Neonatal 6-hydroxydopamine treatment: Noradrenaline levels and in vitro 3H-catecholamine synthesis in discrete brain regions of adult rats

Abstract

Endogenous noradrenaline levels are elevated in medulla oblongata, mesencephalon, pons and thalamus of adult rats which had been treated with 6-hydroxydopamine on days 1, 2, 8 and 15 after birth. Levels in spinal cord, cerebellum, hippocampus/amygdala and cortex are depressed, whereas no significant changes are observed in striatum, hypothalamus and medulla spinalis. The rate at which medulla oblongata synthesizes tritiated noradrenaline and dopamine from tritiated tyrosine is markedly enhanced. No effect was apparent on catecholamine synthesis in hypothalamus. Tritiated noradrenaline synthesis, but not tritiated dopamine synthesis, in the cortex is depressed. These results support the view that neonatal 6-hydroxydopamine treatment causes a degeneration of noradrenaline nerve terminals in the cortex and induces an increase in noradrenaline terminals in the medulla oblongata.