Abstract
Intracisternal administration of 6-hydroxydopamine to immature rats produced marked reductions of norepinephrine, dopamine and tyrosine hydroxylase activity in brain. Accompanying these reductions were alterations in growth and behavior clearly demonstrable when adult. The 6-hydroxydopamine-treated rats showed decrements in eating and drinking, in their intake of a sucrose solution and in the ability to improve performance durimg acquisition of a shuttle-box avoidance response. Since choline acetylase activity and tryptophan hydroxylase activity were not altered in brain after this treatment, it seemed unlikely that these neuronal systems were responsible for the observed deficits. To evaluate the roles of norepinephrine or dopamine in the deficits, methods were developed to reduce these amines preferentially in the brains of immature rats. Animals in which dopamine was preferentially reduced showed similar deficiencies to those described above whereas norepinephrine-depleted rats did not show these alterations. Thus, the data suggest that the decrements in the 6-hydroxydopamine-treated developing rat are due to reduction in brain dopamine and support the view that dopaminerigc neurons are involved in the maintenance of consummatory behavior as well as conditioned avoidance responding.
Footnotes
- Received June 29, 1972.
- Accepted February 26, 1973.
- © 1973 by The Williams & Wilkins Co.