Brain monoamines following castration of aggressive muricidal rats.

The effect of castration on the levels of brain monoamines and their metabolites has been investigated in rats which became or did not become muricidal following long-term isolation. Fourteen brain areas were explored: olfactory bulbs (OB), olfactory tubercles (OT), septum (Se), striatum (Sr), amygdala (A), thalamus (Th), hypothalamus (Hy), hippocampus (Hi), superior colliculus (SC), inferior colliculus (IC), raphe (Ra), pons-medulla (PM), frontal cortex (FC), temporal cortex (TC) and parietal cortex (PC). Except in the raphe of non muricidal rats and in the striatum of muricidal animals, all other areas examined demonstrate some changes of monoamines neurotransmitter or their metabolites after castration. The strongest changes, always increases, were found in the thalamus. In several brain areas, the changes occurring after castration, differ quantitatively and qualitatively in muricidal and non-muricidal rats.