Effects of Ethanol, Chlordiazepoxide, and MK-801 on Performance in the Elevated-Plus Maze and on Locomotor Activity

The effects of ethanol, chlordiazepoxide, and MK-801 on performance in the elevated-plus maze and on activity measured in a circular activity monitor were compared in Sprague-Dawley rats to determine whether these effects of ethanol could be explained by its action on either GABA_A or NMDA receptors. Both ethanol and chlordiarepoxide produced an increase in the time spent in the open arms of the elevated-plus maze and in the ratio of open arm to total arm entries, indicative of an anxiolytic action of these drugs. MK-801 did not alter either the time spent in the open arms or the ratio of open to total arm entries. Chlordiazepoxide and MK-801 produced an increase in total arm entries that suggested that these compounds were increasing locomotor activity. Ethanol also increased total arm entries, but the effect was not statistically reliable. Following habituation to an activity monitor, neither ethanol nor chlordiazepoxide increased activity in this task, whereas MK-801 produced a robust increase in locomotion. Additionally, neither ethanol nor chlordiazepoxide blocked the MK-801-induced locomotor stimulation. The latter finding suggests that the effects of ethanol on GABAA receptors was not Mocking an increased activity level produced by its antagonism of NMDA. Additionally, these results indicate that the anxiolytic and locomotor action of ethanol in rats parallel the effects of a benzodiazepine and not those of an NMDA antagonist. Finally, these results suggest that the consequence of ethanol's antagonism of NMDA receptor function is more restricted than that produced by MK-801.     

Prenatal Ethanol Exposure Differentially Alters Behavior in Males and Females on the Elevated Plus Maze

Rodents prenatally exposed to ethanol demonstrate hypothalamic-pituitary-adrenal and behavioral hyperactivity to a variety of stressful situations. The present study examined both behavioral and corticosterone (CORT) responses to the elevated plus maze (+-maze), an anxiety- or fear-provoking task. Sprague-Dawley male and female offspring from fetal ethanol-exposed (E), pair-fed (PF), and ad libitum-fed control (C) groups were tested at 60 to 90 days of age. In experiment 1, behavior was measured in animals exposed to the +-maze for 5 min on two consecutive days; 2 weeks later, both behavioral and CORT responses were measured in animals confined to the open and closed arms of the maze for 20 min. In experiment 2, animals were placed in an open field (OF) for 5 min before a single 5-min exposure to the +-maze. Factor analysis of the scored behaviors from the two experiments indicated two main factors, designated "exploration" and "fear." E males and females both exhibited higher levels of exploratory behaviors when placed directly on the +-maze from their homecages without prior exposure to the OF, compared with C males and females. In addition, when confined to the closed arms of the +-maze, E males and females demonstrated higher levels of activity, compared with C males and females. After OF exposure, however, both E males and females demonstrated lower levels of exploratory behaviors than C males and females, and E females also had increased CORT levels, compared with PF and C females. Interestingly, E females, but not E males, showed an increase in fear-related behaviors on the +-maze, compared with controls, regardless of prior OF exposure. These data demonstrate that prenatal ethanol exposure may differentially affect both behavioral and hormonal responses of males and females in an aversive behavioral task and suggest that there may be a sex difference in the sensitivity of the mechanism(s) underlying these responses.     

Stress of chronic food restriction attenuates the development of adjuvant arthritis in male Long Evans rats

