Effect of MAO A deficiency on different kinds of aggression and social investigation in mice
Source InformationJanuary 2007, Volume33(Issue1) Page1To6
Monoamine oxidase A (MAO A) degrades serotonin, dopamine and noradrenaline, factors critically involved in the regulation of aggression. Different kinds of aggression were investigated in Tg8, a transgenic mouse strain lacking a functional MAO A gene. MAO A‐deficient mice differ from wild‐type C3H/HeJ (C3H) in terms of showing higher territorial, predatory and isolation‐induced aggression. Tg8 demonstrated shorter latencies to cricket killing and to the first attack after 6 weeks isolation than C3H mice. In the resident–intruder paradigm, MAO A‐lacking mice were more aggressive than C3H when tested as intruders. In contrast to C3H, attack in Tg8 mice did not depend on different aggressiveness of intruders of BALB/c, A/Sn and C3H strains. Tg8 mice displayed no increase in aggression but demonstrated reduced social investigation towards anesthetized, as well as towards juvenile BALB/c males. Thus, MAO A deficiency in Tg8 mice is accompanied by increased expression of different kinds of aggression, as well as by disruption of normal pattern of social interaction. Aggr. Behav. 33:1–6, 2007. © 2006 Wiley‐Liss, Inc.