Motor lateralization, behavioral despair and dopaminergic brain asymmetry after prenatal stress.

This paper presents data suggesting a relationship between rat behavioral despair in the Porsolt test and motor lateralization in the T-maze test. In addition, experimental evidence suggests a functional coupling among dopaminergic systems, behavioral despair and motor lateralization. In the first experiment, female, not male, rats with a high level of behavioral despair showed a low level of behavioral lateralization. The inverse relationship was found in female offspring of mothers stressed during gestation. In comparison with unstressed-mother rats, the female offspring of stressed mothers showed an increase of dopamine (DA) and a decrease of dihydroxyphenylacetic acid (DOPAC) and Homovanillic (HVA) levels and of DOPAC:DA and HVA:DA indexes in the n. accumbens of the right side of the brain. No significant differences were found in the n. accumbens of the left brain. Taken together, the present data provide evidence of a relation between behavioral despair and motor lateralization, suggesting that the biological dopaminergic inervation of n. accumbens could be the basis for this functional coupling. Because the stress of gestant mothers modified these biochemical and behavioral variables, the present study also suggests that lateralization of behavior and emotion during adulthood can be modified by prenatal variables.