presence and clinical characteristics of pain. All patients were examined clinically as well as by Quantitative Sensory Testing (QST) following the protocol of the German Research Network on Neuropathic Pain (DFNS). Additionally, plasma endocannabinoid levels and signs of chronic stress and depression were determined. Almost all patients (10/11) suffered from NMO-associated neuropathic pain for the last three months, and 8 out of 11 patients indicated relevant pain at the time of examination. Symptoms of neuropathic pain were reported in the vast majority of patients with NMO. Psychological testing revealed signs of marked depression. Compared to age and gender-matched healthy controls, QST revealed pronounced mechanical and thermal sensory loss, strongly correlated to ongoing pain suggesting the presence of deafferentation-induced neuropathic pain. Thermal hyperalgesia correlated to MRI-verified signs of spinal cord lesion. Heat hyperalgesia was highly correlated to the time since last relapse of NMO. Patients with NMO exhibited significant mechanical and thermal dysesthesia, namely dynamic mechanical allodynia and paradoxical heat sensation. Moreover, they presented frequently with either abnormal mechanical hypoalgesia or hyperalgesia, which depended significantly on plasma levels of the endogenous cannabinoid 2-arachidonoylglycerole (2-AG). These data emphasize the high prevalence of neuropathic pain and hyperalgesia in patients with NMO. The degree of mechanical hyperalgesia reflecting central sensitization of nociceptive pathways seems to be controlled by the major brain endocannabinoid 2-AG.

Chronic Fatigue Syndrome As An Agent of Infectious Disease: A Review of Etiological Agents

T he C hronicles of C hronic F atigue C hronic fatigue syndrome as an infectious disease : a review of etiological agents Amy Hassenberg Chronic fatigue syndrome has long walked the fine line between being categorized as a mental or a physical disease. More common in women and middle-aged patients, the disease displays symptoms which include chronic fatigue, loss of concentration, musculoskeletal pain, joint pain, severe headache, and extreme exhaustion that last at least six months or longer (Mayo Clinic 2000). Because these are just symptoms (subjective self-reports of the patient) and no physical signs or definitive laboratory methods of diagnoses exist, there is often a stigma attached to whether or not the condition is of psychiatric or physical origin. Recently, however, there has been evidence linking chronic fatigue syndrome to a slew of infectious agents, prompting public health officials to reevaluate the syndrome as an infectious disease. “I s I t A ll I n M y H ead ?” The name “syndrome,” rather than “disease” proper, suggests that chronic fatigue is a figment of the mind; some psychiatrists go so far as to write off the clinical manifestations as simply hypochondriac in nature. In fact, the most common misdiagnoses in patients with (CDC 2006). Because of the nonspecific symptoms and the confusion in pinpointing the origin of the fatigue, it is hard to estimate the number of affected individuals—the CDC estimates it at one million Americans with 80% of cases undiagnosed. Chronic fatigue syndrome has always been closely associated with psychiatric disorder. A study done at the University of Leeds found that patients who had developed chronic fatigue were nine times more likely to have suffered stressful events and difficulties in the three months before the onset of disease than were healthy subjects (Hatcher 1991, 387). Chronic fatigue syndrome patients were also more than three times as likely to suffer from depression. However, Leonard Jason, a professor of psychology at DePaul University in Chicago, when interviewed about the disease reported, “If you ask a person who is depressed, ‘What would you do tomorrow if you were better?’ they say, ‘I don’t know.’ Chronic fatigue sufferers will give you a list of ten things,” (Schorr 2005). H ints of an I nfectious A gent There have been many hypotheses as to the etiology behind chronic fatigue syndrome from purely psychological notions to actual infectious agents. In recent years, however, there has been a greater push towards finding a biological cause of the syndrome for a variety of reasons. First of all, epidemics of chronic fatigue syndrome are sometimes centered about a geographic location, suggesting a common source of a microorganism, or the communicability of a microorganism. Outbreaks in Lake Tahoe, Utah; Key West, Florida; and Punta Gorda, Florida have occurred where dozens of people would acquire chronic fatigue syndrome simultaneously. Entire hospital staffs in both LA county and London, UK have also fallen victim to this syndrome (Patarca-Montero 2004). It is not just a Western affliction, as outbreaks have been documented in remote places like South Africa and tribal New Zealand. Secondly, researchers have found evidence that suggests that in a time of high stress, a viral infection can damage the central nervous system, causing changes in the immune system which reflect the traditional symptoms of chronic fatigue. In various studies, there has been evidence of an elevated number of natural killer cells and activated CD2 cells and T8 cells. While these may be signs of chronic stress and depression, once again suggesting the psychiatric origin of the syndrome, they are also signs of recurrent viral infections (Holmes 1991, 387). In fact, most patients who suffer episodic bouts of chronic fatigue B S J “Because these are just symptoms (subjective self- reports of the patient) and there are no physical signs or definitive laboratory methods of diagnoses, there is often a stigma attached to whether or not the condition is of psychiatric or physical origin” chronic fatigue syndrome are major depression and somatoform disorders which can manifest themselves in physically similar symptoms (Fukuda, et al 1994, 953). There is currently no standard treatment available for the debilitating disease. The syndrome is typically long lived and the rate of recovery is as low as 5% of cases. As a result, it usually consumes a patient’s life 10 • B erkeley S cientific J ournal • I nfectious D isease • F all 2010 • V olume 14 • I ssue 1