OBJECTIVE: To study the effect of the stress of chronic food restriction on the development of adjuvant arthritis in Long Evans male rats. METHODS: Four groups of animals were compared: non-treated control (C) and arthritic (AA) rats, both with free access to food and water and two analogous groups with a 40% food restriction, i.e. non-treated (FR) and arthritic (AA-FR) animals. All rats were killed 22 days following the injection of complete Freund's adjuvant. The parameters measured were: serum levels of albumin (ALB), nitrate, glucose, insulin, corticosterone (CORT), prolactin (PRL) and PRL mRNA in the adenopituitaries. In addition the activity of gamma-glutamyl transpeptidase (GGTP) was measured in the spleen. The pain threshold was determined by the tailflick method. The body weight of the animals was recorded on day 0, 3, 7, 11, 15 and 18 of the disease. RESULTS: Arthritis caused swelling of the hind paw (2.37 +/- 0.15 ml vs 1.1 +/- 0.05ml in controls, p < 0.01) which was prevented in the AA-FR group (1.44 +/- 0.13 ml, not significant against controls). Arthritis increased serum NO and reduced ALB levels; both changes were significantly restored in the FR-AA group. Food restriction did not alter the activation of GGTP, or the decrease of PRL mRNA observed in the AA group. Serum CORT was elevated in rats with food restriction (15.49 +/- 2.1 vs. 3.7 +/- 0.87 microg/dL) and remained enhanced to the same extent in AA and FR-AA groups. The tailflick latency prolonged in the AA group was reduced by food restriction. CONCLUSION: These results show that 40% food restriction associated with elevated CORT levels mitigated the inflammatory parameters activated during AA.     

Novel actions of estrogen receptor-beta on anxiety-related behaviors

Estrogens are reported to have both anxiogenic and anxiolytic properties. This dichotomous neurobiological response to estrogens may be mediated by the existence of two distinct estrogen receptor (ER) systems, ERalpha and ERbeta. In brain, ERalpha plays a critical role in regulating reproductive neuroendocrine function, whereas ERbeta may be more important in regulating nonreproductive functions. To determine whether estrogen's anxiolytic actions could be mediated by ERbeta, we examined anxiety-related behaviors after treatment with ER subtype-selective agonists. Ovariectomized female rats, divided into four treatment groups, were injected with the selective ERbeta agonist diarylpropionitrile (DPN), the ERalpha-selective agonist propyl-pyrazole-triol (PPT), 17beta-estradiol, or vehicle daily for 4d. After injections, behavior was monitored in the elevated plus maze or open field. Rats treated with DPN showed significantly decreased anxiety-related behaviors in both behavioral paradigms. In the elevated plus maze, DPN significantly increased the number of open arm entries and time spent on the open arms of the maze. Furthermore, DPN significantly reduced, whereas PPT increased, anxiogenic behaviors such as the number of fecal boli and time spent grooming. In the open field, DPN-treated females made more rears, interacted more with a novel object, and spent more time in the middle of the open field than did control or PPT-treated rats. To confirm that DPN's anxiolytic actions are ER mediated, the nonselective ER antagonist tamoxifen was administered alone or in combination with DPN. Tamoxifen blocked the previously identified anxiolytic actions of DPN. Taken together, these findings suggest that the anxiolytic properties of estrogens are ERbeta mediated.     

Effects of Lactuca sativa extract on exploratory behavior pattern,locomotor activity and anxiety in mice

ObjectiveTo evaluate antianxiety property of Lactuca sativa, an important and commonly used leafy vegetable known for its medicinal properties belongs to Asteraceae family.MethodsElevated plus maze (EPM), open field test (OFT), rat exposure test, hyponeophagia and marble burying test were performed in mice models to assess the exploratory behaviour and to assess anxiolytic property of hydro-alcohol extract of Lactuca sativa. Diazepam (1 mg/kg body wt.) served as the standard anxiolytic agent for all the tests. The dried extract of the plant leaf in doses of 100, 200 and 400 mg/kg body weight was administered orally to mice for duration of 15 or 30 days and evaluated exploratory behaviour, locomotor and anxiolytic activities.ResultsTime spent and number of entries into the open arm was measured in EPM followed by total locomotor activity in OFT and latency to enter the food zone in hyponeophagia.ConclusionsThe study suggested that hydro-alcohol extract of Lactuca sativa leaves possess potent anxiolytic property.     

