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DOI: 10.1055/s-2005-861301
PNMT Transgenic Mice Have an Aggressive Phenotype
Publication History
Received 16 June 2004
Accepted after revision 7 October 2004
Publication Date:
12 April 2005 (online)
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Abstract
PNMT (phenylethanolamine-N-methyl-transferase) is the enzyme that catalyzes the formation of epinephrine from norepinephrine. In transgenic mice over-expressing PNMT, observations revealed a very high level of aggression compared to their background strain, C57BL/6J. To evaluate the influence of PNMT on aggression and emotionality in this transgenic line, single-sex male and female groups were independently established that consisted of either four wild-type mice or four transgenic mice overexpressing PNMT. The members of each group were littermates. Mixed single-sex groups consisting of two transgenic mice and two wild-type mice were also established. Almost no fights were observed within the female groups. In males, the transgenic line showed a significantly higher level of fighting than controls (p = 0.007) and mixed male groups (p = 0.02). Housing mice from the transgenic line in mixed groups with wild-type mice seems to decrease the level of aggression in the transgenic line. In conclusion, this is the first study to demonstrate a clear, significant increase in aggression arising from PNMT overexpression. This suggests an important role for central epinephrine levels in aggressive behavior.
Keywords
Epinephrine - Mice - Open field - Behavior - C57Bl/6