| 1. |
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| 2. |
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| 3. |
- Alsiö, Johan, et al.
(författare)
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Inverse association of high-fat diet preference and anxiety-like behavior : a putative role for urocortin 2
- 2009
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Ingår i: Genes, Brain and Behavior. - 1601-1848 .- 1601-183X. ; 8:2, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate whether the preference for a palatable high-fat diet (HFD) is associated with response to novelty and with anxiety-like behavior in rats and whether such fat preference correlates with gene expression of hypothalamic neuropeptides related to feeding. We subjected male rats to two tests of exploration of novel environments: the multivariate concentric square field (MCSF) and the elevated plus maze (EPM). The rats were then exposed to a 5-day test of preference for a palatable HFD versus reference diets. Messenger RNA (mRNA) levels of 21 neuropeptides were investigated by quantitative polymerase chain reaction. We found a strong positive correlation of HFD preference and open-arm activity in the EPM (% open-arm time, r(s) = 0.629, df = 26, P < 0.001). Thus, HFD preference was inversely associated with anxiety-like behavior. The same association was found for HFD preference and behavior in the MCSF (bridge entries, r(s) = 0.399, df = 23, P = 0.048). In addition, the HFD preference was positively correlated (r(s) = 0.433, df = 25, P = 0.021) with hypothalamic mRNA levels of urocortin 2 (Ucn 2). Moreover, behavior in the EPM was significantly correlated with expression levels of the receptor for Ucn 2, the corticotropin-releasing factor receptor 2, in the hypothalamus (r(s) = 0.382, df = 33, P = 0.022, pituitary (r(s) = 0.494, df = 31, P = 0.004) and amygdala (r(s) = 0.381, df = 30, P = 0.032). We conclude that preference for palatable HFD is inversely associated with anxiety and propose that Ucn 2 signaling may play a role in this association.
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| 4. |
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| 5. |
- Carter, Nicholas, et al.
(författare)
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Androgen-linked control of carbonic anhydrase III expression occurs in rat perivenous hepatocytes : an immunocytochemical study
- 2001
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Ingår i: Upsala Journal of Medical Sciences. - 0300-9734 .- 2000-1967. ; 106:1, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- Carbonic anhydrase (CA) isozymes CAII and CAIII were assayed by a radioimmunosorbent technique in liver cytosolic fractions and in isolated hepatocytes of adult male and female rats. Male livers contained 0.16 mg of CAII and 57 mg of CAIII per g cytosolic protein. Corresponding values for female livers were 0.34 mg CAII and 4 mg CAIII. Similar values and differences between CAII and III were found in isolated hepatocytes. Neonatal and adult castration of males reduced the CAIII levels to those of the females. Treatment with testosterone for three weeks restored the copulatory behaviour in the males castrated at adult age, but restored only partially the levels of CAIII. No significant effects of the endocrine manipulations were seen on CAII. Oophorectomy, with or without testosterone substitution, had no significant effect on CAII and CAIII levels in female rats. Immunohistochemistry and histochemistry showed that the regulation of CAIII is confined to perivenous hepatocytes. CAIII can therefore serve as a useful marker in the separation of these cells. CAIII appears to belong to the proteins and enzymes of the rat liver, known to be regulated via the hypothalamo-pituitary-liver axis. It may be used as a model of gene regulation in perivenous hepatocytes.
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| 6. |
- Ekmark-Lewén, Sara, et al.
(författare)
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Diffuse traumatic axonal injury in mice induces complex behavioural alterations that are normalized by neutralization of interleukin-1β
- 2016
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Ingår i: European Journal of Neuroscience. - : Wiley. - 0953-816X .- 1460-9568. ; 43:8, s. 1016-1033
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Tidskriftsartikel (refereegranskat)abstract
- Widespread traumatic axonal injury (TAI) results in brain network dysfunction, which commonly leads to persisting cognitive and behavioural impairments following traumatic brain injury (TBI). TBI induces a complex neuroinflammatory response, frequently located at sites of axonal pathology. The role of the pro-inflammatory cytokine interleukin (IL)-1 has not been established in TAI. An IL-1-neutralizing or a control antibody was administered intraperitoneally at 30min following central fluid percussion injury (cFPI), a mouse model of widespread TAI. Mice subjected to moderate cFPI (n=41) were compared with sham-injured controls (n=20) and untreated, naive mice (n=9). The anti-IL-1 antibody reached the target brain regions in adequate therapeutic concentrations (up to similar to 30g/brain tissue) at 24h post-injury in both cFPI (n=5) and sham-injured (n=3) mice, with lower concentrations at 72h post-injury (up to similar to 18g/g brain tissue in three cFPI mice). Functional outcome was analysed with the multivariate concentric square field (MCSF) test at 2 and 9days post-injury, and the Morris water maze (MWM) at 14-21days post-injury. Following TAI, the IL-1-neutralizing antibody resulted in an improved behavioural outcome, including normalized behavioural profiles in the MCSF test. The performance in the MWM probe (memory) trial was improved, although not in the learning trials. The IL-1-neutralizing treatment did not influence cerebral ventricle size or the number of microglia/macrophages. These findings support the hypothesis that IL-1 is an important contributor to the processes causing complex cognitive and behavioural disturbances following TAI.
