Effect of metabolism cage housing on rodent welfare

The metabolic cage is developed to be able to have a control of total intake of feed and water and the excretion with urine and faeces. In addition, one can efficiently collect non contaminated samples of urine and faeces. For the animal, housing in a metabolic cage involves isolation and problems with cage enrichment since that can interfere with the total collection of urine and faeces. However little research has been done to investigate possible welfare problems for rodents placed in metabolic cages. Housing rodents socially isolated may lead to elevated corticosterone levels and more vulnerability to stress compared to group housed individuals. Studies have also found changes in the central nervous system and the immune system in individually housed rodents. Several negative effects of housing on grid floor are documented e.g. lesions and nerve injury in the hind feet of rats, elevated blood pressure, heart rate and body temperature. Especially mice show a strong preference for nesting material and lack of such may be stressful. More research on the effects of metabolism cage housing on rodent welfare are needed to develop a metabolic cage which enables sampling of uncontaminated urine while allowing the animals to perform their natural behaviours.Metabolismburar är framtagna för att kunna studera totalintag och utsöndring (metabolism) av olika ämnen, göra totaluppsamlingar av urin och faeces samt kunna ta okontaminerade prov av urin och faeces. Det har däremot gjorts lite forskning för att påvisa eventuella välfärdsproblem hos gnagare placerade i metabolismburar. Gnagare hållna socialt isolerade kan få förhöjda nivåer av kortikosteron och bli mer känsliga för stress jämfört med grupphållna individer. Studier har också funnit förändringar i det centrala nervsystemet och immunsystemet hos individuellt hållna gnagare. Det finns flera dokumenterade negativa effekter av galler golv som t.ex. sår och nervskador i råttors baktassar, förhöjt blodtryck, förhöjd hjärtfrekvens och kroppstemperatur. Speciellt möss visar en stark preferens för bäddmaterial och avsaknad på detta kan vara stressframkallande. Det behövs mer forskning på hur hållning i metabolismburar kan påverka gnagares välfärd så att en metabolismbur som både ger okontaminerade prov av urin och faeces och tillåter djuren att utföra sina naturliga beteenden, kan utvecklas

Effekte von 2-Bromtergurid, einem Dopamin-D2-Rezeptor-Partialagonisten, in Tiermodellen der Negativsymptomatik und kognitiver Dysfunktionen der Schizophrenie

