Effects of neonatal 6-hydroxydopamine treatment on catecholamine levels and behavior during development and adulthood

The effects of neonatal intraventricular 6-hydroxydopamine (6-OHDA) (50–400 g) treatment on catecholamine levels in various brain regions, and on motor activity, were investigated in rats during development and adulthood. At 30 days catecholamine levels were lower in the frontal cortex and ventral diencephalon: minor reductions were observed in midbrain and pontine regions. At 90 days the effects of 6-OHDA treatment were similar in frontal and rostral midbrain regions but in the pontine area norepinephrine levels were substantially elevated. Behavioral tests in a stabilimeter indicated 6-OHDA-treated rats were hyperactive during development, at 25 and 35 days of age, as well as in adulthood. However, 6-OHDA-treated rats did not differ from controls in habituation. These effects are interpreted as supporting the notion that low catecholamine levels in the forebrain alter activity during development and in adulthood.