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| 7. |
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| 8. |
- Ekmark-Lewén, Sara, et al.
(författare)
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The Multivariate Concentric Square Field Test Reveals Behavioral Profiles of Risk Taking, Exploration, and Cognitive Impairment in Mice Subjected to Traumatic Brain Injury
- 2010
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 27:9, s. 1643-1655
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for more efficient tests to evaluate functional outcome following experimental traumatic brain injury (TBI), reflecting deficits in cognitive, sensory, and motor functions that are seen in TBI patients. The Multivariate Concentric Square Field (TM) (MCSF) test is a relatively new behavioral model that measures exploration, risk taking, risk assessment, and shelter seeking, all of which are evolutionarily-conserved strategies for survival. The multivariate design enables scoring of different functional domains in a single test situation, with a free choice of optional environmental settings. Furthermore, repeated trials permits cognitive effects to be measured. In the present study, 11 anesthetized C57BL6 mice received controlled cortical injury (CCI) (0.5mm and 3.3 m/sec) over the right parietal cerebral cortex or sham surgery (n - 12). Naive mice (n 12) not subjected to any surgical procedure were also included. The animals were evaluated in the MCSF test at 2 and 7 days post-surgery, and behavioral profiles were analyzed. The results revealed differences in risk taking and explorative behavior between the sham animals and the animals subjected to trauma. Animals subjected to trauma were characterized by taking more risks and had a higher level of exploration activity, but they sought less shelter. Repeated exposure to the MCSF caused a general decrease in activity in the naive and sham group, while a more specific behavioral impairment was seen in injured mice, suggesting cognitive dysfunction. We submit that the MCSF test is a useful complementary tool for functional outcome evaluation in experimental TBI.
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| 9. |
- Ekmark-Lewén, Sara, et al.
(författare)
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Traumatic axonal injury in the mouse is accompanied by a dynamic inflammatory response, astroglial reactivity and complex behavioral changes
- 2013
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 10:1, s. 44-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundDiffuse traumatic axonal injury (TAI), a common consequence of traumatic brain injury, is associated with high morbidity and mortality. Inflammatory processes may play an important role in the pathophysiology of TAI. In the murine central fluid percussion injury (cFPI) TAI model, the neuroinflammatory and astroglial response and behavioral changes are unknown.MethodsTwenty cFPI-injured and nine sham-injured mice were used, and the neuroinflammatory and astroglial response was evaluated by immunohistochemistry at 1, 3 and 7 days post-injury. The multivariate concentric square field test (MCSF) was used to compare complex behavioral changes in mice subjected to cFPI (n = 16) or sham injury (n = 10). Data was analyzed using non-parametric statistics and principal component analysis (MCSF data).ResultsAt all post-injury time points, beta-amyloid precursor protein (beta-APP) immunoreactivity revealed widespread bilateral axonal injury and IgG immunostaining showed increased blood--brain barrier permeability. Using vimentin and glial fibrillary acidic protein (GFAP) immunohistochemistry, glial cell reactivity was observed in cortical regions and important white matter tracts peaking at three days post-injury. Only vimentin was increased post-injury in the internal capsule and only GFAP in the thalamus. Compared to sham-injured controls, an increased number of activated microglia (MAC-2), infiltrating neutrophils (GR-1) and T-cells (CD3) appearing one day after TAI (P<0.05 for all cell types) was observed in subcortical white matter. In the MCSF, the behavioral patterns including general activity and exploratory behavior differed between cFPI mice and sham-injured controls.ConclusionsTraumatic axonal injury in mice resulted in marked bilateral astroglial and neuroinflammatory responses and complex behavioral changes. The cFPI model in mice appears suitable for the study of injury mechanisms, including neuroinflammation, and the development of treatments targeting traumatic axonal injury.