Behavioural and biochemical changes in maternally separated Sprague–Dawley rats exposed to restraint stress

Early life adversity has been associated with the development of various neuropsychiatric disorders in adulthood such as depression and anxiety. The aim of this study was to determine if stress during adulthood can exaggerate the depression-/anxiety-like behaviour observed in the widely accepted maternally separated (MS) Sprague–Dawley (SD) rat model of depression. A further aim was to determine whether the behavioural changes were accompanied by changes in hippocampal brain-derived neurotrophic factor (BDNF) and the protein profile of the prefrontal cortex (PFC). Depression-/anxiety-like behaviour was measured in the elevated plus maze, open field and forced swim test (FST) in the MS SD rats exposed to chronic restraint stress in adulthood. As expected, MS increased immobility of SD rats in the FST but restraint stress did not enhance this effect of MS on SD rats. A proteomic analysis of the PFC revealed a decrease in actin-related proteins in MS and non-separated rats subjected to restraint stress as well as a decrease in mitochondrial energy-related proteins in the stressed rat groups. Since MS during early development causes a disruption in the hypothalamic‐pituitary‐adrenal axis and long-term changes in the response to subsequent stress, it may have prevented restraint stress from exerting its effects on behaviour. Moreover, the decrease in proteins related to mitochondrial energy metabolism in MS rats with or without subsequent restraint stress may be related to stress per se and not depression-like behaviour, because rats subjected to restraint stress displayed similar decreases in energy-related proteins and spent less time immobile in the FST than control rats.     

氯沙坦对慢性不可预知温和应激模型大鼠的抗抑郁作用

目的探讨氯沙坦（Los）对慢性不可预知温和应激（CUMS）模型大鼠抑郁行为的影响,对其抗炎和抗氧化作用进行考察,探究其潜在的抗抑郁机制。 方法将24只SD大鼠随机分为4组：对照组（Control）、氯沙坦组（Los）、抑郁组（CUMS）、抑郁+氯沙坦组（CUMS+ Los）,每组6只。Los组、CUMS+Los组每天灌胃10 mg/kg的Los溶液,Control组和CUMS组每日灌胃等体积的生理盐水,连续8周。采用糖水偏好实验、强迫游泳实验和高架十字迷宫实验评估大鼠抑郁样行为。酶联免疫吸附法检测大鼠海马的血管紧张素Ⅱ（Ang Ⅱ）的含量。荧光定量PCR检测血管紧张素Ⅱ1型受体（AT1R）和炎性因子白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）的表达量。分光光度法检测海马的超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量。 结果Los组较Control组糖水的消耗量、进入开放臂的时间、进入开放臂次数以及比率、强迫游泳不动时间、Ang Ⅱ含量、AT1R、IL-6、TNF-α表达量、SOD活性、MDA含量差异均无统计学意义（P>0.05）。CUMS组较Control组糖水的消耗量、进入开放臂的时间、进入开放臂次数以及比率、SOD活性显著降低,强迫游泳不动时间、Ang Ⅱ含量和AT1R、IL-6、TNF-α表达量及MDA含量显著升高,差异具有统计学意义（P<0.05）。CUMS+Los组较CUMS组糖水的消耗量、进入开放臂的时间、进入开放臂次数以及比率、SOD活性均升高,而强迫游泳不动时间、Ang Ⅱ含量和AT1R、IL-6、TNF-α表达量及MDA含量均降低,差异均具有统计学意义（P<0.05）。 结论Los能明显改善CUMS所致的大鼠抑郁样行为,降低炎症反应、减轻氧化损伤降低,且该作用与脑内肾素-血管紧张素系统有关,为抗抑郁的靶向治疗提供了新的方向。     

Sex-specific effects of gonadectomy and hormone treatment on acquisition of a 12-arm radial maze task by Sprague Dawley rats

The effects of gonadectomy and hormone treatment on spatial learning were evaluated in adult male and female rats using a modified version of a 12-arm radial maze task. In this version, procedures were used to minimize the effectiveness of strategies less reliant on working and reference memory. Results demonstrate significant sex differences favoring male performance on the working memory component of the task. In contrast, females performed slightly better than males on the reference memory component of the task. In females, ovariectomy produced a decrease in overall accuracy (i.e. an increase in the number of arm entries necessary to obtain all food pellets) as well as declines in working and reference memory performance. Both accuracy and working memory performance, but not reference memory performance, were restored by estradiol treatment. In males, castration impaired working memory performance but did not significantly affect overall accuracy or reference memory performance. Surprisingly, all groups of males performed poorly on the reference memory component of the task, and testosterone treatment appeared to worsen, rather than improve, both accuracy and reference memory performance in males. This may reflect a male preference for certain strategies that were rendered ineffective on this task. Significant sex differences, as well as treatment effects, on arm preference patterns were also detected; however, these differences were not sufficient to account for the effects of sex and treatment on acquisition. Collectively, the data demonstrate robust effects of gonadectomy and hormone treatment on acquisition of this modified radial arm maze task in females, with lesser effects in males.     