Bronchogenic carcinoma in a male rock wallaby (Petrogale lateralis lateralis)

Rock wallabies (Petrogale spp.) often occur on isolated rocky outcrops in low-rainfall areas. One male wallaby, from a population of black-flanked rock wallabies (P. lateralis lateralis) being surveyed as part of an ecology and fertility study, died following capture. Post mortem examination revealed the animal to be in poor condition with signs of chronic stress and an extensive, metastasising bronchogenic carcinoma.

Chronic stress in women with localised provoked vulvodynia

Background. Localised provoked vulvodynia (former vulvar vestibulitis syndrome) is the most common cause of superficial dyspareunia among young women. In a clinical setting, it is obvious that many women with localised provoked vulvodynia show signs of chronic stress. The objective of this study was to compare chronic stress in a group of women with localised provoked vulvodynia, referred to the vulvar unit at the Division of Obstetrics and Gynecology, Danderyd Hospital, Stockholm, Sweden with control women of the same age and educational level, using two independent methods.Methods. Forty-three women with localised provoked vulvodynia and 35 healthy control women underwent a gynecological examination, filled in a health questionnaire, and self-collected saliva for analysis of cortisol at awakening and after 15, 30 and 45 min (morning awakening cortisol). Thirty-three patients and 28 controls completed a stress questionnaire.Results. Morning awakening cortisol was blunted in women with localised provoked vulvodynia (p < 0.05), indicating chronic stress. The stress questionnaire showed more signs of burnout (p < 0.005), and emotional (p < 0.05) and bodily symptoms of stress (p < 0.005) in women with localised provoked vulvodynia compared with control subjects (students t-test).Conclusion. More women with localised provoked vulvodynia showed blunted morning awakening cortisol and reported more symptoms of stress compared with healthy control women of the same age.

