Alexa Veenema

University of Massachusetts, USA

Abstract

[O03] Does vasopressin regulate intermale aggression? Intracerebral vasopressin release during resident-intruder aggression gives new insights

Alexa H. Veenema¹,², Daniela I. Beiderbeck¹, Michael Lukas¹, Inga D. Neumann¹
¹Department of Behavioral Neuroendocrinology, University of Regensburg, Regensburg, Germany, ²Department of Psychology, University of Massachusetts, Amherst, USA

Vasopressin (AVP) has been implicated in intermale aggression, although the direction of its effects seems inconsistent. Moreover, virtually nothing is known about AVP release patterns within distinct brain regions during the display of intermale aggression and, in turn, its behavioral consequences. We used intracerebral microdialysis to monitor local AVP release within the lateral septum (LS) and the bed nucleus of the stria terminalis (BST) in two genetically selected rat lines that show a difference in trait anxiety and in aggression (HAB: high anxiety, low aggression; LAB: low anxiety, high aggression) and in non-selected (NAB) rats. During exposure to the resident-intruder (RI) test, a significant decrease in AVP release within the LS was found in high-aggressive resident male LAB rats, whereas local AVP release tended to increase in low-aggressive resident male HAB rats. By contrast, AVP release within the LS was significantly increased in aggressive resident male NAB rats, while local AVP release was unchanged in non-aggressive resident male NAB rats. Administration of synthetic AVP (1 µg/ml) or the specific AVP V1a receptor antagonist d(CH2)5Tyr(Me)AVP (10 μg/ml) into the LS via reverse microdialysis (perfusion, 3.3 µl/min for 30 min) did not alter any of the aggressive behaviors in HAB, LAB, nor in NAB rats. Interestingly, AVP release within the BST increased in non-aggressive NAB rats during the RI encounter, while local AVP release was unaltered in aggressive NAB rats. Importantly, bilateral administration of synthetic AVP into the dorsal BST of aggressive NAB rats significantly reduced their level of aggression. These data contradict with the prevailing view that brain AVP generally enhances intermale aggression in rodents. We propose that (i) AVP released within the BST reduces the display of intermale aggression, which may allow the expression of affiliative behaviors, (ii) the aggression-induced change in septal AVP release modulates behaviors, like anxiety and social recognition, that are relevant in the context of present or future aggressive encounters.

This research was supported by the Bayerische Forschungsstiftung (AHV) and the Deutsche Forschungsstiftung (IDN; Ne465/17).

Biography

Dr. Veenema received her PhD in Neuroscience from the University of Groningen, the Netherlands in 2003. She did her first post-doctorate at the University of Regensburg in Germany and is currently a post-doctoral fellow at the University of Massachusetts at Amherst. She is appointed as Assistant Professor in Behavioral Neuroscience at the Department of Psychology, Boston College starting in 2010. Alexa’s research examines the neural basis of complex social behaviors (including play-fighting, aggression and social cognition) and the role of stress in the development of these behaviors. She is using mice and rats to explore the underlying brain neuropeptide systems, with specific focus on vasopressin and oxytocin.