Behavioral and biochemical effects of neonatal treatment of rats with 6-hydroxydopa.

Rats receiving injection of either 6-hydroxydopa (60 mug/g) or saline on Days 1, 3, and 5 of life were studied in adulthood on a number of behavioral tasks before being sacrificed at 8 or 12 months for NE assay. The treated rats exhibited impaired passive avoidance, less shock-induced aggression, and more locomotor open-field activity than the control rats. There were no differences between the groups in male copulatory behavior, food and water intake, or thermoregulation. In comparison to the saline rats, 6-hydroxydopa rats showed elevated levels of endogenous NE in lower brainstem regions, e.g., midbrain and pons-medulla, as well as cerebellum. Hypothalamic NE level was not affected. Significant depletions of NE were obtained in the hippocampus and neocortex.