Asymmetric distribution of brain monoamines in left- and right-handed mice.

Biogenic amine distributions analyzed in the cerebral neocortex, striatum, anterior hypothalamus, and bulbospinal region, were compared between both hemispheres of left- and right-handed mice. The handedness of mice was determined using a paw preference test. The animals were tested 5 times, once every two weeks, and the biochemical analysis was performed two weeks after the last behavioral evaluation. The results indicated that (1) asymmetrical monoaminergic concentrations exist in the mouse brain. Monoamine contents were found to be higher in the right parietal cortex and anterior hypothalamus than in the left ones; (2) besides the behavioral expression of handedness, left- and right-handed subpopulations of mice differ according to asymmetrical distributions of cortical and bulbospinal NE contents as well as DA turnover of the tuberoinfundibular system.