Schizophrenia is a severe psychiatric disorder, affecting about one percent of people. The treatment of schizophrenia involves alleviating the positive symptoms, negative symptoms and cognitive deficits. Overall, available antipsychotic drugs (APDs) can successfully silence the positive symptoms due to antagonistic actions on dopamine D2 receptors. Unfortunately, the APDs are associated with aversive side effects and there is still severe paucity in the treatment of negative symptoms and cognitive impairments. 2-Bromoterguride (2BT) is a dopamine D2 receptor partial agonist that shows antipsychotic-like effects in rats without inducing extrapyramidal side effects and metabolic changes. In addition to its action on D2 receptors, 2BT has affinities for several other receptor types implicated in the pathophysiology of schizophrenia, including the serotonergic and glutamatergic systems, and hence meets the prerequisites for a putative atypical APD. The objective of this PhD study, which consisted of two main projects, was to investigate the effects of 2BT on negative symptoms and cognitive deficits in drug-induced animal models. In the first project, the effect of 2BT on sensory motor gating, was measured via the prepulse inhibition of the acoustic startle response (PPI). PPI deficits in male rats were induced using either apomorphine or the N-methyl-D-aspartate receptor antagonist phencyclidine (PCP). The results showed that 2BT could block the effect of both apomorphine and PCP, indicating that 2BT has an atypical APD character in vivo. For the second experiment, a subchronic PCP (scPCP) treatment protocol was established, which caused cognitive deficits in male rats when these were tested in the Novel Object Recognition (NOR) test. Our results showed that 2BT was effective in ameliorating the scPCP treatment-induced object recognition deficit in the NOR test. In order to evaluate the effect of 2BT on negative symptoms of schizophrenia, the same scPCP treatment protocol which induced cognitive impairments in the NOR test, was used to induce social aversion in male rats. The study showed an effective disruption of social behaviours in the rats by scPCP and that 2BT successfully attenuated the social deficit. For the final study included in the first project, the impact of acute 2BT treatment on prolactin secretion was evaluated by performing a prolactin enzyme-linked immunosorbent assay. The result showed that 2BT belongs to the non-hyperprolactinemia-inducing APDs and implicates that 2BT has a profitable side-effect profile. The results from this PhD study strengthens the hypothesis of the beneficial effects elicited by dopamine D2 partial agonists like 2BT, for treatment of the complete range of symptoms in schizophrenia. Finally, the second project was dedicated to the validation of the scPCP model for social withdrawal in schizophrenia. For this purpose, an olfactory habituation/dishabituation test with both non-social and social odours was conducted to control the absence of PCP-induced anosmia in the animals used to study social interaction in the previous study. Olfactory defects would severely impact the behaviour of the rats in the social interaction test and thus, needed validation due to a serious lack of such control measures in the literature. The results, which did indicate normal olfactory function in the rats treated with scPCP hence, have important implications for the correct interpretation of the social interaction deficit of the scPCP rat model.Schizophrenie ist eine schwere psychiatrische Störung, von der etwa ein Prozent der Weltbevölkerung betroffen ist. Eine effektive Behandlung der Schizophrenie beinhaltet eine Abmilderung bzw. Aufhebung der Positivsymptomatik, der Negativsymptomatik und kognitiver Defizite. Allerdings sind die heute verfügbaren Antipsychotika (APDs) hauptsächlich bei der Behandlung der Positivsymptomatik erfolgreich. Wirksame Behandlungsoptionen für die Negativsymptomatik und kognitive Beeinträchtigungen liegen nicht vor. 2-Bromotergurid (2BT) ist ein Dopamin-D2-Rezeptor-Partialagonist, der bei Ratten eine antipsychotisch-ähnliche Wirkung zeigt, ohne extrapyramidale Nebenwirkungen und Stoffwechselveränderungen auszulösen. Zusätzlich zu seiner Wirkung auf D2-Rezeptoren besitzt 2BT Affinitäten für mehrere andere Rezeptortypen, die an der Pathophysiologie von Schizophrenie beteiligt sind, einschließlich der serotonergen und glutamatergen Systeme und erfüllt somit die Voraussetzungen für ein mutmaßliches atypische APD. Das Hauptziel dieser Doktorarbeit war es, die Wirkung des Dopamin-D2-Rezeptor-Partialagonisten 2BT auf Substanz-induzierte Verhaltenseffekte mit Relevanz zur Symptomatik der Schizophrenie (Negativsymptomatik, kognitive Defizite) in tierexperimentellen Studien an Ratten zu untersuchen. Die Versuchsergebnisse wurden innerhalb von zwei Projekten gewonnen. In dem ersten Projekt der Arbeit wird die Wirkung von 2BT auf die Präpulsinhibition (PPI) der akustisch ausgelösten Schreckreaktion (ASR) beschrieben. PPI-Defizite wurden mit Apomorphin oder dem nicht-kompetitiven N-methyl-D-aspartat-Rezeptor-Antagonisten Phencyclidin (PCP) induziert. Die Ergebnisse der Studie zeigen, dass 2BT die Apomorphin- und PCP-induzierten PPI-Defizite antagonisieren konnte und geben einen ersten Hinweis auf den atypischen Charakter von 2BT. Das zweite Experiment des Projekts beschreibt die Etablierung und Anwendung einer subchronischen PCP-Behandlung im Novel Object Recognition (NOR)-Test. Die wiederholte Gabe von PCP führte im NOR-Test zu kognitiven Defiziten, die durch 2BT signifikant reduziert werden konnten. Für den dritten Versuch des Projekts wurde die oben beschriebene subchronische PCP-Behandlung verwendet, um bei männlichen Ratten eine soziale Aversion zu induzieren. Die Studie zeigt, dass die PCP-Behandlung das Sozialverhalten der Ratten reduzierte und 2BT erfolgreich das soziale Defizit abschwächte. Im abschließenden Experiment des ersten Projekts wurde die Wirkungen von 2BT auf die Prolaktinsekretion mittels eines Enzyme-linked Immunosorbent Assays untersucht. Die Ergebnisse des Experiments legen nahe, dass 2BT zu den nicht-Hyperprolaktinämie-induzierenden APDs gehört und ein vorteilhaftes Nebenwirkungsprofil besitzen könnte. Die Ergebnisse der dargestellten Arbeit stärken die Hypothese, das Dopamin-D2-Partialagonisten wie 2BT für die Behandlung der gesamten Bandbreite der Schizophreniesymptomatik eingesetzt werden könnten. Das zweiteProjekt widmete sich der Validierung des in der ersten Arbeit eingesetzten subchronischen PCP-Modells, mit dem u. a. ein Defizit des Sozialverhaltens induziert wurde. Zu diesem Zweck wurde ein olfaktorischer Habituationstest mit sowohl nicht-sozialen als auch sozialen Gerüchen durchgeführt, um zu kontrollieren, ob PCP eine Beeinträchtigung der Geruchsleistung bei den eingesetzten Tieren auslöst. Obwohl jegliche olfaktorischen Störungen eine deutliche Auswirkung auf das Sozialverhalten der Ratten während des sozialen Interaktionstests hätte und die Aussagekraft der gewonnen Ergebnisse hinterfragt werden müsste, wurden solche Kontrollexperimente in vergleichbaren Studien anderer Arbeitsgruppen nicht durchgeführt. Die Ergebnisse zeigen, dass die wiederholte Gabe von PCP keine olfaktorischen Störungen induzierte und somit von einer korrekten Interpretation der Erkenntnisse ausgegangen werden kann

