Clinicopathological characteristics and survival in Serbian patients with renal cell carcinoma: a retrospective analysis.

PURPOSE: Indications of kidney cancer outcome in lowerincome countries are based on an incidence/mortality ratio due to lack of survival information. This study was conducted to provide outcome data in Serbian patients with renal cell carcinoma (RCC) and to identify prognostic factors that could affect their overall survival (OS). METHODS: This retrospective study included 185 patients who underwent nephrectomy. We assessed certain clinicopathological data including age, gender, tumor size, grade, stage and histological subtypes for their possible impact on OS. RESULTS: The 5-year OS was 63.2%. Significant association was found between OS and age (log-rank 12.455, p=0.006), tumor size (log-rank 26.425, p=0.000), grade (log-rank 13.249, p=0.000) and stage (log-rank 43.235, p=0.000). Univariate analysis indicated size (p=0.000), grade (p=0.001) and stage (p=0.000) as prognostic factors for OS. In multivariate analysis, grade (p=0.014) and stage (p=0.000) remained significant predictors of OS. CONCLUSION: Tumor grade and stage were identified as independent prognostic factors of OS survival in Serbian patients with RCC.

Antioxidant Enzymes in Brain Cortex of Rats Exposed to Acute, Chronic and Combined Stress.

The study deals with manganese superoxide dismutase, copper, zinc superoxide dismutase, and catalase activities in brain cortex of Wistar rats exposed to acute stress (immobilization or cold for 2 h), chronic stress (long-term isolation or long-term forced swimming for 21 days), or to combined chronic/acute stress. We observed that i) single episodes of acute stress by immobilization increased activity of both superoxide dismutases; ii) both types of chronic stresses significantly elevated activities of all examined enzymes; iii) chronic social isolation was a much stronger stressor than physical stress by swimming; iv) in animals pre-exposed to chronic isolation, additional stress by immobilization or cold significantly decreased previously elevated activities of all enzymes, while after chronic swimming, acute immobilization lowered only catalase activity. The obtained results indicate that stress conditions most probably altered the cell redox equilibrium, thus influencing the antioxidant response in brain cortex. Further investigation of neuronal prooxidant/antioxidant cellular conditions is needed to improve the prevention and treatment of various stress induced diseases.

Antioxidative enzymes in irradiated rat brain-indicators of different regional radiosensitivity.

PURPOSE: Previously, we examined manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), and catalase (CAT) activities in rat brain irradiated with 2 or 3 Gy of γ-rays. The results indicated that lower MnSOD activity and inducibility found in hippocampus might explain higher radiosensitivity of this brain region. Thus, in this study, we wanted to determine changes of MnSOD, CuZnSOD, and CAT activities after dose of 5 Gy and to find out if differences in MnSOD activity are caused by changes in its expression. METHODS: Heads of 4-day-old female rats were irradiated with γ-rays, using (60)Co. Animals were sacrificed 1/24 h after exposure. Hippocampus and cortex tissues were prepared for enzyme activity measurements and Western blot analysis. RESULTS: One hour after exposure, γ-rays significantly decreased MnSOD activity in both examined brain regions. Twenty-four hours later, MnSOD recovery showed dose and regional dependence. It was weaker at higher doses and in hippocampal region. MnSOD expression changed in the similar manner as MnSOD activity only at lower doses of γ-rays. In both examined brain regions, gamma radiation significantly decreased CuZnSOD activity and did not change activity of CAT. CONCLUSIONS: Our results confirmed that MnSOD plays an important role in different regional radiosensitivity but also showed that depending on dose, radiation affects MnSOD level by utterly different mechanisms. Postradiation changes of CuZnSOD and CAT are not regionally specific and therefore, cannot account for the different radiosensitivity of the hippocampus and cortex.

Antioxidant status in women with uterine leiomyoma: relation with sex hormones.

