|Fakultät für Biologie und Vorklinische Medizin|
|Lehrstuhl für Neurobiologie und Tierphysiologie|
|Research / Forschung|
The scientific focus of our Department of Behavioural and Molecular Neurobiology lies on the brain mechanisms underlying emotional and social behaviours, and stress-related adaptations - both acute and chronic, in adulthood. We are, in particular, interested in the fine-tuned involvement of neuropeptides of the brain such as oxytocin, vasopressin, corticotropin-releasing factor (CRF) and neuropeptide S in the regulation of anxiety- and depression-related behaviours, social fear, social preference, social avoidance, inter-male and abnormal aggression, and maternal and sexual behaviour in rodents. Another major research topic is related to chronic psychosocial stress, and its consequences on, for example, emotionality, the central metabotropic glutamate system, the hypothalamic-pituitary-adrenal (HPA) axis and immunological functions.
Examples of on-going research projects
1.Behavioural effects of Oxytocin
Oxytocin is a prosocial nonapeptide described to promote maternal, sexual, affiliative, and social cognitive behaviours, and to exert anxiolytic actions. These findings prompted us to monitor local release patterns of oxytocin in response to stressful or social stimuli using intracerebral microdialysis in conjunction with a sensitive radioimmunoassay. Further, we study its role in social preference versus social avoidance, and in social fear in a novel social fear-conditioning paradigm (projects Rohit Menon). There is a strong translational aspect, as social fear and lack of social interactions are symptoms of human social dysfunctions seen in patients suffering from autism or social anxiety disorders.
2.Cellular and molecular mechanisms of neuronal oxytocin actions
Although multiple effects of oxytocin were revealed in human and animal research, underlying receptor-mediated intraneuronal signalling cascades within brain target regions are almost unknown. Using molecular approaches, we aim to reveal molecular mechanisms of these behavioural effects studying oxytocin receptor-mediated intraneuronal signalling cascades in the hypothalamus – a key area of anxiety- and stress-regulation (projects Dr. Benjamin Jurek).
3.Neuropeptides in other social behaviours: From maternal love to sex aggression
Neuropeptides play a major role in various other social behaviours such as maternal behaviour, inter-male aggression or sexual behaviour. For example, we could show that, in addition to oxytocin, the related vasopressin is an important promoter of maternal care and maternal aggression studying rats selectively bred for high (HAB) versus low (LAB) innate anxiety. Furthermore, an active CRF system impairs maternal behaviour and promotes maternal neglect. This project has particular clinical relevance as mal-adaptations of the brain oxytocin or vasopressin as well as of CRF system might be related to postpartum depression often accompanied by child neglect or even infanticide (projects Prof. Dr. Oliver Bosch).
Moreover, aggression and violence are not only highly relevant for human societies, but interesting from the neurobiological point of view. We focus on the genetic factors, social environmental influences and resulting neuronal mechanisms shaping inter-male and abnormal aggression. For example, we could reveal a prominent role of the dopaminergic system in the nucleus accumbens shaping high and abnormal aggression in rats. These studies are part of the Themenverbund Violence and aggression in nature and culture of the University of Regensburg, with participating scientists from 7 different faculties.
Furthermore, we study conduct disorder in young girls using an effective modification of the classic resident-intruder paradigm, the so-called Female Intruder Test (FIT). Here, adolescent or young adult female rats are confronted with a smaller intruder female in their home cage, and their behaviour (aggressive or non-aggressive) is measured. We investigate the, as of yet unknown, neuronal circuitries underlying aggressive behaviour in adolescent and adult females in comparison to males. We test the hypothesis that the neuropeptides oxytocin and vasopressin as well as the classical neurotransmitter serotonin (5-HT) are important brain regulators controlling aggression in a sex-specific manner. In this context, we also aim to identify the brain areas in which these factors, which were shown to be importantly involved in various aspects of social behaviour, act. To do so, we use techniques such as in vivo microdialysis, venous blood sampling, immunohistochemistry, receptor autoradiography, in situ hybridization, qPCR, intracerebral and systemic application of pharmacogenic/psychoactive drugs and extensive behavioural observations. This project is part of and supported by the 7th FP EU program FemNat-CD "Neurobiology and Treatment of Adolescent Female Conduct Disorder: The Central Role of Emotion Processing".
4.Consequences of Chronic Psychosocial Stress
Chronic social stress has repeatedly been shown to be a risk factor for the development of depression and anxiety in vulnerable individuals. The majority of preclinical social stressor paradigms have been reported to increase both anxiety- and depression-related behaviour. This is perhaps unsurprising, as there is high co-morbidity between the two disorders. However, in order to really dissect the mechanisms underlying anxiety or depression, animal models are needed, which specifically induce one phenotype. Taking advantage a mouse model employing psychosocial stress, namely chronic subordinate colony housing (CSC), and in collaboration with Prof Stefan Reber (University of Ulm) who established it, we were able to reveal that CSC leads to an anxiogenic phenotype without resulting in a concomitant depression-like phenotype. We also extended this to reveal that CSC mice display elevated alcohol intake, which mirrors clinical findings showing a link between anxiety and alcohol abuse.
The complex interactions between genes, environmental factors and adult emotionality, chronic stress vulnerability and social behaviours are shown here: