Jerarquía de dominancia social en ratones: modulación por la orina y regiones cerebrales implicadas

Resumen

The phenomenon of social hierarchy and dominance has been extensively studied throughout history due to its implications within animal societies, such as access to resources, reproductive success or reduction of conflict in societies. However, the neurobiological mechanisms behind this process are still not well defined. In this research, we have focused on two aspects potentially involved in the establishment and maintenance of social hierarchy in mice, the mouse urine and the role of the paraventricular nucleus, the prefrontal cortex and the piriform cortex in social hierarchy. Urine is an important source of chemosensory signals that provide information about social status, reproductive status or familiarity between animals. In the case of pheromones present in mouse urine, it is known that the urine of dominant mice has a higher concentration of major urinary proteins, notably MUP20, with numerous biological effects, such as reproduction, social learning or behaviours related to aggressiveness and competitiveness. The results are promising in terms of the role of urine in the competitive interactions of subordinate animals without previous cohabitation or familiarity with each other. As for the brain regions involved in the phenomenon of social hierarchy, numerous studies have sought to identify these regions. In this work, we studied three of these regions, in particular, the paraventricular nucleus, the prefrontal cortex and the piriform cortex, all of which are implicated in some way in social dominance in mice. Different cell populations in these regions were quantified trying to find differences between mice according to their social rank and exposure to urine, to confirm the involvement of these regions in the social hierarchy. However, the results obtained showed no clear differences in the cell populations of these regions between mice.