Basolateral amygdala is not critical for cognitive memory of contextual fear conditioning

Evidence that lesions of the basolateral amygdala complex (BLC) impair memory for fear conditioning in rats, measured by lack of “freezing” behavior in the presence of cues previously paired with footshocks, has suggested that the BLC may be a critical locus for the memory of fear conditioning. However, evidence that BLC lesions may impair unlearned as well as conditioned freezing makes it difficult to interpret the findings of studies assessing conditioned fear with freezing. The present study investigated whether such lesions prevent the expression of several measures of memory for contextual fear conditioning in addition to freezing. On day 1, rats with sham lesions or BLC lesions explored a Y maze. The BLC-lesioned rats (BLC rats) displayed a greater exploratory activity. On day 2, each of the rats was placed in the “shock” arm of the maze, and all of the sham and half of the BLC rats received footshocks. A 24-hr retention test assessed the freezing, time spent per arm, entries per arm, and initial entry into the shock arm. As previously reported, shocked BLC rats displayed little freezing. However, the other measures indicated that the shocked BLC rats remembered the fear conditioning. They entered less readily and less often and spent less time in the shock arm than did the control nonshocked BLC rats. Compared with the sham rats, the shocked BLC rats entered more quickly and more often and spent more time in the shock arm. These findings indicate that an intact BLC is not essential for the formation and expression of long-term cognitive/explicit memory of contextual fear conditioning.     

Mathematical analysis of locomotor behavior by mice in a radial maze

We investigated the effects of beta-estradiol on the locomotor behavior of female mice in a radial maze. Data comprising the total distance traveled during each arm entry were obtained from video records of six consecutive daily recording sessions. Distributions of these data were bimodal for both ovariectomized control and beta-estradiol-treated ovariectomized subjects. Data were fit with the sum of two gamma probability distributions. Three parameters of the analytic fits were useful for quantifying the effect of beta-estradiol on locomotor behavior: (i) the sampling distance (median of the total distance traveled during each arm entry in the short-distance peak of a bimodal distribution), (ii) the committed distance (median of the total per-arm-entry distance traveled in the long-distance peak), and (iii) the partition distance (distance represented by the minimum between the two peaks). Analysis showed that for sampling-distance arm entries beta-estradiol typically had little if any significant effect on female locomotor behavior, whereas it significantly increased the total distance traveled during committed-distance arm entries on the first 2 days of exposure to the empty maze. beta-Estradiol also increased the ability of females to discriminate between empty maze arms and arms that contained intact or castrated male mice and partially prevented loss of this capacity after removal of the males.     

The effects of ��-glucan isolated from Pleurotus ostreatus on methotrexate treatment in rats with adjuvant arthritis

The purpose of this study was to evaluate the effect of β-(1,3/1,6)-d-glucan isolated from Pleurotus ostreatus (β-glucan-PO) on prophylactic treatment of adjuvant arthritis (AA) with methotrexate (MTX) in rats. Groups of rats with AA were treated with methotrexate (1 mg/kg/week), β-glucan-PO (1 mg/kg every second day) or their combination for the period of 28 days from adjuvant application. Body mass, hind paw swelling, arthrogram scores and a level of serum albumin were measured as markers of inflammation and arthritis. Treatment with low dose of MTX significantly inhibited the markers of both inflammation and arthritis. MTX and its combination with β-glucan-PO significantly increased body mass of arthritic rats. β-glucan-PO administered alone significantly decreased both the hind paw swelling and arthritic score. In combination with MTX, β-glucan-PO markedly potentiated the beneficial effects of MTX, which resulted in a more significant reduction of hind paw swelling and arthritic scores. The concentration of albumin in the serum of arthritic controls was significantly lower than in healthy controls. Both MTX alone and the combination treatment with MTX + β-glucan-PO significantly inhibited the decrease in serum albumin. β-Glucan-PO increased the treatment efficacy of basal treatment of AA with MTX.     