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| 10. |
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| 11. |
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| 12. |
- Lindström, Leif H., et al.
(författare)
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The effect of pilocarpine, oxotremorine and arecoline in combination with methyl-atropine or atropine on hormone activated oestrous behaviour in ovariectomized rats
- 1967
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Ingår i: Psychopharmacology. - 0033-3158 .- 1432-2072. ; 11:5, s. 405-405
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Tidskriftsartikel (refereegranskat)abstract
- The effects of pilocarpine, oxotremorine and arecoline were studied on oestradiol/progesterone activated oestrous behaviour in ovariectomized rats. A heat-inhibitory effect was obtained, which could be more effectively counteracted by atrophie than methyl-atropine.No positive correlation was seen between the inhibitory effect on oestrous behaviour and the ability of the different cholinergic compounds to induce tremor or decrease the locomotor activity.The data indicate that in addition to earlier described monoaminergic pathways mediating inhibition of oestrous behaviour, cholinergic mechanisms are also involved.The results of this study were presented in part at the XII Scandinavian Congress of Physiology 1966 at Turku, Finland.
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| 13. |
- Lofgren, Magnus, et al.
(författare)
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The influence of social subordinate housing on the withdrawal effects from progesterone and estradiol in male rats
- 2012
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Ingår i: General and Comparative Endocrinology. - San Diego : Elsevier BV. - 0016-6480 .- 1095-6840. ; 177:1, s. 62-69
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Tidskriftsartikel (refereegranskat)abstract
- Chronic stress and its concomitant neurobiological consequences are, in all probability, provocateurs of mental disease in humans. To gain some insight into the provocative effects of stress on hormonally dependent conditions, we developed a rat model that combines social subordinate housing (SSH) with withdrawal from combined progesterone (P) and estradiol (E) treatment (PEVVD). At the start of the experiment, male Wistar rats were housed in triads consisting of one younger rat (35 days old) and two older rats (55 days old), with the intent of producing subordination stress in the younger animals. Triads containing three 35-day-old rats were used as age controls. Subordination stress was assessed with the elevated plus maze (EPM) and by corticosterone (CORT) analysis. Social rank within the triads was determined using a food competition test (FCT) and a tube test (TT). The younger rats (subordinate) and the dominant rats were assigned to 10 days of treatment with 5 mg/kg P combined with 10 mu g/kg E, or placebo (vehicle). Twenty-four hours after the last injection, the subordinate and dominant animals were tested in an open-field test (OFT) and a social challenge test (SCT). The SCT consisted of a 10-min exposure to three unfamiliar rats. SSH increased baseline CORT levels and reduced EPM open-arm time and post-EPM CORT levels compared to age-control rats. Only in the subordinate animals did PEWD increase locomotor activity and digging behavior, and reduce wrestling and pinning behavior. The behavioral results indicate an interaction between the effects of the lasting social subordinate stress and PEWD.
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| 14. |
- Löfgren, Magnus, 1979-, et al.
(författare)
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Chronic subordination stress augments combined progesterone and estradiol withdrawal behavior
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Exposure to stress is a risk factor for developing pre-menstrual syndrome (PMS) and pre-menstrual dysphoric disorder (PMDD), and stress enhances the anxiogenic effect of female sex steroids in animals. This study examines the interaction between chronic subordination stress and withdrawal from progesterone (P4) and estradiol (E2) (PEWD) in producing behaviors analogous to anxiety and irritability in rats. At the start of the experiment, male Wistar rats were housed in triads consisting of one younger rat (~35 days) and two older rats (~50 days). The housing condition was aimed at producing chronic subordination stress in the younger animals. Chronic subordination stress was assessed by the elevated plus maze (EPM) and by corticosterone (CORT) analysis. A triad of three 35-day-old rats was used as age control. Social rank within the triads was determined using a food competition test (FCT) and the tube test (TT). The younger rats (subordinate) and the dominant rats were assigned to 10 days of treatment with 5 mg/kg progesterone combined with 10 µg/kg 17β estradiol. Twenty-four hours after the last injection, the subordinate and dominant animals were tested in the open-field test (OFT) and in the intruder test (IT). The IT consists of a 10-minute exposure to 3 unfamiliar rats. Chronic subordination stress reduced EPM open-arm time and altered the CORT response. It also made the subordinate animals more vulnerable to PEWD. The effects were increased locomotion in the OFT, increased defensive burying, and increased social anxiety in the intruder test (IT). Dominant animals did not react to PEWD. Thus, chronic subordination stress augments PEWD.
