Adrenocortical reactivity and central serotonin and dopamine turnover in young chicks from a high and low feather-pecking line of laying hens

Feather pecking in domestic fowl is a behavioral abnormality that consists of mild or injurious pecking at feathers of conspecifics. Previously, it was shown that chicks from a high feather-pecking (HFP) and low feather-pecking (LFP) line of laying hens already differ in their propensity to feather peck at 14 and 28 days of age. As a first step in investigating a possible relationship between the development of feather pecking and physiological and neurobiological characteristics of laying hens, two subsequent experiments were carried out. Firstly, we investigated the development of adrenocortical (re)activity in HFP and LFP chicks during the first 8 weeks of life. Secondly, we studied dopamine (DA) and serotonin (5-HT) turnover in the brain of 28-day-old HFP and LFP chicks. In both experiments, chicks were exposed to manual restraint (placing the chicks on its side for 5 min). Plasma corticosterone levels were lower (baseline on Days 3 and 56; restraint-induced on Days 3, 14 and 28) in HFP chicks. Both brain DA and 5-HT turnover were lower in the HFP chicks, as well. Possible consequences for the observed differences in (stress) physiology and neurobiology between the two lines in relation to the feather pecking are discussed.     

Adrenal reactivity in lines of domestic fowl selected on feather pecking behavior

Domestic chicken lines of the White Leghorn layer type differing in their level of feather pecking have been developed by divergent selection specifically on feather pecking behavior. This paper describes an investigation of basal level, reactivity to manual restraint and maximal adrenal response to 1-24 ACTH in breeder birds of the sixth generation of selection (S6) and their control line. Birds from the three lines had comparable basal levels of corticosterone (1.6 ng/ml, anova F_2,101 = 0.62, ns), whereas males had higher basal levels than females, lsmean 1.9 vs. 1.5 ng/ml (anova F_1,103 = 6.03, P < 0.05). Reactivity to handling and restraint for 10 min differed with HFP birds showing higher reactivity than LFP birds, lsmean 11.0 vs. 7.9 ng/ml (t = − 2.00, P < 0.05), while control birds showed intermediate levels (10.2 ng/ml). Males had higher reactivity than females, lsmean 11.2 vs. 8.2 ng/ml (anova F_1,103 = 3.96, P < 0.05). Maximal response did not differ between lines (average 35.7 ng/ml, anova F_2,101 = 1.38, P > 0.05). Males had higher maximal response than females, lsmean 41.3 vs. 33.6 ng/ml (anova F_1,103 = 5.77, P < 0.05). The present study shows that selection against feather pecking behavior have resulted in lower levels of feather pecking as well as lower sensitivity to human handling and restraint in White Leghorn laying hen lines. From an animal welfare point of view this is a positive relationship.     

Maternal care and selection for low mortality affect post-stress corticosterone and peripheral serotonin in laying hens

The aim of the present study was to investigate the effect of brooding and group selection for low mortality on post-stress corticosterone and peripheral serotonin in laying hens. Birds in the experiment originated from the same population and were either group-selected for low mortality (low mortality line) or randomly selected (control line) for two generations. Twelve groups of seven birds from each line were used. Within each line, six groups were brooded by a foster mother and six groups were non-brooded. At 33 weeks of age, birds (n = 42/treatment) were manually restrained for 5 min, during which their behavioral response (number of struggles) was studied. Fifteen minutes after the start of the manual restraint, blood samples were drawn for assessment of plasma corticosterone and whole blood serotonin (5-HT) concentration. In the low mortality line, 80% of the birds struggled and vocalized vs. 72% in the control line (non significant). Birds from the control line had a higher plasma corticosterone concentration after manual restraint than birds from the low mortality line (7.7 vs. 6.0 nmol ml^− 1). Furthermore, birds from the control line that were reared without a mother had a lower whole-blood 5-HT concentration than birds from the other treatments (45 vs. 48 nmol ml^− 1). These results indicate that both brooding and selection for low mortality affect post-stress corticosterone and peripheral serotonin concentration, which may result in a reduced propensity to develop feather pecking.     