Insulin reverses anxiety-like behavior evoked by streptozotocin-induced diabetes in mice

Clinical and preclinical data suggest that diabetes is often associated with anxiety. Insulin, a peptide hormone has been reported to have key functions in the brain and in alleviating several psychological impairments, occur as a consequence of diabetes. However, its effects in diabetes-induced anxiety are scanty. The present study examined whether; insulin can reverse the anxiety-like behavior in streptozotocin (STZ)-induced diabetes in mice. After 8-weeks of diabetes induced by STZ (200 mg/kg, intraperitoneally (i.p.)), mice were given insulin (1–2 IU/kg/day, i.p.)/ diazepam (1 mg/kg/day, i.p.)/ vehicle for 14 days and evaluated for behavioral effects in three validated models of anxiety viz. elevated plus maze (EPM), light–dark (L/D) and hole board (HB) tests. STZ-induced diabetic mice elicited significant behavioral effects which include, decreased percentage open arm entries and time in EPM, reduced latency and time spent in light chamber in L/D, decreased number of head dips, squares crossed and rearings in HB tests respectively. Insulin treatment attenuated the behavioral effects evoked by STZ-induced diabetes in mice as indicated by increased open arms activity in EPM, decreased aversion in light chamber during L/D test and increased exploratory behavior in HB test. In conclusion, this study revealed that insulin can reverse anxiety-like behavior in STZ-induced diabetes in mice.     

Leptin treatment ameliorates anxiety in ob/ob obese mice

We investigated whether or not administered leptin influences anxiety-like behavior in ob/ob mice. Repeated intraperitoneal administrations of leptin were continued for 5 days. Anxiety was assessed in the standard elevated plus maze. Body weight was measured daily. Repeated administrations of leptin significantly increased the percentage of the total number of entries in the open arms and the number of total entries. The body weight was significantly reduced by 13.2% after treatment. Leptin treatment ameliorated not only obesity but also anxiety in ob/ob mice. Our results indicate that the treatment of obesity may lead to the solution of psychological problems.     

Anxiolytic property of Lactuca sativa,effect on anxiety behaviour induced by novel food and height

ObjectiveTo study anxiolytic property of hydro alchohol extract and to estimate polyphenols present in the extract by HPLC.MethodsTo evaluate anxiolytic property two animal models were used viz. Elevated T maze and hyponeophagia. Diazepam (1 mg/kg body wt.) served as the standard anxiolytic agent for all the tests. The dried extract of the plant leaf in doses of 100, 200 and 400 mg/kg body weight was administered orally to mice for duration of 15 or 30 days and locomotor and anxiolytic activities were performed. Polyphenols was estimated using HPLC.ResultsThe HPLC analysis of the polyphenols revealed the presence chlorogenic acid, vanillin, epicatechin, caffeic acid, rutin hydrate, sinapic acid, quercetin-3-rhamnoside, p-coumeric acid and quercitin. Time spent and number of entries into the open arm was improved in 30 days treated animals than that of 15 days treated groups, 200 and 400 mg/kg body weight treated group showed significant results when comparing with the control group.ConclusionsThe hydro alcohol extract rich in Polyphenols and other secondary metabolites is a potent anxiolytic agent.     

Effects of neuropeptide Y on sucrose and ethanol intake and on anxiety-like behavior in high alcohol drinking (HAD) and low alcohol drinking (LAD) rats