Hippocampal volume measurement in patients with Ménière's disease: a pilot study

Conclusion. No signs of chronic stress as in hippocampal atrophy were present in patients with Ménière's disease. Objective. To evaluate the effect of chronic stress (allostatic load) by measuring hippocampal volume in patients with Ménière's disease. Subjects and methods. Ten patients with Menière's disease and 10 healthy controls were evaluated for absolute and relative hippocampal volumes measured on MRI scans, saliva cortisol levels and frequency of daily stressors. The study was performed in a prospective, controlled setting with two raters who were blinded as to subject identity. Results. Saliva cortisol levels and presence of daily stressor scores were similar in both groups. The first rater measured mean hippocampal volumes of 2.80±0.36 cm3 vs 3.15±0.52 cm3 (right) and 2.49±0.32 cm3 vs 3.06±0.46 cm3 (left), for the Ménière's disease and control group, respectively. The second rater measured 3.44±0.35 cm3 vs 3.60±0.52 cm3 (right) and 3.00±0.40 cm3 vs 3.42±0.45 cm3 (left), respectively. The volume of the left hippocampus was significantly smaller in patients with Ménière's disease compared with the controls for both raters (p<0.05) and the right hippocampal volume was not different between the two groups. With correction for variation in head size (partial brain and partial intracranial volume) no significant differences in relative hippocampal volumes were observed between patients with Ménière's disease and the control group.

Perceived stress in women with recurrent vulvovaginal candidiasis

Objective. Recurrent vulvovaginal candidiasis (RVVC) has become very common. The aim of this study was to evaluate if women with RVVC perceive more signs of chronic stress than healthy control subjects.Study design. Thirty-three women with RVVC and 28 healthy control subjects completed a questionnaire about perceived stress at work and in private life, and a health questionnaire. A comparison of the results was performed with the one-way ANOVA test.Results. More women with RVVC than control subjects reported signs of burnout (p < 0.001), emotional symptoms of stress (p < 0.005), impaired balance between work and leisure time (p = 0.01), bodily symptoms of stress (p < 0.05), worrying factors at work (p < 0.05), and presented type D-personality (p < 0.05).Conclusions. The results of this pilot study showed higher degree of perceived stress in women with RVVC compared with healthy controls. These results are in line with our earlier findings of blunted morning rise cortisol and lower mean levels of cortisol in women with RVVC compared with healthy controls.

Somatic pain sensitivity during formation and healing of acetic acid-induced gastric ulcers in conscious rats

A classical feature of visceral pain is its referring to somatic locations. Gastric ulcer is a source of visceral pain. In the present study we investigated whether gastric ulcers may trigger the changes in somatic nociception. For this aim somatic pain sensitivity was estimated under conditions of gastric ulcer development and healing. Gastric ulcers were induced by luminal application of 60% acetic acid under surgical conditions. Control rats were subjected to the same surgical procedure, but with the application of saline instead of the acid. Somatic pain sensitivity (tail flick latency), plasma corticosterone level, adrenal and thymus weight were investigated under conditions of the formation and the healing of gastric ulcers. The application of the acid resulted in the formation of kissing gastric ulcers, the increase of somatic pain sensitivity (the decrease of tail flick latency) as well as the appearance of typical signs of chronic stress: long-lasting increase of plasma corticosterone level, adrenal gland hypertrophy and thymus gland involution. Natural healing of gastric ulcers was accompanied by restoration of pain sensitivity as well as attenuation of the signs of chronic stress. Delay of ulcer healing by the daily indomethacin administration (2 mg/kg, s.c.) prevented the restoration of somatic pain sensitivity. The results suggest that chronic gastric ulcers may trigger somatic hypersensitivity.

Signs of chronic stress in women with recurrent candida vulvovaginitis

The purpose of this study was to determine whether there is an association between recurrent vulvovaginal candida and chronic stress. Chronic stress affects the hypothalamus-pituitary-adrenal axis, which influences the immune function. Recurrent candida vulvovaginitis is increasing. Women with recurrent vulvovaginal candida (n = 35) and age-matched healthy control subjects (n = 35) collected saliva for the analysis of cortisol. Hormone analyses of blood samples and vulvovaginal examinations were performed. A questionnaire was completed. Morning rise cortisol level was significantly blunted among patients compared with control subjects (P < .002). Mean levels of salivary cortisol were lower the first 45 minutes after awakening in women with recurrent vulvovaginal candida, compared with control subjects. More patients than control subjects reported a history of condyloma, bacterial vaginosis, and herpes genitalis. No differences were seen between patients and control subjects regarding sexual hormone binding globulin, dihydroepiandrosterone, testosterone or Hemoglobin A1c. Morning rise salivary cortisol level is blunted in women with recurrent vulvovaginal candida, which indicates signs of chronic stress. The higher incidence of vulvovaginal infections in these women compared with control subjects may reflect impaired immunity, which may be due to chronic stress.