Effects of feeding corticosterone and housing conditions on feather pecking in laying hens (Gallus gallus domesticus)

Feather pecking (FP) and cannibalism in laying hens are disadvantageous to the well-being of the birds. We investigated whether stress could be proposed as a trigger for the development of this abnormal behavior. From Week 11 to 19 after hatching, 16 groups of 15 or 16 hens (white Lohman Selected Leghorn hybrids) were kept in pens with or without foraging material (litter) and fed a diet containing corticosterone (C, 1.5 mg/bird/day) or no C. Birds fed on C had reduced values for weight gain and egg production, prolonged tonic immobility (TI), higher heterophil/lymphocyte ratios (H/L) and higher serum C concentrations. On litter, C-fed birds developed significantly higher rates of FP than when not fed C. However, birds kept on slats also developed high rates of FP but without being fed C. Feeding C to these birds did not significantly further increase the rates of FP. We concluded that FP may develop as a response to increased blood C concentrations, but that housing conditions restricted in relation to foraging material, may as well induce FP in the absence of increased C levels.     

Electrophysiological actions of the dopamine agonist apomorphine in the paraventricular nucleus during penile erection

The ability to achieve and maintain penile erection is necessary for successful copulation. Studies have demonstrated that dopamine receptor stimulation in the paraventricular nucleus (PVN) of the hypothalamus induces penile erection in rodents, and the dopamine agonist apomorphine has been used to treat erectile dysfunction. The aim of this study was to determine the electrophysiological characteristics of PVN neuronal firing activity in anaesthetised rodents during apomorphine-induced erection. Our findings can be placed in two categories; those effects that occur immediately upon apomorphine administration and continue for up to several minutes prior to penile erection, deemed ‘pre-erectile’, and those effects that were only observed during penile erection and seminal emission. In the pre-erectile period, apomorphine acts on two different populations of PVN neurons to increase or decrease firing rates and increases alpha1 frequency band power in local field potentials. Decreased delta and increased theta frequency power in PVN local field potentials occur only during penile erection and seminal emission. These studies provide further understanding of the coordinated neuronal activity that occurs in the PVN during apomorphine-induced penile erection.     

Feather Pecking in Domestic Fowl is Genetically Related to Locomotor Activity Levels: Implications for a Hyperactivity Disorder Model of Feather Pecking

Feather pecking is a major welfare problem in egg production. Genetic lines differing in the level of feather pecking have been developed by genetic selection. In two experiments correlated responses in locomotor activity were investigated. Firstly, general locomotor activity was estimated using electronic transponders. A total of 325 pullets from three lines: an unselected control line (CON), a line selected for low levels of feather pecking (LFP) and a line selected for high levels of feather pecking (HFP) during 6 generations, were reared in mixed line groups and activity was recorded from 13 to 17 weeks of age using antennas placed in the litter. Locomotor activity was significantly higher in the HFP and significantly lower in the LFP compared to the CON line (lsmeans 0.72 vs. 0.62 vs. 0.57 records per hen per h for HFP, CON and LFP respectively). In a second experiment locomotion was recorded in 40 chickens from the LFP and the HFP line at 5 weeks of age during day time from 09.00 to 16.00 h using a very precise computer facilitated tracking system. Distance travelled was found to be significantly higher in the high feather pecking line compared to the low feather pecking line (lsmeans 122 vs. 99 m per hour in HFP and LFP respectively). These results are discussed in relation to the ontogeny of feather pecking and a hyperactivity disorder model of feather pecking is suggested. Edited by Stephen Maxson.     

Heart rate variability during manual restraint in chicks from high- and low-feather pecking lines of laying hens

The purpose of this investigation was to determine whether there is a difference in coping style in chicks from a high (HFP)- and low-feather pecking (HFP) line of laying hens. Active and passive coping styles can be distinguished by differences in sympathetic and parasympathetic activities on the heart. We studied heart rate during baseline conditions and during manual restraint in HFP and LFP hens. Heart rate and locomotor activity were successfully monitored around the clock with a biotelemetric implant. During the light period, the values for locomotor activity and heart rate were highest, whereas during the dark period they were the lowest. These values did not differ in LFP and HFP hens. However, during manual restraint (restraining the bird on its side by hand for 8 min) HFP birds had somewhat faster heart rate than LFP birds (at 4 min, p = 0.066). Studying heart rate variability during manual restraint showed that LFP chickens had a significant higher parasympathetic activity at 5 min (p = 0.023) and at 6 min (p = 0.002) as compared to HFP hens. The results showed that in terms of coping style, LFP chickens are passive, whereas HFP birds are active.     