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| 15. |
- Löfgren, Magnus, 1979-, et al.
(författare)
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Progesterone withdrawal effects in the open field test can be predicted by elevated plus maze performance
- 2006
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X .- 1095-6867. ; 50:2, s. 208-215
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Tidskriftsartikel (refereegranskat)abstract
- Allopregnanolone (3alpha-hydroxy-5alpha-pregnane-20-one) is a ring-A-reduced metabolite of progesterone, which is naturally produced during the luteal phase of the menstrual cycle, during pregnancy and by stressful events. The steroid hormone inhibits neural functions through increased chloride ion flux through the GABAA receptor. The effects and subsequent withdrawal symptoms are similar to those caused by alcohol, benzodiazepines and barbiturates. This study examined the withdrawal effects of progesterone with regards to the influence of individual baseline exploration and risk taking. Rats were tested on the elevated plus maze (EPM) before hormonal treatment, in order to evaluate differences in risk taking and exploration of open and elevated areas. Treatment consisted of ten consecutive once a day progesterone or vehicle s.c. injections. On the last day of treatment, estradiol was injected in addition to progesterone, followed by a 24-h withdrawal before testing in the open field test (OF). Progesterone-treated rats showed a withdrawal effect of open area avoidance in the OF. The vehicle-treated control rats showed strong correlations between the EPM and OF parameters. This relationship was not found for the progesterone group at withdrawal. Rats with greater numbers of open arm entrance in the EPM pretest showed an increased sensitivity to progesterone withdrawal (PWD) compared to rats with low exploration and risk taking. The results indicate that the effects of PWD relate to individual exploration and risk taking. Furthermore, the possible analogy of PWD and PMS/PMDD in relation to individual traits is discussed.
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| 16. |
- Löfgren, Magnus, 1979-, et al.
(författare)
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Withdrawal effects from progesterone and estradiol relate to individual risk-taking and explorative behavior in female rats
- 2009
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Ingår i: Physiology and Behavior. - : Elsevier BV. - 0031-9384 .- 1873-507X. ; 96:1, s. 91-97
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Tidskriftsartikel (refereegranskat)abstract
- Withdrawal from progesterone and estradiol has been used as an animal model of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). In the clinical population individual sensitivity to sex steroid hormones, personality and heredity influence PMS/PMDD. Understanding the phenotypic risk factors of PMS/PMDD and drug development requires an animal model which incorporates individual steroid sensitivity. The main objective of this study was to investigate whether the individual trait of risk-taking and exploration influence the severity of PEWD in female rats. Thirty-two female Wistar rats in their diestrus phase were tested in the open field (OF) and divided into high responders (HR) and low responders (LR). Injections were given i.p. twice daily for 6 days, either 5 mg/kg progesterone combined with 10 mu g/kg 17 beta-estradiol, or vehicle (sesame oil). After a 24-hour withdrawal the animals were tested in the elevated plus maze (EPM). Blood samples for CORT analysis were collected after both behavioral tests. The HR rats withdrawn from progesterone and estradiol, spent less time on the EPM open arms and had lower CORT levels than the HR controls. The LR group showed no differences in EPM behavior and CORT levels during PEWD. The controls showed a stable trait of risk-taking and exploration. indicated by behavioral and CORT level correlations between the OF and EPM tests. These findings show that female rats with the trait of risk-taking and explorative behavior (HR) are more affected by PEWD.
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| 17. |
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| 18. |
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| 19. |
- Meyerson, Bengt J, et al.