Stress Symptoms Induced by Repeated Morphine Withdrawal in Comparison to Other Chronic Stress Models in Mice

The present study was aimed at evaluating chronic stress models in mice with special attention to morphine treatment. We hypothesized that repeated periods of drug withdrawal induce chronic stress. To verify this hypothesis, mice were made dependent on morphine and then subjected to several types of repeated withdrawal. Body weight reduction, thymus involution, adrenal gland enlargement and activation of the hypothalamo-pituitary-adrenal axis were used as signs of chronic stress. The changes were compared to those induced by ‘laboratory’ models of chronic stress (2 weeks of repeated restraint or rat exposure) and to a disease model of streptozotocin-induced diabetes mellitus (STZ-DM). Mice were made dependent using increasing doses of morphine three times a day for 3 days (10–20–40 mg/kg s.c.). Thereafter, withdrawal was induced either spontaneously (morphine 40 mg/kg injected at 24- or 72-hour time intervals for 2 weeks) or repeatedly precipitated by naloxone (10 mg/kg s.c.) injected daily 3 h after morphine. The results show that repeated periods of spontaneous drug withdrawal (24 or 72 h) in morphine-dependent mice represent a mild stress load. Repeated withdrawal precipitated by naloxone induced clear chronic stress-like changes. Changes observed in the naloxone-precipitated withdrawal model were even more pronounced than those found in laboratory models, namely repeated restraint or exposure to the rat. The most severe chronic stress state developed in mice during untreated STZ-DM. Thus, naloxone-precipitated withdrawal in mice seems to be an appropriate model of chronic stress.

Effects of repeated restraint stress on hypothalamo-pituitary-adrenocortical function in vasopressin deficient Brattleboro rats

Arginine-vasopressin (AVP) has been proposed to be an important mediator during chronic stress in the regulation of the hypothalamo-pituitary-adrenal axis. In the present study we addressed the role of AVP in maintaining adrenocortical responsiveness during chronic stress using the AVP deficient mutant Brattleboro rat. Heterozygous Brattleboro rats (di/+) served as controls and were compared to homozygous rats (di/di) with diabetes insipidus. Sixty minutes daily restraint was repeated for 5, 8, 11 or 15 days and organ weights, plasma adrenocorticotropin (ACTH) and corticosterone levels and anterior pituitary proopiomelanocortin (POMC) mRNA and ACTH content were measured. The body, adrenal and thymus weight changes induced by chronic stress became significant between 5 and 8 repetition and AVP deficiency had no effect on these parameters. The first indication that AVP has a role to play appears after 11 repetitions. In the di/di group at the end of 11th restraint, the plasma ACTH was decreased when compared to the di/+ rats. In animals with indwelling cannulas some adaptation could be seen in ACTH response without any difference between di/+ and di/di rats after 15 restraints. The corticosterone- and prolactin-elevations induced by restraint did not habituate in the di/+ and the di/di rats. Chronic stress increased POMC mRNA in the anterior pituitary similarly in di/+ and di/di rats. Although AVP seems to be necessary for a full ACTH response, most of the other signs of chronic stress after repeated restraint occur unchanged in the absence of AVP in both genders. This suggests that either AVP is not indispensable for activating the hypothalamo-pituitary-adrenocortical system by chronic stress or the absence of AVP is compensated by other mediators in Brattleboro rats.