Uterine leiomyomas are benign soft-tissues tumors that arise from uterine smooth muscle tissue. Etiopathogenesis of leiomyomas is not well understood. We aimed to examine whether antioxidant enzyme activities and lipid hydroperoxides level in patients with leiomyoma are influenced by changes in sex hormones and gonadotropins (estradiol (E2), progesterone, FSH, and LH) during menstrual cycle and in postmenopause. The material consisted of blood and uterine tissue specimens. Hormone concentrations were determined and assays for superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities and lipid hydroperoxides concentration were performed. In blood of examined women, a significant difference in catalase, glutathione peroxidase and glutathione reductase activity was recorded among the phases. There was also a positive correlation between the estradiol/progesterone concentration and the catalase activity. Progesterone negatively correlated with lipid hydroperoxides level. In myoma tissue, we recorded a phase-related difference in lipid hydroperoxides level and activities of superoxide dismutase, glutathione peroxidase activities, and glutathione reductase. Negative correlation was observed between FSH and glutathione peroxidase. The results suggest that antioxidant status in patients with uterine leiomyoma is influenced by the changes in sex hormones during the menstrual cycle and in postmenopause, indicating a role of the observed relationship in the leiomyoma etiology.

Treadmill exercise does not change gene expression of adrenal catecholamine biosynthetic enzymes in chronically stressed rats.

Chronic isolation of adult animals represents a form of psychological stress that produces sympatho-adrenomedullar activation. Exercise training acts as an important modulator of sympatho-adrenomedullary system. This study aimed to investigate physical exercise-related changes in gene expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase, dopamine-ß-hydroxylase and phenylethanolamine N-methyltransferase) and cyclic adenosine monophosphate response element-binding (CREB) in the adrenal medulla, concentrations of catecholamines and corticosterone (CORT) in the plasma and the weight of adrenal glands of chronically psychosocially stressed adult rats exposed daily to 20 min treadmill running for 12 weeks. Also, we examined how additional acute immobilization stress changes the mentioned parameters. Treadmill running did not result in modulation of gene expression of catecholamine synthesizing enzymes and it decreased the level of CREB mRNA in the adrenal medulla of chronically psychosocially stressed adult rats. The potentially negative physiological adaptations after treadmill running were recorded as increased concentrations of catecholamines and decreased morning CORT concentration in the plasma, as well as the adrenal gland hypertrophy of chronically psychosocially stressed rats. The additional acute immobilization stress increases gene expression of catecholamine biosynthetic enzymes in the adrenal medulla, as well as catecholamines and CORT levels in the plasma. Treadmill exercise does not change the activity of sympatho-adrenomedullary system of chronically psychosocially stressed rats.

Modulation of catecholamine-synthesizing enzymes in adrenal medulla and stellate ganglia by treadmill exercise of stressed rats.

The sympatho-adrenal system represents one of the main systems involved in the response to stressful events because its stress-induced activation results in an increased release of catecholamines. Exercise training acts as an important modulator of sympatho-adrenal system, adrenal medulla and stellate ganglia being two components of this system. This study aimed at investigating physical exercise-related changes in gene expression of catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), dopamine-ß-hydroxylase (DBH) and phenylethanolamine N-methyltransferase in the adrenal medulla and stellate ganglia of chronically psychosocially stressed adult rats exposed daily to 20-min treadmill exercise for 12 weeks, using TaqMan RT-PCR assay. Chronic psychosocial stress decreased gene expression of the examined enzymes in the adrenal medulla and treadmill exercise did not lead to further modulation of the corresponding gene expression. On the other hand, chronic psychosocial stress produced a significant increase of TH (about 51%) and DBH (about 103%) gene expression in stellate ganglia, while treadmill exercise decreased gene expression of these enzymes to control levels in psychosocially stressed rats. Our data indicate that treadmill exercise leads to a decreased gene transcription of catecholamine biosynthetic enzymes in stellate ganglia and attenuation of cardiac noradrenaline production in stressful situations. Reduction of catecholamine synthesis in stellate ganglia may be linked to the beneficial effects of treadmill exercise on cardiovascular system in stressed animals.