(författare)
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A Rank-Order Procedure Applied to an Ethoexperimental Behavior Model—The Multivariate Concentric SquareField™ (MCSF) Test
- 2013
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Ingår i: Journal of Behavioral and Brain Science. - : Scientific Research Publishing, Inc.. - 2160-5866 .- 2160-5874. ; 3:4, s. 350-361
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Tidskriftsartikel (refereegranskat)abstract
- Designing relevant animal models in order to investigate the neurobiological basis for human mental disorders is an important challenge. The need for new tests to be developed and traditional tests to be improved has recently been em-phasized. The authors propose a multivariate test approach, the multivariate concentric square fieldTM (MCSF) test. To measure and evaluate variation in the behavioral traits, we here put forward a statistical procedure of which the working title is “trend analysis”. Low doses of the benzodiazepine agonist diazepam (DZP; 1.0, 1.5, or 2.0 mg/kg) were used for exploring the use of the trend analysis in combination with multivariate data analysis for assessment of MCSF per-formance in rats. The commonly used elevated plus maze (EPM) test was used for comparison. The trend analysis comparing vehicle and the DZP1.5 groups revealed significantly higher general activity and risk-taking behavior in the DZP1.5 rats relative to vehicle rats. This finding was supported by multivariate data analysis procedures. It is concluded that the trend analysis together with multivariate data analysis procedures offers possibilities to extract information and illustrates effects obtained in the MCSF test. Diazepam in doses that have no apparent increase in open arm activity in the EPM was effective to alter the behavior in the MCSF test. The MCSF test and the use of multivariate data analysis and the proposed trend analysis may be useful alternatives to behavioral test batteries and traditionally used tests for the understanding of mechanisms underlying various mental states. Finally, the impact of an ethological reasoning and multivariate measures enabling behavioral profiling of animals may be a useful complementary methodology when phenotyping animals in behavioral neuroscience.
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| 20. |
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| 21. |
- Meyerson, Bengt J., et al.
(författare)
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The Concentric Square Field : A multivariate test arena for analysis of explorative strategies
- 2006
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Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 168:1, s. 100-113
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we describe the behavior of laboratory rats in a recently developed observation arena, the Concentric Square Field (CSF). The CSF contains a number of areas designed to provoke exploration and behaviors associated with risk assessment, risk taking and security seeking in an environment not previously experienced. The model includes sheltered, open and elevated areas, a hole board device, areas with different light conditions, and wall-enclosed corridors. The rationale behind the CSF is to meet the demand for multivariate test situations that are not predictive in the sense of previous definition of a specific purpose of measuring a certain mental state. We define multivariate as being a free choice of where to stay in areas of different qualities. In the present study, identification of risky as opposed to safe areas is based on the retrieval behavior in lactating females and hoarding of food pellets in food-deprived males. Furthermore, we describe the effects of pre-trial food deprivation, immobilization, social stress, strain differences (Sprague–Dawley, Wistar and Lister Hooded males), sex differences (Sprague–Dawley) and repeated testing. Besides the conventional statistics, a principal component analysis (PCA) helped to discriminate between the various categories tested. Our conclusion is that the multivariate and non-predictive test situation (CSF) and the use of PCA provide a good tool for ethoexperimental analysis.
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| 22. |
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| 23. |
- Meyerson, Bengt
(författare)
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Linnaeus' Course to Achievments in Medicine and Pharmaceutics
- 2015
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Bok (populärvet., debatt m.m.)abstract
- Carl Linnaeus (1707-78) became one of Sweden's most famous scientists at the time not only by means of his scientific production but also for his ability to observe, register, categorize and evaluate the collected data. He had an obvious talent for teaching and to convince the world around of his findings and notions. His interest was mainly for botany but his achievements extended also to medicine and pharmaceutics.The life and achievements of Carl Linnaeus are from several aspects interesting and never cease to fascinate. His great interest for nature science resisted the wish of his parents that he should study theology to become a clergyman.The aim of this publication is to give a general view of the flow of events that have contributed to Linnaeus' course to his achievements in the field of medicine and pharmaceutics.
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| 24. |
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| 25. |
- Palm, Sara, et al.