The growth hormone response to apomorphine at 4 days postpartum in women with a history of major depression

We have examined the responsiveness of dopamine sensitive neurones in the postpartum period in woman with a history of major depression who are at high risk of experiencing a recurrence of illness in the postpartum period. Fourteen women were assessed at 36 weeks of pregnancy and during the 3 months following delivery, using the Schedule for Affective Disorders and Schizophrenia, including its change version. They were not depressed at initial assessment. Five of the 14 women went on to experience a postpartum relapse (2 major depressive disorder, 2 generalised anxiety disorder, 1 panic disorder). On the fourth day postpartum, ie before relapse, the growth hormone response to the dopamine agonist apomorphine was measured as an index of the functional state of hypothalamic dopamine D2 receptors. Women who subsequently relapsed had a significantly greater growth hormone response to apomorphine than those who remained well. This was particularly marked in women with anxiety/panic. The development of increased sensitivity of hypothalamic dopamine D2 receptors in the postpartum period appears to predict the onset of depressive and anxiety disorders.     

Inhibitory avoidance, pain reactivity, and plus-maze behavior in Wistar rats with high versus low rearing activity

Substantial work has shown that rats although identical in strain, sex, age and housing conditions can differ considerably in terms of behavior and physiology. Such individual differences can be rather stable and may be detected by behavioral screening tests. Here, the degree of behavioral activation in a novel open-field situation has been shown to serve as a useful predictor to classify animals of a given population into sub-groups with high or low activity, based on measures like locomotion or rearing activity. We used such a screening test and assigned larger samples of male adult Wistar rats into those with high versus low rearing activity (HRA/LRA). They were then tested in the elevated plus-maze, in an inhibitory avoidance task, and in two tests of pain reactivity (hot-plate, tail-flick). In the open field, HRA rats not only showed more rearing behavior, but also more locomotor activity than LRA rats. In the plus-maze, HRA rats again showed more rearing behavior. Also, they spent less time in the open arms, and entered the closed arm more often than low responder rats, which is indicative of more anxiety-related behavior than in LRA rats. In the inhibitory avoidance test, HRA and LRA rats showed similar basal step-in latencies, whereas HRA rats had shorter retention scores than LRA rats after experience of footshock, especially when using a higher (0.5 mA) shock intensity. In contrast, repeated exposure to the avoidance apparatus without shock did not affect step-in latencies in either group. In the pain test, HRA and LRA rats behaved similarly, indicating that their differences in inhibitory avoidance behavior were probably not determined on the level of pain processing. The relevance of these findings is discussed in the context of previous work, especially with respect to the role of processing of aversive experiences.     

Mammary carcinoma cell lines of high and low metastatic potential differ not in extravasation but in subsequent migration and growth

We examined the extravasation and subsequent migration and growth of murine mammary tumor cell lines (D2A1 and D2.OR) which differ in their metastatic ability in lung and liver, invasiveness in vitro and expression of the cysteine proteinase cathepsin L. In light of the differences in invasiveness and cathepsin L expression, we hypothesized that during hematogenous metastasis the two cell lines would differ primarily in their ability to extravasate. We used in vivo videomicroscopy of mouse liver and chick embryo chorioallantoic membrane to examine the process and timing of extravasation and subsequent steps in metastasis for these cell lines. In contrast to our expectations, no differences were found between the cell lines in either the timing or mechanism of extravasation, at least 95% of cells having extravasated by 3 days after injection. However, after extravasation, the more metastatic and invasive D2A1 cells showed a greater ability to migrate to sites which favor tumor growth and to replicate to form micrometastases. These studies point to post-extravasation events (migration and growth) as being critical in metastasis formation.     