BACKGROUND: In a previous study, neuropeptide Y (NPY) administered into the lateral ventricles decreased ethanol intake in alcohol-preferring (P) rats but not in alcohol-nonpreferring (NP) or unselected Wistar rats. The purpose of the present investigation is to extend these findings in selectively-bred high-alcohol-drinking (HAD)1 and low-alcohol-drinking (LAD)1 rats by examining the effects of intracerebroventricularly administered NPY on the elevated plus maze test of anxiety and on ethanol and sucrose intake. METHODS: Female HAD1 and LAD1 rats were surgically implanted with cannula into the lateral ventricle. Following recovery, a test of anxiety was conducted in which the rats (n = 12-13/group) received either artificial cerebrospinal fluid (aCSF) or NPY (10 microg) 10 min prior to a 5-min test on an elevated plus maze. Following anxiety testing, 11 HAD and 11 LAD rats were trained to self-administer ethanol (8% w/v), and 5 HAD and 8 LAD rats were trained to self-administer sucrose (2.5%) during daily 2-hr sessions. A within-subject design was used in which the rats were pretreated once a week with aCSF, 5 microg NPY, or 10 microg NPY prior to the drinking sessions. RESULTS: HAD and LAD rats treated with aCSF did not differ in time spent in open arms of the plus maze. NPY increased time spent on the open arms to similar degrees in both rat lines. HAD rats consumed more ethanol and sucrose than LAD rats. NPY increased sucrose intake in both rat lines. However, the same doses of NPY reduced ethanol intake in HAD but not in LAD rats. CONCLUSION: The plus maze results indicated that selective breeding for high and low alcohol preference in the HAD1 and LAD1 rats, respectively, did not yield differences in anxiety-like behavior and in response to the anxiolytic effects of NPY. The increases in sucrose intake were consistent with the known orexigenic effects of NPY. The decreased ethanol intake following NPY administration in HAD rats was similar to previous observations with P rats and is consistent with the hypothesis that ethanol intake and NPY activity may be inversely related.     

Methotrexate treatment ameliorated testicular suppression and anorexia related leptin reduction in rats with adjuvant arthritis

Methotrexate (MTX) has been frequently used in the treatment of rheumatoid arthritis (RA). However, its action on arthritis associated male hypogonadism, or anorexia related low leptin production has not yet been studied. The well-established model of human RA is rat adjuvant-induced arthritis (AA). In the present series we aimed at the evaluation of the effects of MTX on AA induced inflammatory parameters, testosterone suppression, and anorexia associated lowered leptin release. AA was induced in male Lewis rats by intradermal injection of heat killed Mycobacterium butyricum in incomplete Freund’s adjuvant in the base of the tail. Arthritic rats were treated with two doses of MTX: 0.3 and 0.5 mg/kg twice a week orally for the period of 28 days. The evaluated parameters were body mass, hind-paw swelling, arthrogram scores, serum albumin, total testosterone and leptin on days 14, 21 and 28 of AA. MTX treatment ameliorated all parameters studied dose dependently. Higher dose of MTX induced a significant reduction in the hind-paw swelling, arthritic score, and an increase in serum albumin in all examined time intervals of AA. This dose also significantly improved the suppressed testosterone and leptin levels found in arthritic rats. Prophylactic MTX treatment of rats with AA improved all inflammatory and arthritic parameters studied indicating its clear anti-inflammatory effects. The significant improvement of testosterone and leptin shows beneficial effects of MTX on reproduction and anorexia related leptin reduction during chronic AA.     

Correlation of cellular changes and spatial memory during aging in rats

We describe neuronal density, neuroplasticity and vascular remodelling and their association with spatial memory in young (4-6 months), middle-aged (9-11 months) and aged (18-20 months) rats of both genders. The neuronal density was reduced in the hippocampus of middle-aged and aged rats, particularly in male rats. However the loss of spatial memory investigated using the Morris water maze, T-maze and 8-radial arm maze tests was found only in the aged groups. The data suggested a pre-symptomatic period of pathological brain aging. Surprisingly, the middle-aged groups showed an elevation of glutamate-decarboxylase immunoreactive neurons in the hippocampus and the striatum, an increase of dopamine output in the striatum and enhanced vascular remodelling in the hippocampus when compared with the young and, in some cases, aged groups. Together, the data suggest that the loss of neurons during midlife may stimulate and enhance neuronal plasticity and vascular remodelling. These compensatory responses to initial neuronal degeneration may play a role in delaying impending memory loss during the pre-symptomatic period of pathological brain aging.     