(författare)
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When is a Wistar a Wistar? : Behavioral profiling of outbred Wistar rats from five different suppliers using the MCSF test
- 2011
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Ingår i: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 135:1-2, s. 128-137
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Tidskriftsartikel (refereegranskat)abstract
- The same strain of rats purchased from different suppliers may exhibit behavioral differences that could give rise to variability and deficient repeatability. We have previously demonstrated that outbred Wistar rats from different suppliers display striking differences in voluntary alcohol intake. Using outbred male Wistar rats from five suppliers, four suppliers in Europe (Charles River, Taconic, Harlan and B&K Universal) and one in the United States (Harlan), the present study investigated the variability in behavioral profiles of the Wistar substrains. To this end, we used the multivariate concentric square field™ (MCSF) test. This test has an ethological foundation and is designed to provoke exploration and behaviors associated with risk assessment, risk taking and shelter seeking. The term “multivariate” refers to the test situation as well as the statistical analysis of the data. Our results demonstrate significant differences in body weight and behavioral profiles between the age-matched groups of Wistar rats. A principal component analysis clearly separated Harlan (US) and Charles River rats from the B&K Universal, Harlan (EU) and Taconic rats. The parameters important for this separation included activity and risk-taking performance. A trend analysis further confirmed this finding. The results emphasize the need for careful specification of the animals used in a given study. The utility of differences in explorative strategies and behavioral profiles among various outbred strains derived from a single strain is discussed. In conclusion, the data support differences between substrains of Wistar rats and illustrate the utility of using a multivariate strategy for behavioral profiling.
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| 26. |
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| 27. |
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| 28. |
- Roman, Erika, et al.
(författare)
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The multivariate concentric square field test reveals different behavioural profiles in male AA and ANA rats with regard to risk taking and environmental reactivity
- 2007
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Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 183:2, s. 195-205
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present investigation was to compare the behavioural profiles in alcohol-preferring AA (Alko, alcohol) and alcohol-avoiding ANA (Alko, non-alcohol) rats. Twelve adult, alcohol-naive male AA and ANA rats were tested in the recently established multivariate concentric square field (MCSF) test. The more traditional open field and elevated plus-maze tests were used as reference tests. Six weeks after the initial MCSF test, a repeated testing was used to explore differences in acquired recognition after a previous experience. The results revealed distinct differences between the two lines. The ANA rats were generally more active in the three tests. In the MCSF, parameters of risk taking and shelter seeking indicated differences between the two lines. The ANA rats had higher shelter seeking behaviour and less risk taking behaviour than the AA rats. Repeated exposure to the MCSF caused a general decrease in activity and reduction in the number of visits to the various zones, especially evident in the ANA rats. The ANA rats showed more shelter seeking than the AA rats and also more shelter seeking than in the first trial, supporting an "anxiety-like" profile in these rats. In conclusion, the parameters related to risk taking and shelter seeking revealed obvious differences between AA and ANA rats. The higher risk taking behaviour seen in the AA rats might relate to their innate propensity for high voluntary alcohol intake. The results are discussed in relation to the reported neurobiological differences and in relation to other alcohol-preferring and alcohol-avoiding rat lines.
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| 29. |
- Roman, Erika, et al.
(författare)
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Variations in opioid peptide levels during the estrous cycle in Sprague-Dawley rats
- 2006
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Ingår i: Neuropeptides. - : Elsevier BV. - 0143-4179 .- 1532-2785. ; 40:3, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- The estrous cycle, with its various hormonal conditions, may provide us with the means of understanding how endocrine states relate to opioid mechanisms. There has been increasing experimental support for interaction between sex steroids and opioid peptides in the central nervous system. Here, we describe fluctuations in endogenous brain immunoreactive (ir) peptide levels during various phases of the estrous cycle in the female Sprague-Dawley rat. Ir levels of dynorphin A, dynorphin B, Leu-enkephalin-Arg(6), Met-enkephalin-Arg(6)Phe(7) and nociceptin/orphanin FQ were measured in the pituitary gland and in 10 areas of the brain during the diestrus, proestrus and estrus phase. In several areas of the brain, basal levels of endogenous opioid peptides showed variation during the course of the estrous cycle. Significant differences were found between the diestrus state and the proestrus and/or estrus conditions, particularly in the nucleus accumbens, caudate putamen and the substantia nigra. The ir levels of the endogenous peptide nociceptin/orphanin FQ became altered in only one of the areas measured, indicating less variance during the estrous cycle. Correlation analyses revealed that significant associations between dynorphin A or dynorphin B and Leu-enkephalin-Arg(6) were found more often during estrus than during the diestrus and proestrus conditions. The ratio between the ir levels of Leu-enkephalin-Arg(6), a cleavage product of the enzymatic conversion of dynorphin peptides into shorter peptides in vivo, and dynorphin peptides was calculated. The significantly lower ratio between Leu-enkephalin-Arg(6) and dynorphin B in diestrus than in proestrus and estrus also indicates cyclic fluctuations in the enzymatic cleavage of dynorphin. These findings are discussed in relation to the possible role of interactions between sex steroids and opioid peptide mechanisms during the normal estrous cycle.