Hippocampal asymmetry in expression of catecholamine synthesizing enzyme and transporters in socially isolated rats.

OBJECTIVES: Right-left asymmetry of human brain function has been known for a century. Brain asymmetry and lateralization has been observed at the neurochemical level. At the neurochemical level, it is important to further correlate changes in monoaminergic activity with the synthesis and reuptake of these monoamines. The aim of the present study was to analyze the effect of social isolation on catecholamine stores as well as on the regulation of catecholamine synthesis and uptake in the right and left hippocampus. METHODS: We examined changes in protein levels of dopamine-ß-hydroxylase (DBH), norepinephrine transporter (NET) and vesicular monoamine transporter 2 (VMAT 2) in the right and left hippocampus of socially isolated adult male rats during 12 weeks by Western blot analysis. RESULTS: Chronic isolation stress reduced norepinephrine content in the right hippocampus. No changes were observed in protein levels of DBH and NET in the right hippocampus, whereas expression of this norepinephrine synthetizing enzyme and transporter were elevated in the left hippocampus. On the other hand, chronic isolation stress caused reduction of VMAT2 protein in the right hippocampus. CONCLUSION: Our results reveale not only the lateralization of stress regulatory system but they also show that long-term isolation stress produces right-left asymmetry of the hippocampus norepinephrine, different regulation of the catecholamines synthesis and reuptake.

Antioxidant protection against curative and palliative doses of ionizing irradiation in human blood decreases with aging.

Reactive oxygen species (ROS) are independently recognized to play a significant role in radiation-induced damage on healthy tissue and in aging process. However, an age-related alteration of antioxidant (AO) system in radiation response in humans is poorly investigated. The aim of this paper was to evaluate the irradiation effects on the activities and expression of AO system in the blood of healthy women during aging. Blood samples were irradiated with curative and palliative doses of 2 Gy or 9 Gy γ-rays. AO capacity for detoxification of O(2)•(-) and H(2)O(2) in response to 2 Gy γ-irradiation decreases in women above 58 years, while in response to 9 Gy shows signs of weakening after 45 years of age. Due to reduction of AO capacity during aging, cytotoxic effects of curative and palliative doses of irradiation, mediated by ROS, may significantly increase in older subjects, while removal of H(2)O(2) excess could reduce them.

Antioxidant defense system in the prefrontal cortex of chronically stressed rats treated with lithium.

Background: This study aimed to investigate the effects of lithium treatment on gene expression and activity of the prefrontal antioxidant enzymes: copper, zinc superoxide dismutase (SOD1), manganes superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPx) in animals exposed to chronic restraint stress (CRS). Methods: The investigated parameters were quantified using real-time RT-PCR, Western blot analyses, and assays of enzyme activities. Results: We found that lithium treatment decreased gene expression of SOD2, as well as the activities of SOD1 and SOD2 in chronically stressed rats to the levels found in unstressed animals. However, lithium treatment in animals exposed to CRS increased prefrontal GPx activity to the levels found in unstressed animals. Conclusions: These findings confirm that treatment with lithium induced the modulation of prefrontal antioxidant status in chronically stressed rats. Our results may be very important in biomedical research for understanding the role of lithium in maintaining the stability of prefrontal antioxidant defense system in neuropsychiatric disorders caused by chronic stress.

Effects of mood stabilizer lithium on noradrenergic turnover in the prefrontal cortex of chronically stressed rats.