Effects of repeated restraint stress on hypothalamo-pituitary-adrenocortical function in vasopressin deficient Brattleboro rats

Arginine-vasopressin (AVP) has been proposed to be an important mediator during chronic stress in the regulation of the hypothalamo-pituitary-adrenal axis. In the present study we addressed the role of AVP in maintaining adrenocortical responsiveness during chronic stress using the AVP deficient mutant Brattleboro rat. Heterozygous Brattleboro rats (di/+) served as controls and were compared to homozygous rats (di/di) with diabetes insipidus. Sixty minutes daily restraint was repeated for 5, 8, 11 or 15 days and organ weights, plasma adrenocorticotropin (ACTH) and corticosterone levels and anterior pituitary proopiomelanocortin (POMC) mRNA and ACTH content were measured. The body, adrenal and thymus weight changes induced by chronic stress became significant between 5 and 8 repetition and AVP deficiency had no effect on these parameters. The first indication that AVP has a role to play appears after 11 repetitions. In the di/di group at the end of 11th restraint, the plasma ACTH was decreased when compared to the di/+ rats. In animals with indwelling cannulas some adaptation could be seen in ACTH response without any difference between di/+ and di/di rats after 15 restraints. The corticosterone- and prolactin-elevations induced by restraint did not habituate in the di/+ and the di/di rats. Chronic stress increased POMC mRNA in the anterior pituitary similarly in di/+ and di/di rats. Although AVP seems to be necessary for a full ACTH response, most of the other signs of chronic stress after repeated restraint occur unchanged in the absence of AVP in both genders. This suggests that either AVP is not indispensable for activating the hypothalamo-pituitary-adrenocortical system by chronic stress or the absence of AVP is compensated by other mediators in Brattleboro rats.

Chronic Stress in Dogs Subjected to Social and Spatial Restriction. I. Behavioral Responses

Six weeks of social and spatial restriction were used as a model to induce chronic stress in Beagles. Behavioral and physiological measurements were performed during a period of enriched spacious outdoor housing in groups (GH) and during a subsequent period of solitary housing in small indoor kennels (IH). Behavioral parameters that may indicate chronic stress in dogs are reported. During IH, the dogs showed significantly (comparison-wise error rate <0.05) lower postures than during GH. IH induced enduring increments in frequencies of autogrooming, paw lifting, and vocalizing, and was associated with incidents of coprophagy and repetitive behavior. So far, we interpret the behavioral changes as signs of chronic stress. Relatively low levels of walking, digging, intentions to change from one state of locomotion to another, and increments in circling are conceived as obvious adaptations to the specific features of the IH system. By challenging the dogs outside their home kennel we tested whether the dogs’ coping abilities were affected by IH. Dogs that were challenged were introduced into a novel environment, given the opportunity to escape from their home kennel, restrained, walked down an unfamiliar corridor, presented a novel object, exposed to loud noise, given food, or confronted with a conspecific. During IH, challenged dogs exhibited higher postures, showed more tail wagging, nosing, circling, urinating, and defecating, and changed more often from one state of locomotion (or posture) to another than during GH. These behavioral changes were observed across the different types of challenges, with the exception of the noise administration test. In the presence of conspecifics, the socially and spatially restricted male dogs behaved more dominantly and aggressive than during the time that they were kept in groups. Such behavior manifested as increased performances of raised hairs, growling, paw laying, and standing over. Both sexes showed increases in paw lifting, body shaking, ambivalent postures, intentions to change from one state of locomotion to another, and trembling in any of the challenges, excluding the walking down the corridor test. In short, during a variety of challenges, socially and spatially restricted dogs exhibited a heightened state of aggression, excitement, and uncertainty. Behavioral differences between dogs that had experienced pleasant and bad weather conditions during GH, suggested that “pleasant-weather individuals” had experienced early stress during the control period, and, as a result, responded to the subsequent period of IH differently. Regardless of the housing conditions, challenged bitches showed stronger indications of acute stress than male dogs. Gender did not affect the chronic stress responses to social and spatial restriction. A low posture and increased autogrooming, paw lifting, vocalizing, repetitive behavior, and coprophagy may indicate chronic stress in dogs, and as such, can help to identify poor welfare. When challenged, chronically stressed dogs may show increased excitement, aggression, and uncertainty, but the nonspecificity of such emotional behavior will complicate its practical use with regard to the assessment of stress.