Changes in alpha-melanotropin in discrete brain areas of isolated aggressive mice

Adult male Swiss-Webster (NIH) mice were isolated for 6 weeks. Aggressive behavior was tested on 2 occasions, 24 hours apart. Immediately following the 2nd test period, aggressors and isolated non-aggressors (controls) were decapitated and alpha-MSH concentration was measured in discrete areas of the brain. Only the nucleus accumbens and preoptic lateralis of the aggressors, showed a higher level of alpha-MSH when compared to the controls. The significance of these changes is discussed.