OBJECTIVE: Data about the dynamics of noradrenaline (NA) transmission, storage and degradation may be very important for understanding the reduction of functional deficiency of NA and maintaining the stability of NA levels in animals with depressive-like behavior treated with lithium. This study aimed to investigate the effects of mood stabilizer lithium on concentrations of NA in the prefrontal cortex (PFC), as well as behavior rats exposed to chronic restraint stress (CRS). In addition, this study examined the effects of lithium on protein levels of noradrenaline transporter (NET), vesicular monoamine transporter 2 (VMAT2) and catechol-O-methyltransferase (COMT), as well as the enzyme activity of monoamine oxidase A (MOA) in the PFC of chronically stressed rats. METHODS: The investigated parameters were quantified by Western blot analysis, CAT Research ELISA kits, and an assay of enzyme activity. Also, the forced swim test (FST) was used to assess the behavior of animals. RESULTS: We found that lithium treatment decreased high protein levels of NET and VMAT2, as well as the enzyme activity of MOA in chronically stressed rats to the levels found in unstressed animals. In addition, lithium treatment decreased the concentration of NA (24%) and immobility in animals exposed to CRS. CONCLUSION: Our data confirm that lithium-induced modulation of prefrontal noradrenergic turnover and stabilized the behavior of chronically stressed rats.

Chronic individual housing-induced stress decreased expression of catecholamine biosynthetic enzyme genes and proteins in spleen of adult rats.

OBJECTIVE: Social isolation is regarded as one of the most relevant causes of diseases in mammalian species. The activation of the sympathoneural system represents one of the key components of the stress response. The sympathetic nervous system is one of the major pathways involved in immune-neuroendocrine interactions. The aim of the present study was to determine plasma epinephrine and norepinephrine in individually housed rats, as well as to find out whether splenic gene expression of catecholamine synthesizing enzymes and their protein levels are affected by chronic psychosocial stress. METHODS: Tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) mRNA levels were quantified by quantitative real-time RT-PCR. The TH, DBH and PNMT immunoproteins were assayed by Western blot. RESULTS: Chronic social isolation of adult male rats produced a significant increase in plasma catecholamine levels and a decrease in splenic TH mRNA, DBH mRNA and PNMT mRNA. Protein levels of TH, DBH and PNMT were also reduced. CONCLUSION: These results suggest that increased plasma catecholamines and decreased gene expression and protein levels of catecholamine biosynthetic enzymes in the spleen of chronically individually housed animals might reduce catecholamine synthesis, thus leaving the immunocompetent tissues depleted of catecholamines and consequently leading to an impairment of immune response.

The effect of antioxidant status on overall survival in renal cell carcinoma.

INTRODUCTION: The oxidative stress contributes to all three phases of carcinogenesis and represents a concomitant condition in renal cell carcinoma (RCC). RCC is the most common type of neoplasm of the kidney, and despite numerous studies the set of predictive and prognostic markers of survival are still unknown. The aim of our study was to examine the relation between antioxidant (AO) status and overall survival (OS) in RCC patients. MATERIAL AND METHODS: Our study included 95 patients with RCC, who underwent radical nephrectomy. We analysed the prognostic role of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, glutathione, and malondialdehyde) and other clinicopathological factors (size, grade, stage, and histological subtype) on the OS of RCC patients. RESULTS: The 5-year OS was 54.6%. The survival analysis related to AO parameters showed no significant difference in survival of RCC patients. The concentration of malondialdehyde, an indicator of lipid peroxidation, also had no significant effect on the survival rate of RCC patients. Univariate and multivariate analysis confirmed the significance of clinicopathological parameters (size, p < 0.001; Fuhrman grade, p = 0.001, and stage, p < 0.001) for patients' survival. CONCLUSIONS: In our cohort of patients, different antioxidant parameters were not found to be predictors for OS of patients with RCC, who underwent radical nephrectomy.

Modulation of Hippocampal Antioxidant Defense System in Chronically Stressed Rats by Lithium.