The Value of Molecular vs. Morphometric and Acoustic Information for Species Identification Using Sympatric Molossid Bats

A fundamental condition for any work with free-ranging animals is correct species identification. However, in case of bats, information on local species assemblies is frequently limited especially in regions with high biodiversity such as the Neotropics. The bat genus Molossus is a typical example of this, with morphologically similar species often occurring in sympatry. We used a multi-method approach based on molecular, morphometric and acoustic information collected from 962 individuals of Molossus bondae, M. coibensis, and M. molossus captured in Panama. We distinguished M. bondae based on size and pelage coloration. We identified two robust species clusters composed of M. molossus and M. coibensis based on 18 microsatellite markers but also on a more stringently determined set of four markers. Phylogenetic reconstructions using the mitochondrial gene co1 (DNA barcode) were used to diagnose these microsatellite clusters as M. molossus and M. coibensis. To differentiate species, morphological information was only reliable when forearm length and body mass were combined in a linear discriminant function (95.9% correctly identified individuals). When looking in more detail at M. molossus and M. coibensis, only four out of 13 wing parameters were informative for species differentiation, with M. coibensis showing lower values for hand wing area and hand wing length and higher values for wing loading. Acoustic recordings after release required categorization of calls into types, yielding only two informative subsets: approach calls and two-toned search calls. Our data emphasizes the importance of combining morphological traits and independent genetic data to inform the best choice and combination of discriminatory information used in the field. Because parameters can vary geographically, the multi-method approach may need to be adjusted to local species assemblies and populations to be entirely informative.publishe

Sex-specific means, [95% CI], sample size and range of forearm length and body mass.

<p>Sex-specific means, [95% CI], sample size and range of forearm length and body mass.</p

Variation of fur color (back) for eight individuals of <i>M</i>. <i>molossus</i>, <i>M</i>. <i>coibensis</i> and <i>M</i>. <i>bondae</i> from Panama.

<p>Variation of fur color (back) for eight individuals of <i>M</i>. <i>molossus</i>, <i>M</i>. <i>coibensis</i> and <i>M</i>. <i>bondae</i> from Panama.</p

Principal Component Analysis of five acoustic parameters for <i>M</i>. <i>molossus</i> (orange) and <i>M</i>. <i>coibensis</i> (blue).

<p>Principal Component Analysis of five acoustic parameters for <i>M</i>. <i>molossus</i> (orange) and <i>M</i>. <i>coibensis</i> (blue).</p

Genetic clustering (<i>K</i> = 2) of 933 <i>Molossus</i> bats from the village of Gamboa.

<p><i>Cluster One</i> is represented in orange and <i>Cluster Two</i> in blue. The two clusters were obtained with four microsatellite primers using the software STRUCTURE. The few individuals at the edge of the two clusters are admixed.</p

Forearm length (mm) plotted against body mass (g) for three Panamanian <i>Molossus</i> species.

<p>The color code is as follows: <i>M</i>. <i>molossus</i> (orange dots), <i>M</i>. <i>coibensis</i> (blue diamonds) and <i>M</i>. <i>bondae</i> (green squares). Following the same color code, the frequency distribution of body mass is plotted above the graph and the frequency distribution of forearm length on the right side of the graph. Points outlined in black are misclassified individuals based on the linear discriminant function and the leave-one-out cross-validation procedure (4.1% of the individuals).</p

Comparison of acoustic parameters between <i>M</i>. <i>molossus</i> and <i>M</i>. <i>coibensis</i>.

<p>Values are means <i>±</i> 1 standard deviation. Values in boldface represent significant differences between species based on a Student’s t-test for the given acoustic parameter. The two figures for sample size indicate the number of individuals and the number of calls.</p

Sonograms of the two types of calls informative for identification found in <i>Molossus molossus</i> and <i>coibensis</i>.

<p>(A) Approach calls with harmonics. (B) Search calls alternating a lower and higher frequency pulse (respectively SI and SII).</p