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| 30. |
- Roos, Magnus W., et al.
(författare)
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Functional evaluation of cerebral microembolization in the rat
- 2003
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Ingår i: Brain Research. - 0006-8993 .- 1872-6240. ; 961:1, s. 15-21
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effects of cerebral microembolism on motor performance and risk assessment behavior in the rat. Cerebral infarcts were produced in rats by injecting small plastic beads into the left heart ventricle under short-acting anesthesia. The functional outcome was tested 24 h later by subjecting the animals to a series of consecutive behavioral tests. Thereafter, the rats were anesthetized and underwent magnetic resonance imaging. On average about seven infarcts per brain were found. The volume of the individual infarcts was largest in the hippocampus (mean=4.26 mm(3)) and smallest in the white matter (mean=0.83 mm(3)). Embolized animals performed spontaneous and evident locomotion. The activity was, however, significantly decreased compared to rats treated with vehicle. More specific tests for motor ability revealed reduced gait capacity and muscular strength. A significant relationship was found between behaviors reflecting motor ability and the total volume of infarcted tissue in the brain stem, cortex and cerebellum. Also the behavioral profile of risk and benefit assessment was found to be altered by the microembolization. It is concluded that the combination of the microembolization method and behavioral tests provides a valuable tool for further studies of the pathophysiology of, and potential treatment for, cerebral infarction.
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| 31. |
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| 32. |
- Åkerberg, Helena, et al.
(författare)
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Peripheral administration of pancreatic polypeptide inhibits components of food- intake behavior in dogs
- 2010
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 31:6, s. 1055-1061
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Tidskriftsartikel (refereegranskat)abstract
- Pancreatic polypeptide (PP) belongs to the neuropeptide Y (NPY) family of peptides and is released from pancreatic F cells postprandially. PP functions as a peptide hormone and has been associated with decreased food intake in humans and rodents. Our study describes the effects of PP on feeding behavior in dogs, whose mammalian order (Carnivora) is more distantly related to primates and rodents than these are to each other. Furthermore, obesity is becoming more prevalent in dogs which makes knowledge about their appetite regulation highly relevant. Repeated peripheral administration of physiological doses of PP (three injections of 30 pmol/kg each that were administered within 30 min) to six male beagle dogs prolonged the median time spent eating three servings of food by 19% but resulted in no reduction of food intake. In addition, PP decreased the duration of food-seeking behavior after the first serving by 71%. Thus, a physiological dose of PP seems to decrease both the appetitive and the consummatory drive in dogs.
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| 33. |
- Åkerberg, Helena, et al.
(författare)
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Test for personality characteristics in dogs used in research
- 2012
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Ingår i: Journal of Veterinary Behavior. - : Elsevier BV. - 1558-7878 .- 1878-7517. ; 7:6, s. 327-338
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Tidskriftsartikel (refereegranskat)abstract
- The great variation in morphological phenotypes displayed by dogs offers not only excellent opportunities for genetic analyses but also a challenge regarding between-breed and even within-breed variation. Also, behavioral responses may vary between individuals, and are to be taken into account in experimental situations. To our knowledge, no standardized test for scoring personality characteristics (TFPC) in dogs maintained for research under controlled conditions has yet been developed. The present article describes a protocol consisting of 9 test situations that are likely to arise in experimental contexts. The intent was to establish an easy-to-use standardized test protocol. Sixteen beagles were used, all housed in constant and controlled conditions. The results revealed considerable individual differences in response to certain stimuli. The largest within-group variation was found when being caged; the responses varied from passivity to escape attempts (score range: 2-5 in a 5-step scale). Substantial variation was also seen in locomotion and food consumption after exposure to stress (score range: 1-5 in a 5-step scale). In a new environment, the females showed more frequent changes in attention (focusing) compared with males (P < 0.01). There was an age-related reaction to sudden sounds (Spearman r sp = -0.52, P < 0.05). We also describe application of the TFPC to a study of food intake in response to pancreatic polypeptide performed with 6 of the male dogs. A within-group rank-order procedure was used, and interesting correlations between personality characteristics and food intake behavior were identified. We discuss how the TFPC may contribute to improvement of experimental studies in dogs.
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