This study examined the effects of lithium on gene expression and activity of the antioxidant enzymes copper zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in the hippocampus of chronically stressed rats. In addition, we examined the effects of lithium on anxiety behaviors, hippocampal concentrations of dopamine (DA) and malondialdehyde (MDA), protein levels of brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), dopamine transporter (DAT), and catechol-O-methyltransferase (COMT), as well as activity of monoamine oxidase (MAO) in chronically stressed rats. The investigated parameters were quantified by real-time RT-PCR, Western blot analyses, and assays of enzyme activities. We found that lithium did not change gene expression of SOD1, CAT, GPx, and GR but decreased gene expression of SOD2 in chronically stressed rats. A very important result in this study was that lithium treatment decreased the enzyme activities of SOD1 and SOD2 but increased the enzyme activities of GPx and GR in stress condition, which indicates the control of redox balance. The reduced concentration of MDA confirms this. In addition, we found that lithium treatment decreased high protein levels of BDNF and DAT in chronically stressed rats to the level found in unstressed animals. Also, lithium treatment increased the expression of TH but decreased the enzyme activity of MAO B, which contributed to the increase of hippocampal concentration of DA in chronically stressed rats to the level of unstressed animals. Finally, lithium treatment in animals exposed to chronic stress increased the time spent in open arms. Lithium-induced modulation of hippocampal antioxidant status and attenuation of oxidative stress stabilized behavior in animals with high anxiety index. In addition, reduced oxidative stress was followed by the changes of both turnover of DA and levels of BDNF protein in chronically stressed rats treated with lithium. These findings may be important in preclinical research of the effects of lithium on oxidative stress level in pathological conditions.

Expression of Antioxidant Enzymes in Patients with Uterine Polyp, Myoma, Hyperplasia, and Adenocarcinoma.

We previously found that compared to patients with benign uterine diseases (polyps, myomas), patients with premalignant (hyperplasia simplex and complex) and malignant (adenocarcinoma) lesions had enhanced lipid peroxidation and altered uterine antioxidant enzyme (AOE) activities. To further elucidate the mechanism of the observed changes, we examined protein and mRNA levels of copper-zinc superoxide dismutase (CuZnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and transcription factor Nrf2. We also examined correlations of AOE expression with AOE activity, lipid hydroperoxides (LOOH) level, and level of Nrf2. Our results showed decreased CuZnSOD, CAT, and Nrf2 levels, and increased GPx and GR levels in hyperplasias, while in patients with adenocarcinoma, the level of CAT was decreased and GR was increased, compared to benign groups. Similar changes in mRNA levels were also detected, indicating predominantly translational control of the AOE expression. The positive correlation of enzyme expression/activity was recorded for CuZnSOD, GPx, and GR, but only among groups with benign diseases. Only GR and GPx expressions were positively correlated with LOOH. Nrf2 protein was positively correlated with mRNA levels of CuZnSOD and GR. Observed results indicate involvement of diverse redox mechanisms in etiopathogenesis of different gynecological diseases, and may improve redox-based approaches in current clinical practice.

Chronic isolation of adult rats decreases gene expression of catecholamine biosynthetic enzymes in adrenal medulla.

OBJECTIVE: Isolation of adult animals represents a form of psychsocial stress that produces sympatho-adrenomedullar activation. The aim of this work was to investigate the changes in gene expression and protein levels of catecholamine biosynthetic enzymes: tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in the adrenal medulla of naive control and chronically (12 weeks) socially isolated adult Wistar rat males and the response of these animals to additional immobilization stress (2 h). METHODS: TH, DBH and PNMT mRNA levels were quantified by quantitative real-time RT-PCR (qRT-PCR). TH, DBH and PNMT immunoproteins were assayed by Western Blot. RESULTS: In chronically isolated rats, gene expression levels of catecholamine biosynthetic enzymes in the adrenal medulla were decreased, but only TH mRNA was significantly decreased. However, protein levels of TH, DBH and PNMT of these animals were elevated by 55%, 20% and 18%, respectively, in relation to the corresponding control. Naive control and chronically socially isolated rats exposed to additional 2-h-immobilization showed increased gene expression of the examined enzymes, the increase being greater in socially isolated rats as compared to the controls. Additional immobilization of naive controls did not affect TH, DBH and PNMT protein levels. In contrast, this stress produced increased TH, DBH and PNMT protein levels in long-term socially isolated rats. CONCLUSION: We can conclude that psychosocial stress expressed a differential influence on gene expression and protein levels of catecholamine biosynthetic enzymes in the adrenal medulla of adult rats. The results indicate a possible adaptation of catecholamine-synthesizing system at the level of TH gene expression in adrenal medulla of chronically isolated animals.