Role of opioid system in modulation of pain sensitivity under conditons of low and high environmental temperature

The dependence of pain sensitivity in acetic acid-induced writhing test on environmental temperature was described by a bell-shaped curve. The maximum number of writhings was observed in thermoneutral environment and minimum in hot and cold environment. Under conditions of opioid receptor blockade with naloxone, naltrindole, norbinaltorphimine, analgesia is partially mediated by μ-, δ-, and κ-opioid receptors. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 145, No. 6, pp. 652–654, June, 2008     

Sex differences in behavioral and neurochemical profiles after chronic stress: role of housing conditions

This experiment sought to identify the extent housing conditions can differentially enhance or dampen the effects chronic restraint stress has on exploration and object memory in male and female rats. Subjects were either pair- or singly housed during stress (21 days of 6-h restraint) and maintained under those conditions during poststress behavior testing (7 days). Neurochemical analysis of neural tissue was accomplished by HPLC with electrochemical detection. Interactions between stress and housing conditions were found across both sexes. Stress was associated with less activity in the center of the forced open-field in both sexes. Stress also decreased the latency for males to enter the free open-field to female levels. Object recognition was greatly impaired in double-housed males but unaffected by stress or housing in females. Object location memory was impaired in stressed males if they were singly housed, and females performed as well as control males only if they were stressed. Both sexes generally showed increased in hippocampal (CA3) norepinephrine levels in their respective stress groups. Singly housed subjects had higher CA1 serotonin levels compared to double-housed subjects, whereas in the prefrontal cortex, a general sex difference was found with females having higher levels of serotonin and dopamine metabolites. These results show that stress affects limbic neurochemistry across sex, although only males exhibit stress-dependent decrements in object memory. Housing condition also has a profound effect on neurochemistry and male performance on object recognition. Thus, housing condition is a critical variable for male models of stress that can influence the extent the stress manipulation affects behavior. The differences observed across sex are further discussed in the context of behavioral inhibition.     

The effects of SB 224289 on anxiety and cocaine-related behaviors in a novel object task

Cocaine facilitates dopamine transmission from ventral tegmental area (VTA) neurons that project to nucleus accumbens (NAcc), and previous experiments suggest that serotonin-1B (5-HT_1B) receptors are involved in this effect. Specifically, activation of 5-HT_1B receptors in VTA during cocaine exposure increases dopamine release in NAcc and enhances cocaine-induced locomotor activity, reward, and reinforcement. Thus, it is reasonable to hypothesize that blocking 5-HT_1B activity may have the opposite effect. To investigate this hypothesis, SB 224289, a highly selective 5-HT_1B antagonist, was used to block this receptor. In an open field/novel object exploration test, SB 224289 reduced cocaine-induced locomotion. However, SB 224289 also increased anxiety-like behavior, both alone and in combination with cocaine. This experiment gives evidence that 5-HT_1B antagonists may reduce some of the behavioral effects of cocaine, but may have negative effects on anxiety as well.     

Odontoclasts in the Chinook salmon differ from mammalian odontoclasts by exhibiting a great proportion of cells with high nuclei number

Odontoclasts resorbing teeth are multinucleated cells. Previously, the authors have investigated the distribution of number of nuclei per human odontoclast and showed that the mean number of nuclei per cell is 5.3, the median is 4, and 93.8% of cells have 10 or fewer nuclei. Teleost odontoclasts have features similar to those of mammals; however, the distribution of number of nuclei per cell remains unknown. The present study aimed to examine the distribution of number of nuclei per odontoclast in a teleost fish, Chinook salmon, Oncorhynchus tshawytscha (Walbaum), and to clarify the difference of number of nuclei in odontoclasts between Chinook salmon and humans. The maxillae and mandibles of Chinook salmon were fixed, decalcified, and embedded in Epon 812. Specimens were serially sectioned into 0.5-µm semithin sections and examined by light microscopy. Cells possessing a brush border adjacent to a resorptive lacuna were identified as odontoclasts, and 246 odontoclasts were investigated to determine the distribution of nuclei per cell. The mean number of nuclei per cell was 21.8 and the median was 17; only 24.4% of odontoclasts had 10 or fewer nuclei, and 95.5% had 50 or fewer nuclei. These results suggest that the range for the number of nuclei per odontoclast in Chinook salmon is greater than that in humans.     