Corticosterone stress response and plasma metabolite levels during breeding and molt in a free-living migratory songbird, the wood thrush (Hylocichla mustelina)

Many birds face energetic trade-offs between different life history stages, such as reproductive effort, feather molt and the non-breeding period. Little is known about how physiological measures of condition (corticosterone, plasma metabolites) in free-living birds change from nesting stages to the post-breeding molt period or whether this is influenced by prior reproductive effort. We evaluated whether corticosterone (CORT) and plasma metabolite levels vary with date, nest stage and sex in a free-living migratory songbird, the wood thrush (Hylocichla mustelina). We also tested whether (1) baseline CORT levels early in the season were predictive of subsequent reproductive success and (2) whether prior reproductive effort influenced CORT levels and blood metabolites during molt. Baseline CORT levels decreased with date during both the incubation stage and nestling stage, but did not vary significantly across stage of breeding season. Stress-induced CORT declined with date during incubation and varied significantly across breeding stage, with lower levels during feather molt. Profiles of the metabolites of β-hydroxybutyrate, glycerol, and triglyceride did not vary significantly with date or breeding stage. Only triglycerides varied significantly with sex, with females having higher levels than males. Reproductive output was highly variable (0-10 fledglings per season) but baseline CORT levels in females during the first incubation period of the season was not related to subsequent reproductive output. Prior reproductive effort, measured as the cumulative number of young hatched during the breeding season, was positively related to stress-induced CORT during molt. High reproductive effort in wood thrush appears to have physiological carry-over effects into the molt period which could potentially affect rate of molt and preparation for fall migration.     

Suppression of adjuvant arthritis in rats by boar seminal immunosuppressive fraction

OBJECTIVE: The effect of the immunosuppressive fraction of boar seminal vesicle fluid (ISF) was tested on the manifestation of adjuvant arthritis (AA) in rats. METHODS: The inhibitory effect of ISF on mitogen-stimulated proliferation of rat lymphocytes was evaluated by immunoassay using bromodeoxyuridine incorporation. Adjuvant arthritis was induced in male Long Evans rats with Mycobacterium butyricum in adjuvant. ISF was administered at the time of the induction of arthritis. At the time of maximal manifestation of the disease, the hind paw swelling and thymus weight were estimated. IgM and IgG in the rat blood sera were quantified by sandwich ELISA. Serum corticosterone was analyzed by radioimmunoassay. Serum NO2-/NO3-were estimated by diazotation. Serum albumin was measured spectrophotometrically. The expression of IL-6 mRNA in peritoneal macrophages was estimated by dot-blot hybridization. RESULTS: Treatment of arthritic rats with ISF attenuated hind paw edema. The production of IgG subclasses dropped in ISF-treated AA rats. The thymus mass and serum albumin concentration were partially restored due to the ISF treatment. Serum corticosterone as well as NO2-/NO3- concentrations were reduced by the ISF effect. The expression of IL-6 in peritoneal macrophages was inhibited in AA rats after ISF treatment. CONCLUSION: ISF attenuated the manifestation of AA in rats and mitigated the inflammation. Immunoglobulin production was most probably inhibited by the decreased proliferation of B lymphocytes.     

Long-term influence of perinatal asphyxia on the social behavior in aging rats

BACKGROUND: Various groups have been addressing the question of whether perinatal asphyxia (PA) affects the behavior of young animals, but no information is available on long-term effects of PA on the behavior in aged rats, although it has been postulated that PA may lead to neurological and psychiatric deficits in adult life. OBJECTIVE: We, therefore, decided to study the effects of PA on social and anxiety-related behaviors in 2-year-old rats, using a noninvasive animal model resembling the clinical situation. METHODS: For the behavioral studies, the open-field test, the elevated plus-maze test, and a social interaction test in pairs were performed. Magnetic resonance imaging of the brain was selected to rule out neuropathological changes due to the aging process per se, as well as asphyxia-induced pathologies in the brain areas known to play an important role in the modulation of behavior. RESULTS: The social interaction test revealed a statistically significant increase in the number of social grooming episodes and the time spent running alone, whereas the numbers of social sniffing and fighting episodes and the time spent running together were decreased in the asphyxiated group. The elevated plus- maze test revealed a higher presence of entries into the closed arm. Furthermore, sniffing and self-grooming episodes were significantly increased in the asphyxiated group. CONCLUSIONS: We found a significantly decreased social aggressiveness and an increased social contact behavior as well as increased anxiety levels in the asphyxiated animals. The present findings may provide important information on the long-term behavioral sequelae of PA in the aged individual.