The effect of repeated physical exercise on hippocampus and brain cortex in stressed rats.

Sensitivity of target cells to glucocorticoids is regulated by the expression of intracellular glucocorticoid receptor (GR), which mediates the effects of glucocorticoids. The level of GR and of its nuclear transporter protein 70 (Hsp70) were followed in hippocampus and brain cortex of adult Wistar rat males exposed to acute (immobilization, cold) and chronic (social isolation, isolation, and 15 min daily swimming) stress or their combinations. Changes in plasma levels of adenocorticotropic hormone and corticosterone were also studied. A significant decrease in cytosol GR and Hsp70 was observed after acute stress. Opposite to that, chronic stress led to negligible changes in both cytosol GR and Hsp70 levels. Isolation, as chronic psychosocial stressor, caused reduced responsiveness to novel acute stressors, judged by the cytosol GR and Hsp70 levels. This was not observed if chronic isolation was combined with 15 min daily swimming prior to acute exposure to immobilization. The data suggest that repeated physical exercise may, at least in some cases, diminish detrimental effects of chronic social isolation on limbic-hypothalamic-pituitary-adrenocortical axis, as judged by the levels of GR and Hsp70 in the Wistar rat brain.

Effects of noradrenaline and serotonin reuptake inhibitors on pituitary-adrenocortical and sympatho-adrenomedullar system of adult rats.

OBJECTIVE: To estimate the influence of long-term treatment with noradrenergic and serotonergic reuptake inhibitors on activity of pituitary-adrenocortical and sympatho-adrenomedullar systems in animals, we compared the effects of maprotiline (a selective inhibitor of noradrenaline reuptake) and fluxilan (a selective inhibitor of serotonin reuptake) on plasma noradrenaline (NA), adrenaline (A), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) levels in unstressed control and rats exposed to chronic unpredictable mild stress (CUMS). METHODS: Plasma NA and A were assayed by a radioenzymatic method. Plasma CORT was measured using RIA kits and plasma ACTH by a chemiluminescent method. RESULTS: CUMS did not affect blood plasma NA, A and ACTH content, but elevated plasma CORT level. Maprotiline elevated plasma NA content both in unstressed control and CUMS group, whereas plasma A remained unchanged. Fluxilan acted significantly increasing plasma NA and A concentrations both in control and CUMS rats. Neither maprotiline nor fluxilan affected plasma ACTH level both in unstressed control and CUMS animals. Plasma CORT level in unstressed control rats remained unchanged after maprotiline and fluxilan treatment, while being significantly decreased in CUMS rats. CONCLUSION: Chronic treatment of adult rat males with maprotiline, a noradrenaline reuptake inhibitor activated sympathoneural system. On the other hand, fluxilan, a serotonin reuptake inhibitor activated both sympathoneural and adrenomedullar system, whereas both antidepressants desensitized HPA axis. The findings described here suggest that elevated plasma catecholamines my contribute to adverse effects of these drugs on cardiovascular parameters during antidepressant therapy.

Novel stressors affected catecholamine stores in socially isolated normotensive and spontaneously hypertensive rats.

Catecholamines in some central (hypothalamus and hippocampus) and peripheral tissues (adrenal glands and heart auricles) of long-term socially isolated normotensive and spontaneously hypertensive rats exposed to novel immobilization stress were determined by a simultaneous single isotope radioenzymatic assay. Long-term isolation (21 days) produced depletion of hypothalamic norepinephrine (NE) stores and hippocampal dopamine (DA) stores in both normotensive and spontaneously hypertensive rats. Acute immobilization stress (2 h) significantly decreased NE and DA stores in hypothalamus and hippocampus of naive normotensive and spontaneously hypertensive rats controls. However, novel immobilization stress applied to normotensive rats previously subjected to long-term isolation produced no changes in catecholamine levels in hypothalamus, while resulting in somewhat higher depletion of NE stores in hypothalamus of spontaneously hypertensive rats treated in the same way. Novel immobilization stress decreased NE and DA stores in hippocampus of normotensive but was without effect on NE and DA stores of spontaneously hypertensive rats. Social isolation did not affect catecholamine stores in peripheral tissues but novel immobilization stress produced a significant decrease in catecholamine content. The results suggest that some central and peripherals tissues of spontaneously hypertensive rats and normotensive rats differ with regard to catecholamine content and that there are certain differences in their responsiveness to stress.