<Emphasis Type="Italic">Syringoplutarchusia nordmanni</Emphasis>, a new genus and species of the feather mite family Syringobiidae (Acari,Astigmata, Pterolichoidea) from the Black-winged Pratincole <Emphasis Type="Italic">Glareola nordmanni</Emphasis> (Charadriiformes,Glareolidae)

Syringoplutarchusia, a new genus of the syringicolous feather mite family Syringobiidae (Pterolichoidea), is described based on a single new species, S. nordmanni sp. nov., collected from the feather quills of a museum specimen of the Black-winged Pratincole Glareola nordmanni Fischer, 1842 (Glareolidae). Absence of adanal discs and complete reduction of setae d and e on tarsi IV in males of the new genus is unique in this family. The highly elongated body shape of both sexes is most similar to the genera Plutarchusia Oudemans, 1904 and Paidoplutarchusia Dabert, 2003 but strong sclerotization of coxal fields and hypertrophied posterior legs with variously shaped apophyses resemble more advanced syringobiid mites, e.g. Syringobia Trouessart et Neumann, 1888. Syringoplutarchusia represents the first syringobiid from this host family. The taxonomic status of the new taxon is discussed.     

Emotional responsiveness in fish from lines artificially selected for a high or low degree of laterality

Evidence showing that cerebral asymmetries exist in a wide range of animals has prompted investigation into the advantages and disadvantages of brain lateralization. In the teleost fish Girardinus falcatus individuals selected for a high degree of lateralization (LAT) performed better than those fish selected for reduced lateralization (NL) in several tasks, including schooling, foraging and spatial orientation. These findings were interpreted as evidence of hemispheric specialization allowing more efficient parallel processing and thus better cognitive performance under conditions that require multitasking, but the possibility that the results may simply reflect line differences in behavioral/physiological coping styles (i.e. in their emotional responsiveness during the tests) could not be ruled out. To test the hypothesis that NL and LAT fish differ in coping style, the present study examined differences in response in these lines to a novel situation in four different conditions. NL and LAT fish did not differ in a behavioral measure of emotional response: their readiness to explore a new environment. After being isolated in a tight space they showed a similar increase in opercular beating rates, suggesting that their physiological response to an acute stressor was comparable. The overall tendency to remain close to a shoalmate after being moved to an unfamiliar place was similar in the two groups but a significant difference was found in the temporal pattern; LAT fish swam closer than NL to their mirror image in the initial stages but this difference was later reversed. NL and LAT males placed in a new, unfamiliar environment did not differ in the number of sexual acts performed but LAT males resumed sexual behavior earlier signifying that cerebral lateralization has some influence on the trade-off between predator surveillance and mating behavior. Although this study found some differences between NL and LAT lines in their response to novelty, present evidence does not seem sufficient to justify the rejection of the hypothesis that the better scores in complex tasks shown by LAT fish in previous studies were primarily due to a cognitive advantage associated with cerebral specialization.     

Characterization of a neuronal interleukin-1 receptor and the corresponding mRNA in the mouse anterior pituitary cell line AtT-20.

The serotonin (5-HT)_1A agonist, LY 165,163 (1-[2-(4-aminophenyl)ethyl]-4-(3-trifluoromethylphenyl)-piperazine), also known as PAPP, has been suggested to exert effects via an interaction with dopamine receptors. Thus, in this study, we examined its ability to induce rotation in rats sustaining unilateral 6-hydroxy-dopamine lesions of the substantia nigra, an in vivo model of dopaminergic activity. In analogy to the direct dopamine (mixed D₁/D₂) agonist, apomorphine, (0.01–0.63 mg/kg), LY 165,163 (0.16–10.0 mg/kg) dose-dependently elicited robust and substained contralateral rotation. Its maximal effect was comparable to that of apomorphine and its duration of action more extended. Rotation elicited by LY 165,163 (10.0 mg/kg) was resistant to the 5-HT_1A antagonist, (−)-alprenolol. It was also unaffected by the selective D₁ antagonist, SCH 23390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5,tetraphydro-1H-3- benzazepine) (2.5 mg/kg) or the selective D₂ antagonist, raclopride (10.0 mg/kg) when each was administered alone. However, upon joint administration they clearly diminished the effect of LY 165,163. The dopamine antagonist, haloperidol (D₂ > D₁) also reduced the action of LY 165,163. This profile of partial antagonism by mixed D₁ and D₂ receptor blockade has been reported previously for apomorphine and contrasts to that seen with selective D₁ or D₂ agonists, the actions of which are completely blocked by D₁ or D₂ antagonists, respectively. In conclusion, the present data demonstrate that LY 165,163 exerts pronounced rotation in nigral-lesioned rats: this reflects a mixed D₁/D₂ action rather than an activation of 5-HT_1A sites. Thus, in addition to an agonist action at 5-HT_1A receptors, dopaminergic effects contribute to the pharmacological profile of LY 165,163.     