Activation of rat pituitary-adrenocortical and sympatho-adrenomedullary system in response to different stressors.

OBJECTIVE: The effects of three different long-term (21 days) stresses: isolation(LTI), forced swimming (LTS) and isolation accompanied by forced swimming (LTI+LTS) on the level of plasma noradrenaline (NA), adrenaline (A), corticosterone (CORT) and adrenocorticotropic hormone (ACTH), both under basal conditions and in response to short-term immobilization and cold as heterotypic additional stressors, were compared. METHODS: Plasma NA and A were assayed by the radioenzymatic method. Plasma CORT was measured using RIA kits. Plasma ACTH was determined by chemiluminescent method. RESULTS: LTI produced a significant elevation of basal plasma CORT and ACTH, while basal plasma NA and A concentrations remained unchanged. Combination of long-term isolation and forced swimming, produced a significant elevation of basal plasma ACTH content only, while LTS did not influence the basal level of this hormone. When LTI rats were exposed to immobilization and cold, a significant elevation of plasma NA and A level was recorded. In LTS and LTI+LTS groups of rats exposed to immobilization or cold, increased plasma NA and A levels were observed, but this increase was lower in comparison with that found in LTI rats. No difference in plasma CORT content between the three long-term stressed groups of animals was observed, while plasma ACTH level was significantly more elevated in LTS and LTI+LTS than in LTI rats. CONCLUSION: Based on these results, it may be concluded that LTI as a psychosocial stress represents a stronger stressor than LTS. Also, daily short-term (15 min, 21 days) swimming stress seems to attenuate the effect of long-term isolation on the activity of sympatho-adrenomedullary system.

Immobilization and cold stress affect sympatho-adrenomedullary system and pituitary-adrenocortical axis of rats exposed to long-term isolation and crowding.

Changes in plasma levels of noradrenaline (NA), adrenaline (A), adrenocorticotropic hormone (ACTH) and corticosterone (CORT), as well as in cytosol glucocorticoid receptor (GR) and heat shock protein 70 (Hsp 70) in hippocampus of adult rat males exposed to two long-term types of psychosocial stress, both under basal conditions and in response to immobilization and cold as heterotypic additional stressor were studied. Long-term isolation produced a significant elevation of basal plasma ACTH and CORT levels, but did not affect that of NA and A, while long-term crowding conditions did not elevate the basal plasma levels of these hormones. Long-term isolation of rats exposed to 2 h of immobilization or cold led to a significant elevation of plasma NA, A and CORT in comparison with the controls. Long-term crowding conditions and exposure of animals to immobilization or cold also resulted in an increased plasma NA, A and CORT levels, but to a lesser extent in comparison with the long-term isolation. At the same time, plasma ACTH was significantly more elevated in long-term crowded than in long-term isolated rats. Both kinds of long-term psychosocial stresses (isolation and crowding) had similar but less pronounced effects on cytosol GR and Hsp 70 concentrations in hippocampus comparing to acute immobilization and cold stress. It seems that long-term psychosocial stresses attenuate the effects of an additional stress on hippocampal GR and Hsp 70 concentrations. These data suggest that individual housing of rats appear to act as a stronger stressor than crowding conditions. When the animals suffering a long-term isolation were exposed to either acute immobilization or cold, a stronger activation of the sympatho-adrenomedullary system (SAS) was recorded in comparison with that found in the long-term crowded group subjected to short-term immobilization or cold. No significant differences in the activity of hypotalamo-pituitary-adrenal (HPA) axis were observed between long-term isolated and long-term crowded rats.