Anxiety-like behaviour is attenuated by gabapentin, morphine and diazepam in a rodent model of HIV anti-retroviral-associated neuropathic pain

Neuropathic pain is commonly associated with affective disorders such as anxiety and depression. We have previously characterised a rodent model of HIV, anti-retroviral-associated neuropathy in which rats develop hypersensitivity to a punctate mechanical stimulus and display anxiety-like behaviour in the open field paradigm. To assess the potential of this behavioural paradigm for the assessment of pain related co-morbidities in rodent models of pain, here we test the sensitivity of this anxiety-like behaviour to the analgesic agents gabapentin and morphine in comparison to the known anxiolytic drug diazepam. We found that gabapentin (30 mg/kg, i.p.) and morphine (2.5 mg/kg, i.p.), which reduce mechanical hypersensitivity in these rats, significantly reduces measures of thigmotaxis in the open field. The effect of gabapentin and morphine did not differ significantly from diazepam (1 mg/kg, i.p.). This study highlights the potential use of this rodent model and behavioural paradigm in the validation of the affective component of novel analgesic pharmacological targets and elucidation of underlying pathophysiological mechanisms.     

Thermosensitivity of preoptic neurones in a hibernator at high and low ambient temperatures

Summary The effect of ambient temperature on the thermosensitivity of preoptic neurones was studied in euthermic golden hamsters. At skin temperatures (T_sk) of 20°C, preoptic units were still responsive to hypothalamic temperatures (T_hy) below 10°C, while at T_sk=36°C these neurones became inactive at T_hy=15°C on the average. These studies suggest that thermoreceptive preoptic neurones, influenced by a high activity of cutaneous cold-receptors, are capable of sensing core temperatures even in deep hibernation.Supported by the Deutsche Forschungsgemeinschaft, Wu 63/2     

小檗碱抑制高转移性人巨细胞肺癌PG细胞侵袭和迁移的研究

目的：研究小檗碱对高转移性人巨细胞肺癌PG细胞侵袭和迁移的作用并探讨其作用机制。方法：采用琼脂糖滴法观察PG细胞的运动能力，用下室加FN的Transwell小室法观察PG细胞的趋化运动能力，用铺Martrigel的Transwell小室观察PG细胞的侵袭能力。通过SABC免疫细胞化学法及图像分析软件，半定量PG细胞MMP2、TIMP2的表达；RT－PCR法检测PG细胞MMP2 mRNA和TIMP2 mRNA的表达。结果：小檗碱（10 mg/L）处理PG细胞 24 h 后：（1）PG细胞的迁移距离明显比对照PG短（P<0.01），趋向FN迁移的穿膜细胞数明显少于对照组（P<0.01）；（2）PG细胞与FN、Martrigel的黏附减少，与对照组比有显著差异（P<0.01）；（3）穿过铺Martrigel的Transwell小室微孔滤膜的PG细胞数明显减少，即可抑制PG细胞的侵袭能力(P<0.05)； （4）MMP2表达明显减少(P<0.05)，而TIMP－2的表达有升高趋势，与对照比无显著差异，但MMP2/TIMP2比值降低；（5） 小檗碱使PG细胞TIMP2 mRNA表达明显增加(P<0.05)，而对MMP2 mRNA表达无影响，MMP2 mRNA/TIMP2 mRNA比值降低。结论：抑制肿瘤细胞的运动能力、与细胞外基质的黏附、对细胞外基质侵袭，调节MMP2/TIMP2表达的平衡，从而维持细胞外基质的完整性，可能是小檗碱抗侵袭和转移作用的机制之一。